Facebook登录Android应用程序

Question

Hi all i'm trying to make a Facebook login in my android application and i want to pass Facebook username and Facebook id to another activity but i don't know how to do it. anyway my login doesn't works, my app closes when i open it. here is my activity:

import android.content.Context;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;

import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.FacebookSdk;
import com.facebook.login.LoginManager;
import com.facebook.login.LoginResult;
import com.facebook.login.widget.LoginButton;


public class LoginActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
    }


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

        CallbackManager callbackManager;
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            FacebookSdk.sdkInitialize(getApplicationContext());

            callbackManager = CallbackManager.Factory.create();

            LoginManager.getInstance().registerCallback(callbackManager,
                    new FacebookCallback<LoginResult>() {
                        @Override
                        public void onSuccess(LoginResult loginResult) {
                            // App code
                        }

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

                        @Override
                        public void onError(FacebookException exception) {
                            // App code
                        }
                    });
        }
        public PlaceholderFragment() {
        }

        public View onCreateView(
                LayoutInflater inflater,
                ViewGroup container,
                Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.activity_login, container, false);

            LoginButton loginButton = (LoginButton) view.findViewById(R.id.login_button);
            loginButton.setReadPermissions("user_friends");
            // If using in a fragment
            loginButton.setFragment(this);
            // Other app specific specialization

            // Callback registration
            CallbackManager callbackManager = null;
            loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
                @Override
                public void onSuccess(LoginResult loginResult) {
                    // App code
                }

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

                @Override
                public void onError(FacebookException exception) {
                    // App code
                }
            });

            return view;

        }


    }
}

i put that

  <com.facebook.login.widget.LoginButton
        android:id="@+id/login_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="30dp"
        android:layout_marginBottom="30dp" />

i'n my fragment.xml and in my activity.xml and this is my manifest.xml

?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.tekinarslan.material.sample" >

    <uses-permission android:name="android.permission.INTERNET" />

    <activity
        android:name="com.facebook.FacebookActivity"
        android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
        android:label="@string/app_name"
        android:theme="@android:style/Theme.Translucent.NoTitleBar" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <meta-data
            android:name="com.facebook.sdk.ApplicationId"
            android:value="@string/facebook_app_id" />

        <activity
            android:name=".SampleActivity"
            android:label="@string/app_name" >
        </activity>

        <activity
            android:name=".LoginActivity"
            android:label="@string/title_activity_login" >

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

the app closes before launch here is logcat

05-07 18:36:58.139    8270-8270/com.tekinarslan.material.sample E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tekinarslan.material.sample/com.tekinarslan.material.sample.LoginActivity}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
            at android.app.ActivityThread.access$700(ActivityThread.java:159)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:176)
            at android.app.ActivityThread.main(ActivityThread.java:5419)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.tekinarslan.material.sample.LoginActivity$PlaceholderFragment.onCreateView(LoginActivity.java:81)
            at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
            at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
            at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1188)
            at android.app.Activity.performStart(Activity.java:5382)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2266)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
            at android.app.ActivityThread.access$700(ActivityThread.java:159)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:176)
            at android.app.ActivityThread.main(ActivityThread.java:5419)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

I made a simple example which can work correctly.

AndroidMenifest.xml

<uses-permission android:name="android.permission.INTERNET"/>

<application
        android:name=".MyApplication"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <meta-data
            android:name="com.facebook.sdk.ApplicationId"
            android:value="@string/facebook_app_id"/>
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
            android:name="com.facebook.FacebookActivity"
            android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
            android:label="@string/app_name"
            android:theme="@android:style/Theme.Translucent.NoTitleBar"/>
</application>

MyApplication.java

public class MyApplication extends Application{
    @Override
    public void onCreate() {
        super.onCreate();
        FacebookSdk.sdkInitialize(this);
    }
}

MyActivity.java

public class MainActivity extends Activity {

    private CallbackManager callbackManager;
    private ProfileTracker profileTracker;
    private Button loginButton;
    private TextView textViewName;
    private ProfilePictureView profilePictureView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        callbackManager = CallbackManager.Factory.create();
        LoginManager.getInstance().registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {
                updateProfile();
            }

            @Override
            public void onCancel() {
                updateProfile();
            }

            @Override
            public void onError(FacebookException e) {
                updateProfile();
            }
        });

        textViewName = (TextView) findViewById(R.id.textViewName);
        profilePictureView = (ProfilePictureView) findViewById(R.id.profilePictureView);
        loginButton = (Button) findViewById(R.id.buttonLogin);
        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AccessToken token = AccessToken.getCurrentAccessToken();
                if (token == null) {
                    LoginManager.getInstance().logInWithReadPermissions(MainActivity.this, Arrays.asList("public_profile", "user_friends", "email"));
                } else {
                    LoginManager.getInstance().logOut();
                }
            }
        });

        profileTracker = new ProfileTracker() {
            @Override
            protected void onCurrentProfileChanged(Profile profile, Profile profile1) {
                updateProfile();
            }
        };
    }

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

    private void updateProfile() {
        Profile profile = Profile.getCurrentProfile();
        if (profile != null) {
            profilePictureView.setProfileId(profile.getId());
            textViewName.setText(profile.getName());
            loginButton.setText("Logout");

        } else {
            profilePictureView.setProfileId(null);
            textViewName.setText("not login yet");
            loginButton.setText("Login");
        }
    }

}

activity_main.xml

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical"
              android:paddingLeft="@dimen/activity_horizontal_margin"
              android:paddingRight="@dimen/activity_horizontal_margin"
              android:paddingTop="@dimen/activity_vertical_margin"
              android:paddingBottom="@dimen/activity_vertical_margin"
              tools:context=".MainActivity">

    <Button
            android:id="@+id/buttonLogin"
            android:text="Login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>


    <com.facebook.login.widget.ProfilePictureView
            android:id="@+id/profilePictureView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            />
    <TextView
            android:id="@+id/textViewName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

</LinearLayout>