“请提出解决方案”
我想建议使用Services。最推荐您阅读 Android Studio here 的文档。
关于服务有很多需要了解的地方，但目前我相信 sn-p 对您最有帮助，这里有一些代码，
创建一个名为 HelloService 的类
并将以下代码粘贴到正确的导入中*
public class HelloService extends Service {
private Looper mServiceLooper;
private ServiceHandler mServiceHandler;
// Handler that receives messages from the thread
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
// Normally we would do some work here, like download a file.
// For our sample, we just sleep for 5 seconds.
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// Restore interrupt status.
Thread.currentThread().interrupt();
}
// Stop the service using the startId, so that we don't stop
// the service in the middle of handling another job
stopSelf(msg.arg1);
}
}
@Override
public void onCreate() {
// Start up the thread running the service. Note that we create a
// separate thread because the service normally runs in the process's
// main thread, which we don't want to block. We also make it
// background priority so CPU-intensive work will not disrupt our UI.
HandlerThread thread = new HandlerThread("ServiceStartArguments",
Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
// Get the HandlerThread's Looper and use it for our Handler
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Toast.makeText(this, "servicestarting",Toast.LENGTH_SHORT).show();
Message msg = mServiceHandler.obtainMessage();
msg.arg1 = startId;
mServiceHandler.sendMessage(msg);
// If we get killed, after returning from here, restart
return START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
// We don't provide binding, so return null
return null;
}
@Override
public void onDestroy() {
Toast.makeText(this, "service done", Toast.LENGTH_SHORT).show();
}
}
“这太夸张了”你可能会这样想。然而事实恰恰相反。
服务 + Firebase 示例
假设您想在某个数据库中发生修改时通知用户，而不是从 Firebase 推送消息
首先，在 Oncreate 上创建数据库引用
mDatabaseLike=FirebaseDatabase.getInstance().getReference().child("Likes");
转到“handleMessage 方法”并添加以下内容
@Override
public void handleMessage(Message msg) {
mDatabaseLike.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
notifyUserOfDBupdate()
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
//stopSelf(msg.arg1);
}
}
这里是 notifyUserOfDBupdate 方法以及如何通知用户
private void notifyUserOfDBupdate() {
//Intents
Intent Pdf_view = new Intent(this, //class to throw the user when they hit on notification\\.class);
PendingIntent pdf_view = PendingIntent.getActivity(this, 0, Pdf_view, 0);
//Notification Manager
NotificationManager nm = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
//The note
Uri soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Notification noti = new NotificationCompat.Builder(getApplicationContext())
.setTicker("TickerTitle")
.setContentTitle("content title")
.setSound(soundUri)
.setContentText("content text")
.setContentIntent(pdf_view).getNotification();
//Execution
noti.flags = Notification.FLAG_AUTO_CANCEL;
nm.notify(0, noti);
}
现在在您的真实设备上运行您的应用程序一次，然后在模拟器上运行第二次。一旦两者中的任何一个修改了您的 firebase 数据库，另一个将立即得到通知。
在 HandleMessage 方法中修改您喜欢的任何方法。它将是永恒的，除非你让它可以被杀死。
最诚挚的问候