How to do them in View ?

16 June 2011
How to remove the button shape of an ImageButton ?

android:background="@null"

07 Sept 2010
How to create Full Screen activity ?

requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.xxx);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

16 Aug 2010
How to know about screen width and height ?

Display display = getWindowManager().getDefaultDisplay();
int width = display.getWidth();
int height = display.getHeight();

How to show an Alert ?

AlertDialog dialog = new AlertDialog.Builder(this)
  .setMessage(R.string.message)
  .setPositiveButton(R.string.yes,
    new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) {
      }
    }
  )
  .setNegativeButton(R.string.no, 
    new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) {
      }
    }
  ).create();
dialog.show();