@Override    public void onAttachedToWindow() {        this.getWindow().setType(                WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);        super.onAttachedToWindow();    }    @Override    public boolean dispatchKeyEvent(KeyEvent event) {        // TODO Auto-generated method stub        if(event.getKeyCode() == KeyEvent.KEYCODE_HOME) {            Toast.makeText(this, "a", Toast.LENGTH_SHORT).show();        }        //使用转到桌面代码        ntent mHomeIntent = new Intent(Intent.ACTION_MAIN, null);        mHomeIntent.addCategory(Intent.CATEGORY_HOME);        mHomeIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);        startActivity(mHomeIntent);        return super.dispatchKeyEvent(event);    }