片段内有两列的ListView

Question

我试图显示一个片段中的列的ListView（使用自定义ListViewAdapter）。

这是我得到的例外：

05-30 14:21:32.913: E/AndroidRuntime(3662): FATAL EXCEPTION: main
05-30 14:21:32.913: E/AndroidRuntime(3662): java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.view.ViewGroup.addViewInner(ViewGroup.java:3509)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.view.ViewGroup.addView(ViewGroup.java:3380)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.view.ViewGroup.addView(ViewGroup.java:3325)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.view.ViewGroup.addView(ViewGroup.java:3301)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.support.v4.app.NoSaveStateFrameLayout.wrap(NoSaveStateFrameLayout.java:40)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:931)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.os.Handler.handleCallback(Handler.java:730)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.os.Looper.loop(Looper.java:137)
05-30 14:21:32.913: E/AndroidRuntime(3662):     at android.app.ActivityThread.main(ActivityThread.java:5103)

MyFragment.java：

public class MyFragment extends ListFragment {
    private ArrayList<HashMap<String, String>> list;
    public static final String FIRST_COLUMN = "Column 1";
    public static final String SECOND_COLUMN = "Column 2";
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);


    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        getActivity().setContentView(R.layout.fragment_my);
        ListView lview = (ListView)getActivity().findViewById(R.id.listview);
        populateList();
        listviewAdapter adapter = new listviewAdapter(getActivity(), list);
        lview.setAdapter(adapter);
        return lview;

    }



    private void populateList() {

        list = new ArrayList<HashMap<String, String>>();

        HashMap<String, String> temp1 = new HashMap<String, String>();
        temp.put(FIRST_COLUMN,"first column key");
        temp.put(SECOND_COLUMN, "first column value");
        list.add(temp);

        HashMap<String, String> temp2 = new HashMap<String, String>();
        // and so on...
    }


}

listviewAdapter.java

   public class listviewAdapter extends BaseAdapter
{

    public static final String FIRST_COLUMN = "Column 1";
    public static final String SECOND_COLUMN = "Column 2";

    public ArrayList<HashMap<String,String>> list;
    Activity activity;

    public listviewAdapter(Activity activity, ArrayList<HashMap<String,String>> list) {
        super();
        this.activity = activity;
        this.list = list;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    private class ViewHolder {
        TextView txtFirst;
        TextView txtSecond;

    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        // TODO Auto-generated method stub
        ViewHolder holder;
        LayoutInflater inflater =  activity.getLayoutInflater();

        if (convertView == null)
        {
            convertView = inflater.inflate(R.layout.rows, null);
            holder = new ViewHolder();
            holder.txtFirst = (TextView) convertView.findViewById(R.id.column1);
            holder.txtSecond = (TextView) convertView.findViewById(R.id.column2);
            convertView.setTag(holder);
        }
        else
        {
            holder = (ViewHolder) convertView.getTag();
        }

        HashMap<String, String> map = list.get(position);
        holder.txtFirst.setText(map.get(FIRST_COLUMN));
        holder.txtSecond.setText(map.get(SECOND_COLUMN));


        return convertView;
    }

}

fragment_my.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ListView
        android:id="@+id/listview"
        android:layout_height="wrap_content"
        android:layout_width="match_parent">
    </ListView>


</LinearLayout>

行.xml

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:paddingTop="4dip"
     android:paddingBottom="6dip"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:orientation="horizontal">

     <TextView android:id="@+id/column1"
         android:layout_width="50dip"
         android:layout_height="wrap_content"/>

     <TextView android:id="@+id/column2"
         android:layout_width="70dip"
         android:layout_height="wrap_content" />



</LinearLayout>

我究竟做错了什么？ 我在Android中有点菜鸟，但我猜问题出在onCreate / onCreateView方法上……有人可以帮忙吗？

Answer 1

你应该改变这个

 getActivity().setContentView(R.layout.fragment_my);

至

View view = inflater.inflate(R.layout.fragment_my, container, false);

并使你的onCreateView(...)像

 @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_my, container, false);
    ListView lview = (ListView)view.findViewById(R.id.listview);
    populateList();
    listviewAdapter adapter = new listviewAdapter(getActivity(), list);
    lview.setAdapter(adapter);
    return view;
}

并改变这个

public class MyFragment extends ListFragment

至

public class MyFragment extends Fragment

这里没有使用ListFragment意思。