java - 如何防止 "Firestore, Provided document path must not be null"错误？

Question

我有一个 Android 应用程序，目前有约 2000 名活跃用户。它使用 Firebase Firestore 数据库来保存用户数据和其他内容。但最近我从 readUserDataFromDatabase 函数收到此错误和崩溃报告:

    private void readUserDataFromDatabase(String uid) {
    db.collection(Constants.PARAM_USERS)
            .document(uid) // (MainActivity.java:215)This is where the crash happens 
            .get()
            .addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
                @Override
                public void onSuccess(DocumentSnapshot documentSnapshot) {
                    UserData userData = documentSnapshot.toObject(UserData.class);
                    if (userData == null) 
                        return;

                    tvName.setText(getString(R.string.welcome, userData.getName()));

                    Picasso
                            .get()
                            .load(userData.getPhotoUrl())
                            .placeholder(getResources().getDrawable(R.drawable.place_holder))
                            .transform(new RoundedCornersTransform())
                            .into(ivPhoto);

                    UserData.getInstance().setCredit(userData.getCredit());
                    UserData.getInstance().setPhotoUrl(userData.getPhotoUrl());
                    UserData.getInstance().setName(userData.getName());

                    if (userData.getInstanceId() != null) {
                        UserData.getInstance().setInstanceId(userData.getInstanceId());
                    }
                }
            });

}

此函数在从登录 Activity 重定向并成功登录过程后运行:

private void setUser(final FirebaseUser user) {
    if (user == null)
        return;

    UserData.getInstance().setUserId(user.getUid());// I'm using this Uid for create node for user.
    DocumentReference docRef = db.collection(Constants.PARAM_USERS).document(user.getUid());

    docRef
            .get()
            .addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
                @Override
                public void onSuccess(DocumentSnapshot documentSnapshot) {
                    UserData userData = documentSnapshot.toObject(UserData.class);
                    if (userData == null) {
                        createUser(user);
                    } else {
                        redirectToHome(); //login succeed
                    }
                }
            }).addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {

        }
    });
}

并从重定向的 Activity 中调用这样的 readUserDataFromDatabase 函数:

 readUserDataFromDatabase(UserData.getInstance().getUserId());

崩溃率约为 %1，但我仍然看不到我在这里错过了什么。 firebase用户id是否有可能返回null或登录成功后，readUserDataFromDatabase在

之前运行

UserData.getInstance().setUserId(user.getUid());

功能？我不知道。谢谢。

编辑 1:添加堆栈跟踪。

Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.alialacan.kpss/com.alialacan.kpss.MainActivity}: java.lang.NullPointerException: Provided document path must not be null. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2781) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2859) at android.app.ActivityThread.-wrap11(Unknown Source) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1592) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:6518) at java.lang.reflect.Method.invoke(Method.java) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

Caused by java.lang.NullPointerException: Provided document path must not be null.
       at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:228)
       at com.google.firebase.firestore.CollectionReference.document(SourceFile:90)
       at com.alialacan.kpss.MainActivity.readUserDataFromDatabase(MainActivity.java:215)
       at com.alialacan.kpss.MainActivity.onCreate(MainActivity.java:114)
       at android.app.Activity.performCreate(Activity.java:7013)
       at android.app.Activity.performCreate(Activity.java:7004)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1215)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2734)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2859)
       at android.app.ActivityThread.-wrap11(Unknown Source)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1592)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loop(Looper.java:164)
       at android.app.ActivityThread.main(ActivityThread.java:6518)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

编辑2:这里是调用setUser函数的位置:

    @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    callbackManager.onActivityResult(requestCode, resultCode, data);

    if (requestCode == Constants.RC_SIGN_IN) {
        GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
        if (result.isSuccess()) {
            GoogleSignInAccount account = result.getSignInAccount();
            firebaseAuthWithGoogle(account);
        } else {
            Toast.makeText(LoginActivity.this, R.string.error_google_login,
                    Toast.LENGTH_SHORT).show();
            hideProgress();
        }
    }
}

 private void handleFacebookAccessToken(AccessToken token) {
    Log.d("", "handleFacebookAccessToken:" + token);

    AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
    auth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if (task.isSuccessful()) {                          
                        Log.d("", "signInWithCredential:success");
                        user = auth.getCurrentUser();
                        setUser(user);
                    } else {
                        setUser(null);
                        Log.w("", "signInWithCredential:failure", task.getException());
                        Toast.makeText(LoginActivity.this, R.string.error_email_already_exist,
                                Toast.LENGTH_SHORT).show();
                        hideProgress();
                    }
                }
            });
}

 private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
    AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
    auth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if (task.isSuccessful()) {
                        FirebaseUser user = auth.getCurrentUser();
                        setUser(user);
                    } else {
                        Toast.makeText(LoginActivity.this, R.string.error_google_login,
                Toast.LENGTH_SHORT).show();
                        setUser(null);
                        hideProgress();
                    }
                }
            });
}

Answer 1

错误消息表明此代码正在将 null 值传递给 readUserDataFromDatabase

readUserDataFromDatabase(UserData.getInstance().getUserId());

这意味着 UserData.getInstance().getUserId() 返回 null。

这里确实没有足够的代码来完全诊断问题，因为您也没有显示调用 setUser 的内容，但您需要将其追溯到源头。