Question

我创建了一个应用，该应用获取用户的电话令牌，以便能够在应用聊天中相互发送消息。

我注意到打开应用程序后第一次安装时会崩溃。

我得到的错误是：

if request.method == "POST":
        bid = Bids.objects.filter(auction=item_id).aggregate(Max('bid_value'))['bid_value__max']

        .....

它出现在此行：

E/AndroidRuntime: FATAL EXCEPTION: Firebase-Messaging-Intent-Handle
    Process: com.example.app, PID: 9048
    java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.firestore.CollectionReference com.google.firebase.firestore.FirebaseFirestore.collection(java.lang.String)' on a null object reference
        at com.example.app.service.MyFirebaseMessagingService.onNewToken(MyFirebaseMessagingService.java:94)
        at com.google.firebase.messaging.FirebaseMessagingService.zzc(com.google.firebase:firebase-messaging@@20.2.1:108)
        at com.google.firebase.messaging.zzh.run(com.google.firebase:firebase-messaging@@20.2.1:2)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at com.google.android.gms.common.util.concurrent.zza.run(com.google.android.gms:play-services-basement@@17.1.1:6)
        at java.lang.Thread.run(Thread.java:764)
I/Process: Sending signal. PID: 9048 SIG: 9
Disconnected from the target VM, address: 'localhost:8601', transport: 'socket'

据我了解，由于没有public class MyFirebaseMessagingService extends FirebaseMessagingService { private FirebaseAuth auth; private FirebaseFirestore db; @Override public void onMessageReceived(RemoteMessage remoteMessage) { createNotificationChannel(); notifyThis(remoteMessage.getData().get("title"),remoteMessage.getData().get("body"),remoteMessage.getData().get( "uniqueID" ),remoteMessage.getData().get("var1"),remoteMessage.getData().get("var2"),remoteMessage.getData().get("var3")); } private void createNotificationChannel() { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { //I CREATE NOTIFICATION HERE } } public void notifyThis(String title, String message, String uniqueID, String var1, String var2, String var3) { //I CREATE NOTIFICATION HERE } @Override public void onNewToken(@NonNull String token) { CollectionReference usernamedb = db.collection( "User" ).document( auth.getUid() ).collection( "Data" ); <-----HERE I GET ERROR usernamedb.get().addOnCompleteListener( task2 -> { if (task2.isSuccessful()) { for (QueryDocumentSnapshot document : task2.getResult()) { Map<String, Object> user_token = new HashMap<>(); user_token.put( "Token", token ); db.collection( "User" ).document( auth.getUid() ).collection( "Data" ).document(document.getId()).update(user_token); } } } ); } }，这是崩溃的，因为这是用户第一次登录。但是，如何确保只有在之后才第一次调用auth.getUid()用户实际上已登录？

安装后首次使用onNewToken会使应用程序崩溃

0 个答案: