Android 自定义listview适配器提供nullpointerexception
我想设置一个显示listview的片段。我这样试过: MainActivity扩展了FragmentActivity 在onCreate中:Android 自定义listview适配器提供nullpointerexception,android,android-listview,android-arrayadapter,Android,Android Listview,Android Arrayadapter,我想设置一个显示listview的片段。我这样试过: MainActivity扩展了FragmentActivity 在onCreate中: FragmentTransaction ft = getFragmentManager().beginTransaction(); Inbox inbox = Inbox.newInstance(); ft.replace(R.id.container, inbox); ft.commit(); 在我
FragmentTransaction ft = getFragmentManager().beginTransaction();
Inbox inbox = Inbox.newInstance();
ft.replace(R.id.container, inbox);
ft.commit();
在我的收件箱片段中:
public static Inbox newInstance() {
Inbox fragmentDemo = new Inbox();
return fragmentDemo;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_inbox, container, false);
smsAdapter = new ListAdapter(getActivity(), smsList);
ListView lv = (ListView) view.findViewById(R.id.list);
lv.setAdapter(smsAdapter);
return view;
}
我的自定义ListAdapter:
public class ListAdapter extends ArrayAdapter<SMSData> {
private String TAG = ListAdapter.class.getName();
private final Context context;
private final List<SMSData> smsList;
public ListAdapter(Context context, List<SMSData> smsList) {
super(context, R.layout.sms_inbox, smsList);
this.context = context;
this.smsList = smsList;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if(convertView == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.sms_inbox, parent, true);
holder = new ViewHolder();
holder.senderNumber = (TextView) convertView.findViewById(R.id.smsNumberText);
convertView.setTag(holder);
}
else
holder = (ViewHolder) convertView.getTag();
holder.senderNumber.setText(smsList.get(position).getNumber());
return convertView;
}
private static class ViewHolder
{
public TextView senderNumber;
}
}
有人能帮我吗?我在网上看过很多教程,但我看不出有什么不同 将方法添加到
列表适配器中
:
@Override
public int getCount() {
return smsList != null ? smsList.size() : 0;
}
第一:所有内容都为空,因为我在设置适配器后正在填充列表 第二:在自定义适配器中,我需要将充气中的布尔值设置为false,这样它就不会耦合到父级
第三:在xml中,将id/list更改为android:id/list如何设置
smsList
变量。它很可能是空的。确保它是有效的对象并包含项。您在片段中的smsList
是在哪里填充的?显示代码。如果您当时没有这样做,smsList
将为空。您是对的。后来我做了。谢谢现在我得到了/code Content has view,id属性为'android.R.id.list',它不是ListView类,但可能是XML错误。将其添加到我的代码中。Thnx。一切正常后,我会发布更新。
<ListView
android:id="@+id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TableRow>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/smsNumberText"/>
</TableRow>
</TableLayout>
05-06 06:13:40.528 2756-2756/com.test E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.test, PID: 2756
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test/com.test.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.widget.ArrayAdapter.getCount(ArrayAdapter.java:330)
at android.widget.ListView.setAdapter(ListView.java:480)
at Fragments.Inbox.onCreateView(Inbox.java:51)
at android.app.Fragment.performCreateView(Fragment.java:1700)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:890)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
at android.app.BackStackRecord.run(BackStackRecord.java:684)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447)
at android.app.Activity.performStart(Activity.java:5240)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2168)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
@Override
public int getCount() {
return smsList != null ? smsList.size() : 0;
}