public void onCreate(Bundle savedInstanceState) {
    ...
    this.registerReceiver(this.myBatteryReceiver , new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
    ...
}
 
private BroadcastReceiver myBatteryReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
        //here you can use level as you wish.
    }
};

 
public interface EventListener
{
	public void onEventHappened();
}

 
public class MyEvent
{
	private EventListener listener;
	private static MyEvent instance;
 
	private MyEvent(){
 
	}
	public static MyEvent getInsance(){
		if (instance == null)
			instance = new MyEvent();
		return instance;
	}
	public void setEventListener(EventListener listen)
	{		
		listener = listen;
	}
 
	public void eventHappened()
	{		
		if (listener != null)
		{
			listener.onEventHappened();
		}
	}
}

MyEvent.getInstance().eventHappened();

MyEvent.getInsance().setEventListener(new EventListener()
		{
 
			@Override
			public void onEventHappened()
			{
                            //here is your code that will happen when the button from the other Activity was pressed
                        }
                 });

public void clearApplicationData()
	{
		File cache = getCacheDir();
		File appDir = new File(cache.getParent());
		if (appDir.exists())
		{
			String[] children = appDir.list();
			for (String s : children)
			{
				if (!s.equals("lib"))
				{
					deleteDir(new File(appDir, s));
					Log.i("TAG", "File /data/data/APP_PACKAGE/" + s + " DELETED ");
				}
			}
		}
	}

registerReceiver(new BroadcastReceiver() {
	        @Override
	        public void onReceive(Context context, Intent intent) {
	           Log.d("MyTag", "You have received a message");
	        }
	    }, new IntentFilter("android.provider.Telephony.SMS_RECEIVED"));

<uses-permission android:name="android.permission.RECEIVE_SMS" >

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

<receiver android:name="com.example.MyBroadcastReceiver">  
    <intent-filter>  
        <action android:name="android.intent.action.BOOT_COMPLETED" />  
    </intent-filter>  
</receiver>

public class MyBroadcastreceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent startServiceIntent = new Intent(context, MyService.class);
        context.startService(startServiceIntent);
    }
}

private void getOverflowMenu() {
 
     try {
        ViewConfiguration config = ViewConfiguration.get(this);
        Field menuKeyField = ViewConfiguration.class.getDeclaredField("sHasPermanentMenuKey");
        if(menuKeyField != null) {
            menuKeyField.setAccessible(true);
            menuKeyField.setBoolean(config, false);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/gridView1"
    android:numColumns="auto_fit"
    android:gravity="center"
    android:columnWidth="100dp"
    android:stretchMode="columnWidth"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
 
</GridView>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="5dp" >
 
    <ImageView
        android:id="@+id/grid_item_image"
        android:layout_width="50px"
        android:layout_height="50px"
        android:layout_marginRight="10px"
        android:src="@drawable/android_logo" >
    </ImageView>
 
    <TextView
        android:id="@+id/grid_item_label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@+id/label"
        android:layout_marginTop="5px"
        android:textSize="15px" >
    </TextView>
 
</LinearLayout>

package com.myapp.android;
 
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
 
import com.mkyong.android.R;
 
public class ImageAdapter extends BaseAdapter {
	private Context context;
	private final String[] mobileValues;
 
	public ImageAdapter(Context context, String[] mobileValues) {
		this.context = context;
		this.mobileValues = mobileValues;
	}
 
	public View getView(int position, View convertView, ViewGroup parent) {
 
		LayoutInflater inflater = (LayoutInflater) context
			.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 
		View gridView;
 
		if (convertView == null) {
 
			gridView = new View(context);
 
			// get layout from custom_adapter.xml
			gridView = inflater.inflate(R.layout.custom_adapter, null);
 
			// set value into textview
			TextView textView = (TextView) gridView
					.findViewById(R.id.grid_item_label);
			textView.setText(mobileValues[position]);
 
			// set image based on selected text
			ImageView imageView = (ImageView) gridView
					.findViewById(R.id.grid_item_image);
 
			String mobile = mobileValues[position];
 //you will need to add this icons in your drawable folder
			if (mobile.equals("Windows")) {
				imageView.setImageResource(R.drawable.windows_logo);
			} else if (mobile.equals("iOS")) {
				imageView.setImageResource(R.drawable.ios_logo);
			} else if (mobile.equals("Blackberry")) {
				imageView.setImageResource(R.drawable.blackberry_logo);
			} else {
				imageView.setImageResource(R.drawable.android_logo);
			}
 
		} else {
			gridView = (View) convertView;
		}
 
		return gridView;
	}
 
	@Override
	public int getCount() {
		return mobileValues.length;
	}
 
	@Override
	public Object getItem(int position) {
		return null;
	}
 
	@Override
	public long getItemId(int position) {
		return 0;
	}
 
}

package com.myapp.android;
 
import com.myapp.android.ImageAdapter;
import android.app.Activity;
import android.os.Bundle;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.TextView;
import android.widget.Toast;
import android.view.View;
import android.widget.AdapterView.OnItemClickListener;
 
public class GridViewActivity extends Activity {
 
	GridView gridView;
 
	static final String[] MOBILE_OS = new String[] { 
		"Android", "iOS","Windows", "Blackberry" };
 
	@Override
	public void onCreate(Bundle savedInstanceState) {
 
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
 
		gridView = (GridView) findViewById(R.id.gridView1);
 
		gridView.setAdapter(new ImageAdapter(this, MOBILE_OS));
 
		gridView.setOnItemClickListener(new OnItemClickListener() {
			public void onItemClick(AdapterView<?> parent, View v,
					int position, long id) {
				Toast.makeText(
				   getApplicationContext(),
				   ((TextView) v.findViewById(R.id.grid_item_label))
				   .getText(), Toast.LENGTH_SHORT).show();
 
			}
		});
 
	}
 
}

<resources>
    <style name="Theme.White" parent="@android:style/Theme.Light">
    </style>
</resources>

<resources>
    <style name="Theme.White" parent="@android:style/Theme.Holo.Light">
    </style>
</resources>

<resources>
    <style name="Theme.White" parent="@android:style/Theme.Holo.Light">
    </style>
</resources>

 <application android:label="@string/app_name">
        <activity android:name=".MyActivity"
                  android:theme="@style/Theme.White"
                  android:label="@string/app_name">
        </activity>

 Drawable drawable = getResources().getDrawable(android.R.drawable.ic_search_category_default);
 
                    Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
                    Drawable d = new BitmapDrawable(getResources(), Bitmap.createScaledBitmap(bitmap, 30, 30, true));

<LinearLayout   android:id="@+id/myLayoutId"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content">
</LinearLayout>

onCreate(){
toolbarWidget = (LinearLayout)findViewById(R.id.toolbarWidget);
toolbarWidget.startAnimation(inFromRightAnimation());
}
 private Animation inFromRightAnimation() {
 
        Animation inFromRight = new TranslateAnimation(
                Animation.RELATIVE_TO_PARENT,  +1.0f, Animation.RELATIVE_TO_PARENT,  0.0f,
                Animation.RELATIVE_TO_PARENT,  0.0f, Animation.RELATIVE_TO_PARENT,   0.0f
        );
        inFromRight.setDuration(1000);
        inFromRight.setInterpolator(new AccelerateInterpolator());
        return inFromRight;
    }