this secures against manual and automatic screenshots http://stackoverflow.com/a/9822607

FlagSecureTestActivity.java

public class FlagSecureTestActivity extends Activity {
  
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
  
    /**
     * secure this activity
     * {@link http://stackoverflow.com/a/9822607}
     */
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE,
  	    WindowManager.LayoutParams.FLAG_SECURE);
  
    setContentView(R.layout.main);
    
    // ...
  }
  
}