ListFragment 中的 IllegalStateException

Question

我有一个应该填充列表视图的类。我在另一个活动（不是片段）中使用了相同的代码，它工作正常。相反，在这个 Fragment 中，它给了我一个“IllegalStateException”...
这是日志：

04-02 14:08:21.505: E/AndroidRuntime(25925): FATAL EXCEPTION: main
04-02 14:08:21.505: E/AndroidRuntime(25925): Process: com.social.bearv2, PID: 25925
04-02 14:08:21.505: E/AndroidRuntime(25925): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.social.bearv2/com.social.bearv2.PagerTabsActivity}: java.lang.IllegalStateException: Content view not yet created
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2215)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2265)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.ActivityThread.access$800(ActivityThread.java:145)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1206)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.os.Handler.dispatchMessage(Handler.java:102)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.os.Looper.loop(Looper.java:136)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.ActivityThread.main(ActivityThread.java:5081)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at java.lang.reflect.Method.invokeNative(Native Method)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at java.lang.reflect.Method.invoke(Method.java:515)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:126)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at dalvik.system.NativeStart.main(Native Method)
04-02 14:08:21.505: E/AndroidRuntime(25925): Caused by: java.lang.IllegalStateException: Content view not yet created
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.support.v4.app.ListFragment.ensureList(ListFragment.java:328)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.support.v4.app.ListFragment.getListView(ListFragment.java:222)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at com.social.bearv2.Page2Fragment.<init>(Page2Fragment.java:46)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at java.lang.Class.newInstanceImpl(Native Method)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at java.lang.Class.newInstance(Class.java:1208)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.support.v4.app.Fragment.instantiate(Fragment.java:402)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.support.v4.app.Fragment.instantiate(Fragment.java:377)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at com.social.bearv2.PagerTabsActivity.onCreate(PagerTabsActivity.java:36)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.Activity.performCreate(Activity.java:5231)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-02 14:08:21.505: E/AndroidRuntime(25925):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2169)
04-02 14:08:21.505: E/AndroidRuntime(25925):    ... 12 more

这是类：

public class Page2Fragment extends ListFragment {
     List<NameValuePair> nameValuePairs;
     ArrayList<String> items = null;
     HttpClient httpclient;
     HttpPost httppost;
     HttpResponse response;
     HttpEntity httpentity;
     String is;
     private static SharedPreferences pref;
     private TextView testo;


    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {


        // Se container è vuoto restituisco null
        if (container == null) {
            return null;
        }
        // Altrimenti faccio l'inflate della view dal layout
        View view = (LinearLayout) inflater.inflate(R.layout.page2, container,
                false);

        Context ctx = getActivity();
          Resources res = ctx.getResources();
          String[] achievements = getResources().getStringArray(R.array.achievements);
          TypedArray immagini = res.obtainTypedArray(R.array.immagini);

          setListAdapter(new TestImmagineAdapter(ctx, R.layout.riga_lista, achievements, immagini));

          //setListAdapter(new ArrayAdapter<String>(this, R.layout.riga_lista, achievements));

          final ListView lv = getListView();
          lv.setTextFilterEnabled(true);
          testo = (TextView) view.findViewById(R.id.testo_vista);
          pref = getActivity().getSharedPreferences("MainActivity", 0);
          final SharedPreferences.Editor editor = pref.edit();
          if(pref.getInt("ach1", 0)== 1) {
              lv.getChildAt(0).setBackgroundColor(Color.WHITE);
          }
          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(getApplicationContext(), testo.getText(),
                  //Toast.LENGTH_SHORT).show();
                int num = position;
                  Log.i("Elemento numero:", Integer.toString(num));   
            }
          });
        return view;
    }

}

Answer 1

1. onCreateView 永远不应该返回 null。

2. 您应该使用onCreateView 只是为了返回膨胀的View 并使用onViewCreated 来查找膨胀视图的元素。 onViewCreated 的第一个参数是你膨胀的View

   public View onCreateView(LayoutInflater inflater, ViewGroup container,
       Bundle savedInstanceState) {
       return  inflater.inflate(R.layout.page2, container,
           false);
   }
   
   @Override 
   public void onViewCreated(View view, Bundle savedInstanceState) {
   
     Context ctx = getActivity();
     Resources res = ctx.getResources();
     String[] achievements = getResources().getStringArray(R.array.achievements);
     TypedArray immagini = res.obtainTypedArray(R.array.immagini);
   
     setListAdapter(new TestImmagineAdapter(ctx, R.layout.riga_lista, achievements, immagini));
   
   
     final ListView lv = getListView();
     lv.setTextFilterEnabled(true);
     testo = (TextView) view.findViewById(R.id.testo_vista);
     pref = getActivity().getSharedPreferences("MainActivity", 0);
     final SharedPreferences.Editor editor = pref.edit();
     if(pref.getInt("ach1", 0)== 1) {
         lv.getChildAt(0).setBackgroundColor(Color.WHITE);
     }
     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(getApplicationContext(), testo.getText(),
             //Toast.LENGTH_SHORT).show();
           int num = position;
             Log.i("Elemento numero:", Integer.toString(num));   
       }
     });
   
   } 
   

Answer 2

我只是猜测，但有没有可能你没有打电话：

setContentView(...)

在您的Activity 的onCreate(...) 方法中？