android 关闭app的情况下触发一个定时广播

要在 Android 应用关闭时触发定时广播，可以使用 Android 的广播接收器和服务。以下是实现步骤：

1. 创建一个 BroadcastReceiver 类，用于接收定时广播。例如：

public class MyBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        // 处理定时广播
    }
}

2. 在 AndroidManifest.xml 文件中注册 BroadcastReceiver。例如：

<receiver android:name=".MyBroadcastReceiver" />

3. 创建一个 Service 类，用于在后台运行广播。例如：

public class MyService extends Service {
    private BroadcastReceiver mBroadcastReceiver;
    private PendingIntent mPendingIntent;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        // 创建定时广播
        mBroadcastReceiver = new MyBroadcastReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("com.example.myapp.MY_BROADCAST");
        registerReceiver(mBroadcastReceiver, intentFilter);

        // 创建 PendingIntent
        Intent intent = new Intent("com.example.myapp.MY_BROADCAST");
        mPendingIntent = PendingIntent.getBroadcast(this, 0, intent, 0);

        // 启动定时器
        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
        long interval = 60 * 1000; // 每分钟触发一次广播
        long startTime = System.currentTimeMillis();
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, startTime, interval, mPendingIntent);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        // 取消定时广播
        unregisterReceiver(mBroadcastReceiver);
        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
        alarmManager.cancel(mPendingIntent);
    }
}

4. 在应用关闭的时候启动 Service。例如：

@Override
protected void onDestroy() {
    super.onDestroy();

    Intent intent = new Intent(this, MyService.class);
    startService(intent);
}

这样，当应用关闭时，就会启动 MyService，并在后台运行定时广播。注意，当应用重新启动时，MyService 也会重新启动，需要在 MyService 中处理这种情况。