android屏蔽返回键和Home键

//屏蔽返回键的代码:
public boolean onKeyDown(int keyCode,KeyEvent event)
{
switch(keyCode)
{
case KeyEvent.KEYCODE_HOME:return true;
case KeyEvent.KEYCODE_BACK:return true;
case KeyEvent.KEYCODE_CALL:return true;
case KeyEvent.KEYCODE_SYM: return true;
case KeyEvent.KEYCODE_VOLUME_DOWN: return true;
case KeyEvent.KEYCODE_VOLUME_UP: return true;
case KeyEvent.KEYCODE_STAR: return true;
}
return super.onKeyDown(keyCode, event);
}

//屏蔽home键的代码:
public void onAttachedToWindow()
{
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}