Facebook登录无法在我的Android应用程序中运行

时间：2016-05-16 09:19:29

标签： android facebook-login

我正在尝试在我的应用程序中实现facebook登录，但每当我启动我的应用程序时它都会崩溃。我正关注facebook developer网站。这是我的代码。

MainActivity.java 

package com.algor7.samplelogin;
...
public class MainActivity extends Activity {

private LoginButton loginButton;
private CallbackManager callbackManager;
private AccessTokenTracker accessTokenTracker;
private AccessToken accessToken;
private ProfileTracker profileTracker;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    FacebookSdk.sdkInitialize(this.getApplicationContext());
    callbackManager = CallbackManager.Factory.create();

    accessTokenTracker = new AccessTokenTracker() {
        @Override
        protected void onCurrentAccessTokenChanged(
                AccessToken oldAccessToken,
                AccessToken currentAccessToken) {
            // Set the access token using
            // currentAccessToken when it's loaded or set.
        }
    };
    // If the access token is available already assign it.
    accessToken = AccessToken.getCurrentAccessToken();

    profileTracker = new ProfileTracker() {
        @Override
        protected void onCurrentProfileChanged(
                Profile oldProfile,
                Profile currentProfile) {
            // App code
        }
    };

    loginButton.findViewById(R.id.login_button);
    loginButton.setReadPermissions("email");
    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
        }
    });

}

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

@Override
public void onDestroy() {
    super.onDestroy();
    accessTokenTracker.stopTracking();
    profileTracker.stopTracking();
}

}

activity_main.xml中

<RelativeLayout 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:gravity="center"
tools:context=".MainActivity">

<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" />

</RelativeLayout>

的strings.xml 

<resources>
<string name="app_name">SampleLogin</string>
<string name="facebook_app_id">4932151xxxxxxxx</string>
<string name="fb_login_protocol_scheme">fb4932151xxxxxxxx</string>

的AndroidManifest.xml 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.algor7.samplelogin" >

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

<application
    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.CustomTabActivity"
        android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />
            <data android:scheme="@string/fb_login_protocol_scheme" />
        </intent-filter>
    </activity>

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

</application>

的build.gradle（项目：）

buildscript {
repositories {
    mavenCentral()
}
 dependencies {
    classpath 'com.android.tools.build:gradle:1.3.0'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
 }
}

allprojects {
  repositories {
    jcenter()
  }
}

的build.gradle（模块：应用）

apply plugin: 'com.android.application'

android {
compileSdkVersion 23
buildToolsVersion "23.0.3"

defaultConfig {
    applicationId "com.algor7.samplelogin"
    minSdkVersion 17
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
}

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:24.0.0-alpha2'
compile 'com.facebook.android:facebook-android-sdk:[4,5)'
}

Logcat：

--------- beginning of crash
05-16 15:28:57.915    2478-2478/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.algor7.samplelogin, PID: 2478
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.algor7.samplelogin/com.algor7.samplelogin.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View com.facebook.login.widget.LoginButton.findViewById(int)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
        at android.app.ActivityThread.-wrap11(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View com.facebook.login.widget.LoginButton.findViewById(int)' on a null object reference
        at com.algor7.samplelogin.MainActivity.onCreate(MainActivity.java:54)
        at android.app.Activity.performCreate(Activity.java:6251)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
        at android.app.ActivityThread.-wrap11(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

请帮我解决这个问题。提前谢谢！

3 个答案:

答案 0 :(得分：0)

Try to do like this:





public class MainActivity extends Activity {
     private CallbackManager mfbCallbackManager;
    private LoginManager mfbLoginManager;
    Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            FacebookSdk.sdkInitialize(getApplicationContext());
            setContentView(R.layout. activity_main);
    mfbCallbackManager = CallbackManager.Factory.create();
            mfbLoginManager = LoginManager.getInstance();
            mfbLoginManager.registerCallback(mfbCallbackManager, new FacebookCallback<LoginResult>() {

                @Override
                public void onSuccess(LoginResult fbLoginResult) {

                    GraphRequest fbGraphRequest = GraphRequest.newMeRequest(fbLoginResult.getAccessToken(), new GraphRequest.GraphJSONObjectCallback() {

                        @Override
                        public void onCompleted(JSONObject object, GraphResponse response) {
                            Profile fbProfile = Profile.getCurrentProfile();
                            String email = null, gender = null, dob = null;
                            try {
                                email = object.getString("email");
                                gender = object.getString("gender");
                                dob = object.getString("birthday");
                            } catch (JSONException e) {
                                AppUtil.writeLog(TAG, e.getMessage());
                            }
                            mCustomer = new Customer();
                            try {
                                mCustomer.setCustFbId(fbProfile.getId());
                                mCustomer.setCustName(fbProfile.getName());
                                mCustomer.setCustFbiImageUrl(fbProfile.getProfilePictureUri(Constants.FB_PROFILE_PIC_WIDTH, Constants.FB_PROFILE_PIC_HEIGHT).toString());
                                mCustomer.setCustEmail(email);
                                mCustomer.setCustGender(gender);
                                mCustomer.setCustType(Constants.CUSTOMER_ROLE);
                                mCustomer.setCustDob(dob);
                            } catch (NullPointerException e) {
                                AppUtil.writeLog(TAG, e.getMessage());
                            }

                            loginWithFb();
                        }
                    });

                    Bundle parameters = new Bundle();
                    parameters.putString("fields", "gender, age_range, email, birthday");
                    fbGraphRequest.setParameters(parameters);
                    fbGraphRequest.executeAsync();

    }

    private void loginWithFb() {
            EndpointInterface apiService = AppUtil.getRetrofitInstance().create(EndpointInterface.class);
            Call<LoginResp> call = apiService.loinWithFacebook(
                    mCustomer.getCustFbId(),
                    mCustomer.getCustName(),
                    mCustomer.getCustType(),
                    mCustomer.getCustFbiImageUrl(),
                    mCustomer.getCustEmail(),
                    mCustomer.getCustDob(),
                    mCustomer.getCustGender(),
                    mAppPreferences.getString(Constants.SETTINGS_GCM_ID, ""),
                    IS_PUSH_ENABLED
            );

final ProgressDialog dialog;
        dialog = new ProgressDialog(LoginActivity.this);
        dialog.setMessage(getString(R.string.fb_login_wait_msg));
        dialog.setCanceledOnTouchOutside(false);
        dialog.show();

        call.enqueue(new Callback<LoginResp>() {
            @Override
            public void onResponse(Call<LoginResp> call, Response<LoginResp> response) {
                mCustomer.setCustId(response.body().getCustId());
                mCustomer.setIsNew(response.body().getIsNew());

                SharedPreferences.Editor preferenceEditor = mAppPreferences.edit();
                preferenceEditor.putString(Constants.SETTINGS_OBJ_CUSTOMER, new Gson().toJson(mCustomer));
                preferenceEditor.putBoolean(Constants.SETTINGS_IS_LOGGED_IN, true);
                preferenceEditor.apply();

                dialog.dismiss();
                startActivity(new Intent(LoginActivity.this, HomeActivity.class));
                finish();
            }

            @Override
            public void onFailure(Call<LoginResp> call, Throwable t) {
                dialog.dismiss();
                Toast.makeText(LoginActivity.this, R.string.server_error + t.getMessage(), Toast.LENGTH_LONG).show();
            }
        });
    }

答案 1 :(得分：0)

而不是

loginButton.findViewById(R.id.login_button);

使用

findViewById(R.id.login_button);

问题是

 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View com.facebook.login.widget.LoginButton.findViewById(int)' on a null object reference
    at com.algor7.samplelogin.MainActivity.onCreate(MainActivity.java:54)

loginButton是null的含义是什么。您正尝试在login_button内找到尚未初始化的视图loginButton。你必须在活动中找到视图。

答案 2 :(得分：-1)

您应该在片段中而不是在活动中进行登录。如果我没错，facebook doc会要求您将登录按钮放在片段中。 Then set up the button in your UI by adding it to a fragment and update your activity to use your fragment.

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