java - 从数据库填充ExpandableListView - 无法正常工作

Question

我有表格收据和日志，表格收据有很多日志。所以在logsrapitation.class上，我按排序和等级对日志进行分组（这两列来自表日志）。
我试图通过ExpandableListView来实现这一点。每组日志的父元素将由数据库中每组的排序和等级组成。
子元素将在子元素、质量、价格和某些计算价格中具有日志计数的文本视图。它应该是这样的：

我已经创建了ExpandableListView布局和适配器。但现在我无法从数据库中填充父元素和子元素。
这是我的代码，你可以看看我到目前为止做了什么。
这是expandablelistaadapter类：

public class ExpandableListAdapter extends BaseExpandableListAdapter {

    private Context _context;
    private List<String> _listDataHeader;
    private HashMap<String, List<String>> _listDataChild;

    public ExpandableListAdapter(Context context, List<String> listDataHeader, HashMap<String, List<String>> listDataChild) {
        this._context = context;
        this._listDataHeader = listDataHeader;
        this._listDataChild = listDataChild;
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition)).get(childPosition);
    }

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

    @Override
    public View getChildView(int groupPosition, final int childPosition, boolean isLastChild,
                             View convertView, ViewGroup parent) {
        final String childText = (String) getChild(groupPosition, childPosition);

        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) this._context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.expendable_items, null);
        }

        TextView logsMass = (TextView) convertView.findViewById(R.id.exp_lis_mass);
        TextView logsPrice = (TextView) convertView.findViewById(R.id.exp_lis_price);
        TextView logsMassPrice = (TextView) convertView.findViewById(R.id.ext_lis_sum_price);
        logsMass.setText(childText);
        logsPrice.setText(childText);
        logsMassPrice.setText(childText);

        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition)).size();
    }

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

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

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        String headerTitle = (String) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) this._context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.expandable_group, null);
        }

        TextView logsSort = (TextView) convertView.findViewById(R.id.exp_gr_sort);
        TextView logsGrade = (TextView) convertView.findViewById(R.id.exp_gr_grade);
        TextView logsCount = (TextView) convertView.findViewById(R.id.exp_gr_logs_count);
        logsSort.setText(headerTitle);
        logsGrade.setText(headerTitle);
        logsCount.setText(headerTitle);

        return convertView;
    }

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

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

这是我的日志投降课：

public class LogsRecapitulation extends AppCompatActivity {

    ExpandableListAdapter listAdapter;
    ExpandableListView expListView;
    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.expandable_layout);
        //recieve RecepitID and query to group_by logs
        final long forwardedId = (long) getIntent().getExtras().get(String.valueOf("recepitID"));
        List<Logs> logsList = new Select().from(Logs.class).where("Receipt = " + forwardedId).groupBy("SortID, Grade").execute();
        //get the listview
        expListView = (ExpandableListView) findViewById(R.id.lvExp);
        prepareListData();
        listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);
        expListView.setAdapter(listAdapter);
    }

    private void prepareListData() {

    }
}

我现在的问题是用数据库中的数据填充ExpandableListView。以下是我的表类：

//receipt table
@Table(name = "Receipt")
public class Receipt extends Model {
    @Column(name="Place")
    String place;
    @Column(name="ShippingNumber")
    String shippingNumber;
    @Column(name="Warehouse")
    String warehouse;
    @Column(name="Carrier")
    String carrier;
    @Column(name="LicencePlate")
    String licencePlate;
    @Column(name = "Driver")
    String driver;
    @Column(name = "Customer")
    String customer;
    @Column(name= "DestWarehouse")
    String destWarehouse;
    @Column(name = "Employee")
    String employee;
    @Column(name = "PriceType")
    String priceType;
    @Column(name = "PriceCorrection")
    Double priceCorrection;
    @Column(name = "PriceCorrection2")
    Double priceCorrection2;
    @Column(name = "Supplier")
    String supplier;
    @Column(name = "CreatedAt")
    Date createdAt;
}
//logs table
@Table(name = "Logs")
public class Logs extends Model {
    @Column(name="PlateNumber")
    String plate_number;
    @Column(name="SortID")
    String sort_id;
    @Column(name="Grade")
    String grade;
    @Column(name = "Diametar")
    double diameter;
    @Column(name="Length")
    double length;
    @Column(name="CreatedAt")
    Date createdAt;
    @Column(name="Receipt")
    Receipt receipt;
    @Column(name = "Price")
    Price price;
}
//price table
@Table(name = "Price")
public class Price extends Model {
    @Column(name = "Sort")
    String sort;
    @Column(name = "Grade")
    String grade;
    @Column(name = "Diameter")
    double diameter;
    @Column(name = "LengthDG")
    double lengthDG;
    @Column(name = "LengthGG")
    double lengthGG;
    @Column(name = "StumpPriceKn")
    double stumpPrice_kn;
    @Column(name = "RoadPriceKn")
    double roadPrice_kn;
}

注意：我正在使用ActiveanDroid。
如果有人知道如何从数据库填充Expandable ListView，请提供帮助。
问题：如何从数据库成功填充ExpandableListView？

Answer 1

我不是ActiveAndroid的专家，但下面是使用光标创建ExpandableListView的步骤。
在db helper类中需要两个方法来收集需要的行。

public Cursor fetchGroup() {
    String query = "SELECT * FROM rooms"
    return mDb.rawQuery(query, null);
}

public Cursor fetchChildren(String room) {
    String query = "SELECT * FROM devices WHERE id_room = '" + room + "'";
    return mDb.rawQuery(query, null);
}

然后需要配置适配器（在活动中）：

  public class MyExpandableListAdapter extends SimpleCursorTreeAdapter {
    public MyExpandableListAdapter(Cursor cursor, Context context,int groupLayout, 
        int childLayout, String[] groupFrom, int[] groupTo, String[] childrenFrom, 
        int[] childrenTo) {
            super(context, cursor, groupLayout, groupFrom, groupTo,
                  childLayout, childrenFrom, childrenTo);
        }
    }

    @Override
    protected Cursor getChildrenCursor(Cursor groupCursor) {
        Cursor childCursor = mDbHelper.fetchChildren(groupCursor.getString(groupCursor.getColumnIndex("id_room"));            
        getActivity().startManagingCursor(childCursor);
        childCursor.moveToFirst();
        return childCursor;
    }
}

最后，调用适配器并将其配置到列表中（在活动中）：

private void fillData() {
    mGroupsCursor = mDbHelper.fetchGroup();
    getActivity().startManagingCursor(mGroupsCursor);
    mGroupsCursor.moveToFirst();

    ExpandableListView elv = (ExpandableListView) getActivity().findViewById(android.R.id.list);

    mAdapter = new MyExpandableListAdapter(mGroupsCursor, getActivity(),
        R.layout.rowlayout_expgroup,                     // Your row layout for a group
        R.layout.rowlayout_itemlist_exp,                 // Your row layout for a child
        new String[] { "id_room" },                      // Field(s) to use from group cursor
        new int[] { android.R.id.room },                 // Widget ids to put group data into
        new String[] { "name_device", "state_device" },  // Field(s) to use from child cursors
        new int[] { R.id.device, R.id.state });          // Widget ids to put child data into

        lv.setAdapter(mAdapter);                         // set the list adapter.
    }
}

所以所有的代码

public class List_Exp extends Activity {
    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mDbHelper = new YourDB(getActivity());
        mDbHelper.open();
        fillData();
    }

    private void fillData() { 
        // set list adapter here
    }

    public class MyExpandableListAdapter extends SimpleCursorTreeAdapter {
        // Your adapter
    }
}

如果要捕获组/子级上的Click事件，请处理事件：

lv.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
    @Override
    public boolean onChildClick(ExpandableListView parent, View v,
        int groupPosition, int childPosition, long id) {
        // Your child click code here
        return true;
    }
});

lv.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
    @Override
    public boolean onGroupClick(ExpandableListView parent, View v,
        int groupPosition, int groupPosition, long id) {
        // Your group click code here
        return true;
    }
});