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• The unary increment operator in pointer arithmetic

  - by RhymesWithDuck

  Hello, this is my first post. I have this function for reversing a string in C that I found. void reverse(char* c) { if (*c != 0) { reverse(c + 1); } printf("%c",*c); } It works fine but if I replace: reverse(c + 1); with: reverse(++c); the first character of the original string is truncated. My question is why would are the statements not equivalent in this instance? Thanks

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• iphone threading speed up startup of app

  - by BahaiResearch.com

  I have an app that must get data from the Sqlite database in order to display the first element to the User. I have created a domain object which wraps the DB access and is a thread safe singleton. Is this following strategy optimal to ensure the fastest load given the iPhone's file access and memory management capabilities in threaded apps: 1) In the AppDelegate's FinishedLaunching event the very first thing I do is create the domain singleton within a new thread. This will cause the domain object to go to Sqlite and get the data it needs without locking the UI thread. 2) I then call the standard Window methods to add the View and MakeKeyAndVisible etc. Is there an earlier stage in the AppDelegate where I should fire off the thread that creates the Domain Object and accesses Sqlite?

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• Testing a quadratic equation

  - by user1201587

  I'm doing a code testing for a program that calculate the results for a quadratic equation I need to have test data for the following situation, when a is not zero and d positive there is two possibilities which are in the code below, I need to find an example for the first satiation when Math.abs(b / a - 200.0) < 1.0e-4 , all the values that I have tried, excute the second one caption= "Two roots"; if (Math.abs(b / a - 200.0) < 1.0e-4) { System.out.println("first one"); x1 = (-100.0 * (1.0 + Math.sqrt(1.0 - 1.0 / (10000.0 * a)))); x2 = (-100.0 * (1.0 - Math.sqrt(1.0 - 1.0 / (10000.0 * a)))); } else { System.out.println("secrst one"); x1 = (-b - Math.sqrt(d)) / (2.0 * a); x2 = (-b + Math.sqrt(d)) / (2.0 * a); } } }

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• is there a way to show what field you updated in mysql?

  - by ggfan

  When users edit their account, I want to display a confirmation page that shows their updated information with the fields that they changed in bold. Is there a mysql statement that allows you to select the fields that a user changes? If not, how exactly can I achieve this Ex: (editaccount.php) first_name: bob last_name: builder email: [email protected] When they change say their first name to "james", the confirmation page shows their first name in bold because they changed that but the other areas are still normal text. first_name: <b>James</b> last_name: builder email: [email protected]

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• How to retrieve the location of a control on the view?

  - by amok

  I have a button on a view, I want to add another button next to it when the first button is touched. Therefore I need it's top left corner to do the math. Here's what is puzzling me greatly: // this code is executed when the button is pressed NSLog(@"X:%f",moreButton.frame.origin.x); that returns on the first and second click the followings: 2010-04-24 22:58:25.883 iPad PopOver[8095:40b] X:-1.999002 2010-04-24 22:58:25.884 iPad PopOver[8095:40b] Y:0.000000 why and how can I get the x,y of an existing button on the view? (button created via IB) Thanks! mE ps: I have looked at similar posts and my code looks fine but I keep getting zeros (it's an ipad app if matters in any way)

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• Select next element in the page source using jQuery

  - by Travis

  I have an arbitrarily deep list of the form: <ul> <li></li> <li> <ul> <li></li> </ul> </li> </ul> I am trying to build a function "nextElement" that returns a jQuery selector. The first time the function is called, it returns the first li in the list. The second time it is called, it returns the next li in the page. Etc. I'd like this function to pay no attention to siblings, parents, children, etc. All I care about is that everytime it is called, the next li in the source gets chosen. Any suggestions on how to go about approaching this? Thanks

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• Most proper way to use inherited classes with shared scopes in Mongo?

  - by Trip

  I have the TestVisual class that is inherited by the Game class : class TestVisual < Game include MongoMapper::Document end class Game include MongoMapper::Document belongs_to :maestra key :incorrect, Integer key :correct, Integer key :time_to_complete, Integer key :maestra_id, ObjectId timestamps! end As you can see it belongs to Maestra. So I can do Maestra.first.games But I can not to Maestra.first.test_visuals Since I'm working specifically with TestVisuals, that is ideally what I would like to pull. Is this possible with Mongo. If it isn't or if it isn't necessary, is there any other better way to reach the TestVisual object from Maestra and still have it inherit Game ?

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• Can tapping next textfield trigger same behavior as "Done" key?

  - by trevrosen

  I've got two textfields in a row for username and password. When you're finished putting in your username, the most natural thing to do is to just tap on the next textfield, like you would with a web form. But that doesn't work -- you can't edit the next field until you press "Done" on the keyboard for the first field and then tap on the second one. My question is: is it possible to set up two textfields so that you end editing on the first one and begin editing the second when you tap the second field?

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• Python sort 2-D list by time string

  - by Mark Kennedy

  How do I sort a multi dimensional list like this based on a time string? The sublists can be of different sizes (i.e. 4 and 5, here) I want to sort by comparing the first time string in each sublist (sublist[-4]) x = (['1513', '08:19PM', '10:21PM', 1, 4], ['1290', '09:45PM', '11:43PM', 1, 4], ['0690', '07:25AM', '09:19AM', 1, 4], ['0201', '08:50AM', '10:50AM', 1, 4], ['1166', '04:35PM', '06:36PM', 1, 4], ['0845', '05:40PM', '07:44PM', 1, 4], ['1267', '07:05PM', '09:07PM', 1, 4], ['1513', '08:19PM', '10:21PM', 1, 4], ['1290', '09:45PM', '11:43PM', 1, 4], ['8772', '0159', '12:33PM', '02:43PM', 1, 5], ['0888', '0570', '09:42PM', '12:20AM', 1, 5], ['2086', '2231', '04:10PM', '06:20PM', 1, 5]) The sorted result would be sortedX = (['0690', '07:25AM', '09:19AM', 1, 4], ['0201', '08:50AM', '10:50AM', 1, 4], ['1166', '04:35PM', '06:36PM', 1, 4], ['0845', '05:40PM', '07:44PM', 1, 4], ['1267', '07:05PM', '09:07PM', 1, 4], ['1513', '08:19PM', '10:21PM', 1, 4], ['1513', '08:19PM', '10:21PM', 1, 4], ['1290', '09:45PM', '11:43PM', 1, 4], ['1290', '09:45PM', '11:43PM', 1, 4], ['8772', '0159', '12:33PM', '02:43PM', 1, 5], ['2086', '2231', '04:10PM', '06:20PM', 1, 5], ['0888', '0570', '09:42PM', '12:20AM', 1, 5]) I tried the following: sortedX = sorted(x, key=lambda k : k[-4]) #k[-4] is the first time string and it works but it doesn't respect the sublist size ordering

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• Sprite background image lags on mouse hover

  - by user351342

  I have basic DOM menu that has sprite background images for the first level of "LI"s. It works just fine, but I guess there is some problem and instead of switching the image right away on hover it goes blank and after about a second the hover image "appears" (shifts). That happens only on first hovering. After that it's smooth like it's supposed to be. Refresh the page and there it is again... Frustrating... Here is a link to check it out: http://goo.gl/6FAM The problem exist on Firefox v3.6.3. Chrome 5.0.375 and IE 8.0.7600 don't have this issue. Any ideas?

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• Git in terminal

  - by goodcow

  I tried making my first repo on github. I copy pasted their code while on the directory of my entire system (I think that was a mistake). As a result, the terminal line always says ~ git:(master) ? before every command. It does not go away even when I quit terminal. I am using zsh. The code I pasted was: touch README.md git init git add README.md git commit -m "first commit" git remote add origin https://github.com/***/***.git git push -u origin master On top of that, I can't even seem to figure out how to add my files to the repo. Help on how to not always have git:(master) before every bash command and how to make a repo? Thanks!

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• Difference in displaying inner div between IE and Chrome

  - by Gaara

  I have this code that has one "outerDIV" that contains an "innerDIV". On chrome the "innerDIV" size is 491px, whereas on IE it is 425px (same as outerDIV). Hence, on Chrome I can see the first two children of "innerdiv": "My test string #1" and "test2". But for IE I can only see the first child. I am not quite sure what the "right" behavior should be, as firefox does the same as IE. However I would like to have IE do the same as Chrome. I have been experimenting with some css styles (mainly overflow and display), but still can't make it right: IE will expand its height instead of its width to make the elements fit. Can you guys help me figure out a way to change the css so that IE will wraps the div elements inline? As a restriction though, I cannot change the width on the HTML. As a benefit, I am using a css that only loads for IE to patch these kind of IE inconsistencies. The same css will NOT load for chrome, so I don't need to worry about messing with chrome when changing the IE CSS. Thanks in advance! <html> <head> <style type="text/css"> <!-- body { font-family: helvetica; } .myContainer { overflow: hidden; border: 1px solid rgba(0, 0, 0, .5); font-size: 14pt; height: 49px; line-height: 49px; overflow: hidden; display: block; } .myContainer > DIV { float: left; white-space: nowrap; display: block; } .myContainer .item:first-child { padding-left: 10px; } .myContainer .item { float: left; padding-right: 32px; } --> </style> </head> <body> <div id="outerDIV" class="myContainer" style="display: block; width: 425px;"> <div id="innerDIV"> <div class="item"> --------My test string #1-------- </div> <div class="item"> ------test2------- </div> <div class="item"> test </div> </div> </div> </body> </html>

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• Python/Numpy - Save Array with Column AND Row Titles

  - by Scott B

  I want to save a 2D array to a CSV file with row and column "header" information (like a table). I know that I could use the header argument to numpy.savetxt to save the column names, but is there any easy way to also include some other array (or list) as the first column of data (like row titles)? Below is an example of how I currently do it. Is there a better way to include those row titles, perhaps some trick with savetxt I'm unaware of? import csv import numpy as np data = np.arange(12).reshape(3,4) # Add a '' for the first column because the row titles go there... cols = ['', 'col1', 'col2', 'col3', 'col4'] rows = ['row1', 'row2', 'row3'] with open('test.csv', 'wb') as f: writer = csv.writer(f) writer.writerow(cols) for row_title, data_row in zip(rows, data): writer.writerow([row_title] + data_row.tolist())

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• MySQL Join Comma Separated Field

  - by neeraj

  I have two tables. First Table is a batch table that contain comma separated student id in field "batch" batch -------------- id batch -------------- 1 1,2 2 3,4 Second Table is marks marks ---------------------- id studentid subject marks 1 1 English 50 2 2 English 40 3 3 English 70 4 1 Math 65 5 4 English 66 6 5 English 75 7 2 Math 55 How we can find those students of first batch id =1 who have scored more than 45 marks in English without using sub query. Problem i found to get this done using a single query is that we can not use IN as an association operator in JOIN statement What changes are required in below query to make it work? SELECT * FROM batch INNER JOIN marks ON marks.studentid IN(batch.batch) where batch.id = 1

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• Reusing an anonymous parameter in a prepared statement

  - by Chris Lieb

  I am customizing the insert SQL generated by hibernate and have hit an issue. When Hibernate generates the query by itself, it inserts data into the first two columns of the table, but this causes a database error since all four columns of the table are non-nullable. For the insert to be performed properly, it must insert the same data into two columns of the new record. This means that I need Hibernate to bind the same data to two different parameters in the query (prepared statement) that I am writing. Is there some SQL syntax that allows me to refer to anonymous parameters bound to a prepared statement in an order different from which they are bound? Details REF_USER_PAGE_XREF ---------------------------------------- PK FK1 | NETWORK_ID | VARCHAR2(100) PK FK1 | PAGE_PATH | VARCHAR2(1000) | USER_LAST_UPDT | VARCHAR2(100) | TMSP_LAST_UPDT | DATE insert into REF_USER_ROLE_XREF( NETWORK_ID, PAGE_PATH, TMSP_LAST_UPDT, USER_LAST_UPDT) values ( ?, /* want to insert the same data here */ ?, ?, /* and here */ (select to_char(sysdate, 'DD-MON-YY') from dual) I want to insert the same data into the first and third anonymous parameters.

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• iPhone - NSURLConnection does not receive data

  - by Jukurrpa

  Hi, I have a pretty weird problem with NSURLRequest. I'm using them to make an asynchronous image loading in an UITableView. The first time the tableView displays, all connections from NSURLRequests open correctly but receive absolutely no data, regardless of how long I wait. But as soon as I scroll down in the tableView, the newly created requests for the new cells work perfectly! The only way for the images on top of the tableView to load is to make them disappear by scrolling down and then up again, in order to create new requests. Here is what I do in "cellForRowAtIndexPath": UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"]; if (cell == nil) { cell = [[UITableViewCell alloc] initWIthFrame:CGRectMake(0, 0, 300, 60)]; AsyncUIImageView imageView = [[AsynUIImageView alloc] initWithFrame:CGRectMake(0, 0, 60, 60)]; imageView.tag = IMG_VIEW // an enum for tags [cell addSubView:imageView]; [imageView release]; } AsyncUIImageView imageView = (AsyncUIImageView*)[cell viewWithTag:IMG_VIEW]; // I do a few cache checks here, but if the image aint cached I do this: [imageView loadImageFromURL:@"http://someurl.com/somepix.jpg"]; // all urls are different, just an example The AsyncUIImageView inherits from UIImageView and contains an NSURLConnection which opens upon calling the loadImageFromURL method: (void) loadImageFromURL:(NSString*)filename { if (self.connection != nil) [self.connection release]; if (self.data != nil) [self.data release]; NSURLRequest* request = [NSURLRequest requestWithURL:[[NSURL alloc] initWithString:fileName] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0]; self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; if (self.connection == nil) return; self.data = [[NSMutableData data] retain]; } I've created the delegate methods "connection: didReceiveData", which appends received data to self.data and "connectionDidFinishLoading" which sets the image and closes the connection once the transfer is complete. These work, but are never called for the first requests I create. I suspect this bug to come from the main thread not giving the first requests the control so they can execute themselves, as the same behavior happens if I keep my finger on the screen after a scroll: connections open themselves, but no data is received until I stop touching the screen. What am I doing wrong?

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• How to post on Facebook with Android using the latest SDK

  - by user645402

  All the samples I have seen so far seem to be using an earlier version of the SDK and the parameters and calls don't match. Using the latest SDK, I'm trying this: String access_token = facebook.getAccessToken(); Bundle bundle = new Bundle(); bundle.putString("access_token", access_token); bundle.putString("app_id", FACEBOOK_APP_ID); bundle.putString("message", "My First Post"); bundle.putString("description", "My First Description"); asyncrunner.request("me/feed", bundle, new RequestListener() { And i get back a call to onComplete() with response = "{"data":[]}. And nothing ever gets posted to my wall on FB. Perhaps I'm not waiting long enough? How long should I need to wait before it shows up?

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• Hi i am creating a php calendar i have a Problem in that

  - by udaya

  Hi i am creating a calendar i which i filled the year and date like this <<<<< Year <<<<< month by clicking on the arrow marks the year and month can be increased and decreased now i have to fill the dates for the year and month selected I calculated the first day of month and last date of the month The dates must be start filling from the first day Say if the first day is thursday the date 1 must be on thursday and the next days must follow that till the last date These are my functions in my controller " function phpcal() { $month=04; $day=01; $year=2010; echo date("D", mktime(0,0,0,$month,$day,$year)); //here i am calculating the first day of the month echo '<br>lastdate'.date("t", strtotime($year . "-" . $month . "-01"));'' here i am calculating the lasdt date of the month //echo '<br>'.$date_end = $this->lastOfMonth(); $this->load->view('phpcal'); } function firstOfMonth($m1,$y1) { return date("m/d/Y", strtotime($m1.'/01/'.$y1.' 00:00:00')); } function lastOfMonth() { return date("m/d/Y", strtotime('-1 second',strtotime('+1 month',strtotime(date('m').'/01/'.date('Y').' 00:00:00')))); } function phpcalview() { $year = $this->input->post('yearvv'); $data['year'] = $this->adminmodel->selectyear(); $data['date'] = $this->adminmodel->selectmonth(); //print_r($data['date'] ); $this->load->view('phpcal',$data); } This is my view page <table cellpadding="2" cellspacing="0" border="1" bgcolor="#CCFFCC" align="center" class="table_Style_Border"> <? if(isset($date)) { foreach($date as $row) {?> <tr> <td><?= $row['dbDate1'];?></td> <td><?= $row['dbDate2'];?></td> <td><?= $row['dbDate3'];?></td> <td><?= $row['dbDate4'];?></td> <td><?= $row['dbDate5'];?></td> <td><?= $row['dbDate6'];?></td> <td><?= $row['dbDate7'];?></td> </tr> <tr bgcolor="#FFFFFF"> <td><?= $row['dbDate8'];?></td> <td><?= $row['dbDate9'];?></td> <td><?= $row['dbDate10'];?></td> <td><?= $row['dbDate11'];?></td> <td><?= $row['dbDate12'];?></td> <td><?= $row['dbDate13'];?></td> <td><?= $row['dbDate14'];?></td> </tr> <tr> <td><?= $row['dbDate15'];?></td> <td><?= $row['dbDate16'];?></td> <td><?= $row['dbDate17'];?></td> <td><?= $row['dbDate18'];?></td> <td><?= $row['dbDate19'];?></td> <td><?= $row['dbDate20'];?></td> <td><?= $row['dbDate21'];?></td> </tr> <tr bgcolor="#FFFFFF"> <td><?= $row['dbDate22'];?></td> <td><?= $row['dbDate23'];?></td> <td><?= $row['dbDate24'];?></td> <td><?= $row['dbDate25'];?></td> <td><?= $row['dbDate26'];?></td> <td><?= $row['dbDate27'];?></td> <td><?= $row['dbDate28'];?></td> </tr> <tr> <td><?= $row['dbDate29'];?></td> <td><?= $row['dbDate30'];?></td> <td><?= $row['dbDate31'];?></td> <td><?= $row['dbDate1'];?></td> <td><?= $row['dbDate1'];?></td> <td><?= $row['dbDate1'];?></td> <td><?= $row['dbDate1'];?></td> </tr> </tr> <? }} ?> </table> How can i insert the dates starting from the day i have calculated in the function phpcal

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• Why does casting to double using "String * 1" fail? Will CDbl(String) work on all systems?

  - by Jamie Bull

  I have an application which contains the line below to assign a parsed XML value to a variant array. V(2) = latNode.Text * 1 This works fine on my system (Windows 7, Excel 2010) but doesn't work on some other system or systems - and I've not been able to get a response from the user who reported the problem. I've switched out the offending line for: V(2) = CDbl(latNode.Text) This still works on my system, but then I had no problem in the first place. The question is on what systems does the first approach fail and why, and will the second method always work? I'm sure I've used the "Stying * 1" trick elsewhere before and would like to know how concerned I should be about tracking down other occurrences. Thanks.

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• Clicking Elements in Android Doesn't Display the Correct Values

  - by Devin

  I apologize if this code looks a bit like a mess (considering the length); I figured I'd just include everything that goes on in my program at the moment. I'm attempting to create a fairly simple Tic Tac Toe app for Android. I've set up my UI nicely so far so that there are a "grid" of TextViews. As a sort of "debug" right now, I have it so that when one clicks on a TextView, it should display the value of buttonId in a message box. Right now, it displays the correct assigned value for the first element I click, but no matter what I click afterwards, it always just displays the first value buttonID had. I attempted to debug it but couldn't exactly find a point where it would pull the old value (to the best of my knowledge, it reassigned the value). There's a good possibility I'm missing something small, because this is my first Android project (of any note). Can someone help get different values of buttonId to appear or point out the error in my logic? The code: package com.TicTacToe.app; import com.TicTacToe.app.R; //Other import statements public class TicTacToe extends Activity { public String player = "X"; public int ALERT_ID; public int buttonId; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //Sets up instances of UI elements final TextView playerText = (TextView)findViewById(R.id.CurrentPlayerDisp); final Button button = (Button) findViewById(R.id.SetPlayer); final TextView location1 = (TextView)findViewById(R.id.location1); final TextView location2 = (TextView)findViewById(R.id.location2); final TextView location3 = (TextView)findViewById(R.id.location3); final TextView location4 = (TextView)findViewById(R.id.location4); final TextView location5 = (TextView)findViewById(R.id.location5); final TextView location6 = (TextView)findViewById(R.id.location6); final TextView location7 = (TextView)findViewById(R.id.location7); final TextView location8 = (TextView)findViewById(R.id.location8); final TextView location9 = (TextView)findViewById(R.id.location9); playerText.setText(player); //Handlers for events button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // Perform action on click if (player.equals("X")){ player = "O"; playerText.setText(player); } else if(player.equals("O")){ player = "X"; playerText.setText(player); } //Sets up the dialog buttonId = 0; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 1; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 2; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location3.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 3; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location4.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 4; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location5.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 5; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location6.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 6; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location7.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 7; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location8.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 8; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); location9.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Sets up the dialog buttonId = 9; ALERT_ID = 0; onCreateDialog(ALERT_ID); showDialog(ALERT_ID); } }); } protected Dialog onCreateDialog(int id){ String msgString = "You are on spot " + buttonId; AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage(msgString) .setCancelable(false) .setNeutralButton("Ok", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { dialog.cancel(); } }); AlertDialog alert = builder.create(); return alert; } }

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• Silverlight caching HTTP POST which results in a 404

  - by Steav

  Situation: I am developing a Silverlight-Application which needs Component based on a local HTTP Listener. The HTTP-Listener can't be 'required' to be installed and running when the Application starts, so the Application does the following: Handshake via HTTP POST If Connection failed open a Click-Once Setup to install the component. So far so good.... now the Problem is: If the HTTP POST for the Handshake fails, because the Listener is not running the POST is cached.... and the following Connection Attempts after the Service is running fail, because the HTTP POST is still in Cache after the first try. NOTE: This is NOT a policy-problem. I'm using SL4 PS: I allready tried adding a random parameter to the URL like First try: Second try: didn't work :-(

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• Which workaround to use for the following SQL deadlock?

  - by Marko

  I found a SQL deadlock scenario in my application during concurrency. I belive that the two statements that cause the deadlock are (note - I'm using LINQ2SQL and DataContext.ExecuteCommand(), that's where this.studioId.ToString() comes into play): exec sp_executesql N'INSERT INTO HQ.dbo.SynchronizingRows ([StudioId], [UpdatedRowId]) SELECT @p0, [t0].[Id] FROM [dbo].[UpdatedRows] AS [t0] WHERE NOT (EXISTS( SELECT NULL AS [EMPTY] FROM [dbo].[ReceivedUpdatedRows] AS [t1] WHERE ([t1].[StudioId] = @p0) AND ([t1].[UpdatedRowId] = [t0].[Id]) ))',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; and exec sp_executesql N'INSERT INTO HQ.dbo.ReceivedUpdatedRows ([UpdatedRowId], [StudioId], [ReceiveDateTime]) SELECT [t0].[UpdatedRowId], @p0, GETDATE() FROM [dbo].[SynchronizingRows] AS [t0] WHERE ([t0].[StudioId] = @p0)',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; The basic logic of my (client-server) application is this: Every time someone inserts or updates a row on the server side, I also insert a row into the table UpdatedRows, specifying the RowId of the modified row. When a client tries to synchronize data, it first copies all of the rows in the UpdatedRows table, that don't contain a reference row for the specific client in the table ReceivedUpdatedRows, to the table SynchronizingRows (the first statement taking part in the deadlock). Afterwards, during the synchronization I look for modified rows via lookup of the SynchronizingRows table. This step is required, otherwise if someone inserts new rows or modifies rows on the server side during synchronization I will miss them and won't get them during the next synchronization (explanation scenario to long to write here...). Once synchronization is complete, I insert rows to the ReceivedUpdatedRows table specifying that this client has received the UpdatedRows contained in the SynchronizingRows table (the second statement taking part in the deadlock). Finally I delete all rows from the SynchronizingRows table that belong to the current client. The way I see it, the deadlock is occuring on tables SynchronizingRows (abbreviation SR) and ReceivedUpdatedRows (abbreviation RUR) during steps 2 and 3 (one client is in step 2 and is inserting into SR and selecting from RUR; while another client is in step 3 inserting into RUR and selecting from SR). I googled a bit about SQL deadlocks and came to a conclusion that I have three options. Inorder to make a decision I need more input about each option/workaround: Workaround 1: The first advice given on the web about SQL deadlocks - restructure tables/queries so that deadlocks don't happen in the first place. Only problem with this is that with my IQ I don't see a way to do the synchronization logic any differently. If someone wishes to dwelve deeper into my current synchronization logic, how and why it is set up the way it is, I'll post a link for the explanation. Perhaps, with the help of someone smarter than me, it's possible to create a logic that is deadlock free. Workaround 2: The second most common advice seems to be the use of WITH(NOLOCK) hint. The problem with this is that NOLOCK might miss or duplicate some rows. Duplication is not a problem, but missing rows is catastrophic! Another option is the WITH(READPAST) hint. On the face of it, this seems to be a perfect solution. I really don't care about rows that other clients are inserting/modifying, because each row belongs only to a specific client, so I may very well skip locked rows. But the MSDN documentaion makes me a bit worried - "When READPAST is specified, both row-level and page-level locks are skipped". As I said, row-level locks would not be a problem, but page-level locks may very well be, since a page might contain rows that belong to multiple clients (including the current one). While there are lots of blog posts specifically mentioning that NOLOCK might miss rows, there seems to be none about READPAST (never) missing rows. This makes me skeptical and nervous to implement it, since there is no easy way to test it (implementing would be a piece of cake, just pop WITH(READPAST) into both statements SELECT clause and job done). Can someone confirm whether the READPAST hint can miss rows? Workaround 3: The final option is to use ALLOW_SNAPSHOT_ISOLATION and READ_COMMITED_SNAPSHOT. This would seem to be the only option to work 100% - at least I can't find any information that would contradict with it. But it is a little bit trickier to setup (I don't care much about the performance hit), because I'm using LINQ. Off the top of my head I probably need to manually open a SQL connection and pass it to the LINQ2SQL DataContext, etc... I haven't looked into the specifics very deeply. Mostly I would prefer option 2 if somone could only reassure me that READPAST will never miss rows concerning the current client (as I said before, each client has and only ever deals with it's own set of rows). Otherwise I'll likely have to implement option 3, since option 1 is probably impossible... I'll post the table definitions for the three tables as well, just in case: CREATE TABLE [dbo].[UpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY CLUSTERED, [RowId] [uniqueidentifier] NOT NULL, [UpdateDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX IX_RowId ON dbo.UpdatedRows ([RowId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[ReceivedUpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY NONCLUSTERED, [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]), [StudioId] [uniqueidentifier] NOT NULL REFERENCES, [ReceiveDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE CLUSTERED INDEX IX_Studios ON dbo.ReceivedUpdatedRows ([StudioId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[SynchronizingRows]( [StudioId] [uniqueidentifier] NOT NULL [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]) PRIMARY KEY CLUSTERED ([StudioId], [UpdatedRowId]) ) ON [PRIMARY] GO PS! Studio = Client. PS2! I just noticed that the index definitions have ALLOW_PAGE_LOCK=ON. If I would turn it off, would that make any difference to READPAST? Are there any negative downsides for turning it off?

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• Getting a "summary" of a webpage

  - by MattiasK

  I have something of a a hairy problem, I'd like to generate a couple of paragraphs of "description" of a given url, normally the start of an article. The Meta description field is one way to go but it isn't always good or set properly. It's fair to say it's a bit problematic to accomplish this from the screenscraped HTML. I had a general idea that perhaps one could scan the HTML for the first "appropriate" segment but it's hard to say what that is, perhaps something like the first paragraph containing a certain amount of text... Anyone have any good ideas? :) It doesn't have to be foolproof

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• PHP Get images from a UL list

  - by benjamin shrimpton

  I have a long UL list and each LI contains an image tag, dynamically generated from SLideshowPro Director. I need to get the widths of ALL the images inside the UL to use in a CSS width calculation. I have been able to get the image width for the first item, but not all. My PHP is pretty limited, but do I have to make this list into an ARRAY first to allow me to get all the widths? And how do i do that?? These images contain very long id's generated by the CMS, so reading through a directory is not possible, as the images in cache bare not relation to the file names that are output to the HTML page. It has to all be done from the content that's sent to the page. Or could I even use JQuery to do this??

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• jquery find child

  - by Sir Lojik

  hi all, ive got a jquery DOM traversing problem... i would like to get the first div (child) of li with id='wpc_pics2840' from the markup below. ie <div class="ui-btn-inner"> <li id="wpc_pics2840"> <div class="ui-btn-inner"> <div class="ui-btn-text"> <a href="#" class="ui-link-inherit"> <img width="40" height="40" src="http://www.veepiz.com/members/jimmydeantony/media/443_thumb.jpg" class="ui-li-thumb ui-corner-bl"> <div style="font-size:9pt;font-weight:normal;">upload a bigger picture....</div> </a> </div><span class="ui-icon ui-icon-arrow-r"></span></div></li> btw, please dont say something like $('.ui-btn-inner')... its got to be the first child div of element with id='wpc_pics2840'

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