Question

我正在我的应用程序中运行Firebase Firestore。而且我在调用前两行时得到了Null Pointer Exception：

FirebaseApp.initializeApp(this)
val db = FirebaseFirestore.getInstance()

从build.gradle-项目：

classpath 'com.google.gms:google-services:4.1.0' (also tried 4.0.0)

从build.gradle-应用程序：（当前最新）

implementation 'com.google.firebase:firebase-core:16.0.5'
implementation 'com.google.firebase:firebase-firestore:17.1.3'

如果我在创建实例时设置断点-我最终会遇到ActivityThread类-registerOnActivityPausedListener方法。 http://take.ms/Fdh7z

代码在其他设备上也可以正常使用。但是在其中一个（Wileyfox Swift 2）上，我得到了NLP并且没有很好的解释：

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.firebase.auth.internal.zzab.zzf(int)' on a null object reference
        at com.google.firebase.auth.FirebaseAuth.addIdTokenListener(Unknown Source)
        at com.google.firebase.firestore.auth.FirebaseAuthCredentialsProvider.<init>(com.google.firebase:firebase-firestore@@17.1.3:76)
        at com.google.firebase.firestore.FirebaseFirestore.newInstance(com.google.firebase:firebase-firestore@@17.1.3:109)
        at com.google.firebase.firestore.FirestoreMultiDbComponent.get(com.google.firebase:firebase-firestore@@17.1.3:51)
        at com.google.firebase.firestore.FirebaseFirestore.getInstance(com.google.firebase:firebase-firestore@@17.1.3:87)
        at com.google.firebase.firestore.FirebaseFirestore.getInstance(com.google.firebase:firebase-firestore@@17.1.3:72)
        at com.myjob.exchange.activity.SplashActivity.onCreate(SplashActivity.kt:25)
        at android.app.Activity.performCreate(Activity.java:6723)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)

Answer 1

确保您已将应用程序与Firebase（google-services.json）文件连接，然后尝试执行以下操作：

FirebaseFirestore db = FirebaseFirestore.getInstance();
FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
        .setTimestampsInSnapshotsEnabled(true)
        .build();
db.setFirestoreSettings(settings);

Answer 2

问题出在以下几行：

implementation 'com.google.firebase:firebase-core:16.0.5'
implementation 'com.google.firebase:firebase-firestore:17.1.3'

更改为这些内容后，恢复工作：

'com.google.firebase:firebase-core:16.0.3' implementation 'com.google.firebase:firebase-firestore:17.1.0'

Answer 3

更改类别

classpath 'com.google.gms:google-services:4.1.0'

TO

classpath 'com.google.gms:google-services:4.2.0'

FirebaseFirestore.getInstance（）给出Null指针异常

3 个答案: