java - 获取 sqlite 数据到 ExpandableListView

Question

我创建了一个 ExpandableListView 并使用静态数据，我的问题是我不确定如何从我的 sqlite 数据库 中获取数据到 ExpandableListView。我尝试了多个网站和帖子，但收效甚微。

如果有人可以，请查看我下面的代码并提出可行的解决方案。

谢谢

package com.example.pooveshin.vennsroadaccident2;

import android.app.Activity;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class MainActivity extends Activity {

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

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // get the listview
    expListView = (ExpandableListView) findViewById(R.id.lvExp);

    // preparing list data
    prepareListData();

    listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);

    // setting list adapter
    expListView.setAdapter(listAdapter);

    // Listview Group click listener
    expListView.setOnGroupClickListener(new OnGroupClickListener() {

        @Override
        public boolean onGroupClick(ExpandableListView parent, View v,
                                    int groupPosition, long id) {
            // Toast.makeText(getApplicationContext(),
            // "Group Clicked " + listDataHeader.get(groupPosition),
            // Toast.LENGTH_SHORT).show();
            return false;
        }
    });

    // Listview Group expanded listener
    expListView.setOnGroupExpandListener(new OnGroupExpandListener() {

        @Override
        public void onGroupExpand(int groupPosition) {
            Toast.makeText(getApplicationContext(),
                    listDataHeader.get(groupPosition) + " Expanded",
                    Toast.LENGTH_SHORT).show();
        }
    });

    // Listview Group collasped listener
    expListView.setOnGroupCollapseListener(new OnGroupCollapseListener() {

        @Override
        public void onGroupCollapse(int groupPosition) {
            Toast.makeText(getApplicationContext(),
                    listDataHeader.get(groupPosition) + " Collapsed",
                    Toast.LENGTH_SHORT).show();

        }
    });

    // Listview on child click listener
    expListView.setOnChildClickListener(new OnChildClickListener() {

        @Override
        public boolean onChildClick(ExpandableListView parent, View v,
                                    int groupPosition, int childPosition, long id) {
            // TODO Auto-generated method stub
            Toast.makeText(
                    getApplicationContext(),
                    listDataHeader.get(groupPosition)
                            + " : "
                            + listDataChild.get(
                            listDataHeader.get(groupPosition)).get(
                            childPosition), Toast.LENGTH_SHORT)
                    .show();
            return false;
        }
    });
}

/*
 * Preparing the list data
 */
private void prepareListData() {
    listDataHeader = new ArrayList<String>();
    listDataChild = new HashMap<String, List<String>>();

    // Adding child data
    listDataHeader.add("Accident Number : 1");
    listDataHeader.add("Accident Number : 2");
    listDataHeader.add("Accident Number : 3");

    // Adding child data
    List<String> AccYV = new ArrayList<String>();
    AccYV.add("Accident Number : ");
    AccYV.add("Registration Number : ");
    AccYV.add("Make & Model");
    AccYV.add("Address of Owner");
    AccYV.add("Name of Driver");
    AccYV.add("Address of Driver");
    AccYV.add("Tel no.Driver");

    List<String> AccOV = new ArrayList<String>();
    AccOV.add("Name of Driver");
    AccOV.add("Identity Number");
    AccOV.add("Residential Address");
    AccOV.add("Tel no.Work");
    AccOV.add("Make & Model");
    AccOV.add("Licence Number");

    List<String> AccCD = new ArrayList<String>();
    AccCD.add("Date");
    AccCD.add("Time");
    AccCD.add("Place");
    AccCD.add("Weather");
    AccCD.add("Road Surface");

    listDataChild.put(listDataHeader.get(0), AccYV); // Header, Child data
    listDataChild.put(listDataHeader.get(1), AccOV);
    listDataChild.put(listDataHeader.get(2), AccCD);
}
}  

在 DBHelper.java 中

public Cursor getYVAllData()
{
    SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
    Cursor res = sqLiteDatabase.rawQuery("SELECT * FROM " + TABLE_NAME,null);
    return res;
}

Answer 1

你应该像这样为可扩展 ListView 制作一个适配器

 public class ExpandListAdapter extends BaseExpandableListAdapter {

        private Context context;
        private ArrayList<ExpandListGroup> groups;
        public ExpandListAdapter(Context context, ArrayList<ExpandListGroup> groups) {
            this.context = context;
            this.groups = groups;
        }

        public void addItem(ExpandListChild item, ExpandListGroup group) {
            if (!groups.contains(group)) {
                groups.add(group);
            }
            int index = groups.indexOf(group);
            ArrayList<ExpandListChild> ch = groups.get(index).getItems();
            ch.add(item);
            groups.get(index).setItems(ch);
        }
        public Object getChild(int groupPosition, int childPosition) {
            // TODO Auto-generated method stub
            ArrayList<ExpandListChild> chList = groups.get(groupPosition).getItems();
            return chList.get(childPosition);
        }

        public long getChildId(int groupPosition, int childPosition) {
            // TODO Auto-generated method stub
            return childPosition;
        }

        public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View view,
                                 ViewGroup parent) {
            ExpandListChild child = (ExpandListChild) getChild(groupPosition, childPosition);
            if (view == null) {
                LayoutInflater infalInflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
                view = infalInflater.inflate(R.layout.expandlist_child_item, null);
            }
            TextView tv = (TextView) view.findViewById(R.id.tvChild);
            tv.setText(child.getName().toString());
            tv.setTag(child.getTag());
            // TODO Auto-generated method stub
            return view;
        }

        public int getChildrenCount(int groupPosition) {
            // TODO Auto-generated method stub
            ArrayList<ExpandListChild> chList = groups.get(groupPosition).getItems();

            return chList.size();

        }

        public Object getGroup(int groupPosition) {
            // TODO Auto-generated method stub
            return groups.get(groupPosition);
        }

        public int getGroupCount() {
            // TODO Auto-generated method stub
            return groups.size();
        }

        public long getGroupId(int groupPosition) {
            // TODO Auto-generated method stub
            return groupPosition;
        }

        public View getGroupView(int groupPosition, boolean isLastChild, View view,
                                 ViewGroup parent) {
            ExpandListGroup group = (ExpandListGroup) getGroup(groupPosition);
            if (view == null) {
                LayoutInflater inf = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
                view = inf.inflate(R.layout.expandlist_group_item, null);
            }

            TextView tv = (TextView) view.findViewById(R.id.tvGroup);
            tv.setText(group.getName());
            // TODO Auto-generated method stub
            return view;
        }

        public boolean hasStableIds() {
            // TODO Auto-generated method stub
            return true;
        }

        public boolean isChildSelectable(int arg0, int arg1) {
            // TODO Auto-generated method stub
            return true;
        }

    }

那么你应该像这样为列表创建子类和组类

child :

 public class ExpandListChild {
        private String Name;
        private String Tag;
        public String getName() {
            return Name;
        }
        public void setName(String Name) {
            this.Name = Name;
        }
        public String getTag() {
            return Tag;
        }
        public void setTag(String Tag) {
            this.Tag = Tag;
        }
    }

组:

public class ExpandListGroup {
    private String Name;
    private ArrayList<ExpandListChild> Items;

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        this.Name = name;
    }

    public ArrayList<ExpandListChild> getItems() {
        return Items;
    }

    public void setItems(ArrayList<ExpandListChild> Items) {
        this.Items = Items;
    }

}

这是在您的 MainActivity 中的用法:

     ExpandList = (ExpandableListView) findViewById(R.id.expandableListView);
                        ExpListItems = SetStandardGroups(da.queryName());
                        ExpAdapter = new ExpandListAdapter(MainActivity.this, ExpListItems);

and this is my method for fiil that list:





      public ArrayList<ExpandListGroup> SetStandardGroups(Cursor crsr) {
                ArrayList<ExpandListGroup> list = new ArrayList<ExpandListGroup>();
                ArrayList<ExpandListChild> list2;
                Cursor c = crsr;
                if (c.moveToFirst()) {
                    do {
                        String English = c.getString(c.getColumnIndex("English"));
                        String Farsi = c.getString(c.getColumnIndex("Farsi"));
                        ExpandListGroup gru1 = new ExpandListGroup();
                        gru1.setName(English);
                        ExpandListChild ch1_1 = new ExpandListChild();
                        ch1_1.setName(Farsi);
                        ch1_1.setTag(null);
                        list2 = new ArrayList<ExpandListChild>();
                        list2.add(ch1_1);
                        gru1.setItems(list2);
                        list.add(gru1);
                    } while (c.moveToNext());
                }
                c.close();

                return list;
            }