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  • Matlab wont extract first row & column because of matrix dimensions !

    - by ZaZu
    Hey guys, I am tracking an object that is thrown in air, and this object governs a parabolic pattern. Im tracking the object through a series of 30 images. I managed to exclude all the background and keep the object apparent, then used its centroid to get its coordinates and plot them. Now im supposed to predict where the object is going to fall, so I used polyfit & polyval .. the problem is, matlab says ??? Index exceeds matrix dimensions. Now the centroid creates its own structure with a row and 2 columns. Everytime the object moves in the loop, it updates the first row only .. Here is part of the code : For N=1:30 . . . x=centroid(1,1); % extract first row and column for x y=centroid(1,2); % extract secnd row and column for x plot_xy=plot(x,y) set(plot_xy,'XData',x(1:N),'YData',y(1:N)); fitting=polyfit(x(1:N),y(1:N),2); parabola=plot(x,nan(23,1)); evaluate=polyval(fitting,x); set(parabola,'YData',evaluate) . . end The error message I get is ??? Index exceeds matrix dimensions. It seems that (1:N) is causing the problems .. I honestly do not know why .. But when I remove N, the object is plotted along with its points, but polyfitting wont work, it gives me an error saying : Warning: Polynomial is not unique; degree >= number of data points. > In polyfit at 72 If I made it (1:N-1) or something, it plots more points before it starts giving me the same error (not unique ...) . Any ideas why ?? Thanks alot !!

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  • Adding NavigationControl to a TabBar Application containing UITableViews

    - by kungfuslippers
    Hi, I'm new to iPhone dev and wanted to get advice on the general design pattern / guide for putting a certain kind of app together. I'm trying to build a TabBar type application. One of the tabs needs to display a TableView and selecting a cell from within the table view will do something else - maybe show another table view or a web page. I need a Navigation Bar to be able to take me back from the table view/web page. The approach I've taken so far is to: Create an app based around UITabBarController as the rootcontroller i.e. @interface MyAppDelegate : NSObject <UIApplicationDelegate> { IBOutlet UIWindow *window; IBOutlet UITabBarController *rootController; } Create a load of UIViewController derived classes and associated NIBs and wire everything up in IB so when I run the app I get the basic tabs working. I then take the UIViewController derived class and modify it to the following: @interface MyViewController : UIViewController<UITableViewDataSource, UITableViewDelegate> { } and I add the delegate methods to the implementation of MyViewController - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 2; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } if (indexPath.row == 0) { cell.textLabel.text = @"Mummy"; } else { cell.textLabel.text = @"Daddy"; } return cell; } Go back to IB , open MyViewController.xib and drop a UITableView onto it. Set the Files Owner to be MyViewController and then set the delegate and datasource of the UITableView to be MyViewController. If I run the app now, I get the table view appearing with mummy and daddy working nicely. So far so good. The question is how do I go about incorporating a Navigation Bar into my current code for when I implement: - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath() { // get row selected NSUInteger row = [indexPath row]; if (row == 0) { // Show another table } else if (row == 1) { // Show a web view } } Do I drop a NavigationBar UI control onto MyControllerView.xib ? Should I create it programmatically? Should I be using a UINavigationController somewhere ? I've tried dropping a NavigationBar onto my MyControllerView.xib in IB but its not shown when I run the app, only the TableView is displayed.

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  • Unintentional concatenation in Bison/Yacc grammar.

    - by troutwine
    I am experimenting with lex and yacc and have run into a strange issue, but I think it would be best to show you my code before detailing the issue. This is my lexer: %{ #include <stdlib.h> #include <string.h> #include "y.tab.h" void yyerror(char *); %} %% [a-zA-Z]+ { yylval.strV = yytext; return ID; } [0-9]+ { yylval.intV = atoi(yytext); return INTEGER; } [\n] { return *yytext; } [ \t] ; . yyerror("invalid character"); %% int yywrap(void) { return 1; } This is my parser: %{ #include <stdio.h> int yydebug=1; void prompt(); void yyerror(char *); int yylex(void); %} %union { int intV; char *strV; } %token INTEGER ID %% program: program statement EOF { prompt(); } | program EOF { prompt(); } | { prompt(); } ; args: /* empty */ | args ID { printf(":%s ", $<strV>2); } ; statement: ID args { printf("%s", $<strV>1); } | INTEGER { printf("%d", $<intV>1); } ; EOF: '\n' %% void yyerror(char *s) { fprintf(stderr, "%s\n", s); } void prompt() { printf("> "); } int main(void) { yyparse(); return 0; } A very simple language, consisting of no more than strings and integer and a basic REPL. Now, you'll note in the parser that args are output with a leading colon, the intention being that, when combined with the first pattern of the rule of the statement the interaction with the REPL would look something like this: > aaa aa a :aa :a aaa> However, the interaction is this: > aaa aa a :aa :a aaa aa aa > Why does the token ID in the following rule statement: ID args { printf("%s", $<strV>1); } | INTEGER { printf("%d", $<intV>1); } ; have the semantic value of the total input string, newline included? How can my grammar be reworked so that the interaction I intended?

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  • What Amazon S3 .NET Library is most useful and efficient?

    - by Geo
    There are two main open source .net Amazon S3 libraries. Three Sharp LitS3 I am currently using LitS3 in our MVC demo project, but there is some criticism about it. Has anyone here used both libraries so they can give an objective point of view. Below some sample calls using LitS3: On demo controller: private S3Service s3 = new S3Service() { AccessKeyID = "Thekey", SecretAccessKey = "testing" }; public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; return View("Index",s3.GetAllBuckets()); } On demo view: <% foreach (var item in Model) { %> <p> <%= Html.Encode(item.Name) %> </p> <% } %> EDIT 1: Since I have to keep moving and there is no clear indication of what library is more effective and kept more up to date, I have implemented a repository pattern with an interface that will allow me to change library if I need to in the future. Below is a section of the S3Repository that I have created and will let me change libraries in case I need to: using LitS3; namespace S3Helper.Models { public class S3Repository : IS3Repository { private S3Service _repository; #region IS3Repository Members public IQueryable<Bucket> FindAllBuckets() { return _repository.GetAllBuckets().AsQueryable(); } public IQueryable<ListEntry> FindAllObjects(string BucketName) { return _repository.ListAllObjects(BucketName).AsQueryable(); } #endregion If you have any information about this question please let me know in a comment, and I will get back and edit the question. EDIT 2: Since this question is not getting attention, I integrated both libraries in my web app to see the differences in design, I know this is probably a waist of time, but I really want a good long run solution. Below you will see two samples of the same action with the two libraries, maybe this will motivate some of you to let me know your thoughts. WITH THREE SHARP LIBRARY: public IQueryable<T> FindAllBuckets<T>() { List<string> list = new List<string>(); using (BucketListRequest request = new BucketListRequest(null)) using (BucketListResponse response = service.BucketList(request)) { XmlDocument bucketXml = response.StreamResponseToXmlDocument(); XmlNodeList buckets = bucketXml.SelectNodes("//*[local-name()='Name']"); foreach (XmlNode bucket in buckets) { list.Add(bucket.InnerXml); } } return list.Cast<T>().AsQueryable(); } WITH LITS3 LIBRARY: public IQueryable<T> FindAllBuckets<T>() { return _repository.GetAllBuckets() .Cast<T>() .AsQueryable(); }

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  • LINQ Query Returning Multiple Copies Of First Result

    - by Mike G
    I'm trying to figure out why a simple query in LINQ is returning odd results. I have a view defined in the database. It basically brings together several other tables and does some data munging. It really isn't anything special except for the fact that it deals with a large data set and can be a bit slow. I want to query this view based on a long. Two sample queries below show different queries to this view. var la = Runtime.OmsEntityContext.Positions.Where(p => p.AccountNumber == 12345678).ToList(); var deDa = Runtime.OmsEntityContext.Positions.Where(p => p.AccountNumber == 12345678).Select(p => new { p.AccountNumber, p.SecurityNumber, p.CUSIP }).ToList(); The first one should hand back a List. The second one will be a list of anonymous objects. When I do these queries in entities framework the first one will hand me back a list of results where they're all exactly the same. The second query will hand me back data where the account number is the one that I queried and the other values differ. This seems to do this on a per account number basis, ie if I were to query for one account number or another all the Position objects for one account would have the same value (the first one in the list of Positions for that account) and the second account would have a set of Position objects that all had the same value (again, the first one in it's list of Position objects). I can write SQL that is in effect the same as either of the two EF queries. They both come back with results (say four) that show the correct data, one account number with different securities numbers. Why does this happen??? Is there something that I could be doing wrong so that if I had four results for the first query above that the first record's data also appears in the 2-4th's objects??? I cannot fathom what would/could be causing this. I've searched Google for all kinds of keywords and haven't seen anyone with this issue. We partial class out the Positions class for added functionality (smart object) and some smart properties. There are even some constructors that provide some view model type support. None of this is invoked in the request (I'm 99% sure of this). However, we do this same pattern all over the app. The only thing I can think of is that the mapping in the EDMX is screwy. Is there a way that this would happen if the "primary keys" in the EDMX were not in fact unique given the way the view is constructed? I'm thinking that the dev who imported this model into the EDMX let the designer auto select what would be unique. Any help would give a haggered dev some hope!

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  • ASP.NET MVC 2 AJAX dilemma: Lose Models concept or create unmanageable JavaScript

    - by Slightly Frustrated
    Hi, Ok, let's assume we are working with ASP.NET MVC 2 (latest and greatest preview) and we want to create AJAX user interface with jQuery. So what are our real options here? Option 1 - Pass Json from the Controller to the view, and then the view submits Json back to the controller. This means (in the order given): User opens some View (let's say - /Invoices/January) which has to visualize a list of data (e.g. <IEnumerable<X.Y.Z.Models.Invoice>>) Controller retrieves the Model from the repository (assuming we are using repository pattern). Controller creates a new instance of a class which we will serialize to Json. The reasaon we do this, is because the model may not be serializable (circular reference ftl) Controller populates the soon-to-be-serialized class with data Controller serializes the class to Json and passes it the view. User does some change and submits the 'form' The View submits back Json to the controller The Controller now must 'manually' validate the input, because the Json passed does not bind to a Model See, if our View is communicating to the controller via Json, we lose the Model validation, which IMHO is incredible disadvantage. In this case, forget about data annotations and stuff. Option 2 - Ok, the alternative of the first approach is to pass the Models to the Views, which is the default behavior in the template when you start a new project. We pass a strong typed model to the view The view renders the appropriate html and javascript, sticking to the model property names. This is important! The user submits the form. If we stick to the model names, when we .serialize() the form and submit it to the controller it will map to a model. There is no Json mapping. The submitted form directly binds to a strongly typed model, hence, we can use the model validation. E.g. we keep the business logic where it should be. Problem with this approach is, if we refactor some of the Models (change property names, types, etc), the javascript we wrote would become invalid. We will have to manually refactor the scripting and hope we don't miss something. There is no way you can test it either. Ok, the question is - how to write an AJAX front end, which keeps the business logic validation in the model (e.g. controller passes and receives a Model type), but in the same time doesn't screw up the javascript and html when we refactor the model?

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  • XSLT - make xsl:analyze-string return string instead of sequence of strings?

    - by tohuwawohu
    Is it possible to make xsl:analyze-string return one string instead of a sequence of strings? Background: I'd like to use xsl:analyze-string in a xsl:function that should encapsulate the pattern matching. Ideally, the function should return an xs:string to be used as sort criteria in an xsl:sort element. At the moment, i have to apply string-join() on every result of the function call since xsl:analyze-string returns a sequence of strings, and xsl:sort doesn't accept such a sequence as sort criteria. See line 24 of the stylesheet: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:my="www.my-personal-namespa.ce" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xsl:output indent="yes" method="xml" /> <xsl:function name="my:sortierung" > <xsl:param name="inputstring" as="xs:string"/> <xsl:analyze-string select="$inputstring" regex="[0-9]+"> <xsl:matching-substring> <xsl:value-of select="format-number(number(.), '00000')" /> </xsl:matching-substring> <xsl:non-matching-substring> <xsl:value-of select="." /> </xsl:non-matching-substring> </xsl:analyze-string> </xsl:function> <xsl:template match="/input"> <result> <xsl:apply-templates select="value" > <xsl:sort select="string-join((my:sortierung(.)), ' ')" /> </xsl:apply-templates> </result> </xsl:template> <xsl:template match="value"> <xsl:copy-of select="." /> </xsl:template> </xsl:stylesheet> with this input: <?xml version="1.0" encoding="UTF-8"?> <input> <value>A 1 b 120</value> <value>A 1 b 1</value> <value>A 1 b 2</value> <value>A 1 b 1a</value> </input> In my example, is there a way to modify the xsl:function to return a xs:string instead of a sequence?

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  • Performance tuning of a Hibernate+Spring+MySQL project operation that stores images uploaded by user

    - by Umar
    Hi I am working on a web project that is Spring+Hibernate+MySQL based. I am stuck at a point where I have to store images uploaded by a user into the database. Although I have written some code that works well for now, but I believe that things will mess up when the project would go live. Here's my domain class that carries the image bytes: @Entity public class Picture implements java.io.Serializable{ long id; byte[] data; ... // getters and setters } And here's my controller that saves the file on submit: public class PictureUploadFormController extends AbstractBaseFormController{ ... protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception{ MutlipartFile file; // getting MultipartFile from the command object ... // beginning hibernate transaction ... Picture p=new Picture(); p.setData(file.getBytes()); pictureDAO.makePersistent(p); // this method simply calls getSession().saveOrUpdate(p) // committing hiernate transaction ... } ... } Obviously a bad piece of code. Is there anyway I could use InputStream or Blob to save the data, instead of first loading all the bytes from the user into the memory and then pushing them into the database? I did some research on hibernate's support for Blob, and found this in Hibernate In Action book: java.sql.Blob and java.sql.Clob are the most efficient way to handle large objects in Java. Unfortunately, an instance of Blob or Clob is only useable until the JDBC transaction completes. So if your persistent class defines a property of java.sql.Clob or java.sql.Blob (not a good idea anyway), you’ll be restricted in how instances of the class may be used. In particular, you won’t be able to use instances of that class as detached objects. Furthermore, many JDBC drivers don’t feature working support for java.sql.Blob and java.sql.Clob. Therefore, it makes more sense to map large objects using the binary or text mapping type, assuming retrieval of the entire large object into memory isn’t a performance killer. Note you can find up-to-date design patterns and tips for large object usage on the Hibernate website, with tricks for particular platforms. Now apparently the Blob cannot be used, as it is not a good idea anyway, what else could be used to improve the performance? I couldn't find any up-to-date design pattern or any useful information on Hibernate website. So any help/recommendations from stackoverflowers will be much appreciated. Thanks

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  • Internal class and access to external members.

    - by Knowing me knowing you
    I always thought that internal class has access to all data in its external class but having code: template<class T> class Vector { template<class T> friend std::ostream& operator<<(std::ostream& out, const Vector<T>& obj); private: T** myData_; std::size_t myIndex_; std::size_t mySize_; public: Vector():myData_(nullptr), myIndex_(0), mySize_(0) { } Vector(const Vector<T>& pattern); void insert(const T&); Vector<T> makeUnion(const Vector<T>&)const; Vector<T> makeIntersection(const Vector<T>&)const; class Iterator : public std::iterator<std::bidirectional_iterator_tag,T> { private: T** itData_; public: Iterator()//<<<<<<<<<<<<<------------COMMENT { /*HERE I'M TRYING TO USE ANY MEMBER FROM Vector<T> AND I'M GETTING ERR SAYING: ILLEGAL CALL OF NON-STATIC MEMBER FUNCTION*/} Iterator(T** ty) { itData_ = ty; } Iterator operator++() { return ++itData_; } T operator*() { return *itData_[0]; } bool operator==(const Iterator& obj) { return *itData_ == *obj.itData_; } bool operator!=(const Iterator& obj) { return *itData_ != *obj.itData_; } bool operator<(const Iterator& obj) { return *itData_ < *obj.itData_; } }; typedef Iterator iterator; iterator begin()const { assert(mySize_ > 0); return myData_; } iterator end()const { return myData_ + myIndex_; } }; See line marked as COMMENT. So can I or I can't use members from external class while in internal class? Don't bother about naming, it's not a Vector it's a Set. Thank you.

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  • How do I add a trailing slash for Django MPTT-based categorization app?

    - by Patrick Beeson
    I'm using Django-MPTT to develop a categorization app for my Django project. But I can't seem to get the regex pattern for adding a trailing slash that doesn't also break on child categories. Here's an example URL: http://mydjangoapp.com/categories/parentcat/childcat/ I'd like to be able to use http://mydjangoapp.com/categories/parentcat and have it redirect to the trailing slash version. The same should apply to http://mydjangoapp.com/categories/parentcat/childcat (it should redirect to http://mydjangoapp.com/categories/parentcat/childcat/). Here's my urls.py: from django.conf.urls.defaults import patterns, include, url from django.views.decorators.cache import cache_page from storefront.categories.models import Category from storefront.categories.views import SimpleCategoryView urlpatterns = patterns('', url(r'^(?P<full_slug>[-\w/]+)', cache_page(SimpleCategoryView.as_view(), 60 * 15), name='category_view'), ) And here is my view: from django.core.exceptions import ImproperlyConfigured from django.core.urlresolvers import reverse from django.views.generic import TemplateView, DetailView from django.views.generic.detail import SingleObjectTemplateResponseMixin, SingleObjectMixin from django.utils.translation import ugettext as _ from django.contrib.syndication.views import Feed from storefront.categories.models import Category class SimpleCategoryView(TemplateView): def get_category(self): return Category.objects.get(full_slug=self.kwargs['full_slug']) def get_context_data(self, **kwargs): context = super(SimpleCategoryView, self).get_context_data(**kwargs) context["category"] = self.get_category() return context def get_template_names(self): if self.get_category().template_name: return [self.get_category().template_name] else: return ['categories/category_detail.html'] And finally, my model: from django.db import models from mptt.models import MPTTModel from mptt.fields import TreeForeignKey class CategoryManager(models.Manager): def get(self, **kwargs): defaults = {} defaults.update(kwargs) if 'full_slug' in defaults: if defaults['full_slug'] and defaults['full_slug'][-1] != "/": defaults['full_slug'] += "/" return super(CategoryManager, self).get(**defaults) class Category(MPTTModel): title = models.CharField(max_length=255) description = models.TextField(blank=True, help_text='Please use <a href="http://daringfireball.net/projects/markdown/syntax">Markdown syntax</a> for all text-formatting and links. No HTML is allowed.') slug = models.SlugField(help_text='Prepopulates from title field.') full_slug = models.CharField(max_length=255, blank=True) template_name = models.CharField(max_length=70, blank=True, help_text="Example: 'categories/category_parent.html'. If this isn't provided, the system will use 'categories/category_detail.html'. Use 'categories/category_parent.html' for all parent categories and 'categories/category_child.html' for all child categories.") parent = TreeForeignKey('self', null=True, blank=True, related_name='children') objects = CategoryManager() class Meta: verbose_name = 'category' verbose_name_plural = 'categories' def save(self, *args, **kwargs): orig_full_slug = self.full_slug if self.parent: self.full_slug = "%s%s/" % (self.parent.full_slug, self.slug) else: self.full_slug = "%s/" % self.slug obj = super(Category, self).save(*args, **kwargs) if orig_full_slug != self.full_slug: for child in self.get_children(): child.save() return obj def available_product_set(self): """ Returns available, prioritized products for a category """ from storefront.apparel.models import Product return self.product_set.filter(is_available=True).order_by('-priority') def __unicode__(self): return "%s (%s)" % (self.title, self.full_slug) def get_absolute_url(self): return '/categories/%s' % (self.full_slug)

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  • How can i convert this to a factory/abstract factory?

    - by Amitd
    I'm using MigraDoc to create a pdf document. I have business entities similar to the those used in MigraDoc. public class Page{ public List<PageContent> Content { get; set; } } public abstract class PageContent { public int Width { get; set; } public int Height { get; set; } public Margin Margin { get; set; } } public class Paragraph : PageContent{ public string Text { get; set; } } public class Table : PageContent{ public int Rows { get; set; } public int Columns { get; set; } //.... more } In my business logic, there are rendering classes for each type public interface IPdfRenderer<T> { T Render(MigraDoc.DocumentObjectModel.Section s); } class ParagraphRenderer : IPdfRenderer<MigraDoc.DocumentObjectModel.Paragraph> { BusinessEntities.PDF.Paragraph paragraph; public ParagraphRenderer(BusinessEntities.PDF.Paragraph p) { paragraph = p; } public MigraDoc.DocumentObjectModel.Paragraph Render(MigraDoc.DocumentObjectModel.Section s) { var paragraph = s.AddParagraph(); // add text from paragraph etc return paragraph; } } public class TableRenderer : IPdfRenderer<MigraDoc.DocumentObjectModel.Tables.Table> { BusinessEntities.PDF.Table table; public TableRenderer(BusinessEntities.PDF.Table t) { table =t; } public MigraDoc.DocumentObjectModel.Tables.Table Render(Section obj) { var table = obj.AddTable(); //fill table based on table } } I want to create a PDF page as : var document = new Document(); var section = document.AddSection();// section is a page in pdf var page = GetPage(1); // get a page from business classes foreach (var content in page.Content) { //var renderer = createRenderer(content); // // get Renderer based on Business type ?? // renderer.Render(section) } For createRenderer() i can use switch case/dictionary and return type. How can i get/create the renderer generically based on type ? How can I use factory or abstract factory here? Or which design pattern better suits this problem?

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  • How to access static members in a Velocity template?

    - by matt b
    I'm not sure if there is a way to do this in Velocity or not: I have a User POJO which a property named Status, which looks like an enum (but it is not, since I am stuck on Java 1.4), the definition looks something like this: public class User { // default status to User private Status status = Status.USER; public void setStatus(Status status) { this.status = status; } public Status getStatus() { return status; } And Status is a static inner class: public static final class Status { private String statusString; private Status(String statusString) { this.statusString = statusString; } public final static Status USER = new Status("user"); public final static Status ADMIN = new Status("admin"); public final static Status STATUS_X = new Status("blah"); //.equals() and .hashCode() implemented as well } With this pattern, a user status can easily be tested in a conditional such as if(User.Status.ADMIN.equals(user.getStatus())) ... ... without having to reference any constants for the status ID, any magic numbers, etc. However, I can't figure out how to test these conditionals in my Velocity template with VTL. I'd like to just print a simple string based upon the user's status, such as: Welcome <b>${user.name}</b>! <br/> <br/> #if($user.status == com.company.blah.User.Status.USER) You are a regular user #elseif($user.status == com.company.blah.User.Status.ADMIN) You are an administrator #etc... #end But this throws an Exception that looks like org.apache.velocity.exception.ParseErrorException: Encountered "User" at webpages/include/dashboard.inc[line 10, column 21] Was expecting one of: "[" ... From the VTL User Guide, there is no mention of accessing a Java class/static member directly in VTL, it appears that the right hand side (RHS) of a conditional can only be a number literal, string literal, property reference, or method reference. So is there any way that I can access static Java properties/references in a Velocity template? I'm aware that as a workaround, I could embed the status ID or some other identifier as a reference in my controller (this is a web MVC application using Velocity as the View technology), but I strongly do not want to embed any magic numbers or constants in the view layer.

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  • Inline HTML Syntax for Helpers in ASP.NET MVC

    - by kouPhax
    I have a class that extends the HtmlHelper in MVC and allows me to use the builder pattern to construct special output e.g. <%= Html.FieldBuilder<MyModel>(builder => { builder.Field(model => model.PropertyOne); builder.Field(model => model.PropertyTwo); builder.Field(model => model.PropertyThree); }) %> Which outputs some application specific HTML, lets just say, <ul> <li>PropertyOne: 12</li> <li>PropertyTwo: Test</li> <li>PropertyThree: true</li> </ul> What I would like to do, however, is add a new builder methid for defining some inline HTML without having to store is as a string. E.g. I'd like to do this. <% Html.FieldBuilder<MyModel>(builder => { builder.Field(model => model.PropertyOne); builder.Field(model => model.PropertyTwo); builder.ActionField(model => %> Generated: <%=DateTime.Now.ToShortDate()%> (<a href="#">Refresh</a>) <%); }).Render(); %> and generate this <ul> <li>PropertyOne: 12</li> <li>PropertyTwo: Test</li> <li>Generated: 29/12/2008 <a href="#">Refresh</a></li> </ul> Essentially an ActionExpression that accepts a block of HTML. However to do this it seems I need to execute the expression but point the execution of the block to my own StringWriter and I am not sure how to do this. Can anyone advise?

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  • WCF Service with callbacks coming from background thread?

    - by Mark Struzinski
    Here is my situation. I have written a WCF service which calls into one of our vendor's code bases to perform operations, such as Login, Logout, etc. A requirement of this operation is that we have a background thread to receive events as a result of that action. For example, the Login action is sent on the main thread. Then, several events are received back from the vendor service as a result of the login. There can be 1, 2, or several events received. The background thread, which runs on a timer, receives these events and fires an event in the wcf service to notify that a new event has arrived. I have implemented the WCF service in Duplex mode, and planned to use callbacks to notify the UI that events have arrived. Here is my question: How do I send new events from the background thread to the thread which is executing the service? Right now, when I call OperationContext.Current.GetCallbackChannel<IMyCallback>(), the OperationContext is null. Is there a standard pattern to get around this? I am using PerSession as my SessionMode on the ServiceContract. UPDATE: I thought I'd make my exact scenario clearer by demonstrating how I'm receiving events from the vendor code. My library receives each event, determines what the event is, and fires off an event for that particular occurrence. I have another project which is a class library specifically for connecting to the vendor service. I'll post the entire implementation of the service to give a clearer picture: [ServiceBehavior( InstanceContextMode = InstanceContextMode.PerSession )] public class VendorServer:IVendorServer { private IVendorService _vendorService; // This is the reference to my class library public VendorServer() { _vendorServer = new VendorServer(); _vendorServer.AgentManager.AgentLoggedIn += AgentManager_AgentLoggedIn; // This is the eventhandler for the event which arrives from a background thread } public void Login(string userName, string password, string stationId) { _vendorService.Login(userName, password, stationId); // This is a direct call from the main thread to the vendor service to log in } private void AgentManager_AgentLoggedIn(object sender, EventArgs e) { var agentEvent = new AgentEvent { AgentEventType = AgentEventType.Login, EventArgs = e }; } } The AgentEvent object contains the callback as one of its properties, and I was thinking I'd perform the callback like this: agentEvent.Callback = OperationContext.Current.GetCallbackChannel<ICallback>(); How would I pass the OperationContext.Current instance from the main thread into the background thread?

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  • Initialization of components with interdependencies - possible antipattern?

    - by Rosarch
    I'm writing a game that has many components. Many of these are dependent upon one another. When creating them, I often get into catch-22 situations like "WorldState's constructor requires a PathPlanner, but PathPlanner's constructor requires WorldState." Originally, this was less of a problem, because references to everything needed were kept around in GameEngine, and GameEngine was passed around to everything. But I didn't like the feel of that, because it felt like we were giving too much access to different components, making it harder to enforce boundaries. Here is the problematic code: /// <summary> /// Constructor to create a new instance of our game. /// </summary> public GameEngine() { graphics = new GraphicsDeviceManager(this); Components.Add(new GamerServicesComponent(this)); //Sets dimensions of the game window graphics.PreferredBackBufferWidth = 800; graphics.PreferredBackBufferHeight = 600; graphics.ApplyChanges(); IsMouseVisible = true; screenManager = new ScreenManager(this); //Adds ScreenManager as a component, making all of its calls done automatically Components.Add(screenManager); // Tell the program to load all files relative to the "Content" directory. Assets = new CachedContentLoader(this, "Content"); inputReader = new UserInputReader(Constants.DEFAULT_KEY_MAPPING); collisionRecorder = new CollisionRecorder(); WorldState = new WorldState(new ReadWriteXML(), Constants.CONFIG_URI, this, contactReporter); worldQueryUtils = new WorldQueryUtils(worldQuery, WorldState.PhysicsWorld); ContactReporter contactReporter = new ContactReporter(collisionRecorder, worldQuery, worldQueryUtils); gameObjectManager = new GameObjectManager(WorldState, assets, inputReader, pathPlanner); worldQuery = new DefaultWorldQueryEngine(collisionRecorder, gameObjectManager.Controllers); gameObjectManager.WorldQueryEngine = worldQuery; pathPlanner = new PathPlanner(this, worldQueryUtils, WorldQuery); gameObjectManager.PathPlanner = pathPlanner; combatEngine = new CombatEngine(worldQuery, new Random()); } Here is an excerpt of the above that's problematic: gameObjectManager = new GameObjectManager(WorldState, assets, inputReader, pathPlanner); worldQuery = new DefaultWorldQueryEngine(collisionRecorder, gameObjectManager.Controllers); gameObjectManager.WorldQueryEngine = worldQuery; I hope that no one ever forgets that setting of gameObjectManager.WorldQueryEngine, or else it will fail. Here is the problem: gameObjectManager needs a WorldQuery, and WorldQuery needs a property of gameObjectManager. What can I do about this? Have I found an anti-pattern?

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  • How to fine tune FluentNHibernate's auto mapper?

    - by Venemo
    Okay, so yesterday I managed to get the latest trunk builds of NHibernate and FluentNHibernate to work with my latest little project. (I'm working on a bug tracking application.) I created a nice data access layer using the Repository pattern. I decided that my entities are nothing special, and also that with the current maturity of ORMs, I don't want to hand-craft the database. So, I chose to use FluentNHibernate's auto mapping feature with NHibernate's "hbm2ddl.auto" property set to "create". It really works like a charm. I put the NHibernate configuration in my app domain's config file, set it up, and started playing with it. (For the time being, I created some unit tests only.) It created all tables in the database, and everything I need for it. It even mapped my many-to-many relationships correctly. However, there are a few small glitches: All of the columns created in the DB allow null. I understand that it can't predict which properties should allow null and which shouldn't, but at least I'd like to tell it that it should allow null only for those types for which null makes sense in .NET (eg. non-nullable value types shouldn't allow null). All of the nvarchar and varbinary columns it created, have a default length of 255. I would prefer to have them on max instead of that. Is there a way to tell the auto mapper about the two simple rules above? If the answer is no, will it work correctly if I modify the tables it created? (So, if I set some columns not to allow null, and change the allowed length for some other, will it correctly work with them?) EDIT: I managed to achieve the above by using Fluent NHibernate's convention API. Thanks to everyone who helped! However, there is one more thing: after checking out the convention API, I really would like my IDs to be calld "ID", not "Id", but it seems to me that the PrimaryKey.Name.Is(x => "ID") is not working at all. If I add it to the conventions collection and rewrite my entities' properties to "ID" instead of "Id", it throws an exception that there is no primary key mapped. Any thoughts on this?

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  • Myself throwing NullReferenceException... needs help

    - by Amit Ranjan
    I know it might be a weird question and its Title too, but i need your help. I am a .net dev , working on platform for the last 1.5 years. I am bit confused on the term usually we say " A Good Programmer ". I dont know ,what are the qualities of a good programmer ? Is the guy who writes a bug free code? or Can develop applications solely? or blah blah blah...lots of points. I dont know... But as far i am concerned , I know I am not a good programmer, still in learning phase an needs a lot to learn in coming days. So you guys are requested to please help me with this two problems of mine My first problem is regarding the proper Error Handling, which is a most debatable aspect of programming. We all know we use ` try { } catch { } finally { } ` in our code to manage exception. But even if I use try { } catch(exception ex) { throw ex } finally { } , different guys have different views. I still dont know the good way to handle errors. I can write code, use try-catch but still i feel I lacks something. When I saw the codes generated by .net fx tools even they uses throw ex or `throw new Exception("this is my exception")`.. I am just wondering what will be the best way to achieve the above. All means the same thing but why we avoid something. If it has some demerits then it must be made obselete.Anyways I still dont have one [how to handle errors efficiently?]. I generally follow the try-catch(execoption ex){throw ex}, and usually got stucked in debates with leads why you follow this why not that... 2.Converting your entire code blocks in modules using Design patterns of some OOPs concepts. How do you guys decide what architeture or pattern will be the best for my upcoming application based on its working, flow etc. I need to know what you guys can see that I can't. Since I know , I dont have that much experience but I can say, with my experience that experience doesnot comes either from degree/certificates or success you made instead it cames from failures you faced or got stucking situations. Pleas help me out.

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  • Emails sent using Flex app are delayed

    - by user363825
    I'm currently building an application in Flex that utilizes SMTP Mailer to automatically send out emails to the user when a particular condition is satisfied. The application checks this condition every 30 seconds. The condition is satisfied based on new records being returned from a database table. The problem is as follows: When the condition is first satisfied, the email is delivered to the user with no issues. The second time the condition is satisfied, the email is not delivered. In the smtp logs, the delivery attempt appears to get hung up on the following line: 354 Start mail input; end with <CRLF>.<CRLF> No error codes are present in the smtp logs, but I do trace the following event from the SMTP Mailer class: [Event type="mailError" bubbles=false cancelable=false eventPhase=2] When the condition is satisfied a third time, the email that was not delivered when the condition was satisfied the previous time is now delivered, along with the email for this instance. This pattern then repeats itself, with the next email not being sent followed by two emails being sent simulatneously when the condition is met again. The smtp server being used is Windows 2003, on an internal network. The email is being sent to an outlook account hosted on an exchange server that is also on this internal network. Here is the actionscript code that creates the SMTPMailer object: public var testMail:SMTPMailer = null; public function alertNotify() { Security.loadPolicyFile("crossdomain.xml"); this.testMail = new SMTPMailer("myserver.ec.local",25); this.testMail.addEventListener(SMTPEvent.MAIL_SENT, onEmailEvent); this.testMail.addEventListener(SMTPEvent.MAIL_ERROR, onEmailError); this.testMail.addEventListener(SMTPEvent.DISCONNECTED, onEmailConn); this.testMail.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onEmailError); } Here is the code that creates the email body and calls the method to send the email: public function alertUser(emailAC:ArrayCollection):void { trace ("In alertUser() before send, testMail.connected = " + testMail.connected.toString()); var testStr:String = " Key Location Event Type Comment Update Time "; for each (var event:rEntity in emailAC) { testStr = testStr + "" + event.key.toString() + "" + event.xml.address.toString() + " " + [email protected]() + "" + [email protected]() + "" + [email protected]() + "" + event.xml.attribute("update-time").toXMLString() + ""; } testStr = testStr + ""; testMail.flush(); testMail.sendHTMLMail("[email protected]","[email protected]","Event Notification",testStr); } Really not sure where the email that gets hung up is being stored until it is finally sent.... Any suggestions as to how to begin to remedy this issue would be much appreciated.

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  • Unresolved External Symbol linker error (C++)

    - by Niranjan
    Hi, I am trying to develop abstract design pattern code for one of my project as below.. But, I am not able to compile the code ..giving some compile errors(like "unresolved external symbol "public: virtual void __thiscall Xsecs::draw_lines(double,double)" (?draw_lines@Xsecs@@UAEXNN@Z)" ).. Can any one please help me out in this... #include "stdafx.h" #include <iostream> #include <vector> #include "Xsecs.h" using namespace std; //Product class class Xsecs { public: virtual void draw_lines(double pt1, double pt2); virtual void draw_curves(double pt1, double rad); }; class polyline: public Xsecs { public: virtual void draw_lines(double pt1,double pt2) { cout<<"draw_line in polygon"<<endl; } virtual void draw_curves(double pt1, double rad) { cout<<"Draw_curve in circle"<<endl; } /*void create_polygons() { cout<<"create_polygon_thru_draw_lines"<<endl; }*/ }; class circle: public Xsecs { public: virtual void draw_lines(double pt1,double pt2) { cout<<"draw_line in polygon"<<endl; } virtual void draw_curves(double pt1, double rad) { cout<<"Draw_curve in circle"<<endl; } /*void create_circles() { cout<<"Create circle"<<endl; }*/ }; //Factory class class Factory { public: virtual polyline* create_polyline()=0; virtual circle* create_circle()=0; }; class Factory1: public Factory { public: polyline* create_polyline() { return new polyline(); } circle* create_circle() { return new circle(); } }; class Factory2: public Factory { public: circle* create_circle() { return new circle(); } polyline* create_polyline() { return new polyline(); } }; int _tmain(int argc, _TCHAR* argv[]) { Factory1 f1; Factory * fp=&f1; return 0; }

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  • Is it ok to dynamic cast "this" as a return value?

    - by Panayiotis Karabassis
    This is more of a design question. I have a template class, and I want to add extra methods to it depending on the template type. To practice the DRY principle, I have come up with this pattern (definitions intentionally omitted): template <class T> class BaseVector: public boost::array<T, 3> { protected: BaseVector<T>(const T x, const T y, const T z); public: bool operator == (const Vector<T> &other) const; Vector<T> operator + (const Vector<T> &other) const; Vector<T> operator - (const Vector<T> &other) const; Vector<T> &operator += (const Vector<T> &other) { (*this)[0] += other[0]; (*this)[1] += other[1]; (*this)[2] += other[2]; return *dynamic_cast<Vector<T> * const>(this); } } template <class T> class Vector : public BaseVector<T> { public: Vector<T>(const T x, const T y, const T z) : BaseVector<T>(x, y, z) { } }; template <> class Vector<double> : public BaseVector<double> { public: Vector<double>(const double x, const double y, const double z); Vector<double>(const Vector<int> &other); double norm() const; }; I intend BaseVector to be nothing more than an implementation detail. This works, but I am concerned about operator+=. My question is: is the dynamic cast of the this pointer a code smell? Is there a better way to achieve what I am trying to do (avoid code duplication, and unnecessary casts in the user code)? Or am I safe since, the BaseVector constructor is private?

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  • How do you create a MANIFEST.MF that's available when you're testing and running from a jar in produ

    - by warvair
    I've spent far too much time trying to figure this out. This should be the simplest thing and everyone who distributes Java applications in jars must have to deal with it. I just want to know the proper way to add versioning to my Java app so that I can access the version information when I'm testing, e.g. debugging in Eclipse and running from a jar. Here's what I have in my build.xml: <target name="jar" depends = "compile"> <property name="version.num" value="1.0.0"/> <buildnumber file="build.num"/> <tstamp> <format property="TODAY" pattern="yyyy-MM-dd HH:mm:ss" /> </tstamp> <manifest file="${build}/META-INF/MANIFEST.MF"> <attribute name="Built-By" value="${user.name}" /> <attribute name="Built-Date" value="${TODAY}" /> <attribute name="Implementation-Title" value="MyApp" /> <attribute name="Implementation-Vendor" value="MyCompany" /> <attribute name="Implementation-Version" value="${version.num}-b${build.number}"/> </manifest> <jar destfile="${build}/myapp.jar" basedir="${build}" excludes="*.jar" /> </target> This creates /META-INF/MANIFEST.MF and I can read the values when I'm debugging in Eclipse thusly: public MyClass() { try { InputStream stream = getClass().getResourceAsStream("/META-INF/MANIFEST.MF"); Manifest manifest = new Manifest(stream); Attributes attributes = manifest.getMainAttributes(); String implementationTitle = attributes.getValue("Implementation-Title"); String implementationVersion = attributes.getValue("Implementation-Version"); String builtDate = attributes.getValue("Built-Date"); String builtBy = attributes.getValue("Built-By"); } catch (IOException e) { logger.error("Couldn't read manifest."); } } But, when I create the jar file, it loads the manifest of another jar (presumably the first jar loaded by the application - in my case, activation.jar). Also, the following code doesn't work either although all the proper values are in the manifest file. Package thisPackage = getClass().getPackage(); String implementationVersion = thisPackage.getImplementationVersion(); Any ideas?

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  • can this code be broken?

    - by user105165
    Consider the below html string <p>This is a paragraph tag</p> <font>This is a font tag</font> <div>This is a div tag</div> <span>This is a span tag</span> This string is processed to tokanize the text found in it and we get 2 results as below 1) Token Array : $tokenArray == array( 'This is a paragraph tag', 'This is a div tag', '<font>This is a font tag</font>', '<span>This is a span tag</span>' ); 2) Tokenized template : $templateString == "<p>{0}</p>{2}<div>{1}</div>{3}"; If you observe, the sequence of the text strings segments from the original HTML strings is different from the tokenized template The PHP code below is used to order the tokenized template and accordingly the token array to match the original html string class CreateTemplates { public static $tokenArray = array(); public static $tokenArrayNew = array(); function foo($templateString,$tokenArray) { CreateTemplates::$tokenArray = $tokenArray; $ptn = "/{[0-9]*}*/"; // Search Pattern from the template string $templateString = preg_replace_callback($ptn,array(&$this, 'callbackhandler') ,$templateString); // function call return $templateString; } // Function defination private static function callbackhandler($matches) { static $newArr = array(); static $cnt; $tokenArray = CreateTemplates::$tokenArray; array_push($newArr, $matches[0]); CreateTemplates::$tokenArrayNew[count($newArr)] = $tokenArray[substr($matches[0],1,(strlen($matches[0])-2))]; $cnt = count($newArr)-1; return '{'.$cnt.'}'; } // function ends } // class ends Final output is (ordered template and token array) $tokenArray == array('This is a paragraph tag', '<font>This is a font tag</font>', 'This is a div tag', '<span>This is a span tag</span>' ); $templateString == "<p>{0}</p>{1}<div>{2}</div>{3}"; Which is the expected result. Now, I am not confident whether this is the right way to achieve this. I want to see how this code can be broken or not. Under what conditions will this code break? (important) Is there any other way to achieve this? (less important)

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  • Design patterns and interview question

    - by user160758
    When I was learning to code, I read up on the design patterns like a good boy. Long after this, I started to actually understand them. Design discussions such as those on this site constantly try to make the rules more and more general, which is good. But there is a line, over which it becomes over-analysis starts to feed off itself and as such I think begins to obfuscate the original point - for example the "What's Alternative to Singleton" post and the links contained therein. http://stackoverflow.com/questions/1300655/whats-alternative-to-singleton I say this having been asked in both interviews I’ve had over the last 2 weeks what a singleton is and what criticisms I have of it. I have used it a few times for items such as user data (simple key-value eg. last file opened by this user) and logging (very common i'm sure). I've never ever used it just to have what is essentially global application data, as this is clearly stupid. In the first interview, I reply that I have no criticisms of it. He seemed disappointed by this but as the job wasn’t really for me, I forgot about it. In the next one, I was asked again and, as I wanted this job, I thought about it on the spot and made some objections, similar to those contained in the post linked to above (I suggested use of a factory or dependency injection instead). He seemed happy with this. But my problem is that I have used the singleton without ever using it in this kind of stupid way, which I had to describe on the spot. Using it for global data and the like isn’t something I did then realised was stupid, or read was stupid so didn’t do, it was just something I knew was stupid from the start. Essentially I’m supposed to be able to think of ways of how to misuse a pattern in the interview? Which class of programmers can best answer this question? The best ones? The medium ones? I'm not sure.... And these were both bright guys. I read more than enough to get better at my job but had never actually bothered to seek out criticisms of the most simple of the design patterns like this one. Do people think such questions are valid and that I ought to know the objections off by heart? Or that it is reasonable to be able to work out what other people who are missing the point would do on the fly? Or do you think I’m at least partially right that the question is too unsubtle and that the questions ought to be better thought out in order to make sure only good candidates can answer. PS. Please don’t think I’m saying that I’m just so clever that I know everything automatically - I’ve learnt the hard way like everyone else. But avoiding global data is hardly revolutionary.

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  • ActionResult - Service

    - by cem
    I bored, writing same code for service and ui. Then i tried to write a converter for simple actions. This converter, converting Service Results to MVC result, seems like good solution for me but anyway i think this gonna opposite MVC pattern. So here, I need help, what you think about algorithm - is this good or not? Thanks ServiceResult - Base: public abstract class ServiceResult { public static NoPermissionResult Permission() { return new NoPermissionResult(); } public static SuccessResult Success() { return new SuccessResult(); } public static SuccessResult<T> Success<T>(T result) { return new SuccessResult<T>(result); } protected ServiceResult(ServiceResultType serviceResultType) { _resultType = serviceResultType; } private readonly ServiceResultType _resultType; public ServiceResultType ResultType { get { return _resultType; } } } public class SuccessResult<T> : ServiceResult { public SuccessResult(T result) : base(ServiceResultType.Success) { _result = result; } private readonly T _result; public T Result { get { return _result; } } } public class SuccessResult : SuccessResult<object> { public SuccessResult() : this(null) { } public SuccessResult(object o) : base(o) { } } Service - eg. ForumService: public ServiceResult Delete(IVUser user, int id) { Forum forum = Repository.GetDelete(id); if (!Permission.CanDelete(user, forum)) { return ServiceResult.Permission(); } Repository.Delete(forum); return ServiceResult.Success(); } Controller: public class BaseController { public ActionResult GetResult(ServiceResult result) { switch (result.ResultType) { case ServiceResultType.Success: var successResult = (SuccessResult)result; return View(successResult.Result); break; case ServiceResultType.NoPermission: return View("Error"); break; default: return View(); break; } } } [HandleError] public class ForumsController : BaseController { [ValidateAntiForgeryToken] [Transaction] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Delete(int id) { ServiceResult result = ForumService.Delete(WebUser.Current, id); /* Custom result */ if (result.ResultType == ServiceResultType.Success) { TempData[ControllerEnums.GlobalViewDataProperty.PageMessage.ToString()] = "The forum was successfully deleted."; return this.RedirectToAction(ec => Index()); } /* Custom result */ /* Execute Permission result etc. */ TempData[ControllerEnums.GlobalViewDataProperty.PageMessage.ToString()] = "A problem was encountered preventing the forum from being deleted. " + "Another item likely depends on this forum."; return GetResult(result); } }

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  • Problem setting row backgrounds in Android Listview

    - by zchtodd
    I have an application in which I'd like one row at a time to have a certain color. This seems to work about 95% of the time, but sometimes instead of having just one row with this color, it will allow multiple rows to have the color. Specifically, a row is set to have the "special" color when it is tapped. In rare instances, the last row tapped will retain the color despite a call to setBackgroundColor attempting to make it otherwise. private OnItemClickListener mDirectoryListener = new OnItemClickListener(){ public void onItemClick(AdapterView parent, View view, int pos, long id){ if (stdir.getStationCount() == pos) { stdir.moreStations(); return; } if (playingView != null) playingView.setBackgroundColor(Color.DKGRAY); view.setBackgroundColor(Color.MAGENTA); playingView = view; playStation(pos); } }; I have confirmed with print statements that the code setting the row to gray is always called. Can anyone imagine a reason why this code might intermittently fail? If there is a pattern or condition that causes it, I can't tell. I thought it might have something to do with the activity lifecycle setting the "playingView" variable back to null, but I can't reliably reproduce the problem by switching activities or locking the phone. private class DirectoryAdapter extends ArrayAdapter { private ArrayList<Station> items; public DirectoryAdapter(Context c, int resLayoutId, ArrayList<Station> stations){ super(c, resLayoutId, stations); this.items = stations; } public int getCount(){ return items.size() + 1; } public View getView(int position, View convertView, ViewGroup parent){ View v = convertView; LayoutInflater vi = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (position == this.items.size()) { v = vi.inflate(R.layout.morerow, null); return v; } Station station = this.items.get(position); v = vi.inflate(R.layout.songrow, null); if (station.playing) v.setBackgroundColor(Color.MAGENTA); else if (station.visited) v.setBackgroundColor(Color.DKGRAY); else v.setBackgroundColor(Color.BLACK); TextView title = (TextView)v.findViewById(R.id.title); title.setText(station.name); return v; } };

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