解析+ Facebook授权:已注册<facebook>的回调: com.parse.ParseFacebookUtils

Question

我需要在我的应用程序中通过Parse添加Facebook授权。我按照https://parse.com/docs/android/guide#users-facebook-users上的说明进行操作。但是如果我运行app，然后按Back按钮，然后再次运行它，我总是得到这样的错误：

java.lang.RuntimeException: Unable to start activity ComponentInfo{.AuthActivity}: java.lang.IllegalStateException: Callback already registered for <facebook>: com.parse.ParseFacebookUtils$1@28d04f8f
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2693)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)
    at android.app.ActivityThread.access$900(ActivityThread.java:177)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:5942)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)
 Caused by: java.lang.IllegalStateException: Callback already registered for <facebook>: com.parse.ParseFacebookUtils$1@28d04f8f
    at com.parse.ParseAuthenticationManager.register(ParseAuthenticationManager.java:35)
    at com.parse.ParseUser.registerAuthenticationCallback(ParseUser.java:1094)
    at com.parse.ParseFacebookUtils$ParseUserDelegateImpl.registerAuthenticationCallback(ParseFacebookUtils.java:562)
    at com.parse.ParseFacebookUtils.initialize(ParseFacebookUtils.java:109)
    at com.parse.ParseFacebookUtils.initialize(ParseFacebookUtils.java:92)
    at .AuthActivity.onCreate(AuthActivity.java:47)
    at android.app.Activity.performCreate(Activity.java:6289)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758) 
    at android.app.ActivityThread.access$900(ActivityThread.java:177) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:145) 
    at android.app.ActivityThread.main(ActivityThread.java:5942) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:372) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195) 

这就是我的活动的样子：

public class AuthActivity extends AppCompatActivity {
    …

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ParseFacebookUtils.initialize(this); // crash here

        setupEvents();

        …
    }

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

    private void setupEvents() {
        findViewById(R.id.fb_login).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                loginViaFacebook();
            }
        });
    }

    private void loginViaFacebook() {
        ParseFacebookUtils.logInWithReadPermissionsInBackground(AuthActivity.this, null, new LogInCallback() {
            @Override
            public void done(ParseUser user, ParseException err) {
                …
            }
        });
    }
}

这是怎么回事？

Answer 1

您应该将ParseFacebookUtils初始化为应用程序类，而不是AppCompatActivity类。

您可以创建一个java类并将其命名为Configs，在清单中设置它的名称

    <application
        android:name=".Configs"
        ...

Configs类将如下所示：

public class Configs extends Application {
…

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ParseFacebookUtils.initialize(this); 

    …
}