Android Firebase制作认证

Question

我正在尝试使用Firebase身份验证使用Facebook个人资料唱歌，但我在运行代码时遇到错误：

java.lang.IllegalStateException：名称为 [DEFAULT] 的 FirebaseApp 不存在。

这是我的代码。有人能帮我解决那个问题吗？

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    checkFullscreen();
    setContentView(R.layout.activity_sign_in);
    callbackManager = CallbackManager.Factory.create();

    mAuth = FirebaseAuth.getInstance();

    facebookSignIn = (Button) findViewById(R.id.facebook_sing_in);
    facebookSignIn.setOnClickListener(this);

}



@Override
public void onClick(View v) {
    switch (v.getId()){
        case R.id.facebook_sing_in:
        {
            LoginManager.getInstance().registerCallback(callbackManager,
                    new FacebookCallback<LoginResult>() {
                        @Override
                        public void onSuccess(LoginResult loginResult) {
                            handleFacebookToken(loginResult.getAccessToken());
                             }

                        @Override
                        public void onCancel() {
                            // App code
                        }

                        @Override
                        public void onError(FacebookException exception) {
                            // App code
                        }
                    });
            LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile","email"));

            break;
        }
    }

}

private void handleFacebookToken(AccessToken token) {
    AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
    mAuth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {

                    }



            });
}

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

Answer 1

不用担心这个异常< code >(Java . lang . illegalstateexception:名为[DEFAULT]的FirebaseApp不存在)。因为，这是一个firebase bug。你的应用程序不会出现任何问题，所以忘记这个异常吧。

Answer 2

这应该适用于使用Firebase登录Facebook

LoginManager mLoginManager;

//Firebase Variables
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthStateListener;

private CallbackManager mCallbackManager;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    FacebookSdk.sdkInitialize(getApplicationContext());

mAuth = FirebaseAuth.getInstance();

    mAuthStateListener = new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
            FirebaseUser user = firebaseAuth.getCurrentUser();
            updateUI(user);
        }
    };

    mCallbackManager = CallbackManager.Factory.create();
     btnFacebookSignIn = (LoginButton) findViewById(R.id.button_facebook_signin);
    btnFacebookSignIn.setReadPermissions("email","public_profile");
    btnFacebookSignIn.registerCallback(mCallbackManager, new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            handleFacebookAccessToken(loginResult.getAccessToken());
        }

        @Override
        public void onCancel() {
        }

        @Override
        public void onError(FacebookException error) {
        }
    });

// [START onactivityresult]
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    mCallbackManager.onActivityResult(requestCode, resultCode, data);
}

 private void handleFacebookAccessToken(AccessToken token) {
    // ...
    AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
    mAuth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {

                    // If sign in fails, display a message to the user. If sign in succeeds
                    // the auth state listener will be notified and logic to handle the
                    // signed in user can be handled in the listener.
                    if (!task.isSuccessful()) {
                        Toast.makeText(LoginActivity.this, "Authentication failed.",
                                Toast.LENGTH_SHORT).show();
                    }

                    // ...
                }
            });
}

   private void updateUI(FirebaseUser user) {
    if (user != null) {

    }
 }
}

在updateUi（）方法中编写用户登录时的代码