Android Facebook登录按钮onActivityResult空指针异常
我正在尝试为我的Android应用程序实现Facebook登录。我正在发布我在这里写的测试代码Android Facebook登录按钮onActivityResult空指针异常,android,facebook,login,nullpointerexception,Android,Facebook,Login,Nullpointerexception,我正在尝试为我的Android应用程序实现Facebook登录。我正在发布我在这里写的测试代码 public class MainActivity extends Activity { private LoginButton loginButton; private UiLifecycleHelper uiHelper; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(save
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);
}
当我使用登录按钮登录Facebook时,这会引发一些异常。完整堆栈跟踪如下所示:
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
你认为我哪里错了?你在
onCreate
方法覆盖全局uilifecyclehelp
中再次定义了uilifecyclehelp
uiHelper = new UiLifecycleHelper(this, callback);
在onCreate内部,您只需初始化UiLifeCyclehelper
uiHelper = new UiLifecycleHelper(this, callback);
你喜欢这样吗
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);
}
谢谢阿披舍克,这是一个愚蠢的错误(根本不是安卓系统的错误),但你的回答解决了我的问题。谢谢