Question

为什么我无法在facebook身份验证代码中启动活动？

1.代码运行良好，但登录后我想开始一个活动，意味着它应该放在某个地方放置startActivity方法

public class LoginActivity extends AppCompatActivity {
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
private static final String TAG = "Login";
private CallbackManager mCallbackManager;
Intent intent=new Intent(this,MainActivity.class);
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    FacebookSdk.sdkInitialize(getApplicationContext());
    setContentView(R.layout.activity_login);

    AppEventsLogger.activateApp(this);


    mAuth = FirebaseAuth.getInstance();

    mAuthListener = new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
            FirebaseUser user = firebaseAuth.getCurrentUser();
            if (user != null) {
                // User is signed in
                Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
            } else {
                // User is signed out
                Log.d(TAG, "onAuthStateChanged:signed_out");
            }
            // ...
        }
    };


    // Initialize Facebook Login button
    mCallbackManager = CallbackManager.Factory.create();
    LoginButton loginButton = (LoginButton) findViewById(R.id.button_facebook_login);
    loginButton.setReadPermissions("email", "public_profile");
    loginButton.registerCallback(mCallbackManager, new FacebookCallback<LoginResult>() {


        @Override
        public void onSuccess(LoginResult loginResult) {
            Log.d(TAG, "facebook:onSuccess:" + loginResult);
            handleFacebookAccessToken(loginResult.getAccessToken());
            //startActivity(intent);
        }

        @Override
        public void onCancel() {
            Log.d(TAG, "facebook:onCancel");
            // ...
        }

        @Override
        public void onError(FacebookException error) {
            Log.d(TAG, "facebook:onError", error);
            // ...
        }

    });

    // ...
}


@Override
public void onStart() {
    super.onStart();
    mAuth.addAuthStateListener(mAuthListener);
}

@Override
public void onStop() {
    super.onStop();
    if (mAuthListener != null) {
        mAuth.removeAuthStateListener(mAuthListener);
    }

}

// ...

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

        // Pass the activity result back to the Facebook SDK
        mCallbackManager.onActivityResult(requestCode, resultCode, data);
    }private void handleFacebookAccessToken(AccessToken token) {
    Log.d(TAG, "handleFacebookAccessToken:" + token);
    // [START_EXCLUDE silent]
    //showProgressDialog
    // [END_EXCLUDE]

    AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
    mAuth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful());

                    // 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()) {
                        Log.w(TAG, "signInWithCredential", task.getException());
                        Toast.makeText(LoginActivity.this, "Authentication failed.",
                                Toast.LENGTH_SHORT).show();
                    }

                    // [START_EXCLUDE]
                    //hideProgressDialog();
                    // [END_EXCLUDE]
                }
            });
}
// [END auth_with_facebook]

}

Answer 1

您可以在AuthStateListener目前拥有的地方执行此操作：

        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
        FirebaseUser user = firebaseAuth.getCurrentUser();
        if (user != null) {
            // User is signed in
            Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
            // you can also add anything else that should happen when user
            // has successfully signed in
        } else {
            // User is signed out
            Log.d(TAG, "onAuthStateChanged:signed_out");
        }

正如评论所述，当user != null用户登录时，您就可以在其中开始您的活动或您想要做的任何事情。

当用户通过Facebook（或您添加的任何其他登录）成功登录Firebase Auth时，将调用onAuthStateChanged方法。

在firebase facebook身份验证代码中启动活动

1 个答案: