[英]Android Facebook LoginButton onActivityResult null pointer exception
我正在嘗試為我的Android應用程序實現Facebook登錄。 我正在發布我在這里編寫的測試代碼。
public class MainActivity extends Activity {
private LoginButton loginButton;
private UiLifecycleHelper uiHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
loginButton = (LoginButton) findViewById(R.id.facebookLogin);
loginButton.setOnErrorListener(new ErrorHandler());
StatusCallback callback = new CallBackHandler();
loginButton.setSessionStatusCallback(callback);
UiLifecycleHelper uiHelper = new UiLifecycleHelper(this, callback);
uiHelper.onCreate(savedInstanceState);
}
private class CallBackHandler implements Session.StatusCallback {
@Override
public void call(Session session, SessionState state,
Exception exception) {
Log.d("facebook", "changing");
Log.d("facebook state", state.toString());
if (state.isOpened()) {
Log.d("facebook", "facebook connected");
}
if (state.isClosed()) {
Log.d("facebook", "facebook disconnected");
}
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
uiHelper.onActivityResult(requestCode, resultCode, data);
}
當我使用登錄按鈕登錄Facebook時,這引發了一些異常。 完整的堆棧跟蹤在這里:
11-20 04:48:34.582: E/AndroidRuntime(2164): FATAL EXCEPTION: main
11-20 04:48:34.582: E/AndroidRuntime(2164): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=64206, result=-1, data=Intent { (has extras) }} to activity {com.example.facebooklogin/com.example.facebooklogin.MainActivity}: java.lang.NullPointerException
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.ActivityThread.deliverResults(ActivityThread.java:3319)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3362)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.ActivityThread.access$1100(ActivityThread.java:141)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1282)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.os.Handler.dispatchMessage(Handler.java:99)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.os.Looper.loop(Looper.java:137)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.ActivityThread.main(ActivityThread.java:5041)
11-20 04:48:34.582: E/AndroidRuntime(2164): at java.lang.reflect.Method.invokeNative(Native Method)
11-20 04:48:34.582: E/AndroidRuntime(2164): at java.lang.reflect.Method.invoke(Method.java:511)
11-20 04:48:34.582: E/AndroidRuntime(2164): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-20 04:48:34.582: E/AndroidRuntime(2164): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-20 04:48:34.582: E/AndroidRuntime(2164): at dalvik.system.NativeStart.main(Native Method)
11-20 04:48:34.582: E/AndroidRuntime(2164): Caused by: java.lang.NullPointerException
11-20 04:48:34.582: E/AndroidRuntime(2164): at com.example.facebooklogin.MainActivity.onActivityResult(MainActivity.java:59)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.Activity.dispatchActivityResult(Activity.java:5293)
11-20 04:48:34.582: E/AndroidRuntime(2164): at android.app.ActivityThread.deliverResults(ActivityThread.java:3315)
11-20 04:48:34.582: E/AndroidRuntime(2164): ... 11 more
您認為我哪里錯了?
您已經定義UiLifecycleHelper
再次onCreate
方法覆蓋全球UiLifecycleHelper
在onCreate內,您只需要初始化UiLifeCyclehelper
uiHelper = new UiLifecycleHelper(this, callback);
像這樣
private LoginButton loginButton;
private UiLifecycleHelper uiHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
loginButton = (LoginButton) findViewById(R.id.facebookLogin);
loginButton.setOnErrorListener(new ErrorHandler());
StatusCallback callback = new CallBackHandler();
loginButton.setSessionStatusCallback(callback);
uiHelper = new UiLifecycleHelper(this, callback);
uiHelper.onCreate(savedInstanceState);
}
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