In [android.util.DisplayMetrics][1], you can see that scaling factor is **0.00625**:


    /**
     * Scaling factor to convert a density in DPI units to the density scale.
     * @hide
     */
    public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT;

Where as [DENSITY_DEFAULT][2] is 160 --&gt; scaling factor = 1.0f / 160 = 0.00625.

    sizeScale = DENSITY_DEFAULT_SCALE * DENSITY_DPI

From this:

 * **ldpi** = 0.00625 * [120][3] -&gt; **0.75**
 * **mdpi** = 0.00625 * [160][4] -&gt; **1.0**
 * **hdpi** = 0.00625 * [240][5] -&gt; **1.5**
 * **xhdpi** = 0.00625 * [320][6] -&gt; **2.0**
 * **xxhdpi** = 0.00625 * [480][7] -&gt; **3.0**
 * **xxxhdpi** = 0.00625 * [640][8] -&gt; **4.0**

Not exactly a rocket science, but hope this will be useful for someone :)


  [1]: https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/util/DisplayMetrics.java
  [2]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_DEFAULT
  [3]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_LOW
  [4]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_MEDIUM
  [5]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_HIGH
  [6]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_XHIGH
  [7]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_XXHIGH
  [8]: http://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_XXXHIGH

If you look at [Metrics and Grids][1] you&#39;ll see that xxhdpi is 480 dpi which is 3 times that of the baseline (mdpi @ 1.0). In other words the scale factor for xxhdpi is 3.0

  [1]: http://developer.android.com/design/style/metrics-grids.html

How to build a url with query parameters in Angularjs.

I see the API [$location.search()][1]

the problem is $location(url) is to redirect to the url. In my case, I want to pass a url and key:value pairs for the query params and build the url. something like

url: `/a/b/c`
params: `{field1: value1, field2: value2}`

result: `/a/b/c?field1=value1&amp;field2=value2`

I like to use this url for links. I have also seen angular encode `?` , `&amp;` characters. Can I avoid this?

Edit:
--
My intention was to use the url as href for anchor elements. I do use $http to send the request, but sometimes I need to provide a link, with query params (based on the current object) 

Thanks

  [1]: http://docs.angularjs.org/api/ng.$location

Build query string from parameters object

I have been searching for a performance benchmarking between `Contains`, `Exists` and `Any` methods available in the `List&lt;T&gt;`. I wanted to find this out just out of curiosity as I was always confused among these. Many questions on SO described definitions of these methods such as: 

 1. [LINQ Ring: Any() vs Contains() for Huge Collections][1]
 2. [Linq .Any VS .Exists - Whats the difference?][2]
 3. [LINQ extension methods - Any() vs. Where() vs. Exists()][3]

So I decided to do it myself. I am adding it as an answer. Any more insight on the results is most welcomed. I also did this benchmarking for arrays to see the results


  [1]: https://stackoverflow.com/questions/4445219/linq-ring-any-vs-contains-for-huge-collections
  [2]: https://stackoverflow.com/questions/879391/linq-any-vs-exists-whats-the-difference?rq=1
  [3]: https://stackoverflow.com/questions/3703256/linq-extension-methods-any-vs-where-vs-exists?lq=1

Performance Benchmarking of Contains, Exists and Any

according to http://developer.android.com/training/multiscreen/screendensities.html

The following scale factors are mentioned 


xhdpi: 2.0
hdpi: 1.5
mdpi: 1.0 (baseline)
ldpi: 0.75


I was wondering what the scale factor would be for xxhdpi?

Scale factor for xxhdpi android?

according to <a href="http://developer.android.com/training/multiscreen/screendensities.html" target="_blank" rel="noopener noreferrer">http://developer.android.com/training/multiscreen/screendensities.html</a>
The following scale factors are mentioned
xhdpi: 2.0
hdpi: 1.5
mdpi: 1.0 (baseline)
ldpi: 0.75
I was wondering what the scale factor would be for xxhdpi?

**Explanation and solution at the bottom.**

I am developing one slider layout animation, the animation work fine but when all processes end, they get next Exception.

I guess `RelativeLayout` parent have something to do in exception, but I don&#39;t know how to resolve it.

    09-06 11:24:58.952: E/Trace(30884): error opening trace file: No such file or directory (2)
    09-06 11:25:09.113: E/AndroidRuntime(30884): FATAL EXCEPTION: main
    09-06 11:25:09.113: E/AndroidRuntime(30884): java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.FrameLayout$LayoutParams
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.widget.FrameLayout.onMeasure(FrameLayout.java:311)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.View.measure(View.java:15264)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4916)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.View.measure(View.java:15264)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4916)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1390)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.widget.LinearLayout.measureVertical(LinearLayout.java:681)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.View.measure(View.java:15264)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4916)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2161)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.View.measure(View.java:15264)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2129)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1240)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1433)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1125)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4607)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:747)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.Choreographer.doCallbacks(Choreographer.java:567)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.Choreographer.doFrame(Choreographer.java:536)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:733)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.os.Handler.handleCallback(Handler.java:615)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.os.Handler.dispatchMessage(Handler.java:92)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.os.Looper.loop(Looper.java:153)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at android.app.ActivityThread.main(ActivityThread.java:5086)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at java.lang.reflect.Method.invokeNative(Native Method)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at java.lang.reflect.Method.invoke(Method.java:511)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
    09-06 11:25:09.113: E/AndroidRuntime(30884): 	at dalvik.system.NativeStart.main(Native Method)


activity_home.xml

    &lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:tools=&quot;http://schemas.android.com/tools&quot;
        android:layout_width=&quot;match_parent&quot;
        android:layout_height=&quot;match_parent&quot; &gt;
    
        &lt;LinearLayout
            android:id=&quot;@+id/leftView&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;match_parent&quot;
            android:background=&quot;#cad000&quot;
            android:orientation=&quot;vertical&quot; &gt;
        &lt;/LinearLayout&gt;
    
        &lt;LinearLayout
            android:id=&quot;@+id/mainView&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;match_parent&quot;
            android:background=&quot;#876000&quot;
            android:orientation=&quot;vertical&quot; &gt;
    
            &lt;LinearLayout
                android:layout_width=&quot;match_parent&quot;
                android:layout_height=&quot;50dp&quot;
                android:background=&quot;#cecece&quot;
                android:orientation=&quot;horizontal&quot; &gt;
    
                &lt;Button
                    android:id=&quot;@+id/btnSlide&quot;
                    style=&quot;@style/btn1&quot;
                    android:layout_width=&quot;wrap_content&quot;
                    android:layout_height=&quot;wrap_content&quot;
                    android:text=&quot;X&quot; /&gt;
            &lt;/LinearLayout&gt;
        &lt;/LinearLayout&gt;
    
    &lt;/RelativeLayout&gt;

Activity

    public class HomeActivity extends Activity implements OnClickListener {
    
    	UserStorage userStorage = new UserStorage();
    
    	private Button btnSlide;
    	private LinearLayout mainView, leftView;
    	private SliderAnimation slideAnimation;
    
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_home);
    		
    		this.leftView = (LinearLayout) findViewById(R.id.leftView);
    		this.mainView = (LinearLayout) findViewById(R.id.mainView);
    		
    		this.btnSlide = (Button) findViewById(R.id.btnSlide);
    		this.btnSlide.setOnClickListener(this);
    
    		this.slideAnimation = new SliderAnimation(this);
    
    		this.slideAnimation.initializeFilterAnimations(this.mainView, this.leftView);
    	}
    
    	@Override
    	public void onClick(View v) {
    
    		switch (v.getId()) {
    
    		case R.id.btnSlide:
    
    			this.slideAnimation.toggleLeftSliding();
    
    			break;
    		}
    	}
    }

AnimationListener

    public class SliderAnimation implements AnimationListener {
    
    	private Context context;
    
    	private LinearLayout mainView, leftView;
    
    	private Animation mainSlideIn, mainSlideOut;
    
    	private boolean leftAnimated, rightAnimated = false;
    
    	private int deviceWidth;
    
    	public SliderAnimation(Context context) {
    
    		this.context = context;
    
    		DisplayMetrics displayMetrics = context.getResources()
    				.getDisplayMetrics();
    
    		this.deviceWidth = displayMetrics.widthPixels;
    	}
    
    	public void initializeFilterAnimations(LinearLayout mainView,
    			LinearLayout leftView) {
    
    		this.mainView = mainView;
    		this.leftView = leftView;
    
    		this.mainSlideIn = AnimationUtils.loadAnimation(context,
    				R.anim.main_slide_in);
    		this.mainSlideIn.setAnimationListener(this);
    
    		this.mainSlideOut = AnimationUtils.loadAnimation(context,
    				R.anim.main_slide_out);
    		this.mainSlideOut.setAnimationListener(this);
    	}
    
    	public void toggleLeftSliding() {
    
    		if (!this.leftAnimated) {
    
    			this.mainView.startAnimation(this.mainSlideIn);
    		} else {
    
    			this.mainView.startAnimation(this.mainSlideOut);
    		}
    	}
    
    	@Override
    	public void onAnimationEnd(Animation animation) {
    
    		if (!this.leftAnimated) {
    
    			LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
    					(this.deviceWidth * 20) / 100, this.mainView.getHeight());
    
    			params.leftMargin = (this.deviceWidth * 80) / 100;
    
    			this.mainView.setLayoutParams(params);
    
    			this.leftAnimated = true;
    		} else {
    
    			LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
    					this.deviceWidth, this.mainView.getHeight());
    
    			params.leftMargin = 0;
    
    			this.mainView.setLayoutParams(params);
    
    			this.leftAnimated = false;
    		}
    	}
    
    	@Override
    	public void onAnimationRepeat(Animation animation) {
    	}
    
    	@Override
    	public void onAnimationStart(Animation animation) {
    	}
    }

Thank you in advance.

**EXPLANATION AND SOLUTION**

We&#39;ve to know the parent ViewGroup container for the view, because views are filled with their parent LayoutParams for measure purposes.

If we don&#39;t know through a simple glance on the xml which is the parent ViewGroup for the View, we can get always its reference with .getParent() method from the View instance.

LinearLayout$LayoutParams cannot be cast to android.widget.FrameLayout$LayoutParams

I want to implement `Horizontal ScrollView` with some features of Gallery,
![enter image description here][1]


  [1]: http://i.stack.imgur.com/2VaLc.png

In Gallery the scroll made at some distance it arrange in pair, i.e If we have three images shown in screen, clicking last image will arrange at center. 

How would I implement `HorizontalSCrollView` as mentioned?

How to implement HorizontalScrollView like Gallery?

Currently I am trying to deal with a strange Exception when opening a BluetoothSocket on my Nexus 7 (2012), with Android 4.3 (Build JWR66Y, I guess the second 4.3 update). I have seen some related postings (e.g. [https://stackoverflow.com/questions/13648373/bluetoothsocket-connect-throwing-exception-read-failed][1]), but none seems to provide a workaround for this issue. Also, as suggested in these threads, re-pairing does not help, and constantly trying to connect (through a stupid loop) also has no effect.

I am dealing with an embedded device (a noname OBD-II car adapter, similar to [http://images04.olx.com/ui/15/53/76/1316534072_254254776_2-OBD-II-BLUTOOTH-ADAPTERSCLEAR-CHECK-ENGINE-LIGHTS-WITH-YOUR-PHONE-Oceanside.jpg][2]). My Android 2.3.7 phone does not have any issues connecting, and the Xperia of a colleague (Android 4.1.2) also works. Another Google Nexus (I dont know if &#39;One&#39; or &#39;S&#39;, but not &#39;4&#39;) also fails with Android 4.3.

Here is the Snippet of the connection establishment. It is running in its own Thread, created within a Service.

    private class ConnectThread extends Thread {
        
        private static final UUID EMBEDDED_BOARD_SPP = UUID
			.fromString(&quot;00001101-0000-1000-8000-00805F9B34FB&quot;);
        
		private BluetoothAdapter adapter;
		private boolean secure;
		private BluetoothDevice device;
		private List&lt;UUID&gt; uuidCandidates;
		private int candidate;
		protected boolean started;

        public ConnectThread(BluetoothDevice device, boolean secure) {
        	logger.info(&quot;initiliasing connection to device &quot;+device.getName() +&quot; / &quot;+ device.getAddress());
        	adapter = BluetoothAdapter.getDefaultAdapter();
            this.secure = secure;
            this.device = device;

            setName(&quot;BluetoothConnectThread&quot;);
            
            if (!startQueryingForUUIDs()) {
            	this.uuidCandidates = Collections.singletonList(EMBEDDED_BOARD_SPP);
            	this.start();
            } else{
            	logger.info(&quot;Using UUID discovery mechanism.&quot;);
            }
            /*
             * it will start upon the broadcast receive otherwise
             */
        }
        
    	private boolean startQueryingForUUIDs() {
			Class&lt;?&gt; cl = BluetoothDevice.class;
			
			Class&lt;?&gt;[] par = {};
			Method fetchUuidsWithSdpMethod;
			try {
				fetchUuidsWithSdpMethod = cl.getMethod(&quot;fetchUuidsWithSdp&quot;, par);
			} catch (NoSuchMethodException e) {
				logger.warn(e.getMessage());
				return false;
			}
			
			Object[] args = {};
			try {
				BroadcastReceiver receiver = new BroadcastReceiver() {
				    @Override
				    public void onReceive(Context context, Intent intent) {
				        BluetoothDevice deviceExtra = intent.getParcelableExtra(&quot;android.bluetooth.device.extra.DEVICE&quot;);
				        Parcelable[] uuidExtra = intent.getParcelableArrayExtra(&quot;android.bluetooth.device.extra.UUID&quot;);
				        
				        uuidCandidates = new ArrayList&lt;UUID&gt;();
				        for (Parcelable uuid : uuidExtra) {
				        	uuidCandidates.add(UUID.fromString(uuid.toString()));
						}

				        synchronized (ConnectThread.this) {
				        	if (!ConnectThread.this.started) {
				        		ConnectThread.this.start();
				        		ConnectThread.this.started = true;
				        		unregisterReceiver(this);
				        	}
				        	
				        }
				    }

				};
				registerReceiver(receiver, new IntentFilter(&quot;android.bleutooth.device.action.UUID&quot;));
				registerReceiver(receiver, new IntentFilter(&quot;android.bluetooth.device.action.UUID&quot;));
				
				fetchUuidsWithSdpMethod.invoke(device, args);
			} catch (IllegalArgumentException e) {
				logger.warn(e.getMessage());
				return false;
			} catch (IllegalAccessException e) {
				logger.warn(e.getMessage());
				return false;
			} catch (InvocationTargetException e) {
				logger.warn(e.getMessage());
				return false;
			}			
			
			return true;
		}

		public void run() {
			boolean success = false;
			while (selectSocket()) {
            
	            if (bluetoothSocket == null) {
	            	logger.warn(&quot;Socket is null! Cancelling!&quot;);
	            	deviceDisconnected();
	                openTroubleshootingActivity(TroubleshootingActivity.BLUETOOTH_EXCEPTION);
	            }
	            
	            // Always cancel discovery because it will slow down a connection
	            adapter.cancelDiscovery();
	
	            // Make a connection to the BluetoothSocket
	            try {
					// This is a blocking call and will only return on a
	                // successful connection or an exception
            		bluetoothSocket.connect();
            		success = true;
	            	break;
		            		
	            } catch (IOException e) {
	                // Close the socket
	                try {
	                	shutdownSocket();
	                } catch (IOException e2) {
	                    logger.warn(e2.getMessage(), e2);
	                }
	            }
        	}
			
			if (success) {
				deviceConnected();
			} else {
				deviceDisconnected();
                openTroubleshootingActivity(TroubleshootingActivity.BLUETOOTH_EXCEPTION);
			}
        }

		private boolean selectSocket() {
			if (candidate &gt;= uuidCandidates.size()) {
				return false;
			}
			
			BluetoothSocket tmp;
			UUID uuid = uuidCandidates.get(candidate++);
			logger.info(&quot;Attempting to connect to SDP &quot;+ uuid);
			try {
                if (secure) {
                    tmp = device.createRfcommSocketToServiceRecord(
                            uuid);
                } else {
                    tmp = device.createInsecureRfcommSocketToServiceRecord(
                    		uuid);
                }
                bluetoothSocket = tmp;
                return true;
            } catch (IOException e) {
            	logger.warn(e.getMessage() ,e);
            }
			
			return false;
		}

    }

The code is failing at `bluetoothSocket.connect()`. I am getting a `java.io.IOException: read failed, socket might closed, read ret: -1`. This is the corresponding source at GitHub: [https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L504][3]
Its called through readInt(), called from [https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L319][4]

Some metadata dump of the used socket resulted in the following information. These are exactly the same on Nexus 7 and my 2.3.7 phone.

    Bluetooth Device &#39;OBDII&#39;
    Address: 11:22:33:DD:EE:FF
    Bond state: 12 (bonded)
    Type: 1
    Class major version: 7936
    Class minor version: 7936
    Class Contents: 0
    Contents: 0

I have some other OBD-II adapters (more expansives) and they all work. Is there any chance, that I am missing something or might this be a bug in Android?


  [1]: https://stackoverflow.com/questions/13648373/bluetoothsocket-connect-throwing-exception-read-failed &quot;another SO questionquot;&quot;
  [2]: http://images04.olx.com/ui/15/53/76/1316534072_254254776_2-OBD-II-BLUTOOTH-ADAPTERSCLEAR-CHECK-ENGINE-LIGHTS-WITH-YOUR-PHONE-Oceanside.jpg &quot;these&quot;
  [3]: https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L504 &quot;BluetoothSocket.java#L504&quot;
  [4]: https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L319 &quot;BluetoothSocket.java#L319&quot;

IOException: read failed, socket might closed - Bluetooth on Android 4.3

From my main `activity`, I need to call an inner class and in a method within the class, I need to show `AlertDialog`. After dismissing it, when the OK button is pressed, forward to Google Play for purchase.

Things work perfectly for most of the times, but for few users it is crashing on `builder.show()` and I can see `&quot;android.view.WindowManager$BadTokenException:` Unable to add window&quot; from crash log. Please suggest.

My code is pretty much like this:

    public class classname1 extends Activity{

      public void onCreate(Bundle savedInstanceState) {
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.&lt;view&gt;); 

        //call the &lt;className1&gt; class to execute
      }

      private class classNamename2 extends AsyncTask&lt;String, Void, String&gt;{

        protected String doInBackground(String... params) {}

        protected void onPostExecute(String result){
          if(page.contains(&quot;error&quot;)) 
          {
            AlertDialog.Builder builder = new AlertDialog.Builder(classname1.this);
            builder.setCancelable(true);
            builder.setMessage(&quot;&quot;);
            builder.setInverseBackgroundForced(true);
            builder.setNeutralButton(&quot;Ok&quot;,new DialogInterface.OnClickListener() {
              public void onClick(DialogInterface dialog, int whichButton){
                dialog.dismiss();
                if(!&lt;condition&gt;)
                {
                  try
                  {
                    String pl = &quot;&quot;; 

                    mHelper.&lt;flow&gt;(&lt;class&gt;.this, SKU, RC_REQUEST, 
                      &lt;listener&gt;, pl);
                  }

                  catch(Exception e)
                  {
                    e.printStackTrace();
                  }
                }  
              }
            });

            builder.show();
          }
        }
      }
    }

I have also seen the error in another alert where I am not forwarding to any other `activity`. It&#39;s simple like this:                                                       

    AlertDialog.Builder builder = new AlertDialog.Builder(classname1.this);
    	builder.setCancelable(true);
    	
    	//if successful
    	builder.setMessage(&quot; &quot;);
    	builder.setInverseBackgroundForced(true);
    	builder.setNeutralButton(&quot;Ok&quot;,new DialogInterface.OnClickListener() {
    		public void onClick(DialogInterface dialog, int whichButton){
    			// dialog.dismiss();
                       }
    	});
    	builder.show();
    }

&quot;android.view.WindowManager$BadTokenException: Unable to add window&quot; on buider.show()

After I updated Android Studio to version 0.2.7, I got the following error:

     org.gradle.tooling.GradleConnectionException: Could not execute build
     using Gradle distribution
    &#39;http://services.gradle.org/distributions/gradle-1.6-bin.zip&#39;.: Could
     not execute build using Gradle distribution
    &#39;http://services.gradle.org/distributions/gradle-1.6-bin.zip&#39;.

This is my build.gradle:

    buildscript {
        repositories {
            mavenCentral()
        }
        dependencies {
            classpath &#39;com.android.tools.build:gradle:0.5.+&#39;
        }
    }
    apply plugin: &#39;android&#39;

    dependencies {
        compile files(&#39;libs/android-support-v4.jar&#39;)
    }

    android {
        compileSdkVersion 17
        buildToolsVersion &quot;17.0.0&quot;

    defaultConfig {
        minSdkVersion 10
        targetSdkVersion 17
    }
    }

Does anyone know this error?

Gradle error: could not execute build using gradle distribution

When supporting different screen sizes (densities) in **Android** often the focus is on creating different layouts for every possible screen. I.E.

 - ldpi
 - mdpi
 - hdpi
 - xhdpi
 - xxhdpi
 - xxxhdpi

I designed a layout for an **xhdpi** screen as a reference, and defined it&#39;s **dimensions** in ***dimens.xml***. Now **I want to give support it to every possible screen size. How can I do that?**

As far as I know, I can use [this][1] tool to figure out the proper ***dimens.xml*** for other screen sizes and add it to my project. Is this the right way to do it in my situation?

Another question, **do I only need to create *dimens.xml* for above screen dimensions? If yes then what is *`w820dp`*?**

Thanks for your help. I need to support **phones only** (not tablets or other devices).


  [1]: http://androidpixels.net/

Content Type	Original Author	Original Content on Stackoverflow
Question	Muhammad Ahmed AbuTalib	View Question on Stackoverflow
Solution 1 - Android	ozbek	View Answer on Stackoverflow
Solution 2 - Android	Squonk	View Answer on Stackoverflow

Scale factor for xxhdpi android?

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