android - 尝试在 facebook 集成中调用虚拟方法 'int java.lang.Object.hashCode()'

Question

我在尝试 facebook 集成时遇到以下错误:

11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #2
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime: Process: com.creaa.admin.mylogin, PID: 23052
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:746)
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:774)
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at com.facebook.internal.Utility.queryAppSettings(Utility.java:822)
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at com.facebook.login.widget.LoginButton$1.run(LoginButton.java:489)
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
11-18 15:57:54.186 23052-23093/com.creaa.admin.mylogin E/AndroidRuntime:     at java.lang.Thread.run(Thread.java:818)

以下是我的主要 Activity :

public class MainActivity extends Activity {

    private static String APP_ID = "1500167156975715"; // Replace your App ID here
    CallbackManager callbackManager;
    ArrayList<String> permissions;
    Context cv = this;
    boolean loginflag = false;
    private ProfileTracker profiletracker;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //initilise fb sdk
        FacebookSdk.sdkInitialize(getApplicationContext());
        //logout any previous logins
        AccessToken accessToken = AccessToken.getCurrentAccessToken();
        accessToken.setCurrentAccessToken(null);
        Profile.getCurrentProfile().setCurrentProfile(null);
        LoginManager.getInstance().logOut();
        setContentView(R.layout.activity_main);
        permissions = new ArrayList<String>();
        permissions.add("email");
        permissions.add("user_likes");
        permissions.add("user_friends");
        permissions.add("public_profile");
        permissions.add("user_birthday");


        try {
            PackageInfo info = getPackageManager().getPackageInfo(
                    "com.example.facebooklogin",
                    PackageManager.GET_SIGNATURES);
            for (Signature signature : info.signatures) {
                MessageDigest md = MessageDigest.getInstance("SHA");
                md.update(signature.toByteArray());
                Log.d("Parth", "KeyHash : " + Base64.encodeToString(md.digest(), Base64.DEFAULT));
            }
        } catch (NameNotFoundException e) {

        } catch (NoSuchAlgorithmException e) {

        }
        callbackManager = CallbackManager.Factory.create();
        LoginButton loginbutton = (LoginButton) findViewById(R.id.login_button);
        loginbutton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if (AccessToken.getCurrentAccessToken() != null && Profile.getCurrentProfile() != null) {
                    if (loginflag) {
                        AccessToken accessToken = AccessToken.getCurrentAccessToken();
                        accessToken.setCurrentAccessToken(null);
                        Profile.getCurrentProfile().setCurrentProfile(null);
                        Toast.makeText(cv, "Logout", Toast.LENGTH_SHORT).show();
                        LoginManager.getInstance().logOut();
                    }
                } else {
                    if (!loginflag) {
                        Toast.makeText(cv, "Login", Toast.LENGTH_SHORT).show();
                        LoginManager.getInstance().logInWithReadPermissions(MainActivity.this, permissions);
                    }
                }
            }
        });
        loginbutton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {

            @Override
            public void onSuccess(LoginResult result) {
                // TODO Auto-generated method stub
                Toast.makeText(cv, "in onSucess", Toast.LENGTH_SHORT).show();
                //get account details
                GraphRequest request = GraphRequest.newMeRequest(result.getAccessToken(), new GraphJSONObjectCallback() {

                    @Override
                    public void onCompleted(JSONObject object, GraphResponse response) {
                        // TODO Auto-generated method stub
                        Log.d("Parth", response.toString() + "\njson" + object.toString());
                        try {
                            String email = (String) object.get("email");
                            Toast.makeText(cv, email, Toast.LENGTH_SHORT).show();
                        } catch (JSONException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }

                    }
                });
                Bundle parameters = new Bundle();
                parameters.putString("fields", "id,name,email,gender,birthday");
                request.setParameters(parameters);
                request.executeAsync();
            }

            @Override
            public void onError(FacebookException error) {
                // TODO Auto-generated method stub
                Toast.makeText(cv, "in onError", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onCancel() {
                // TODO Auto-generated method stub
                Toast.makeText(cv, "in oncancel", Toast.LENGTH_SHORT).show();
            }
        });
        profiletracker = new ProfileTracker() {

            @Override
            protected void onCurrentProfileChanged(Profile oldProfile, Profile currentProfile) {
                // TODO Auto-generated method stub
                if (currentProfile != null) {
                    Toast.makeText(cv, "in Currentprofilechanged", Toast.LENGTH_SHORT).show();
                    String name = currentProfile.getName();
                    String fname = currentProfile.getFirstName();
                    Toast.makeText(MainActivity.this, fname, Toast.LENGTH_SHORT).show();
                }
            }
        };
    }
}

下面是应用程序gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.creaa.admin.mylogin"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
repositories { mavenCentral() }
dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.facebook.android:facebook-android-sdk:4.6.0'
}

下面是 list 文件:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.creaa.admin.mylogin" >
<uses-permission android:name="android.permission.INTERNET"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" >
        <activity android:name=".MainActivity" >
            <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" />
        <meta-data android:name="com.facebook.sdk.ApplicationId" android:value="1500167156975715"/>
        <provider
            android:name="com.facebook.FacebookContentProvider"
            android:authorities="com.facebook.app.FacebookContentProvider233936543368280"
            android:exported="true" />
    </application>

</manifest>

我已经尝试了所有可能的事情，但我无法找出错误。如果有人能帮我解决这个问题，那就太好了。我刚刚从 eclipse 转移到 android studio。此代码在 eclipse 中运行良好，但在 android studio 中不起作用。

Answer 1

经过如此多的研发，我已经解决了这个问题。您需要做的只是在 string.xml 中定义 facebook APPID，并在应用程序标签下的 list 中的元数据中使用该字符串。

字符串.xml

<string name="facebook_app_id">XXXXXX</string>

list .xml

 <meta-data
            android:name="com.facebook.sdk.ApplicationId"
            android:value="@string/facebook_app_id"/>