Android 无法使用自定义适配器理解NullPointerException

我正在尝试创建一个列表视图，它作为文本视图，可以显示html内容、网络视图和其他基本文本视图。我尝试扩展SimpleAdapter，但我遇到了这个问题，如果有人能指出我所犯的错误，我将非常高兴

在onCreate方法中

 ArrayList<HashMap<String, String>> mylist= resultfromXmlparser();

 adap = new MyAdapter(TourLandingPage.this, mylist, R.layout.row,
            new String[] {"Name", "desc","Duration","Price","imgurl"},  new int[]
            {R.id.productname,R.id.des,R.id.duration,R.id.pricefrom,R.id.photo});

setListAdapter(adap);


My custom Adapter looks like this

 private class MyAdapter extends SimpleAdapter {

             ArrayList<HashMap<String,String>> elements;
             Context ctx;
             public MyAdapter(Context context, ArrayList<HashMap<String,String>> mylist,int textViewResourceId,String[] names,int[] resouceid) {
             super(context, mylist,textViewResourceId, names,resouceid);
             this.elements=mylist;
             this.ctx=context;

             }
             @Override
             public int getCount() {
                  return elements.size();
                 }
             @Override
             public Object getItem(int position) {
                  return elements.get(position);
              }
            @Override
            public long getItemId(int position) {
                  return position;
                 }


                  @Override
           public View getView(int position, View convertView, ViewGroup parent) {
             RelativeLayout rowLayout;
                    if (convertView == null) {
                     rowLayout = (RelativeLayout) 
                         LayoutInflater.from(ctx).inflate(R.layout.rowfor_tourlist, parent, false);

               } else {

                rowLayout = (RelativeLayout) convertView;
                     }


                  TextView in = (TextView)rowLayout.findViewById(R.id.introduction);
                  TextView du = (TextView)rowLayout.findViewById(R.id.duration);
                  TextView pf = (TextView)rowLayout.findViewById(R.id.pricefrom);
                  TextView pn = (TextView)rowLayout.findViewById(R.id.productname);
                  WebView wv=(WebView)rowLayout.findViewById(R.id.photo);  
                  in.setText(Html.fromHtml(mylist.get(position).get("desc")));
                  du.setText(mylist.get(position).get("Duration"));
                  pf.setText(mylist.get(position).get("Price"));
                  pn.setText(mylist.get(position).get("Name"));
                  wv.getSettings().setJavaScriptEnabled(true);
                  wv.loadUrl(mylist.get(position).get("imgurl"));


                 return convertView;
             }         
         }//class

我犯的错误是

04-28 19:46:17.749: ERROR/AndroidRuntime(976): Uncaught handler: thread main exiting due to uncaught exception
04-28 19:46:17.769: ERROR/AndroidRuntime(976): java.lang.NullPointerException
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.setupChild(ListView.java:1693)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.makeAndAddView(ListView.java:1671)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.fillDown(ListView.java:637)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.fillFromTop(ListView.java:694)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.layoutChildren(ListView.java:1521)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.AbsListView.onLayout(AbsListView.java:1113)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1108)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.onLayout(LinearLayout.java:920)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.onLayout(LinearLayout.java:918)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.onLayout(LinearLayout.java:918)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.ViewRoot.performTraversals(ViewRoot.java:996)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1633)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.os.Looper.loop(Looper.java:123)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.app.ActivityThread.main(ActivityThread.java:4338)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at java.lang.reflect.Method.invokeNative(Native Method)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at java.lang.reflect.Method.invoke(Method.java:521)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at dalvik.system.NativeStart.main(Native Method)
04-28 19:46:17.789: INFO/Process(52): Sending signal. PID: 976 SIG: 3
04-28 19:46:17.799: INFO/dalvikvm(976): threadid=7: reacting to signal 3
04-28 19:46:17.829: INFO/dalvikvm(976): Wrote stack trace to '/data/anr/traces.txt'

---

不确定这是否是原因，但SimpleAdapter构造函数的最后一个参数都应该是TextView

---

正如我在上面的代码中看到的，您的问题出现在“return convertView；”行中。您刚刚返回了一个输入视图，而不是膨胀的视图。

如果您可以重新格式化它，将所有代码放在“代码”块中，等等，这将更容易筛选。我只是忘记了

返回convertView在
BaseAdapter
中。感谢同志们不辞辛劳地回答我的问题。我终于在下面找到了解决方案注释//rowLayout=（RelativeLayout）LayoutFlater.from（ctx）。充气（R.layout.row，parent，false）；并替换这个LayoutInflater vi=（LayoutInflater）getSystemService（Context.LAYOUT\u INFLATER\u SERVICE）；v=vi.充气（R.布局.行，空）；现在我遇到了另一个问题，我无法选择我的listView，即我的listView上的setOnItemClickListener不工作，有人能帮我吗？@ganesh，是将
LayoutFlater.from（ctx）
更改为
（LayoutFlater）getSystemService（Context.LAYOUT\u INFLATER\u SERVICE）的解决方案
或修复是否来自使用
充气（R.layout.row，null）
而不是
充气（R.layout.row，parent，false）？
04-28 19:46:17.749: ERROR/AndroidRuntime(976): Uncaught handler: thread main exiting due to uncaught exception
04-28 19:46:17.769: ERROR/AndroidRuntime(976): java.lang.NullPointerException
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.setupChild(ListView.java:1693)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.makeAndAddView(ListView.java:1671)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.fillDown(ListView.java:637)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.fillFromTop(ListView.java:694)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.ListView.layoutChildren(ListView.java:1521)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.AbsListView.onLayout(AbsListView.java:1113)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1108)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.onLayout(LinearLayout.java:920)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.onLayout(LinearLayout.java:918)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.LinearLayout.onLayout(LinearLayout.java:918)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.View.layout(View.java:6831)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.ViewRoot.performTraversals(ViewRoot.java:996)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1633)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.os.Looper.loop(Looper.java:123)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at android.app.ActivityThread.main(ActivityThread.java:4338)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at java.lang.reflect.Method.invokeNative(Native Method)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at java.lang.reflect.Method.invoke(Method.java:521)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-28 19:46:17.769: ERROR/AndroidRuntime(976):     at dalvik.system.NativeStart.main(Native Method)
04-28 19:46:17.789: INFO/Process(52): Sending signal. PID: 976 SIG: 3
04-28 19:46:17.799: INFO/dalvikvm(976): threadid=7: reacting to signal 3
04-28 19:46:17.829: INFO/dalvikvm(976): Wrote stack trace to '/data/anr/traces.txt'