自定义阵列适配器中的空指针异常

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我正在使用自定义适配器来显示列表视图。不过，我正在得到NullPointerException。自定义阵列适配器中的空指针异常

public class moderationrequests extends Fragment { 
    public moderationrequests() { 
    } 

    private moderationrequestsadapter tableRowAdapter; 

    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     Log.v("ListFragment", "onCreate()"); 
    } 

    public void onActivityCreated(Bundle savedInstanceState) { 
     super.onActivityCreated(savedInstanceState); 
     Log.v("ListFragment", "onActivityCreated()."); 
     Log.v("ListsavedInstanceState", savedInstanceState == null ? "true" 
       : "false"); 

     // Generate list View from ArrayList 
     displayListView(); 

    } 

    public static final String ARG_SECTION_NUMBER = "section_number"; 

    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 
     View v = inflater 
       .inflate(R.layout.moderationrequests, container, false); 
     return v; 
    } 

    private void displayListView() { 

     String[] urlList = { "From Krishna on Business - 2 hours ago.", 
       "From Krishna on Business - 2 hours ago." }; 


     tableRowAdapter = new moderationrequestsadapter(getActivity(), 
       R.layout.mod_req_list, urlList); 
     ListView listView = (ListView) getView().findViewById(R.id.list_view); 
     listView.setAdapter(tableRowAdapter); 


    } 
}

适配器类

public class moderationrequestsadapter extends ArrayAdapter<String> { 
    private final Activity context; 
    private final String[] names; 
    private Button deleteButton = null; 

    public moderationrequestsadapter(Activity context, int itemResId, 
      String[] names) { 
     super(context, itemResId, names); 
     this.context = context; 
     this.names = names; 

    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     // LayoutInflater inflater = context.getLayoutInflater(); 
     // View rowView = inflater.inflate(R.layout.mod_req_list, null, true); 

     View rowView = null; 
     if (convertView == null) { 
      LayoutInflater inflater = context.getLayoutInflater(); 
      rowView = inflater.inflate(R.layout.mod_req_list, null); 

     } else { 
      rowView = convertView; 
     } 

     deleteButton = (Button) rowView.findViewById(R.id.icon); 
     deleteButton.setTag(position); 
     TextView textView = (TextView) rowView.findViewById(R.id.rowId); 
     textView.setText(names[position]); 
     Log.d("views", rowView.toString()); 
     return rowView; 

    } 

}

logcat的

07-10 09:10:38.280: E/AndroidRuntime(3113): FATAL EXCEPTION: main 
07-10 09:10:38.280: E/AndroidRuntime(3113): java.lang.NullPointerException 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at com.main.udebate.moderationrequestsadapter.getView(moderationrequestsadapter.java:40) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.AbsListView.obtainView(AbsListView.java:2159) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.ListView.measureHeightOfChildren(ListView.java:1246) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.ListView.onMeasure(ListView.java:1158) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.RelativeLayout.measureChild(RelativeLayout.java:666) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1389) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:847) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:847) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2176) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.View.measure(View.java:15518) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1874) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1089) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1265) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.Choreographer.doCallbacks(Choreographer.java:562) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.Choreographer.doFrame(Choreographer.java:532) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.os.Handler.handleCallback(Handler.java:725) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.os.Handler.dispatchMessage(Handler.java:92) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.os.Looper.loop(Looper.java:137) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at android.app.ActivityThread.main(ActivityThread.java:5041) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at java.lang.reflect.Method.invokeNative(Native Method) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at java.lang.reflect.Method.invoke(Method.java:511) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
07-10 09:10:38.280: E/AndroidRuntime(3113):  at dalvik.system.NativeStart.main(Native Method)

来源

2013-07-10 asifa

什么是在moderationrequestsadapter.java的40行？ –

你需要重写此\t'@覆盖 \t公众诠释getCount将（）{ \t \t \t \t回names.size（）; \t}' – Raghunandan

也发布了mod_req_list的xml。 –

尝试通过getActivity().getApplicationContext()代替getActivity()而下面一行

new moderationrequestsadapter(getActivity(), R.layout.mod_req_list, urlList);

初始化适配器，并同时在适配器的构造函数接受它，将其更改为上下文而不是活动。

而且同时适配器增加观看，请尝试以下代码段适配器的getView方法：

View rowView = convertView; 
if (rowView == null) { 
     LayoutInflater inflater = context.getLayoutInflater(); 
     rowView = inflater.inflate(R.layout.mod_req_list, null); 

} 
    deleteButton = (Button) rowView.findViewById(R.id.icon); 
    deleteButton.setTag(position); 
    TextView textView = (TextView) rowView.findViewById(R.id.rowId); 
    textView.setText(names[position]); 
    Log.d("views", rowView.toString()); 
    return rowView;

来源

2013-07-10 10:09:13

您正在使用的网卡错误。这是一个ArrayAdapter<String>，意味着它已经有一个ArrayList<String>来保存数据。不需要声明一个额外的字符串数组。您创建适配器后

myAdapter.addAll(names);

：只需将names数据添加到适配器。

内getView()获取数据项为：

String name = getItem(position);

来源

2013-07-10 09:37:58

自定义阵列适配器中的空指针异常

回答

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