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• What's the best way to return different cells depending on position in a UITableView

  - by Robert Conn

  I have a grouped UITableView that has 3 sections and a number of cells in each section that each need to be a different custom cell, with different display requirements. I currently have a large if statement in cellForRowAtIndexPath, with each branch instantiating and returning the appropriate custom cell based on interrogating the indexPath's section and row properties. e.g. if (indexPath.section == 0 && indexPath.row == 0) { // instantiate and return cell A } else if (indexPath.section == 1 && indexPath.row == 2) { // instantiate and return cell B } //etc etc What is best practice for this scenario? A large if statement does the job, but is it the best implementation?

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• Returning and instance of a Class given its .class (MyClass.class)

  - by jax

  I have an enum that will hold my algorithms. I cannot instantiate these classes because I need the application context which is only available once the application has started. I want to load the class at runtime when I choose by calling getAlgorithm(Context cnx). How do I easily instantiate a class at runtime given its .class (and my constructor takes arguments)? All my classes are subclasses of Algorithm. public enum AlgorithmTypes { ALL_FROM_9_AND_LAST_FROM_10_ID(AlgorithmFactory.AlgorithmAllFrom9AndLastFrom10Impl.class), ALL_FROM_9_AND_LAST_FROM_10_CURRENCY_ID(AlgorithmFactory.AlgorithmAllFrom9AndLastFrom10Impl.class), DIVIDE_BY_9_LESS_THAN_100(AlgorithmFactory.AlgorithmAllFrom9AndLastFrom10Impl.class), TABLES_BEYOND_5_BY_5(AlgorithmFactory.AlgorithmAllFrom9AndLastFrom10Impl.class); private Class<? extends Algorithm> algorithm; AlgorithmTypes(Class<? extends Algorithm> c) { algorithm = c; } public Algorithm getAlgorithm(Context cnx) { return //needs to return the current algoriths constructor which takes the Context Algorithm(Context cnx); } }

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• C# class code loaded in RAM ?

  - by Spi1988

  hi, I would like to know whether the actual code of a C# class gets loaded in RAM when you instantiate the class? So for example if I have 2 Classes CLASS A , CLASS B, where class A has 10000 lines of code but just 1 field, an int. And class B has 10 lines of code and also 1 field an int as well. If I instantiate Class A will it take more RAM than Class B due to its lines of code ? A supplementary question, If the lines of code are loaded in memory together with the class, will they be loaded for every instance of the class? or just once for all the instances? Thanks in advance.

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• wpf get access to other classes

  - by Calvin

  I am currently working on a wpf application. There are some methods in other classes in which I want to trigger to do some work instead of trying to figure out how to rewrite them in. How is it that I can get to those classes? Would I have to for example instantiate the class? If so, once I instantiate it, how would I be able access them. Keep in mind that these classes have abstract classes on top of abstract classes.

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• Unity 2D Instantiating a prefab with it's components

  - by TazmanNZL

  I have some block prefabs that I add to an array of game objects: public GameObject[]blocks; Each prefab has a BoxCollider2D, Script & Rigidbody2D components. But when I try to instantiate the prefab in the scene it doesn't appear to have the components attached? Here is how I am instantiating the prefab: for (int i = 0; i < 4; i++) { for (int j = 0; j < gridWidth; j++) { blockClone = Instantiate (blocks [Random.Range (0, blocks.Length)] as GameObject, new Vector3 (j, -i-2, 0f), transform.rotation) as GameObject; } } What am I doing wrong?

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• Pass variable number of variables to a class in PHP

  - by user325282

  I need to pass a variable number of strings to instantiate different classes. I can always do a switch on the size of the array: switch(count($a)) { case 1: new Class(${$a[0]}); break; case 2: new Class(${$a[0]}, ${$a[1]}); break; etc... There has to be a better way to do this. If I have an array of strings ("variable1", "variable2", 'variable3", ...), how can I instantiate a Class without manually accounting for every possibility?

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• using ‘using’ and scope. Not try finally!

  - by Edward Boyle

  An object that implements IDisposable has, you guessed it, a Dispose() method. In the code you write you should both declare and instantiate any object that implements IDisposable with the using statement. The using statement allows you to set the scope of an object and when your code exits that scope, the object will be disposed of. Note that when an exception occurs, this will pull your code out of scope, so it still forces a Dispose() using (mObject o = new mObject()) { // do stuff } //<- out of Scope, object is disposed. // Note that you can also use multiple objects using // the using statement if of the same type: using (mObject o = new mObject(), o2 = new mObject(), o3 = new mObject()) { // do stuff } //<- out of Scope, objects are disposed. What about try{ }finally{}? It is not needed when you use the using statement. Additionally, using is preferred, Microsoft’s own documents put it this way: As a rule, when you use an IDisposable object, you should declare and instantiate it in a using statement. When I started out in .NET I had a very bad habit of not using the using statement. As a result I ran into what many developers do: #region BAD CODE - DO NOT DO try { mObject o = new mObject(); //do stuff } finally { o.Dispose(); // error - o is out of scope, no such object. } // and here is what I find on blogs all over the place as a solution // pox upon them for creating bad habits. mObject o = new mObject(); try { //do stuff } finally { o.Dispose(); } #endregion So when should I use the using statement? Very simple rule, if an object implements IDisposable, use it. This of course does not apply if the object is going to be used as a global object outside of a method. If that is the case, don’t forget to dispose of the object in code somewhere. It should be made clear that using the try{}finally{} code block is not going to break your code, nor cause memory leaks. It is perfectly acceptable coding practice, just not best coding practice in C#. This is how VB.NET developers must code, as there is no using equivalent for them to use.

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• Need to make animation whereby the character shatters into a bunch of pieces

  - by theprojectabot

  I would like to take a 3d character model, cut out a bunch of shapes (or a bunch of triangles in the shape of the pieces I want) and then have the pieces separate from each other at the beginning of the animation and fall apart with gravity so it looks like the model is falling apart in shattered pieces. Is there a way to run a script on a mesh, cut out these pieces, instantiate all of them as separate models and then run gravity on them during the simulation?

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• What is a good resource for learning how the .Net Framework works? [on hold]

  - by Till Death Developer

  I've been developing web apps, for a while now so i know how to get the job done, what i don't know is how every thing really works, i know some but the rest i can't get a grasp on like how abstract works, what happens when i instantiate an object from a class that inherits from an abstract class?, where things get stored Heap vs Stack?, in other words the Interview questions that i suck at, so any advice would be great, books, videos, online courses, whatever you can provide would really help me.

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• Randomly placing items script not working - sometimes items spawn in walls, sometimes items spawn in weird locations

  - by Timothy Williams

  I'm trying to figure out a way to randomly spawn items throughout my level, however I need to make sure they won't spawn inside another object (walls, etc.) Here's the code I'm currently using, it's based on the Physics.CheckSphere(); function. This runs OnLevelWasLoaded(); It spawns the items perfectly fine, but sometimes items spawn partway in walls. And sometimes items will spawn outside of the SpawnBox range (no clue why it does that.) //This is what randomly generates all the items. void SpawnItems () { if (Application.loadedLevelName == "Menu" || Application.loadedLevelName == "End Demo") return; //The bottom corner of the box we want to spawn items in. Vector3 spawnBoxBot = Vector3.zero; //Top corner. Vector3 spawnBoxTop = Vector3.zero; //If we're in the dungeon, set the box to the dungeon box and tell the items we want to spawn. if (Application.loadedLevelName == "dungeonScene") { spawnBoxBot = new Vector3 (8.857f, 0, 9.06f); spawnBoxTop = new Vector3 (-27.98f, 2.4f, -15); itemSpawn = dungeonSpawn; } //Spawn all the items. for (i = 0; i != itemSpawn.Length; i ++) { spawnedItem = null; //Zeroes out our random location Vector3 randomLocation = Vector3.zero; //Gets the meshfilter of the item we'll be spawning MeshFilter mf = itemSpawn[i].GetComponent<MeshFilter>(); //Gets it's bounds (see how big it is) Bounds bounds = mf.sharedMesh.bounds; //Get it's radius float maxRadius = new Vector3 (bounds.extents.x + 10f, bounds.extents.y + 10f, bounds.extents.z + 10f).magnitude * 5f; //Set which layer is the no walls layer var NoWallsLayer = 1 << LayerMask.NameToLayer("NoWallsLayer"); //Use that layer as your layermask. LayerMask layerMask = ~(1 << NoWallsLayer); //If we're in the dungeon, certain items need to spawn on certain halves. if (Application.loadedLevelName == "dungeonScene") { if (itemSpawn[i].name == "key2" || itemSpawn[i].name == "teddyBearLW" || itemSpawn[i].name == "teddyBearLW_Admiration" || itemSpawn[i].name == "radio") randomLocation = new Vector3(Random.Range(spawnBoxBot.x, -26.96f), Random.Range(spawnBoxBot.y, spawnBoxTop.y), Random.Range(spawnBoxBot.z, -2.141f)); else randomLocation = new Vector3(Random.Range(spawnBoxBot.x, spawnBoxTop.x), Random.Range(spawnBoxBot.y, spawnBoxTop.y), Random.Range(-2.374f, spawnBoxTop.z)); } //Otherwise just spawn them in the box. else randomLocation = new Vector3(Random.Range(spawnBoxBot.x, spawnBoxTop.x), Random.Range(spawnBoxBot.y, spawnBoxTop.y), Random.Range(spawnBoxBot.z, spawnBoxTop.z)); //This is what actually spawns the item. It checks to see if the spot where we want to instantiate it is clear, and if so it instatiates it. Otherwise we have to repeat the whole process again. if (Physics.CheckSphere(randomLocation, maxRadius, layerMask)) spawnedItem = Instantiate(itemSpawn[i], randomLocation, Random.rotation); else i --; //If we spawned something, set it's name to what it's supposed to be. Removes the (clone) addon. if (spawnedItem != null) spawnedItem.name = itemSpawn[i].name; } } What I'm asking for is if you know what's going wrong with this code that it would spawn stuff in walls. Or, if you could provide me with links/code/ideas of a better way to check if an item will spawn in a wall (some other function than Physics.CheckSphere). I've been working on this for a long time, and nothing I try seems to work. Any help is appreciated.

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• Polymorphic NHibernate mappings

  - by Ben Aston

  I have an interface IUserLocation and a concrete type UserLocation. When I use ICriteria, specifying the interface IUserLocation, I want NHibernate to instantiate a collection of the concrete UserLocation type. I have created an HBM mapping file using the table per concrete type strategy (shown below). However, when I query NHibernate using ICriteria I get: NHibernate cannot instantiate abstract class or interface MyNamespace.IUserLocation Can anyone see why this is? (source code for the relevant bit of NHibernate here (I think)) My ICriteria: var filter = DetachedCriteria.For<IUserLocation>() .Add(Restrictions.Eq("UserId", userId)); return filter.GetExecutableCriteria(UoW.Session) .List<IUserLocation>(); My mapping file: <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="true"> <class xmlns="urn:nhibernate-mapping-2.2" name="MyNamespace.IUserLocation,MyAssembly" abstract="true" table="IUserLocations"> <composite-id> <key-property name="UserId" column="UserId" type="System.Guid"></key-property> <key-many-to-one name="Location" column="LocationId" class="MyNamespace.ILocation,MyAssembly"></key-many-to-one> </composite-id> <union-subclass table="UserLocations" name="MyNamespace2.UserLocation,MyAssembly2"> <property name="IsAdmin" /> </union-subclass> </class> </hibernate-mapping>

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• AlertDialog in if-stetement doesn't show()

  - by Steffen Kern

  I have the following code: public void button_login(View view) { // Instantiate an AlertDialog.Builder with its constructor AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { /* User clicked OK button */ } }); // Preserve EditText values. EditText ET_username = (EditText) findViewById(R.id.username); EditText ET_password = (EditText) findViewById(R.id.password); String str_username = ET_username.toString(); String str_password = ET_password.toString(); // Intercept missing username and password. if(str_username.length() == 0) { builder.setMessage(R.string.hint_username_empty); AlertDialog dialog = builder.create(); dialog.show(); } } I have an activity that includes the two EditText-Views and a button. When I click the button the shown method will be called. My problem: The AlertDialog doesnt show up! When I put the create and show at beginning like this: // Instantiate an AlertDialog.Builder with its constructor AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { /* User clicked OK button */ } }); builder.setMessage(R.string.hint_username_empty); AlertDialog dialog = builder.create(); dialog.show(); // Preserve EditText values. EditText ET_username = (EditText) findViewById(R.id.username); EditText ET_password = (EditText) findViewById(R.id.password); String str_username = ET_username.toString(); String str_password = ET_password.toString(); // Intercept missing username and password. if(str_username.length() == 0) { } } Then the Dialog shows up. Any ideas why the dialog doesnt show up in the first place? Greetz, Steffen

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• Command-Line Parsing API from TestAPI library - Type-Safe Commands how to

  - by MicMit

  Library at http://testapi.codeplex.com/ Excerpt of usage from http://blogs.msdn.com/ivo_manolov/archive/2008/12/17/9230331.aspx A third common approach is forming strongly-typed commands from the command-line parameters. This is common for cases when the command-line looks as follows: some-exe COMMAND parameters-to-the-command The parsing in this case is a little bit more involved: Create one class for every supported command, which derives from the Command abstract base class and implements an expected Execute method. Pass an expected command along with the command-line arguments to CommandLineParser.ParseCommand – the method will return a strongly-typed Command instance that can be Execute()-d. // EXAMPLE #3: // Sample for parsing the following command-line: // Test.exe run /runId=10 /verbose // In this particular case we have an actual command on the command-line (“run”), which we want to effectively de-serialize and execute. public class RunCommand : Command { bool? Verbose { get; set; } int? RunId { get; set; } public override void Execute() { // Implement your "run" execution logic here. } } Command c = new RunCommand(); CommandLineParser.ParseArguments(c, args); c.Execute(); ============================ I don't get if we instantiate specific class before parsing arguments , what's the point of command line argument "run" which is very first one. I thought the idea was to instantiate and execute command/class based on a command line parameter ( "run" parameter becomes instance RunCommand class, "walk" becomes WalkCommand class and so on ). Can it be done with the latest version ?

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• Macro access to members of object where macro is defined

  - by Marc Grue

  Say I have a trait Foo that I instantiate with an initial value val foo = new Foo(6) // class Foo(i: Int) and I later call a second method that in turn calls myMacro foo.secondMethod(7) // def secondMethod(j: Int) = macro myMacro then, how can myMacro find out what my initial value of i (6) is? I didn't succeed with normal compilation reflection using c.prefix, c.eval(...) etc but instead found a 2-project solution: Project B: object CompilationB { def resultB(x: Int, y: Int) = macro resultB_impl def resultB_impl(c: Context)(x: c.Expr[Int], y: c.Expr[Int]) = c.universe.reify(x.splice * y.splice) } Project A (depends on project B): trait Foo { val i: Int // Pass through `i` to compilation B: def apply(y: Int) = CompilationB.resultB(i, y) } object CompilationA { def makeFoo(x: Int): Foo = macro makeFoo_impl def makeFoo_impl(c: Context)(x: c.Expr[Int]): c.Expr[Foo] = c.universe.reify(new Foo {val i = x.splice}) } We can create a Foo and set the i value either with normal instantiation or with a macro like makeFoo. The second approach allows us to customize a Foo at compile time in the first compilation and then in the second compilation further customize its response to input (i in this case)! In some way we get "meta-meta" capabilities (or "pataphysic"-capabilities ;-) Normally we would need to have foo in scope to introspect i (with for instance c.eval(...)). But by saving the i value inside the Foo object we can access it anytime and we could instantiate Foo anywhere: object Test extends App { import CompilationA._ // Normal instantiation val foo1 = new Foo {val i = 7} val r1 = foo1(6) // Macro instantiation val foo2 = makeFoo(7) val r2 = foo2(6) // "Curried" invocation val r3 = makeFoo(6)(7) println(s"Result 1 2 3: $r1 $r2 $r3") assert((r1, r2, r3) ==(42, 42, 42)) } My question Can I find i inside my example macros without this double compilation hackery?

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• Error when instantiating .NET/COM interop class via classic ASP

  - by Lee D

  Hi all, I am having a problem when trying to instantiate a C# .NET class that's been exposed to COM in a classic ASP application. I've used tlbexp to generate a typelib and registered it in Component Services; now when trying to create the object as such: Server.CreateObject("The.Class.Name") I am getting the error: Server object error 'ASP 0177 : 80131534' Server.CreateObject Failed I've searched around online for information on this error, and found numerous discussions but no solution. The error code 0x80131534 apparently means "COR_E_TYPEINITIALIZATION, a type failed to initialize", which would suggest the problem would be in the constructor. The constructor of the class in question sets a private field to an instance of another class from the same assembly, and then reads some configuration settings from an XML file. This behaviour is unit tested and I've checked that the file exists; I can't see anything else that could be breaking in there. A few other points which may or may not be of use: A test .NET project referencing the DLL can instantiate the class just fine; however a test VB6 project referencing the TLB blows up with the same error. Both the DLL and the TLB are in the same location. This application is running locally, on Windows XP Professional SP3 and IIS 5.1. The .NET assembly is built with .NET Framework 2.0, although 3.5 is installed on the machine. I know other people who don't get this error on their builds, so I believe it may be something environmental. Any suggestions are welcome as I've been struggling to fix this for some time. Thanks in advance.

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• Hibernate fails with NullPointerException in EntityTuplizerFactory.constructTuplizer? Why?

  - by Subtwo

  I have a problem when I try to instantiate Hibernate and connect with a MySQL database (see error message below). Curiously enough the connection works fine using the exact same hibernate.cfg.xml file when running Junit tests but it refuses to work when run from Tomcat... I am starting to run out of ideas. Any clues or tip where to look? Caused by: org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.DynamicMapEntityTuplizer] at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:110) at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:135) at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.(EntityEntityModeToTuplizerMapping.java:69) at org.hibernate.tuple.entity.EntityMetamodel.(EntityMetamodel.java:323) at org.hibernate.persister.entity.AbstractEntityPersister.(AbstractEntityPersister.java:456) at org.hibernate.persister.entity.SingleTableEntityPersister.(SingleTableEntityPersister.java:131) at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:84) at org.hibernate.impl.SessionFactoryImpl.(SessionFactoryImpl.java:267) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341) at se.fmt.atlantism.util.HibernateUtil.buildSessionFactory(HibernateUtil.java:16) ... 38 more Caused by: java.lang.NullPointerException at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:107) ... 47 more

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• Generic object to object mapping with parametrized constructor

  - by Rody van Sambeek

  I have a data access layer which returns an IDataRecord. I have a WCF service that serves DataContracts (dto's). These DataContracts are initiated by a parametrized constructor containing the IDataRecord as follows: [DataContract] public class DataContractItem { [DataMember] public int ID; [DataMember] public string Title; public DataContractItem(IDataRecord record) { this.ID = Convert.ToInt32(record["ID"]); this.Title = record["title"].ToString(); } } Unfortanately I can't change the DAL, so I'm obliged to work with the IDataRecord as input. But in generat this works very well. The mappings are pretty simple most of the time, sometimes they are a bit more complex, but no rocket science. However, now I'd like to be able to use generics to instantiate the different DataContracts to simplify the WCF service methods. I want to be able to do something like: public T DoSomething<T>(IDataRecord record) { ... return new T(record); } So I'd tried to following solutions: Use a generic typed interface with a constructor. doesn't work: ofcourse we can't define a constructor in an interface Use a static method to instantiate the DataContract and create a typed interface containing this static method. doesn't work: ofcourse we can't define a static method in an interface Use a generic typed interface containing the new() constraint doesn't work: new() constraint cannot contain a parameter (the IDataRecord) Using a factory object to perform the mapping based on the DataContract Type. does work, but: not very clean, because I now have a switch statement with all mappings in one file. I can't find a real clean solution for this. Can somebody shed a light on this for me? The project is too small for any complex mapping techniques and too large for a "switch-based" factory implementation.

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• Shape object in Processing, translate individual shapes.

  - by Zain

  I am relatively new to Processing but have been working in Java for about 2 years now. I am facing difficulty though with the translate() function for objects as well as objects in general in processing. I went through the examples and tried to replicate the manners by which they instantiated the objects but cannot seem to even get the shapes to appear on the screen no less move them. I instantiate the objects into an array using a nested for loop and expect a grid of the objects to be rendered. However, nothing at all is rendered. My nested for loop structure to instantiate the tiles: for(int i=0; i<102; i++){ for(int j=0; j<102; j++){ tiles[i][j]=new tile(i,0,j); tiles[i][j].display(); } } And the constructors for the tile class: tile(int x, int y, int z){ this.x=x; this.y=y; this.z=z; beginShape(); vertex(x,y,z); vertex(x+1,y,z); vertex(x+1,y,z-1); vertex(x,y,z-1); endShape(); } Nothing is rendered at all when this runs. Furthermore, if this is of any concern, my translations(movements) are done in a method I wrote for the tile class called move which simply calls translate. Is this the correct way? How should one approach this? I can't seem to understand at all how to render/create/translate individual objects/shapes. Thanks for any help any of you are able to provide!

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• C# reflection instantiation

  - by NickLarsen

  I am currently trying to create a generic instance factory for which takes an interface as the generic parameter (enforced in the constructor) and then lets you get instantiated objects which implement that interface from all types in all loaded assemblies. The current implementation is as follows:     public class InstantiationFactory     {         protected Type Type { get; set; }         public InstantiationFactory()         {             this.Type = typeof(T);             if (!this.Type.IsInterface)             {                 // is there a more descriptive exception to throw?                 throw new ArgumentException(/* Crafty message */);             }         }         public IEnumerable GetLoadedTypes()         {             // this line of code found in other stack overflow questions             var types = AppDomain.CurrentDomain.GetAssemblies()                 .SelectMany(a = a.GetTypes())                 .Where(/* lambda to identify instantiable types which implement this interface */);             return types;         }         public IEnumerable GetImplementations(IEnumerable types)         {             var implementations = types.Where(/* lambda to identify instantiable types which implement this interface */                 .Select(x = CreateInstance(x));             return implementations;         }         public IEnumerable GetLoadedImplementations()         {             var loadedTypes = GetLoadedTypes();             var implementations = GetImplementations(loadedTypes);             return implementations;         }         private T CreateInstance(Type type)         {             T instance = default(T);             var constructor = type.GetConstructor(Type.EmptyTypes);             if (/* valid to instantiate test */)             {                 object constructed = constructor.Invoke(null);                 instance = (T)constructed;             }             return instance;         }     } It seems useful to me to have my CreateInstance(Type) function implemented as an extension method so I can reuse it later and simplify the code of my factory, but I can't figure out how to return a strongly typed value from that extension method. I realize I could just return an object:     public static class TypeExtensions     {         public object CreateInstance(this Type type)         {             var constructor = type.GetConstructor(Type.EmptyTypes);             return /* valid to instantiate test */ ? constructor.Invoke(null) : null;         }     } Is it possible to have an extension method create a signature per instance of the type it extends? My perfect code would be this, which avoids having to cast the result of the call to CreateInstance():     Type type = typeof(MyParameterlessConstructorImplementingType);     MyParameterlessConstructorImplementingType usable = type.CreateInstance();

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• Correct use of Classloader (especially in Android)

  - by Sebi

  I read some documentations about classloaders, but im still not sure where and why they are needed. The Android API says: Loads classes and resources from a repository. One or more class loaders are installed at runtime. These are consulted whenever the runtime system needs a specific class that is not yet available in-memory. So if i understand this correct, there can be many classlaoders which are responsible for loading new classes. But how the system decides which to use? And in which situation should a developer instantiate a new classloader? In the Android API for Intent there is a method public void setExtrasClassLoader (ClassLoader loader) The description says: Sets the ClassLoader that will be used when unmarshalling any Parcelable values from the extras of this Intent. So can i define there a special classloader so that i can pass object with an Intent which are not defined in the receiving activity? An example: If activity A which is located in Project A (in Eclipse) defines an object which i want to send to Activity B in Project B using putExtra of the Intent object. If this object which is send over the Intent is not defined (source code in project B), then there is a NoClassDefFoundException. So can i use the method setExtraClassloader to avoid this exception? If yes, how can i decide which classloader object i have to pass? And how do I instantiate it correctly?

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• Ninject giving NullReferenceException

  - by Iceman

  I'm using asp.net MVC 2 and Ninject 2. The setup is very simple. Controller calls service that calls repository. In my controller I use inject to instantiate the service classes with no problem. But the service classes don't instantiate the repositories, giving me NullReferenceException. public class BaseController : Controller { [Inject] public IRoundService roundService { get; set; } } This works. But then this does not... public class BaseService { [Inject] public IRoundRepository roundRepository { get; set; } } Giving a NullReferenceException, when I try to use the roundRepository in my RoundService class. IList<Round> rounds = roundRepository.GetRounds( ); Module classes... public class ServiceModule : NinjectModule { public override void Load( ) { Bind( ).To( ).InRequestScope( ); } } public class RepositoryModule : NinjectModule { public override void Load( ) { Bind<IRoundRepository>( ).To<RoundRepository>( ).InRequestScope( ); } } In global.axax.cs protected override IKernel CreateKernel( ) { return new StandardKernel( new ServiceModule( ), new RepositoryModule( ) ); }

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• Dynamically overriding an abstract method in c#

  - by ng

  I have the following abstract class public abstract class AbstractThing { public String GetDescription() { return "This is " + GetName(); } public abstract String GetName(); } Now I would like to implement some new dynamic types from this like so. AssemblyName assemblyName = new AssemblyName(); assemblyName.Name = "My.TempAssembly"; AssemblyBuilder assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run); ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("DynamicThings"); TypeBuilder typeBuilder = moduleBuilder.DefineType(someName + "_Thing", TypeAttributes.Public | TypeAttributes.Class, typeof(AbstractThing)); MethodBuilder methodBuilder = typeBuilder.DefineMethod("GetName", MethodAttributes.Public | MethodAttributes.ReuseSlot | MethodAttributes.Virtual | MethodAttributes.HideBySig, null, Type.EmptyTypes); ILGenerator msil = methodBuilder.GetILGenerator(); msil.EmitWriteLine(selectionList); msil.Emit(OpCodes.Ret); However when I try to instantiate via typeBuilder.CreateType(); I get an exception saying that there is no implementation for GetName. Is there something I am doing wrong here. I can not see the problem. Also, what would be the restrictions on instantiating such a class by name? For instance if I tried to instantiate via "My.TempAssembly.x_Thing" would it be availble for instantiation without the Type generated?

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• Passing variables to a Custom Zend Form Element

  - by user322003

  Hi, I'm trying to create a custom form element which extends Zend_Form_Element_Text with a validator (so I don't have to keep setting up the validator when I use certain elements). Anyway, I'm having trouble passing $maxChars variable to it when I instantiate it in my Main form. I've provided my shortened code below This is my custom element below class My_Form_Custom_Element extends Zend_Form_Element_Text { public $maxChars public function init() { $this->addValidator('StringLength', true, array(0, $this->maxChars)) } public function setProperties($maxChars) { $this->maxChars= $maxChars; } } This is where I instantiate my custom form element. class My_Form_Abc extends Zend_Form { public function __construct($options = null) { parent::__construct($options); $this->setName('abc'); $customElement = new My_Form_Custom_Element('myCustomElement'); $customElement->setProperties(100); //**<----This is where i set the $maxChars** $submit = new Zend_Form_Element_Submit('submit'); $submit -> setAttrib('id', 'submitbutton'); $this->addElements(array($customElement ,$submit)); } } When I try to pass '100' using $customElement-setProperties(100) in my Form, it doesnt get passed properly to my StringLength validator. I assume it's because the validator is getting called in Init? How can I fix this?

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• OOP - Handling Automated Instances of a Class - PHP

  - by dscher

  This is a topic that, as a beginner to PHP and programming, sort of perplexes me. I'm building a stockmarket website and want users to add their own stocks. I can clearly see the benefit of having each stock be a class instance with all the methods of a class. What I am stumped on is the best way to give that instance a name when I instantiate it. If I have: class Stock() { ....doing stuff..... } what is the best way to give my instances of it a name. Obviously I can write: $newStock = new Stock(); $newStock.getPrice(); or whatever, but if a user adds a stock via the app, where can the name of that instance come from? I guess that there is little harm in always creating a new child with $newStock = new Stock() and then storing that to the DB which leads me to my next question! What would be the best way to retrieve 20 user stocks(for example) into instances of class Stock()? Do I need to instantiate 20 new instances of class Stock() every time the user logs in or is there something I'm missing? I hope someone answers this and more important hope a bunch of people answer this and it somehow helps someone else who is having a hard time wrapping their head around what probably leads to a really elegant solution. Thanks guys!

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• Drawbacks with using Class Methods in Objective C.

  - by RickiG

  Hi I was wondering if there are any memory/performance drawbacks, or just drawbacks in general, with using Class Methods like: + (void)myClassMethod:(NSString *)param { // much to be done... } or + (NSArray*)myClassMethod:(NSString *)param { // much to be done... return [NSArray autorelease]; } It is convenient placing a lot of functionality in Class Methods, especially in an environment where I have to deal with memory management(iPhone), but there is usually a catch when something is convenient? An example could be a thought up Web Service that consisted of a lot of classes with very simple functionality. i.e. TomorrowsXMLResults; TodaysXMLResults; YesterdaysXMLResults; MondaysXMLResults; TuesdaysXMLResults; . . . n I collect a ton of these in my Web Service Class and just instantiate the web service class and let methods on this class call Class Methods on the 'Results' Classes. The classes are simple but they handle large amount of Xml, instantiate lots of objects etc. I guess I am asking if Class Methods lives or are treated different on the stack and in memory than messages to instantiated objects? Or are they just instantiated and pulled down again behind the scenes and thus, just a way of saving a few lines of code?

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