Just pass `things.toArray(new Thing[things.size()])`.

The variadic argument is internally interpreted as an array. So you should convert it into an array beforehands. Also in your `doIt` method you should access things-s elements with array indexing.

I am trying to solve [equivalent binary trees](https://tour.golang.org/concurrency/7) exercise on go tour. Here is what I did;

    package main
    
    import &quot;tour/tree&quot;
    import &quot;fmt&quot;
    
    // Walk walks the tree t sending all values
    // from the tree to the channel ch.
    func Walk(t *tree.Tree, ch chan int) {
    	if t.Left != nil {
    		Walk(t.Left, ch)
    	}
    	ch &lt;- t.Value
    	if t.Right != nil {
    		Walk(t.Right, ch)
    	}
    
    }
    
    // Same determines whether the trees
    // t1 and t2 contain the same values.
    func Same(t1, t2 *tree.Tree) bool {
    	ch1 := make(chan int)
    	ch2 := make(chan int)
    	go Walk(t1, ch1)
    	go Walk(t2, ch2)
    	for k := range ch1 {
    		select {
    		case g := &lt;-ch2:
    			if k != g {
    				return false
    			}
    		default:
    			break
    		}
    	}
    	return true
    }
    
    func main() {
    	fmt.Println(Same(tree.New(1), tree.New(1)))
    	fmt.Println(Same(tree.New(1), tree.New(2)))
    }

However, I couldn&#39;t find out how to signal if any no more elements left in trees. I can&#39;t use `close(ch)` on `Walk()` because it makes the channel close before all values are sent (because of recursion.) Can anyone lend me a hand here?

Go Tour Exercise #7: Binary Trees equivalence

I have a django application which has two models like this:

    class MyModel(models.Model):
        name = models.CharField()
        country = models.ForeignKey(&#39;Country&#39;)

    class Country(models.Model):
        code2 = models.CharField(max_length=2, primary_key=True)
        name = models.CharField()


The admin class for `MyModel` looks like this:

    class MyModelAdmin(admin.ModelAdmin):
        list_display = (&#39;name&#39;, &#39;country&#39;,)
        list_filter = (&#39;country&#39;,)
    admin.site.register(models.MyModel, MyModelAdmin)

The `Country` table contains ~250 countries. Only a handful of countries are actually referenced by some `MyModel` instance.

The problem is that the list filter in the django admin **lists ALL countries** in the filter panel. Listing all countries (and not just those that are referenced by an instance) pretty much defeats the purpose of having the list filter in this case.

Is there some to only display the countries referenced by `MyModel` as choices in the list filter? (I use Django 1.3.)

Can I make list_filter in django admin to only show referenced ForeignKeys?

I have a `List&lt;Thing&gt;` and I would like to pass it to a method declared `doIt(final Thing... things)`.  Is there a way to do that?

The code looks *something* like this:

    public doIt(final Thing... things)
    {
        // things get done here
    }

    List&lt;Thing&gt; things = /* initialized with all my things */;

    doIt(things);

That code obviously doesn&#39;t work because `doIt()` takes `Thing` not `List&lt;Thing&gt;`. 

Is there a way to pass in a List as the varargs?

**This is in an Android App, but I don&#39;t see why the solution will not apply to anything Java**

Passing a List in as varargs

I have a <code>List&#x3C;Thing></code> and I would like to pass it to a method declared <code>doIt(final Thing... things)</code>. Is there a way to do that?
The code looks something like this:
<pre><code class="hljs language-scss">public doIt(final Thing... things)
{
 // things get done here
}

List&#x3C;Thing> things = /* initialized with all my things */;

doIt(things);
</code></pre>
That code obviously doesn't work because <code>doIt()</code> takes <code>Thing</code> not <code>List&#x3C;Thing></code>.
Is there a way to pass in a List as the varargs?
This is in an Android App, but I don't see why the solution will not apply to anything Java

Consider:

    int[][] multD = new int[5][];
    multD[0] = new int[10];

Is this how you create a two-dimensional array with 5 rows and 10 columns?

I saw this code online, but the syntax didn&#39;t make sense.


Syntax for creating a two-dimensional array in Java

I&#39;ve just started to develop REST services, but I&#39;ve come across a difficult situation: sending files from my REST service to my client. So far I&#39;ve gotten the hang of how to send simple data types (strings, integers, etc) but sending a file is a different matter since there are so many file formats that I don&#39;t know where I should even begin. My REST service is made on Java and I&#39;m using Jersey, I&#39;m sending all the data using the JSON format.

I&#39;ve read about base64 encoding, some people say it&#39;s a good technique, others say it isn&#39;t because of file size issues. What is the correct way? This is how a simple resource class in my project is looking:

    import java.sql.SQLException;
    import java.util.List;
    
    import javax.ws.rs.GET;
    import javax.ws.rs.Path;
    import javax.ws.rs.Produces;
    import javax.ws.rs.core.Context;
    import javax.ws.rs.core.MediaType;
    import javax.ws.rs.core.Request;
    import javax.ws.rs.core.UriInfo;
    
    import com.mx.ipn.escom.testerRest.dao.TemaDao;
    import com.mx.ipn.escom.testerRest.modelo.Tema;
    
    @Path(&quot;/temas&quot;)
    public class TemaResource {
    		
    	@GET
    	@Produces({MediaType.APPLICATION_JSON})
    	public List&lt;Tema&gt; getTemas() throws SQLException{
    
    		TemaDao temaDao = new TemaDao();		
    		List&lt;Tema&gt; temas=temaDao.getTemas();
    		temaDao.terminarSesion();
    		
    		return temas;
    	}
    }

I&#39;m guessing the code for sending a file would be something like:

    import java.sql.SQLException;
    
    import javax.ws.rs.GET;
    import javax.ws.rs.Path;
    import javax.ws.rs.Produces;
    
    @Path(&quot;/resourceFiles&quot;)
    public class FileResource {
    		
    	@GET
    	@Produces({application/x-octet-stream})
    	public File getFiles() throws SQLException{ //I&#39;m not really sure what kind of data type I should return
    
    		// Code for encoding the file or just send it in a data stream, I really don&#39;t know what should be done here
    		
    		return file;
    	}
    }

What kind of annotations should I use? I&#39;ve seen some people recommend for a `@GET` using `@Produces({application/x-octet-stream})`, is that the correct way? The files I&#39;m sending are specific ones so the client doesn&#39;t need to browse through the files. Can anyone guide me into how am I supposed to send the file? Should I encode it using base64 to send it as a JSON object? or the encoding isn&#39;t necessary to send it as a JSON object? Thanks for any help you may give.

what&#39;s the correct way to send a file from REST web service to client?

I have a string that is built out of three parts. The word I want the string to be (changes), a seperating part (doesn&#39;t change) and the last part which changes. I want to delete the seperating part and the ending part. The seperating part is &quot; - &quot; so what I&#39;m wondering is if theres a way to delete everything after a certaint part of the string.

An example of this scenario would be if I wanted to turn this: &quot;Stack Overflow - A place to ask stuff&quot; into this: &quot;Stack Overflow&quot;. Any help is appreciated!

Delete everything after part of a string

How to make an entire excel row cells bold text using Apache POI?

*E.g:*  
Column headings should be in bold. Instead of applying style for each and every cell of heading row, how can I apply some style to an entire row?

How to apply bold text style for an entire row using Apache POI?

After having a short look at Google I found this [link][1] that describes the difference, yet from a syntax point of view.

When would one be preferred over the other in a programming scenario?


  [1]: http://www.dotnetfunda.com/interview/exam4309-difference-json-arrary-vs-json-object.aspx

Difference between JSONObject and JSONArray

I am trying to understand the `ListView` concept and how it works and I&#39;m trying to create my own adapter which extends `BaseAdapter`. For `ArrayAdapter` for instance, there is the `notifyDataSetChanged()` method which should be called after you&#39;ve updated the array list which holds all your data, in order to refresh the `ListView`. 

But I am creating my own subclass of `BaseAdapter`. That method is not available to me, or is it? How do i implement this method? Basically, what does that method do exactly, maybe I&#39;ll understand then.

In case of the `ArrayAdapter` i&#39;m guessing it looks at what position the `ListView` is currently displaying and it checks if it&#39;s the same one as in the `ArrayList` after it was updated? Or...

It says that the method:

&gt; Notifies the attached observers that the underlying data has been
&gt; changed and any View reflecting the data set should refresh itself.

But how exactly does it refresh itself?

Can someone explain please?

Android. How does notifyDataSetChanged() method and ListViews work?

I have a PopupWindow on my activity, the thing is my PopupWindow still shows even when I&#39;m interacting with my activity (say scrolling on my list).  I can scroll through my list and the PopupWindow is still there.


What I want to achieve is when I&#39;m touching/scrolling/clicking/etc on the screen which is not the PopupWindow, I want to dismiss the PopupWindow.  Just like how a menu works.  If you clicked outside of the menu, the menu will be dismissed.

I&#39;ve tried `setOutsideTouchable(true)` but it won&#39;t dismiss the window.  Thanks.

PopupWindow - Dismiss when clicked outside

I&#39;ve worked for some time with Unity3d and found it&#39;s 2D part with OnGUI() or GUITextures too clumsy. Also, even a smallest game done on Unity3d is at least 10MB download which is just too much for a 2D game. 

So, I&#39;m currently looking for an engine for 2D. I&#39;ve tried Cocos2D but it&#39;s iOS only and I wouldn&#39;t like to rewrite everything into another language for Android (so, e.g. Java port of Cocos2d for Android is not an option). Instead, I want to write the code once and with least hassle deploy it on iOS, Android and possibly Windows Phone 7. I have both Mac and Windows.

Just to be more detailed, here are my requirements to the engine: 

 - must be cross-platform 
 - must be efficient
 - should be C++, Java, C# or Objective C since I&#39;m comfortable with them and *NOT* Flash, Javascript, HTML5 since I am not a web developer
 - must have a large community, tutorials, additional libraries which cover most of the stuff you&#39;d have when developing on iOS or Android directly (in-app billing, facebook etc.) 
 - the final delivered package must be not too large
 - the engine can be free, but I also wouldn&#39;t mind paying a reasonable price 

I&#39;ve found the following engines:

 - [Marmalade][1] (and [IwGame engine][2] on top of it) - C++, found overall very positive reviews of Marmalade but not sure about IwGame. **EDIT (March 2013)**: Looks like Marmalade SDK now includes Cocos2Dx and some in-built IDE which makes it much better (and costs $150 per year for indie dev which is ok with me).
 - [Corona SDK][3] - Lua (efficiency doubtful), also needs internet connection to compile code
 - [Cocos2d-x][4] - C++, received lots of reviews from developers, mostly positive and many think it&#39;s best for 2D
 - [Particle code][5] - Java+Eclipse, found no reviews or comments
 - [Moai][6] - Lua, coudn&#39;t find any reviews/opinions on it
 - [Monkey engine][7] - seems to have too few features
 - [Haxenme][8] - it&#39;s Flash, I&#39;ve never used it and don&#39;t want to
 - use [Unity3d][9] but with 2D packages like 2D Toolkit
 - ports of [SDL][10] to [Android][11] (also [here][12]) and [iOS][13] - doesn&#39;t look to have much support or current development (?)
 - [GLBasic][14] - Basic language, I don&#39;t like it
 - [playN][15] - seems to be early in development (?)
 - [Gamvas][16] - HTML5, doesn&#39;t look like a mature engine to me
 - [Ignifuga][17] - Python, also doesn&#39;t look mature
 - [ORX][18] - not sure if it&#39;s still developed (?)
 - [Construct 2][19] - reminds GameMaker, might be ok for rapid prototypes but definitely not for industry-level games
 - [XNA][20] and then port the game using [ExEn][21] (would need [Mono Touch][22] to port to iOS and [Mono for Android][23] to port to Android) - C#, and is probably more thought for folks coming from Microsoft products like xBox (I come from Android). Also, those Mono tools cost $800 in total for small developers
 - [Impact][24] - JavaScript, uses HTML5. I&#39;m not much into JavaScript (e.g. preferred C# on Unity3d), also not sure about efficiency since it runs in the browser (?)
 - [GameMaker][25] - own scripting language GML and I actually remember this one as a tool for non-programmers. Has it actually grown into a real engine, I mean for serious development?
 - [AppGameKit][26] - C++, yet seems to be still pretty new. Haven&#39;t found any reviews on it
 - use [Cocos2D][27] and Objective C to develop for iOS only and then make an APK for Android out of it using [Stella SDK][28]. Has anyone done this? I&#39;m pretty sure there will be limitations, and how about Google&#39;s in-app billing, AdMob and Facebook integration on Android?
 - [Moscrif][29] - JavaScript, looks like it&#39;s more for former web-developers
 - [Starling][30] - Flash 11, i&#39;m not much into Flash
 - [ND2D][31] - not yet 1.0, does it have many features?

So, I&#39;d be happy if you could comment from your experiences with the engines and suggest which one in the list (or anything else that I&#39;ve missed) is the best for the described requirements. I also may be wrong with my first impressions about some of the engines.

I&#39;m currently thinking of Marmalade+IwGame as the best option but since I don&#39;t have much info about Cocos2d-x and Particle code, I am not really sure about it.

Thank you!


**EDIT (June 2013)**: So far I made 2 cross-platform 2D games and used Unity3D with 2D Toolkit plugin for both. For the game with simple GUI I used a simple self-made GUI system based on Unity&#39;s own. For more complex one (e.g. where GUI elements can overlap) I used the NGUI plugin. Recently 2D Toolkit added some more classes for GUI which is very handy since one had to use 2 different systems for texture atlases when combining NGUI with 2D Toolkit. I&#39;ll definitely try that one in the next 2D game. The main reason for choosing Unity3D for 2D games was that I already was deep into Unity3D both in terms of experience and accumulated code snippets for re-use. Also, I purchased Unity3D pro (with Android Pro and iOS Pro) for 3D games and it made full sense to just pay additional $60 for the 2D Toolkit to get 2D games also covered. I so far don&#39;t regret my decision, it seems to have been optimal for my case. The only thing which gave me headache was adding social features with the Prime31&#39;s plugins (Android &amp; iOS social plugins) but I assume that their bugs are not the fault of Prime31 but of Twitter/Facebook instead, so I probably would see the same bugs on any other engine or plugin.

**EDIT (Jan 2014)**: I guess with Unity 4.3 the answer to my question is pretty obvious now: the Unity&#39;s new sprites system and maybe also 2DToolkit totally beat anything else, especially for people who have (like me) been on Unity for a while and purchased the Pro version with add-ons.

  [1]: http://www.madewithmarmalade.com/marmaladesdk
  [2]: http://www.drmop.com/index.php/iwgame-engine/
  [3]: http://www.coronalabs.com/products/corona-sdk/
  [4]: http://www.cocos2d-x.org/
  [5]: http://www.particlecode.com/features/core-api/
  [6]: http://getmoai.com/products/sdk/
  [7]: http://jmonkeyengine.com/
  [8]: http://www.haxenme.org/
  [9]: http://unity3d.com/
  [10]: http://www.libsdl.org/
  [11]: http://www.anddev.org/sdl_port_for_android_sdk-ndk_16-t9218.html
  [12]: http://forums.libsdl.org/viewtopic.php?t=6471&amp;sid=e8752d0c482fa77a95243b9210c9e33c
  [13]: http://immersedcode.org/2011/4/25/sdl-on-ios/
  [14]: http://www.glbasic.com/
  [15]: http://code.google.com/p/playn/
  [16]: http://gamvas.com/
  [17]: http://ignifuga.org/features/
  [18]: http://orx-project.org/about
  [19]: http://www.scirra.com/construct2/event-editor
  [20]: https://dev.windowsphone.com/en-us/downloadsdk
  [21]: http://andrewrussell.net/exen/
  [22]: http://xamarin.com/monotouch
  [23]: http://xamarin.com/monoforandroid
  [24]: http://impactjs.com/
  [25]: http://www.yoyogames.com/gamemaker/studio
  [26]: http://www.appgamekit.com/
  [27]: http://cocos2d.org/
  [28]: http://www.yeecco.com/stella
  [29]: http://moscrif.com/why-moscrif
  [30]: http://gamua.com/starling/features/
  [31]: http://www.nulldesign.de/

2D cross-platform game engine for Android and iOS?

I have a class that implements `Parcelable` interface:

    class A implements Parcelable {
    
    }

I have another class `B` that contains an `A` object as an instance variable. In the `writeToPacel` inside class `B`, I want to write object `B` to the `Parcel`:

    class B implements Parcelable{

        public void writeToParcel(Parcel dest, int flags) {
    		dest.write ??? 
    	}
    }


How can I write and read it?



Write a sub class of Parcelable to another Parcel

As we know Android coming with various device which having different
Features, Resolution, and Screen-size so while developing an Application which support
multiple (small and big) screen there is an obstacle of size and layout.

This leads to different combinations of *screen sizes, resolutions, and DPIs* and creates quite a challenge when designing and developing for Android devices. While some other Manufacturer (non Android) have different resolutions and DPI, they share the same screen size and the resolutions follow the same aspect ratio. Therefore, an image can be created to fit the non Android devices.

My question is that is there a proper flow or architecture that one should follow to meet the requirement?

![enter image description here][1]

*Remember we do have Tablets of different Size and Resolution.*

I&#39;m aware that [**Android Developer**][2] contains this information but my view is from implementation.

From my knowledge what I understood is that for designing Android graphics even Programmer must know the designing concept.

  [1]: http://i.stack.imgur.com/qemPf.png
  [2]: http://developer.android.com/guide/practices/screens_support.html

Application Skeleton to support multiple screens

How can I convert a list into a space-separated string in Python?

For example, I want to convert this list:

    my_list = [how,are,you]

Into the string `&quot;how are you&quot;` 

The spaces are important. I don&#39;t want to get `howareyou` as I have with my attempt so far of using

    &quot;&quot;.join(my_list)


How do I convert a list into a string with spaces in Python?

I am learning the concept of filters in Python. I am running a simple code like this.

    &gt;&gt;&gt; def f(x): return x % 2 != 0 and x % 3 != 0
    &gt;&gt;&gt; filter(f, range(2, 25))

But instead of getting a list, I am getting some message like this.

    &lt;filter object at 0x00FDC550&gt;

What does this mean? Does it means that my filtered object i.e list to come out is stored at that memory location? How do I get the list which I need?

Calling filter returns &lt;filter object at ... &gt;

I&#39;m trying to build my first responsive layout. I want to display list items in a vertical line, depending on width.

    &lt;div style=&quot;height:800px;&quot;&gt;
        &lt;ul&gt;
           &lt;li&gt;1&lt;/li&gt;
           &lt;li&gt;2&lt;/li&gt;
           &lt;li&gt;3&lt;/li&gt;
           &lt;li&gt;4&lt;/li&gt;
           &lt;li&gt;5&lt;/li&gt;
           &lt;li&gt;6&lt;/li&gt;
           &lt;li&gt;7&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;

&lt;pre&gt;
1   5
2   6
3   7
4
&lt;/pre&gt;

If the browser gets resized, I want it to become

&lt;pre&gt;
1  4  7
2  5
3  6
&lt;/pre&gt;

Can someone help me? I&#39;ve been trying for hours and I can&#39;t get anything. I&#39;ve tried using tables but I can&#39;t do it like that either.

How to display list items as columns?

Is the only difference between sets and lists in Python the fact that you can use the union, intersect, difference, symmetric difference functions to compare two sets? Why can&#39;t these functions simply be applied to lists? In what situations are sets more useful than lists?

What is the difference between sets and lists in Python?

List A:  
     
    1, 2, 3, 4

List B: 

    2, 5



How to check if list A contains any value from list B?

e.g. something like A.contains(a=&gt;a.id = B.id)?

How to check list A contains any value from list B?

I understand this occurs with Java 7 when using varargs with a generic type;

But my question is..

What exactly does Eclipse mean when it says &quot;its use could potentially pollute the heap?&quot;

And 

How does the new `@SafeVarargs` annotation prevent this?

Possible heap pollution via varargs parameter

I&#39;ve recently come across the java `@SafeVarargs` annotation. Googling for what makes a variadic function in Java unsafe left me rather confused (heap poisoning? erased types?), so I&#39;d like to know a few things:

1. What makes a variadic Java function unsafe in the `@SafeVarargs` sense (preferably explained in the form of an in-depth example)?

2. Why is this annotation left to the discretion of the programmer? Isn&#39;t this something the compiler should be able to check?

3. Is there some standard one must adhere to in order to ensure his function is indeed varags safe? If not, what are the best practices to ensure it?

Java SafeVarargs annotation, does a standard or best practice exist?

I&#39;m trying to combine the slice `[1, 2]` and the slice `[3, 4]`. How can I do this in Go?

I tried:

    append([]int{1,2}, []int{3,4})

but got:

    cannot use []int literal (type []int) as type int in append

However, [the documentation](http://golang.org/pkg/builtin/#append) seems to indicate this is possible, what am I missing?

    slice = append(slice, anotherSlice...)


Concatenate two slices in Go

I have a method which takes a variable length string (String...) as parameter. I have a `List&lt;String&gt;` with me. How can I pass this to the method as argument?

How to convert a List to variable argument parameter java

I tried this and get weird behavior from JAVA, can someone explain this for me?

    boolean testNull(String... string) {
        if(string == null) {
            return true;
        } else {
            System.out.println(string.getClass());
            return false;
        }
    }

    boolean callTestNull(String s) {
        return testNull(s);
    }

Then I have test case:

        @Test
        public void test_cases() {
            assertTrue(instance.testNull(null)); // NULL
            assertFalse(instance.testNull()); // NOT NULL
            assertFalse(instance.callTestNull(null)); // NOT NULL
        }

The question is if I call `testNull()` directly with parameter `null`, I will get `true` back, but if call `callTestNull()` with `null`, which calls `testNull()`, it tells me the parameter is not null, but empty array.
 

Content Type	Original Author	Original Content on Stackoverflow
Question	xbakesx	View Question on Stackoverflow
Solution 1 - Java	SLaks	View Answer on Stackoverflow
Solution 2 - Java	zeller	View Answer on Stackoverflow

Passing a List in as varargs

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Can I make list_filter in django admin to only show referenced ForeignKeys?

Go Tour Exercise #7: Binary Trees equivalence

Attributions