Question

当我在前台发送带有数据有效负载的通知消息时，我的应用程序崩溃。当它处于后台或已终止状态时，它可以正常运行，但为什么不能在前景上运行？

这是错误：

java.lang.NullPointerException 在... MyFirebaseMessagingService.onMessageReceived（MyFirebaseMessagingService.java:57）

，错误表示，该行在MyFirebaseMessagingService中给出：

if(dataType.equals(getString(R.string.direct_message))){

编译器已经发现了问题，并显示：

方法调用“等于”可能会产生“ java.lang.NullPointerException”

这是 Firebase Messaging Service 类的一小部分：

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseMsgService";
    private static final int BROADCAST_NOTIFICATION_ID = 1;

    @Override
    public void onDeletedMessages() {
        super.onDeletedMessages();
    }

    /**
     * Called when message is received.
     *
     * @param remoteMessage Object representing the message received from Firebase Cloud Messaging.
     */
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {

        String notificationBody = "";
        String notificationTitle = "";
        String notificationData = "";
        try{
           notificationData = remoteMessage.getData().toString();
           notificationTitle = remoteMessage.getNotification().getTitle();
           notificationBody = remoteMessage.getNotification().getBody();
        }catch (NullPointerException e){
           Log.e(TAG, "onMessageReceived: NullPointerException: " + e.getMessage() );
        }
        Log.d(TAG, "onMessageReceived: data: " + notificationData);
        Log.d(TAG, "onMessageReceived: notification body: " + notificationBody);
        Log.d(TAG, "onMessageReceived: notification title: " + notificationTitle);


        String dataType = remoteMessage.getData().get(getString(R.string.data_type));
        if(dataType.equals(getString(R.string.direct_message))){
        Log.d(TAG, "onMessageReceived: new incoming message.");
            String title = remoteMessage.getData().get(getString(R.string.data_title));
            String message = remoteMessage.getData().get(getString(R.string.data_message));
            String messageId = remoteMessage.getData().get(getString(R.string.data_message_id));
            sendMessageNotification(title, message, messageId);

        }
    }
}

我猜(getString(R.string.direct_message)为空，但我不知道为什么前台它为空。我该如何解决这个问题？

在前台发送通知时，应用程序崩溃

0 个答案: