As far as I understand:
[Context][1] is the Base Object. So every [Activity][2]  same as [Application][3] derives from Context. This means that every Activity and every `Application` IS a `Context`;

From `developer.android.com` [Activity][4]

    java.lang.Object
      ↳ android.content.Context
          ↳ android.content.ContextWrapper
              ↳	android.view.ContextThemeWrapper
                  ↳ android.app.Activity

And [Application][3]

    java.lang.Object
    ↳ 	android.content.Context
  	   ↳ 	android.content.ContextWrapper
  	  	   ↳ 	android.app.Application

An Application context lasts, as long as your app is alive, while the Activity context dies with your Activity (it is not valid after `onDestroy` of that Activity). 

So if you need the Context across Activities (i.e. in a Singleton) you will be better off using an Application context.


Usually on Android Framework methods where a context is expected, it makes no difference which one you pass. But be always aware of [MemoryLeaks][5] if you&#39;re keeping long-living References to a Context


  [1]: http://developer.android.com/reference/android/content/Context.html
  [2]: http://developer.android.com/reference/android/app/Activity.html
  [3]: http://developer.android.com/reference/android/app/Application.html
  [4]: http://developer.android.com/reference/android/app/Activity.html#jd-content
  [5]: https://android-developers.googleblog.com/2009/01/avoiding-memory-leaks.html

As You can see on the [Android doc](http://developer.android.com/reference/android/app/Activity.html): 

The Activity class extends from &quot;ContextThemeWrapper&quot;, and this one from &quot;ContextWrapper&quot;, and that one from &quot;Context&quot;.

So, yes, An Activity extends the Context!

I&#39;ve written a couple of complex queries (at least to me) with Ruby on Rail&#39;s query interface:

    
    watched_news_posts = Post.joins(:news =&gt; :watched).where(:watched =&gt; {:user_id =&gt; id})
    watched_topic_posts = Post.joins(:post_topic_relationships =&gt; {:topic =&gt; :watched}).where(:watched =&gt; {:user_id =&gt; id})

Both of these queries work fine by themselves.  Both return Post objects.  I would like to combine these posts into a single ActiveRelation.  Since there could be hundreds of thousands of posts at some point, this needs to be done at the database level.  If it were a MySQL query, I could simply user the `UNION` operator.  Does anybody know if I can do something similar with RoR&#39;s query interface?

ActiveRecord Query Union

Looking at an online source code I came across this at the top of several source files.

    var FOO = FOO || {};
    FOO.Bar = …;

But I have no idea what `|| {}` does.

I know `{}` is equal to `new Object()` and I think the `||` is for something like &quot;if it already exists use its value else use the new object.

Why would I see this at the top of a source file?


What does &quot;var FOO = FOO || {}&quot; (assign a variable or an empty object to that variable) mean in Javascript?

Are Activity and Context the same, or are there differences?

When should I have a method pass an Activity, and when a Context?

What is the difference between Activity and Context?

<p>Are Activity and Context the same, or are there differences?</p>
<p>When should I have a method pass an Activity, and when a Context?</p>


I tried to use following code to get screen width and height in android app development:

    Display display = getWindowManager().getDefaultDisplay(); 
    int screenWidth = display.getWidth();
    int screenHeight = display.getHeight();

 but I got **NullPointerException** for my `display`, why? how to get screen width and height then?


How to get screen width and height

I there a way to get a list of the active `PendingIntent`s in a device?

I am starting to work with `AlarmManager` and I like to see if my `PendingIntent`s are created and removed correctly.

It would also be nice to see what other `PendingIntent`s are there, just as a curiosity to see if some app is doing some &quot;extra work&quot;.

Get list of active PendingIntents in AlarmManager

I&#39;m confused when it comes down to saving a state. So I know that `onSaveInstanceState(Bundle)` is called when the activity is about to be destroyed. But how do you store your information in it and bring it back to its original state in `onCreate(Bundle savedInstanceState)`? I don&#39;t understand how this bundle will restore information. It would be helpful if someone can provide an example.
The Dev guide doesn&#39;t do a good job of explaining this.

    public class Conversation extends Activity {
    	private ProgressDialog progDialog;
    	int typeBar;
    	TextView text1;
    	EditText edit;
    	Button respond;
    	private String name;
    	private String textAtView;
    	private String savedName;
    	
    	public void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		
			setContentView(R.layout.dorothydialog);
    		text1 = (TextView)findViewById(R.id.dialog);
    		edit = (EditText)findViewById(R.id.repsond);
    		respond = (Button)findViewById(R.id.button01);
    		
    		if(savedInstanceState != null){
    			savedInstanceState.get(savedName);
				text1.setText(savedName);
    		}
			else{
    			text1.setText(&quot;Hello! What is your name?&quot;);
	    		respond.setOnClickListener(new View.OnClickListener() {
    			
    				@Override
	    			public void onClick(View v) {
    					name = edit.getText().toString();
	    				text1.setText(&quot;Nice to meet you &quot;+ name);
    				}	
    			});
    		}
    	}
    	
   		@Override
   		public void onSaveInstanceState(Bundle outState){
   			super.onSaveInstanceState(outState);
   			outState.putString(savedName, name);
        }
    }


How to use onSavedInstanceState example please

First a little background:

I have a layout inside a scrollview. At first, when the user scrolls on the screen, the scrollview scrolls. However, after a certain amount of scroll, I was to disable the scroll on the scroll view the move the &quot;scroll focus&quot; onto a webview inside the child layout. This way, the scrollview sticks and all the scroll events go to the webview inside it.

So, for a solution, when the scroll threshold is reached, I remove the child layout from the scrollview and put it in scrollview&#39;s parent.(And make the scrollview invisible).

    // Remove the child view from the scroll view
    scrollView.removeView(scrollChildLayout);
    
    // Get scroll view out of the way
    scrollView.setVisibility(View.GONE);
    
    // Put the child view into scrollview&#39;s parent view
    parentLayout.addView(scrollChildLayout);

General Idea: (-&gt; means contains)

Before: parentlayout -&gt; scrollview -&gt; scrollChildLayout

After : parentLayout -&gt; scrollChildLayout


The above code is giving me this exception:

    java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child&#39;s parent first.
               at android.view.ViewGroup.addViewInner(ViewGroup.java:1976)
               at android.view.ViewGroup.addView(ViewGroup.java:1871)
               at android.view.ViewGroup.addView(ViewGroup.java:1828)
               at android.view.ViewGroup.addView(ViewGroup.java:1808)

Do you know what&#39;s going on? I am clearly calling removeView on the parent.

Call removeView() on the child&#39;s parent first

Basically I would like to know if we can have fragment layouts in devices with Android OS &lt; 3.0.

My app had a header on top with 5 different buttons and on start always the first button is clicked by default so the view below these buttons is for the first view. Now when you click on the second button beside it, I don&#39;t want the header images to be refreshed but the view just below it needs to be refreshed. So its like updating the fragments below the header image buttons.

So can we have fragments in Android in devices with OS &lt; 3.0.

Sana.

Fragments in Android 2.2.1, 2.3, 2.0. Is this possible?

Firstly, I know that one should not really kill/restart an application on Android. In my use case, I want to factory-reset my application in a specific case where a server sends a piece of specific information to the client.

The user can only be logged in on the server with ONE instance of the application (i.e. multiple devices are not allowed). If another instance gets that &quot;logged-in&quot;-lock then all other instances of that user have to delete their data (factory-reset), to maintain consistency.

It is possible to forcibly get the lock because the user might delete the app and reinstall it which would result in a different instance-id and the user would not be able to free the lock anymore. Therefore it is possible to forcibly get the lock.

Because of that force-possibility, we need to always check in a concrete instance that it has the lock. That is done on (almost) each request to the server. The server might send a &quot;wrong-lock-id&quot;. If that is detected, the client application must delete everything.

----

That was the use-case.

I have an `Activity` A that starts the Login `Activity` L or the app&#39;s main `Activity` B depending on a sharedPrefs value. After starting L or B it closes itself so that only L or B is running. So in the case that the user is logged in already B is running now.

B starts C. C calls `startService` for the `IntentService` D. That results in this stack:

(A) &gt; B &gt; C &gt; D

From the onHandleIntent method of D, an event is sent to a [ResultReceiver][1] R.

R now handles that event by providing the user a dialog where he can choose to factory-reset the application (delete the database, sharedPrefs, etc.)

After the factory-reset I want to restart the application (to close all activities) and only start A again which then launches the login `Activity` L and finishes itself:

(A) &gt; L

The Dialog&#39;s onClick-method looks like this:

    @Override
    public void onClick(DialogInterface dialog, int which) {

        // Will call onCancelListener
        MyApplication.factoryReset(); // (Deletes the database, clears sharedPrefs, etc.)
        Intent i = new Intent(MyApp.getContext(), A.class);
        i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        MyApp.getContext().startActivity(i);
    }

And that&#39;s the `MyApp` class:

    public class MyApp extends Application {
        private static Context context;

        @Override
        public void onCreate() {
            super.onCreate();
            context = getApplicationContext();
        }

        public static Context getContext() {
            return context;
        }

        public static void factoryReset() {
            // ...
        }
    }

The problem is if I use the `FLAG_ACTIVITY_NEW_TASK` the Activities B and C are still running. If I hit the back button on the login `Activity` I see C, but I want to go back to the home screen.

If I do not set the `FLAG_ACTIVITY_NEW_TASK` I get the error:

    07-07 12:27:12.272: ERROR/AndroidRuntime(9512): android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity  context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want?

I cannot use the Activities&#39; `Context`, because the `ServiceIntent` D might also be called from a background task which is started by the `AlarmManager`.

So how could I solve this to the activity stack becoming (A) &gt; L?

  [1]: http://developer.android.com/reference/android/os/ResultReceiver.html



How do I programmatically &quot;restart&quot; an Android app?

&gt; **Possible Duplicate:**  
&gt; [Android Activity Life Cycle - difference between onPause() and OnStop()](https://stackoverflow.com/questions/8515936/android-activity-life-cycle-difference-between-onpause-and-onstop)  

&lt;!-- End of automatically inserted text --&gt;

I was wondering - **what is the difference between `onCreate()` and `onStart()` methods?**

I think that `onStart()` is a redundant method. `onCreate()` will ALWAYS be called (At least in my last two projects).

Can any one explain the difference?

Difference between onCreate() and onStart()?

I&#39;m a new Android programmer and recently, a lot of my projects have been getting this error:

    07-31 23:45:19.592: ERROR/AndroidRuntime(716): java.lang.RuntimeException: Unable to start     

    activity ComponentInfo{com.amrit.musifind/com.amrit.musifind.Main}: 

    java.lang.NullPointerException

Can anyone help me solve this problem?


Here&#39;s the entire logcat stack trace:


    07-31 23:45:18.512: INFO/ActivityManager(63): Starting activity: Intent {     
    act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000   
    cmp=com.amrit.musifind/.Main }
    07-31 23:45:18.682: INFO/ActivityManager(63): Start proc com.amrit.musifind for activity   
    com.amrit.musifind/.Main: pid=716 uid=10025 gids={3003}
    07-31 23:45:18.962: INFO/jdwp(716): received file descriptor 20 from ADB
    07-31 23:45:19.102: DEBUG/ddm-heap(716): Got feature list request
    07-31 23:45:19.572: DEBUG/AndroidRuntime(716): Shutting down VM
    07-31 23:45:19.572: WARN/dalvikvm(716): threadid=3: thread exiting with uncaught   
    exception (group=0x4001aa28)
    07-31 23:45:19.572: ERROR/AndroidRuntime(716): Uncaught handler: thread main exiting due 
    to uncaught exception
    07-31 23:45:19.592: ERROR/AndroidRuntime(716): java.lang.RuntimeException: Unable to    
    start activity ComponentInfo{com.amrit.musifind/com.amrit.musifind.Main}:    
    java.lang.NullPointerException
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at    
    android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at    
    android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at    
    android.app.ActivityThread.access$2100(ActivityThread.java:116)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    android.os.Handler.dispatchMessage(Handler.java:99)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at       
    android.os.Looper.loop(Looper.java:123)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    android.app.ActivityThread.main(ActivityThread.java:4203)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at    
    java.lang.reflect.Method.invokeNative(Native Method)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    java.lang.reflect.Method.invoke(Method.java:521)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    dalvik.system.NativeStart.main(Native Method)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716): Caused by: java.lang.NullPointerException
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at   
    com.amrit.musifind.Main.onCreate(Main.java:44)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at 
    android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     at     
    android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)
    07-31 23:45:19.592: ERROR/AndroidRuntime(716):     ... 11 more
    07-31 23:45:19.612: INFO/Process(63): Sending signal. PID: 716 SIG: 3
    07-31 23:45:19.612: INFO/dalvikvm(716): threadid=7: reacting to signal 3
    07-31 23:45:19.642: INFO/dalvikvm(716): Wrote stack trace to &#39;/data/anr/traces.txt&#39;
    07-31 23:45:21.422: INFO/Process(716): Sending signal. PID: 716 SIG: 9
    07-31 23:45:21.442: INFO/ActivityManager(63): Process com.amrit.musifind (pid 716) has   
    died.
    07-31 23:45:21.583: WARN/UsageStats(63): Unexpected resume of com.android.launcher while    
    already resumed in com.amrit.musifind
    07-31 23:45:21.712: WARN/InputManagerService(63): Window already focused, ignoring focus    
    gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@439559d0
    07-31 23:45:23.482: DEBUG/AndroidRuntime(725): &gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt; AndroidRuntime START    
    &lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;
    07-31 23:45:23.482: DEBUG/AndroidRuntime(725): CheckJNI is ON
    07-31 23:45:23.812: DEBUG/AndroidRuntime(725): --- registering native functions ---
    07-31 23:45:23.832: INFO/jdwp(725): received file descriptor 20 from ADB
    07-31 23:45:24.193: DEBUG/ddm-heap(725): Got feature list request
    07-31 23:45:25.052: DEBUG/AndroidRuntime(725): Shutting down VM
    07-31 23:45:25.052: DEBUG/dalvikvm(725): DestroyJavaVM waiting for non-daemon threads to   
    exit
    07-31 23:45:25.062: DEBUG/dalvikvm(725): DestroyJavaVM shutting VM down
    07-31 23:45:25.062: DEBUG/dalvikvm(725): HeapWorker thread shutting down
    07-31 23:45:25.062: DEBUG/dalvikvm(725): HeapWorker thread has shut down
    07-31 23:45:25.073: DEBUG/jdwp(725): JDWP shutting down net...
    07-31 23:45:25.073: DEBUG/jdwp(725): +++ peer disconnected
    07-31 23:45:25.073: INFO/dalvikvm(725): Debugger has detached; object registry had 1   
    entries
    07-31 23:45:25.093: DEBUG/dalvikvm(725): VM cleaning up
    07-31 23:45:25.113: DEBUG/dalvikvm(725): LinearAlloc 0x0 used 665652 of 4194304 (15%)
    07-31 23:47:22.712: DEBUG/dalvikvm(104): GC freed 9173 objects / 524184 bytes in 149ms


Heres the 1st activity: start.java

    package com.amrit.musifind;

    import java.io.BufferedReader;
    import java.io.InputStreamReader;

    import org.apache.http.HttpResponse;
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.impl.client.DefaultHttpClient;
   
    import com.amrit.musifind.R;
  
    import android.app.ListActivity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.AdapterView.OnItemClickListener;
    import android.widget.ListAdapter;
    import android.widget.ListView;
    import android.widget.SimpleAdapter;
    import android.widget.Toast;
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
 
    public abstract class start extends Activity implements OnClickListener {
   
	Button buttonGo, buttonReset;
	EditText EditTextinput;
	String input = &quot;&quot;;
	String ur = &quot;http://www.tastekid.com/ask/ws?q=&quot;;
	String l = &quot;&amp;f=musifin2125&amp;k=mjjlnzkyzwuz&amp;format=JSON&quot;;
    String url = &quot;&quot; ;
	
	/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        buttonGo = (Button) findViewById(R.id.buttonGo);
        buttonReset = (Button) findViewById(R.id.buttonReset);
        
        EditTextinput = (EditText) findViewById(R.id.EditTextinput);
        
        //Button listener
        buttonReset.setOnClickListener(this);
        buttonGo.setOnClickListener(this);
    }

    public void onClick (View src){
        switch(src.getId()){
            case R.id.buttonGo:
                input = EditTextinput.getText().toString();
    			url = ur + input + l  ;
    			        		
 			    Intent Main = new Intent(this, ToClass.class);
           		Main.putExtra(&quot;userurl&quot;, url);
           		startActivity(Main);
    	        break;
    			        	
           	case R.id.buttonReset:
           		EditTextinput.setText(&quot;&quot;);
           		break;
   			}
   		}
    }
        

The second activity: Main.java

    package com.amrit.musifind;

    import java.util.ArrayList;
    import java.util.HashMap;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    import org.w3c.dom.Document;
    import org.w3c.dom.Element;
    import org.w3c.dom.NodeList;

    import com.amrit.musifind.JSONfunctions;
    import com.amrit.musifind.R;

    import android.app.ListActivity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.AdapterView.OnItemClickListener;
    import android.widget.ListAdapter;
    import android.widget.ListView;
    import android.widget.SimpleAdapter;
    import android.widget.Toast;
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;

    public class Main extends ListActivity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listplaceholder);
        
        Intent intent = getIntent();
        String url = intent.getExtras().getString(&quot;userurl&quot;);

        ArrayList&lt;HashMap&lt;String, String&gt;&gt; mylist = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;    
        ();
       
        JSONObject json = JSONfunctions.getJSONfromURL(url);
                
        try{
        	JSONObject earthquakes = json.getJSONObject(&quot;Similar&quot;);
            JSONArray info = earthquakes.getJSONArray(&quot;Results&quot;);

            for (int i = 0; i &lt; info.length(); i++) {
                HashMap&lt;String, String&gt; map = new HashMap&lt;String, String&gt;();
                JSONObject e = info.getJSONObject(i);

                map.put(&quot;id&quot;, String.valueOf(i));
                map.put(&quot;name&quot;, &quot;Name:&quot; + e.getString(&quot;Name&quot;));
                map.put(&quot;type&quot;, &quot;Type: &quot; + e.getString(&quot;Type&quot;));
                mylist.add(map);
            }
        	
        	JSONArray  results = json.getJSONArray(&quot;Results&quot;);
        	
	        for(int i=0;i&lt;results.length();i++){						
				HashMap&lt;String, String&gt; map = new HashMap&lt;String, String&gt;();	
				JSONObject e = results.getJSONObject(i);
				
				map.put(&quot;id&quot;,  String.valueOf(i));
	        	map.put(&quot;name&quot;, &quot;Name:&quot; + e.getString(&quot;name&quot;));
	        	map.put(&quot;type&quot;, &quot;Type: &quot; +  e.getString(&quot;type&quot;));
	        	mylist.add(map);			
			}		
        } catch(JSONException e) {
        	 Log.e(&quot;log_tag&quot;, &quot;Error parsing data &quot;+e.toString());
        }
        
        ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.main, 
             new String[] { &quot;name&quot;, &quot;type&quot; }, 
             new int[] { R.id.item_title, R.id.item_subtitle });
        
        setListAdapter(adapter);
        
        final ListView lv = getListView();
        lv.setTextFilterEnabled(true);	
        lv.setOnItemClickListener(new OnItemClickListener() {
        	public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position, long id) {        		
                @SuppressWarnings(&quot;unchecked&quot;)
	        	HashMap&lt;String, String&gt; o = (HashMap&lt;String, String&gt;) lv.getItemAtPosition(position);	        		
                Toast.makeText(Main.this, &quot;ID &#39;&quot; + o.get(&quot;id&quot;) + &quot;&#39; was clicked.&quot;, 
                    Toast.LENGTH_SHORT).show(); 
    			}
	    	});
        }
    }


Lastly, my manifest file: AndroidManifest.xml

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;manifest xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        package=&quot;com.amrit.musifind&quot;
        android:versionCode=&quot;1&quot;
        android:versionName=&quot;1.0&quot;&gt;
        &lt;uses-sdk android:minSdkVersion=&quot;4&quot; /&gt;

        &lt;application android:icon=&quot;@drawable/icon&quot; android:label=&quot;@string/app_name&quot;&gt;
            &lt;activity android:name=&quot;.start&quot; android:label=&quot;@string/app_name&quot;&gt;
                &lt;intent-filter&gt;
                    &lt;action android:name=&quot;android.intent.action.start&quot; /&gt;
                    &lt;category android:name=&quot;android.intent.category.LAUNCHER&quot; /&gt;
                &lt;/intent-filter&gt;
            &lt;/activity&gt;
            &lt;activity android:name= &quot;.Main&quot;&gt;
                &lt;intent-filter&gt;
                    &lt;action android:name=&quot;android.intent.action.Main&quot; /&gt;
                &lt;/intent-filter&gt;
            &lt;/activity&gt;
        &lt;/application&gt;

    	&lt;uses-permission android:name=&quot;android.permission.INTERNET&quot; /&gt;

    &lt;/manifest&gt;

Any help is much appreciated, without solving this problem I can&#39;t test my app out!


Android app unable to start activity componentinfo

How can I use properly the Intent flag `FLAG_ACTIVITY_NO_ANIMATION` in AndroidManifest file? I supose my problem is trivial, but I can&#39;t find good example or solution to it.
```lang-xml
    &lt;intent-filter&gt;
        &lt;data android:name=&quot;android.content.Intent.FLAG_ACTIVITY_NO_ANIMATION&quot; /&gt;
    &lt;/intent-filter&gt;
```
However no error is reported by compliator, but `data` isn&#39;t correct.
I just want to disable animation in case switching between activities. I can use `getWindow().setWindowAnimations(0);` in onCreate or onResume rather but using flag is better way, isn&#39;t it?

I can use also in code:
```lang-java
    Intent intent = new Intent(v.getContext(), newactivity.class);
    intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
    getContext().startActivity(intent);
```
But I want to use this flag in Android Manifest. To disable animation also in case returning from second activity to first.

How to switch activity without animation in Android?

I am aware of the availability of [Context.getApplicationContext()][1] and [View.getContext()][2], through which I can actually call [Context.getPackageName()][3] to retrieve the package name of an application.

They work if I call from a method to which a `View` or an `Activity` object is available, but if I want to find the package name from a totally independent class with no `View` or `Activity`, is there a way to do that (directly or indirectly)?


  [1]: http://developer.android.com/reference/android/content/Context.html#getApplicationContext%28%29
  [2]: http://developer.android.com/reference/android/view/View.html#getContext%28%29
  [3]: http://developer.android.com/reference/android/content/Context.html#getPackageName%28%29

How to get package name from anywhere?

What is the difference between:

1. `getApplicationContext()`
2. `getBasecontext()`
3. `getApplication()`
4. `getParent()`

Can you elaborate with one simple example?  

getApplicationContext(), getBaseContext(), getApplication(), getParent()

I would like to get the context of application which has reference/hosted my library at run-time inside one class of my library project. Is it possible? If yes, how?

Thanks

**Update**
I don&#39;t want my user to pass context in parameter to my library project because it is possible that my library project will be called through JNI and I have no idea how I can get context in JNI and pass it to Java layer.

Is it possible to get application&#39;s context in an Android Library Project?

There has been a lot of posting about what these two contexts are.. But I&#39;m still not getting it quite right

As I understand it so far:
Each is an instance of its class which means that some programmers recommend you to use `this.getApplicationContext()` as often as possible in order to not &quot;leak&quot; out any memory. This is because the other `this` (getting the `Activity` instance context) points to an `Activity` that is being destroyed each time the user tilts the phone or leave the app etc.. Which apparently the Garbage Collector (GC) doesn&#39;t catch and therefore uses too much memory.. 

But can anyone please come up with some really good coding examples where it would be the right thing to use `this` (getting the context of the current `Activity` instance) and the application context will be useless/wrong?

When to call activity context OR application context?

I am trying to use getResources method in a non-activity class. How do I get the reference to the &quot;resources&quot; object so that I can access the xml file stored under resources folder?

Example:

    XmlPullParser xpp = getResources().getXml(R.xml.samplexml);

Content Type	Original Author	Original Content on Stackoverflow
Question	Android	View Question on Stackoverflow
Solution 1 - Android	Rafael T	View Answer on Stackoverflow
Solution 2 - Android	zapotec	View Answer on Stackoverflow

What is the difference between Activity and Context?

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