如何在Android Studio中通过fragments和viewpager使用Facebook登录进行Firebase身份验证？

Question

我的构建成功完成，但应用程序崩溃。有人会像我的代码中那样，在Android Studio中使用Viewpager和片段编写一个关于如何将Firebase Auth与Facebook登录链接的教程吗？我的应用程序中需要一个滑块。

    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;
 @Override 
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activitenter code herey_main);
 mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.

        mViewPager = (ViewPager) findViewById(R.id.container);
    enter code here
        mViewPager.setAdapter(mSectionsPagerAdapter);

        mAuth = FirebaseAuth.getInstance();

        // Initialize Facebook Login button
        mCallbackManager = CallbackManager.Factory.create();
        LoginButton loginButton = findViewById(R.id.login_button);

//Here problem start

        loginButton.setReadPermissions("email", "public_profile");

        loginButton.registerCallback(mCallbackManager, new 

FacebookCallback<LoginResult>() {

            @Override
    enter code here
            public void onSuccess(LoginResult loginResult) {

                Log.d(TAG, "facebook:onSuccess:" + loginResult);

               handleFacebookAccessToken(loginResult.getAccessToken());
            }

            @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();

        // Check if user is signed in (non-null) and update UI accordingly.

        FirebaseUser currentUser = mAuth.getCurrentUser();
        if(currentUser != null){
            updateUI();

        }
    }

    private void updateUI() {

        Toast.makeText(MainActivity.this, "You are logged in!" , 
Toast.LENGTH_LONG).show();

    }

    @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);

        AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
        mAuth.signInWithCredential(credential)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            Log.d(TAG, "signInWithCredential:success");
                            FirebaseUser user = mAuth.getCurrentUser();
                            updateUI();
                        } else {
                            // If sign in fails, display a message to the user.
                            Log.w(TAG, "signInWithCredential:failure", task.getException());
                            Toast.makeText(MainActivity.this, "Authentication failed."[enter image description here][1],
                                    Toast.LENGTH_SHORT).show();

                        }

                        // ...
                    }
                });
    }





/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View rootView = null;

        switch (getArguments().getInt(ARG_SECTION_NUMBER)) {
            case 1:
            rootView = inflater.inflate(R.layout.fragment_main, container, false);



                break;

            case 2:
                rootView = inflater.inflate(R.layout.fragment_second, container, false);

                break;
        }

    return rootView;
    }
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */



public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class below).
        return PlaceholderFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        // Show 2 total pages.
        return 2;`enter code here`
    }
}

没有碎片的应用程序工作得非常完美。有人知道为什么吗？

这是例外：

2019-01-19 11:13:05.129 8439-8439/jimmy.jimmyfindgymbuddyptl.com.myapplicationE/AndroidRuntime： FATAL EXCEPTION：主进程：jimmy.jimmyfindgymbuddyptl.com.myapplication， PID： 8439java.lang.RuntimeExc0019：无法启动活动ComponentInfo{jimmy.jimmyfindgymbuddyptl.com.myapplication/jimmy.jimmyfindgymbuddyptl.com.myapplication.MainActivity}：java.lang.在android.app.ActivityThread.perform启动活动（ActivityThread.java:2646）的空对象引用上，尝试调用虚拟方法“无效com.facebook.login.widget.LoginButton.set读取权限（java.lang.字符串[]）”ActivityThread.handle启动活动（ActivityThread.java:2707）在android.app.ActivityThread.-wrap12（ActivityThread.java）在android.app.ActivityThread$H. handleMessage（ActivityThread.java:1460）在android.os.Handler.dispatch消息（Handler. java： 102）在android. os.在android. app.ActivityThread. main（ActivityThread. java： 6077）在java. lang.反射。方法调用（本机方法）在com. android. interal. os。ZygoteInit$method odAndArgsCaller. run（ZygoteInit. java： 866）在com. android. interal. os。ZygoteInit. main（ZygoteInit. java： 756）引起：java. lang.NullPointerExcture：尝试调用虚拟方法'无效com. facebook. login. widget。java. lang.字符串[]）'在一个空对象引用在jimmy. jimmyfindymadddyptl. com. myApplication.在android. app.在android. app.在android. app.在android. app上的ActivityThread. performLaunch活动（ActivityThread. java： 2599）。处理启动活动（ActivityThread. java： 2707）

此按钮为xml格式：

<com.facebook.login.widget.LoginButton android:id="@+id/login_button" 
  android:layout_width="190dp" android:layout_height="wrap_content" 
  android:layout_above="@+id/textView7" android:layout_alignParentStart="true" 
  android:layout_marginStart="95dp" android:layout_marginBottom="6dp" />

Answer 1

您可以使用Firebase Facebook身份验证。检查https://firebase.google.com/docs/auth/android/facebook-login留档

Answer 2

我在同一个地方也犯了类似的错误。不确定这是否对您有帮助，但我忘了将我的内容视图设置为resources/layout文件夹中的facebook活动。

即。

在onCreate方法中。。。

setContentView(R.layout.activity_facebook);

我希望这能有所帮助。

Answer 3

看起来您正在使用Firebase Auth的旧方法。最近在使用Firebase Auth SDK方面进行了更新，新方法非常简单，代码也非常少。请参阅此处了解更多详细信息https://firebase.google.com/docs/auth/android/firebaseui

这是设置Facebook身份验证提供商和启动身份验证意图的方法。您需要为Callaback处理和用户界面定制（如果适用）添加单独的逻辑，这些逻辑也可在上述文档链接上获得。请检查一次，希望这将减少您的代码并解决问题。

// Choose authentication providers
List<AuthUI.IdpConfig> providers = Arrays.asList(
        new AuthUI.IdpConfig.FacebookBuilder().build());

// Create and launch sign-in intent
startActivityForResult(
        AuthUI.getInstance()
                .createSignInIntentBuilder()
                .setAvailableProviders(providers)
                .build(),
        RC_SIGN_IN);