java - 使用JAVA在Android中打印ListView的ClickedItem的位置失败

Question

下面的类扩展自

public class LocationListFragment extends ListFragment implements LoaderManager.LoaderCallbacks<List<Location>>{

    private final static String TAG = LocationListFragment.class.getName();

    private LocationListLoader locationListLoader;
    private LocationListAdapter locationListAdapter;
    private int userId;
    Context context;
   @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        ListView lv = getListView();
        lv.setTextFilterEnabled(true);
        lv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
              // When clicked, show a toast with the TextView text
              Toast.makeText(getActivity(), ((TextView) view).getText(),
                  Toast.LENGTH_SHORT).show();
              Log.i("position",""+position);
            }
            });


        int locationListType = getArguments().getInt(LocationListActivityFinal.LOCATION_LIST_TYPE);
        switch (locationListType) {
            case LocationListActivityFinal.DOMESTIC:
                userId = getArguments().getInt(LocationListActivityFinal.ASSIGNED_USER_ID);
                break;

            case LocationListActivityFinal.COMMERCIAL:
                userId = getArguments().getInt(LocationListActivityFinal.ASSIGNED_USER_ID);
                break;

            default:
                break;
        }
     getLoaderManager().initLoader(101,null,this);
    }

    @Override
    public void onListItemClick(ListView l,View v, int position, long id) {

        Log.i("DataListFragment", "Item clicked: " + id);
    }
    @Override
    public Loader<List<Location>> onCreateLoader(int id, Bundle args) {
        locationListLoader = new LocationListLoader(getActivity());
        return locationListLoader;
    }

    @Override
    public void onLoadFinished(Loader<List<Location>> arg0, List<Location> locations) {
         locationListAdapter = new LocationListAdapter(getActivity(),locationListLoader);
         setListAdapter(locationListAdapter);

         if (isResumed()) {
             setListShown(true);
         } else {
             setListShownNoAnimation(true);
         }
         locationListAdapter.notifyDataSetChanged();

    }
}

我正在从服务填充 ListView，它工作正常，但是当尝试单击 ListView 时，它显示此 LogCat:

 01-14 04:21:29.995: E/AndroidRuntime(3174): FATAL EXCEPTION: main
 01-14 04:21:29.995: E/AndroidRuntime(3174):
 java.lang.ClassCastException: android.widget.LinearLayout cannot be
 cast to android.widget.TextView 01-14 04:21:29.995:
 E/AndroidRuntime(3174):    at
 com.mrfs.android.surveyapp.activities.fragments.LocationListFragment$1.onItemClick(LocationListFragment.java:45)
 01-14 04:21:29.995: E/AndroidRuntime(3174):    at
 android.widget.AdapterView.performItemClick(AdapterView.java:301)
 01-14 04:21:29.995: E/AndroidRuntime(3174):    at
 android.widget.AbsListView.performItemClick(AbsListView.java:1276)
 01-14 04:21:29.995: E/AndroidRuntime(3174):    at
 android.widget.AbsListView$PerformClick.run(AbsListView.java:3067)
 01-14 04:21:29.995: E/AndroidRuntime(3174):    at
 android.widget.AbsListView$1.run(AbsListView.java:3963) 01-14
 04:21:29.995: E/AndroidRuntime(3174):  at
 android.os.Handler.handleCallback(Handler.java:615) 01-14
 04:21:29.995: E/AndroidRuntime(3174):  at
 android.os.Handler.dispatchMessage(Handler.java:92) 01-14
 04:21:29.995: E/AndroidRuntime(3174):  at
 android.os.Looper.loop(Looper.java:137) 01-14 04:21:29.995:
 E/AndroidRuntime(3174):    at
 android.app.ActivityThread.main(ActivityThread.java:4898) 01-14
 04:21:29.995: E/AndroidRuntime(3174):  at
 java.lang.reflect.Method.invokeNative(Native Method) 01-14
 04:21:29.995: E/AndroidRuntime(3174):  at
 java.lang.reflect.Method.invoke(Method.java:511) 01-14 04:21:29.995:
 E/AndroidRuntime(3174):    at
 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
 01-14 04:21:29.995: E/AndroidRuntime(3174):    at
 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 01-14
 04:21:29.995: E/AndroidRuntime(3174):  at
 dalvik.system.NativeStart.main(Native Method)

尝试滚动 ListView 时出错:

01-14 04:35:02.555: E/AndroidRuntime(6964): FATAL EXCEPTION: main 01-14 04:35:02.555: E/AndroidRuntime(6964): java.lang.NullPointerException 01-14 04:35:02.555: E/AndroidRuntime(6964): at com.mrfs.android.surveyapp.adapter.LocationListAdapter.getView(LocationListAdapter.java:91) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.AbsListView.obtainView(AbsListView.java:2445) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.ListView.makeAndAddView(ListView.java:1775) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.ListView.fillDown(ListView.java:678) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.ListView.fillGap(ListView.java:642) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.AbsListView.trackMotionScroll(AbsListView.java:5525) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.AbsListView.scrollIfNeeded(AbsListView.java:3413) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.widget.AbsListView.onTouchEvent(AbsListView.java:3901) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.View.dispatchTouchEvent(View.java:7337) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2410) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2145) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2159) 01-14 04:35:02.555: E/AndroidRuntime(6964): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2115) 01-14 04:35:02.555: E/AndroidRuntime(6964): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1468) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.app.Activity.dispatchTouchEvent(Activity.java:2487) 01-14 04:35:02.555: E/AndroidRuntime(6964): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2063) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.View.dispatchPointerEvent(View.java:7520) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3376) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3308) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4402) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4380) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4484) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:163) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:4452) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:4503) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.Choreographer.doCallbacks(Choreographer.java:555) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.Choreographer.doFrame(Choreographer.java:523) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.os.Handler.handleCallback(Handler.java:615) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.os.Handler.dispatchMessage(Handler.java:92) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.os.Looper.loop(Looper.java:137) 01-14 04:35:02.555: E/AndroidRuntime(6964): at android.app.ActivityThread.main(ActivityThread.java:4898) 01-14 04:35:02.555: E/AndroidRuntime(6964): at java.lang.reflect.Method.invokeNative(Native Method) 01-14 04:35:02.555: E/AndroidRuntime(6964): at java.lang.reflect.Method.invoke(Method.java:511) 01-14 04:35:02.555: E/AndroidRuntime(6964): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) 01-14 04:35:02.555: E/AndroidRuntime(6964): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 01-14 04:35:02.555: E/AndroidRuntime(6964): at dalvik.system.NativeStart.main(Native Method)

Answer 1

您的异常(exception)情况如下:

 java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.TextView 01-14 04:21:29.995: E/AndroidRuntime(3174): at com.mrfs.android.surveyapp.activities.fragments.LocationListFragment$1.onItemClick(LocationListFragment.java:45)

所以我猜这将是导致异常的行。该 View 不是 TextView，而是线性布局。尝试使用 view.findViewById(R.id.theTextViewIdFromALayoutFile) 代替。并将其转换到 TextView。

Toast.makeText(getActivity(), ((TextView) view).getText(),
              Toast.LENGTH_SHORT).show();