安卓调用铃声、震动及设置Toast不重复弹出

        MediaPlayer mp=new MediaPlayer();
        try {
            mp.setDataSource(this, RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION));
            mp.prepare();
            mp.start();
        } catch (IOException e) {
            e.printStackTrace();
        }

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

Vibrator vibrator = (Vibrator)getSystemService(Context.VIBRATOR_SERVICE);
long [] pattern = {100,400,100,400}; // 停止 开启 停止 开启
vibrator.vibrate(pattern,2); //重复两次上面的pattern 如果只想震动一次，index设为-1
//取消代码
vibrator.cancel();

public void showToast(String text) {
        if(toast == null) {
            toast = Toast.makeText(MainActivity.this, text, Toast.LENGTH_SHORT);
        } else {
            toast.setText(text);
            toast.setDuration(Toast.LENGTH_SHORT);
        }
        toast.show();
    }

    public void cancelToast() {
        if (toast != null) {
            toast.cancel();
        }
    }