Android Firebase验证返回按钮

我的android应用程序中的firebase身份验证没有后退按钮。如果onActivityResult生成取消结果，我希望能够导航回主活动

如何启用此功能？我正在使用预构建的身份验证

    final int RC_SIGN_IN = 0;
    List<AuthUI.IdpConfig> providers = Arrays.asList(
            new AuthUI.IdpConfig.EmailBuilder().build(),
            new AuthUI.IdpConfig.PhoneBuilder().build(),
            new AuthUI.IdpConfig.GoogleBuilder().build()
    );

    Intent intent = AuthUI.getInstance()
            .createSignInIntentBuilder()
            .setAvailableProviders(providers)
            .setTheme(R.style.FirebaseUI)
            .build();

    startActivityForResult(intent, RC_SIGN_IN);

final int RC\u SIGN\u IN=0；
列表提供程序=Arrays.asList(
新建AuthUI.IdpConfig.EmailBuilder（）.build（），
新建AuthUI.IdpConfig.PhoneBuilder（）.build（），
新建AuthUI.IdpConfig.GoogleBuilder（）.build（）
);
Intent=AuthUI.getInstance（）
.CreateSignInEntBuilder（）
.setAvailableProviders（提供程序）
.setTheme（R.style.FirebaseUI）
.build（）；
startActivityForResult（意向、RC登录）；

调用

super.onBackPressed（）

将导航回上一个活动

    private static final int RC_SIGN_IN = 1;

    private void signIn () {
        Intent signInIntent = mGoogleSignInClient.getSignInIntent ();
        startActivityForResult ( signInIntent, RC_SIGN_IN );
        //Show user that authentication has started
    }

    @Override
    public void onActivityResult ( int requestCode, int resultCode, Intent data ) {
        super.onActivityResult ( requestCode, resultCode, data );
        if (requestCode == RC_SIGN_IN) {
            Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent ( data );
            try {
                GoogleSignInAccount account = task.getResult ( ApiException.class );
                assert account != null;
                firebaseAuthWithGoogle ( account.getIdToken () );
            } catch (ApiException e) {
                Toast.makeText ( this, "Google Sign In failed", Toast.LENGTH_SHORT ).show ();
                mGoogleSignInClient.signOut ();
                mAuth.signOut ();
                //Show user that authentication failed
                //In your case navigate to MainActivity()
                super.onBackPressed (); //Navigates to previous activity
            }
        }
    }

    private void firebaseAuthWithGoogle ( String idToken ) {
        AuthCredential credential = GoogleAuthProvider.getCredential ( idToken, null );
        mAuth.signInWithCredential ( credential )
                .addOnCompleteListener ( this, task -> {
                    if (task.isSuccessful ()) {
                        FirebaseUser user = mAuth.getCurrentUser ();
                        if (user != null) {
                            //Authenticated successfully
                        } else {
                            //Try to authenticate again
                            //This might not happen in most scenarios
                            signIn ();
                        }
                    } else {
                        Toast.makeText ( this, "Google Sign In failed", Toast.LENGTH_SHORT ).show ();
                        mGoogleSignInClient.signOut ();
                        mAuth.signOut ();
                        //Show user that authentication failed
                        //In your case navigate to MainActivity()
                        super.onBackPressed (); //Navigates to previous activity
                    }
                } );
    }

我假设您使用的是firebase google身份验证。如果发生任何故障，以下代码片段可能会帮助您导航回MainActivity

要启动身份验证，请调用

signIn（）

方法

如果发生任何API异常，

onActivityResult（）

方法将导航回上一个活动

    private static final int RC_SIGN_IN = 1;

    private void signIn () {
        Intent signInIntent = mGoogleSignInClient.getSignInIntent ();
        startActivityForResult ( signInIntent, RC_SIGN_IN );
        //Show user that authentication has started
    }

    @Override
    public void onActivityResult ( int requestCode, int resultCode, Intent data ) {
        super.onActivityResult ( requestCode, resultCode, data );
        if (requestCode == RC_SIGN_IN) {
            Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent ( data );
            try {
                GoogleSignInAccount account = task.getResult ( ApiException.class );
                assert account != null;
                firebaseAuthWithGoogle ( account.getIdToken () );
            } catch (ApiException e) {
                Toast.makeText ( this, "Google Sign In failed", Toast.LENGTH_SHORT ).show ();
                mGoogleSignInClient.signOut ();
                mAuth.signOut ();
                //Show user that authentication failed
                //In your case navigate to MainActivity()
                super.onBackPressed (); //Navigates to previous activity
            }
        }
    }

    private void firebaseAuthWithGoogle ( String idToken ) {
        AuthCredential credential = GoogleAuthProvider.getCredential ( idToken, null );
        mAuth.signInWithCredential ( credential )
                .addOnCompleteListener ( this, task -> {
                    if (task.isSuccessful ()) {
                        FirebaseUser user = mAuth.getCurrentUser ();
                        if (user != null) {
                            //Authenticated successfully
                        } else {
                            //Try to authenticate again
                            //This might not happen in most scenarios
                            signIn ();
                        }
                    } else {
                        Toast.makeText ( this, "Google Sign In failed", Toast.LENGTH_SHORT ).show ();
                        mGoogleSignInClient.signOut ();
                        mAuth.signOut ();
                        //Show user that authentication failed
                        //In your case navigate to MainActivity()
                        super.onBackPressed (); //Navigates to previous activity
                    }
                } );
    }

---

我希望这个答案可以帮助你

如果你问如何改变Firebase UI的工作方式，你可以通过复制其源代码并添加你想要的内容来做任何事情：调用

finish（）

停止当前活动并返回不是更容易吗？嗨@DougStevenson！。是的，你说得对。调用

finish（）。正如@onStackOverflowListener的问题一样，如何导航回去，我只是使用了
super.onBackPressed（）
方法来实现这个目的。还有一个优点是，
finish（）
不能被覆盖。但是可以覆盖
onBackPressed（）
，这可能有助于在导航到上一个活动时进一步添加功能。我使用的是内置的身份验证系统。这是通过编写自己的身份验证流来实现的唯一方法。