Question

所以我正在尝试为我正在制作的另一个应用程序制作基本前景我只是试图让我的片段中的listView填充在屏幕上。（要创建可滑动的标签视图）

我在这一行上不断收到nullPointerException：

List.setAdapter(Adapter);

这是我的全班：

public class List_View extends ListFragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.listviewtest, container, false);
    ListView List = (ListView) getActivity().findViewById(R.id.listView1); 

    List<HashMap<String, String>> Data = new ArrayList<HashMap<String, String>>();
    {
        HashMap<String, String> temp1 = new HashMap<String, String>();
        temp1.put("Item", "Item 1");
        Data.add(temp1);
        HashMap<String, String> temp2 = new HashMap<String, String>();
        temp2.put("Item", "Item 2");
        Data.add(temp2);
        HashMap<String, String> temp3 = new HashMap<String, String>();
        temp3.put("Item", "Item 3");
        Data.add(temp3);
    }

    SimpleAdapter Adapter = new SimpleAdapter(this.getActivity(),
            Data, R.layout.custom_row_view, new String[] {
                    "Item" }, new int[] { R.id.text1});

    List.setAdapter(Adapter);

    List.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

            switch (position) {

            case 1:
                AlertDialog.Builder dlgAlert = new AlertDialog.Builder(
                        getActivity());
                dlgAlert.setMessage("Set Message Text");
                dlgAlert.setTitle("Set Message Title");
                dlgAlert.setNeutralButton("View info",
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog,
                                    int which) {

                                dialog.dismiss();
                            }
                        });

                dlgAlert.setCancelable(false);
                dlgAlert.create().show();

                break;
            }
        }
    });

    return rootView;
}
}

据我所知，这不应该返回null ..

Answer 1

我认为你的膨胀操作返回null。检查此行

ListView List = (ListView) getActivity().findViewById(R.id.listView1);

您应该从片段的父视图中膨胀ListView，而不是从父活动中膨胀。

应该是这样的

ListView List = (ListView) rootView.findViewById(R.id.listView1);  and make sure that

setAdapter（）在ListFragment中返回null

1 个答案: