当收到来自firebase PHP API的通知时，应用程序崩溃

Question

我想通过firebase PHP API向用户发送通知。我遵循了一个教程，但当API运行时，应用程序崩溃，如果应用程序不打开，什么都不会发生。

这是代码：

<?php
define( 'API_ACCESS_KEY', 'Server_key' ); // get API access key from Google/Firebase API's Console
$registrationIds = array( 'fUAIyAPjSSGfiykT6Y0PwC:APA91bGxIDUfgD01tfNjyd12NxMsPq_Dv_O72ifh6fYL-_6P_WLanGJCjyxKo7JkF2QyyJjIsF__HKePJACI7bMl9NEkeXN1uyUhiu1-DkISpworIoVNpzT4gXLy0w92dtEF94mD5T8G' ); //Replace this with your device token

// Modify custom payload here
$msg = array
(
'mesgTitle'     => 'SMART TESTING',
'alert'         => 'This is sample notification'
);
$fields = array
(
'registration_ids'      => $registrationIds,
'data'                  => $msg
);
$headers = array
(
'Authorization: key=' . API_ACCESS_KEY,
'Content-Type: application/json'
);
$ch = curl_init();
curl_setopt( $ch,CURLOPT_URL, 'https://fcm.googleapis.com/fcm/send' ); //For firebase, use https://fcm.googleapis.com/fcm/send
curl_setopt( $ch,CURLOPT_POST, true );
curl_setopt( $ch,CURLOPT_HTTPHEADER, $headers );
curl_setopt( $ch,CURLOPT_RETURNTRANSFER, true );
curl_setopt( $ch,CURLOPT_SSL_VERIFYPEER, false );
curl_setopt( $ch,CURLOPT_POSTFIELDS, json_encode( $fields ) );
$result = curl_exec($ch );
curl_close( $ch );
echo $result;
?>

我可以通过firebase发送通知，没有任何问题。注意：我使用Xampp在localhost上运行PHP代码。

这是我的应用程序代码：

主要活动

protected void onCreate(Bundle savedInstanceState) {
checkFirstRun=Boolean.FALSE;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
prefs = getSharedPreferences("com.example.fonefinder", MODE_PRIVATE);



NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
NotificationChannel notificationChannel=
new NotificationChannel(MyNotification.CHANNEL_ID,MyNotification.CHANNEL_NAME,NotificationManager.IMPORTANCE_HIGH);
notificationChannel.setDescription(MyNotification.CHANNEL_DESCRIPTION);
//notificationChannel.enableLights(true);
//notificationChannel.setLightColor(Color.RED);
notificationChannel.enableVibration(true);
notificationManager.createNotificationChannel(notificationChannel);

}

FirebaseInstanceIdService:

public class FirebaseInstance extends FirebaseInstanceIdService {
public String refreshedToken;
@Override
public void onTokenRefresh() {
// Get updated InstanceID token.
refreshedToken = FirebaseInstanceId.getInstance().getToken();
//Log.d("MyToken",refreshedToken);

FirebaseMessagingService：

public class FirebaseMessaging extends FirebaseMessagingService {
@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
String title=remoteMessage.getNotification().getTitle();
String body=remoteMessage.getNotification().getBody();
MyNotification.getInstance(getApplicationContext()).displayNotification(title,body);

}
}

MyNotification：

public class MyNotification {
public static final String CHANNEL_ID="myChannelID";
public static final String CHANNEL_NAME="myChannelName";
public static final String CHANNEL_DESCRIPTION="myChannelDescription";
private Context nCtx;
private static MyNotification myNotification;
private MyNotification(Context context){
nCtx = context;
}
public static synchronized MyNotification getInstance(Context context){
if (myNotification==null){
myNotification = new MyNotification(context);
}
return myNotification;
}
public void displayNotification(String title,String body){
NotificationCompat.Builder nBuilder = new NotificationCompat.Builder(nCtx,CHANNEL_ID)
.setSmallIcon(R.drawable.icon)
.setContentText(title)
.setContentTitle(body);
Intent intent = new Intent(nCtx,MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(nCtx,0,intent,PendingIntent.FLAG_UPDATE_CURRENT);
nBuilder.setContentIntent(pendingIntent);
NotificationManager notificationManager = (NotificationManager) nCtx.getSystemService(Context.NOTIFICATION_SERVICE);
if (notificationManager!=null){
notificationManager.notify(1,nBuilder.build());
}
}
}

错误：

2020-12-20 17:17:32.602 19407-19484/com.example.fonefinder E/AndroidRuntime: FATAL EXCEPTION: Firebase-Messaging-Intent-Handle
Process: com.example.fonefinder, PID: 19407
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.messaging.RemoteMessage$Notification.getTitle()' on a null object reference
at com.example.fonefinder.FirebaseMessaging.onMessageReceived(FirebaseMessaging.java:9)
at com.google.firebase.messaging.FirebaseMessagingService.dispatchMessage(com.google.firebase:firebase-messaging@@21.0.0:64)
at com.google.firebase.messaging.FirebaseMessagingService.passMessageIntentToSdk(com.google.firebase:firebase-messaging@@21.0.0:34)
at com.google.firebase.messaging.FirebaseMessagingService.handleMessageIntent(com.google.firebase:firebase-messaging@@21.0.0:27)
at com.google.firebase.messaging.FirebaseMessagingService.handleIntent(com.google.firebase:firebase-messaging@@21.0.0:17)
at com.google.firebase.messaging.EnhancedIntentService.lambda$processIntent$0$EnhancedIntentService(com.google.firebase:firebase-messaging@@21.0.0:43)
at com.google.firebase.messaging.EnhancedIntentService$$Lambda$0.run(Unknown Source:6)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
at com.google.android.gms.common.util.concurrent.zza.run(Unknown Source:6)
at java.lang.Thread.run(Thread.java:784)

Answer 1

我发现了问题：

public class FirebaseMessaging extends FirebaseMessagingService {
@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
String title=remoteMessage.getNotification().getTitle();
String body=remoteMessage.getNotification().getBody();
MyNotification.getInstance(getApplicationContext()).displayNotification(title,body);

}
}

firebase API不支持remoteMessage，所以如果您删除它并手动设置标题和正文，问题就会得到解决。

我不知道如何从API获得标题和正文。