如何修复从 SQLite 数据库中提取的组和子数据到可扩展列表视图

Question

在 java main activity 中，我已经在我的 initData 方法中加载了数据，但是当我运行应用程序时，类别分组仅列出数据库中的一个类别每个类别列表的数据列表项。正确的功能是列出所有类别数据，然后列出每个分组下的项目。下面是我的代码

我在 XML 中创建了一个可扩展列表视图，还创建了可扩展列表适配器 class，它从我的 SQLite 数据库中的两个表中提取项目类别和项目类别列表。在 java main activity 中我已经加载了数据，但是当我运行应用程序时，类别分组仅列出数据库中的一个类别和数据列表项。

这是我的 initData 方法

     private void initData() {


        Cursor category1 = controller.categotyforGroupedLv();
        Cursor itemListCategory = controller.getFPMsster();
        listDataHeader = new ArrayList<>();
        List<String> listDataItem = new ArrayList<>();
        listHash = new HashMap<>();

        if (category1.getCount() != 0) {
            //move to the first row
            category1.moveToFirst();
           // Toast.makeText(this, "Data found", Toast.LENGTH_SHORT).show();
            //return;
        }


        for (int i = 0; i < category1.getCount(); i++) {

            while (category1.moveToNext()) {
                while (itemListCategory.moveToNext()) {
                    listDataHeader.add(" " + category1.getString(1));
                    listDataItem.add(" " + itemListCategory.getString(2));

                }
                listHash.put(listDataHeader.get(0), listDataItem);
            }


        }
    }

}

这是我的可扩展列表适配器class

public class ExpandableListAdapter extends BaseExpandableListAdapter {
    private Context context;
    private List<String> listDataHeader;
    private HashMap<String,List<String>> listHashMap;

    public ExpandableListAdapter(Context context, List<String> listDataHeader, HashMap<String, List<String>> listHashMap) {
        this.context = context;
        this.listDataHeader = listDataHeader;
        this.listHashMap = listHashMap;
    }

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

    @Override
    public int getChildrenCount(int i) {
        return listHashMap.get(listDataHeader.get(i)).size();
    }

    @Override
    public Object getGroup(int i) {
        return listDataHeader.get(i);
    }

    @Override
    public Object getChild(int i, int i1) {
        return listHashMap.get(listDataHeader.get(i)).get(i1);   //i = group item , i1 =Child item
    }

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

    @Override
    public long getChildId(int i, int i1) {
        return i1;
    }

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

    @Override
    public View getGroupView(int i, boolean b, View view, ViewGroup viewGroup) {
        String headerTitle = (String)getGroup(i);
        if (view == null)
        {
            LayoutInflater inflater = (LayoutInflater)this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(R.layout.order_taking_screen_listgroup_for_listview, null);
        }
        TextView listheader1 = (TextView)view.findViewById(R.id.listheader);
        listheader1.setTypeface(null, Typeface.BOLD);
        listheader1.setText(headerTitle);
        return view;
    }

    @Override
    public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) {
       final String childText = (String)getChild(i, i1);
       if(view == null)
       {
           LayoutInflater inflater = (LayoutInflater)this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
           view = inflater.inflate(R.layout.order_taking_screen_listitem_for_listview, null);
       }
        TextView listchild = (TextView)view.findViewById(R.id.listitem);
        listchild.setText(childText);
        return view;

    }

    @Override
    public boolean isChildSelectable(int i, int i1) {
        return true;
    }
}

Answer 1

试试这个：

private void initData() {
    Cursor category1 = controller.categotyforGroupedLv();
    Cursor itemListCategory;
    listDataHeader = new ArrayList<>();
    listHash = new HashMap<>();
    if (category1.getCount() != 0) {
        //move to the first row
        category1.moveToFirst();
        // Toast.makeText(this, "Data found", Toast.LENGTH_SHORT).show();
        //return;

        while (category1.moveToNext()) {
            listDataHeader.add(" " + category1.getString(1));

            // Child item should be based on group data.
            itemListCategory = controller.getFPMsster(category1.getString(1));

            // Create single child list.
            List<String> listDataItem = new ArrayList<>();
            if (itemListCategory.getCount() != 0) {
                while(itemListCategory.moveToNext()) {
                    listDataItem.add(" " + itemListCategory.getString(2));
                }
            }
            // Add single child into the overall child list.
            listHash.put(listDataHeader.get(listDataHeader.size() - 1), listDataItem);
        }
    }
}

请注意，您需要更改 getFPMsster() 方法以获取参数，因为游标应该只 return 特定组的数据。您也可以看看这个 link：希望对您有所帮助！

如何修复从 SQLite 数据库中提取的组和子数据到可扩展列表视图

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