Question

我用新片段替换现有片段，我能够看到我的视图，但在按钮上设置点击监听器时，它返回null。我得到以下异常：

?:??: W/?(?): java.lang.NullPointerException
?:??: W/?(?):   at com.biggu.shopsavvy.fragments.xxxxxxxx.onCreateView(xxxxxx.java:34)
?:??: W/?(?):   at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:870)
?:??: W/?(?):   at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
?:??: W/?(?):   at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:622)
?:??: W/?(?):   at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1416)
?:??: W/?(?):   at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:420)
?:??: W/?(?):   at android.os.Handler.handleCallback(Handler.java:615)
?:??: W/?(?):   at android.os.Handler.dispatchMessage(Handler.java:92)
?:??: W/?(?):   at android.os.Looper.loop(Looper.java:137)
?:??: W/?(?):   at android.app.ActivityThread.main(ActivityThread.java:4745)
?:??: W/?(?):   at java.lang.reflect.Method.invokeNative(Native Method)
?:??: W/?(?):   at java.lang.reflect.Method.invoke(Method.java:511)
?:??: W/?(?):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
?:??: W/?(?):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
?:??: W/?(?):   at dalvik.system.NativeStart.main(Native Method)

我不知道发生了什么事？

OnCreateView上的代码：

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.capture_card_phone_number, container, false);
        mPhone = (AutoCompleteTextView) getActivity().findViewById(R.id.phone_number);
        Button next = (Button) getActivity().findViewById(R.id.capture_phone_next);
        next.setOnClickListener(this);
        // next.setEnabled(false);

        return view;

我还导入了com.big.xxxxxxx.R

提前感谢您的帮助

Answer 1

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle 

    savedInstanceState) {
            View view = inflater.inflate(R.layout.capture_card_phone_number, container, false);
            mPhone = (AutoCompleteTextView) getActivity().findViewById(R.id.phone_number);
            Button next = (Button) view.findViewById(R.id.capture_phone_next);
            next.setOnClickListener(this);


            return view;

你必须在你的视图上调用findViewById - 而不是你的活动。

Answer 2

原因是在onCreateView中尚未创建片段视图，因此它返回null。尝试在onResume中执行它，它将返回视图：

@Override
public void onResume() {
    super.onResume();
    mPhone = (AutoCompleteTextView) getActivity().findViewById(R.id.phone_number);
    Button next = (Button) getActivity().findViewById(R.id.capture_phone_next);
    next.setOnClickListener(this);   
}

findViewById在片段中返回null

2 个答案: