java - Android ExpandableListView 在应用程序中不可见

Question

我正在尝试在 Android 中制作一个 ExpandableListView 来显示问题列表。当我运行应用程序时，屏幕上没有显示任何内容。我不确定为什么或如何发生这种情况。谁能帮我解决这个问题。

我不想明确表示我从服务器获取数据，这些数据保存在对象中(也称为问题)。我已经对此进行了很多测试，这段代码没有任何问题。因此要显示的数据可用但不会显示在应用中。

我正在使用以下代码:

PlaceHolderFragment:

public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        // Progress dialog
        private ProgressDialog pDialog;

        private static String TAG = Problems.class.getSimpleName();

        private ArrayList<Problem> myProblems = new ArrayList<Problem>();

        private SparseArray<Group> groups = new SparseArray<Group>();

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {

            //Here comes code that handles data input from server ( which correctly works btw )

            for(int i = 0; i < myProblems.size(); i++){
                Group group = new Group(myProblems.get(i).getTitle());
                group.children.add(myProblems.get(i).domainsToString());
                group.children.add(myProblems.get(i).getDescription());
                groups.append(i, group);
            }

            View rootView = inflater.inflate(R.layout.fragment_my_problems, container, false);

            mMyProblems = (ExpandableListView) rootView.findViewById(R.id.my_problems);
            //mMyProblems.setAdapter(adapterMyP);
            MyProblemExpandableListViewAdapter adapter = new MyProblemExpandableListViewAdapter(this.getActivity(), groups);
            mMyProblems.setAdapter(adapter);

            return rootView;
        }

        private void showpDialog() {
            if (!pDialog.isShowing())
                pDialog.show();
        }

        private void hidepDialog() {
            if (pDialog.isShowing())
                pDialog.dismiss();
        }

    }

适配器:

public class MyProblemExpandableListViewAdapter extends BaseExpandableListAdapter {
    private final SparseArray<Group> groups;
    public LayoutInflater inflater;
    public Activity activity;

    public MyProblemExpandableListViewAdapter(Activity act, SparseArray<Group> groups) {
        activity = act;
        this.groups = groups;
        inflater = act.getLayoutInflater();
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return groups.get(groupPosition).children.get(childPosition);
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return 0;
    }

    @Override
    public View getChildView(int groupPosition, final int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {
        final String children = (String) getChild(groupPosition, childPosition);
        TextView text = null;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.listrow_details, null);
        }
        text = (TextView) convertView.findViewById(R.id.textView1);
        text.setText(children);
        convertView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(activity, children,
                        Toast.LENGTH_SHORT).show();
            }
        });
        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return groups.get(groupPosition).children.size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return groups.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        return groups.size();
    }

    @Override
    public void onGroupCollapsed(int groupPosition) {
        super.onGroupCollapsed(groupPosition);
    }

    @Override
    public void onGroupExpanded(int groupPosition) {
        super.onGroupExpanded(groupPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return 0;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.listrow_group, null);
        }
        Group group = (Group) getGroup(groupPosition);
        ((CheckedTextView) convertView).setText(group.string);
        ((CheckedTextView) convertView).setChecked(isExpanded);
        return convertView;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return false;
    }

}

和组类:

public class Group {
    public String string;
    public final List<String> children = new ArrayList<String>();

    public Group(String string) {
        this.string = string;
    }
}

以及相应的 xml 文件:

fragementMyProblems.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.wsi.wesupportit.Problems$PlaceholderFragment" >

    <ExpandableListView
        android:id="@+id/my_problems"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ExpandableListView>

</LinearLayout>

listrow_group.xml

<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:layout_marginLeft="8dp"
    android:gravity="left"
    android:paddingLeft="32dp"
    android:paddingTop="8dp"
    android:text="Test"
    android:textSize="14sp"
    android:textStyle="bold" />

listrow_details.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:clickable="true"android:orientation="vertical"
    android:paddingLeft="40dp">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:drawablePadding="5dp"
        android:gravity="center_vertical"
        android:text="@string/hello_world"
        android:textSize="14sp"
        android:textStyle="bold" >
    </TextView>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@android:color/black" />

</LinearLayout>

提前致谢。

Answer 1

使您的 MyProblemExpandableListViewAdapter final 并将其放在类的顶部。并确保每次更改组

的内容时都 通知您的适配器