Android的ExpandableListView和SQLite数据库 [英] Android ExpandableListView and SQLite Database

问题描述

我有两个表在我的数据库 - 房间和设备。每间客房都可以有许多设备。我想提出一个可扩展的ListView与房间名组和设备的名称和状态，儿童（或关闭）。

任何一个可以给我一个简单的想法，因为我是一种新的与Android和所有的教程是很难做出

这是我的数据库：

 公共无效的onCreate（SQLiteDatabase DB）{
        如果不存在房db.execSQL（CREATE TABLE（
                                    id_room整数主键自动增量，
                +name_room文字不为空
                +）;）;
        如果不存在设备db.execSQL（CREATE TABLE（
                                    id_device整数主键自动增量，
                +name_device文字不为空，
                +state_device文字不为空，
                +id_room引用房
                +）;）;
    }
 

解决方案

以下是一个非常简单的，没有多余的装饰扩展列表实现。

您需要在您的分贝辅助类两种方法来收集你需要的光标。

 公开光标fetchGroup（）{
    查询字符串=SELECT * FROM房
    返回mDb.rawQuery（查询，NULL）;
}

公共光标fetchChildren（字符串房）{
    查询字符串=SELECT * FROM设备WHERE id_room ='+房+';
    返回mDb.rawQuery（查询，NULL）;
}
 

然后，你需要设置你的适配器（在您的活动）：

 公共类MyExpandableListAdapter扩展SimpleCursorTreeAdapter {
    公共MyExpandableListAdapter（光标指针，上下文语境，诠释的GroupLayout，
        INT childLayout，字符串[] groupFrom，INT [] groupTo，字符串[] childrenFrom，
        INT [] childrenTo）{
            超（背景下，光标的GroupLayout，groupFrom，groupTo，
                  childLayout，childrenFrom，childrenTo）;
        }
    }

    @覆盖
    受保护的光标getChildrenCursor（光标groupCursor）{
        光标childCursor = mDbHelper.fetchChildren（groupCursor.getString（groupCursor.getColumnIndex（id_room））;
        。getActivity（）startManagingCursor（childCursor）;
        childCursor.moveToFirst（）;
        返回childCursor;
    }
}
 

最后调用适配器并将其设置为您的列表（在你的活动）：

 私人无效fillData（）{
    mGroupsCursor = mDbHelper.fetchGroup（）;
    。getActivity（）startManagingCursor（mGroupsCursor）;
    mGroupsCursor.moveToFirst（）;

    ExpandableListView ELV =（ExpandableListView）getActivity（）findViewById（android.R.id.list）。

    mAdapter =新MyExpandableListAdapter（mGroupsCursor，getActivity（）
        R.layout.rowlayout_expgroup，//你排布置为一组
        R.layout.rowlayout_itemlist_exp，//你行布局为孩子
        新的String [] {id_room} //场（S）从组光标使用
        新的INT [] {} android.R.id.room，//控件的ID将数据分组到
        新的String [] {name_device，state_device} //场（S）从子游标使用
        新的INT [] {R.id.device，R.id.state}）; //控件的ID将子数据成

        lv.setAdapter（mAdapter）; //设置列表适配器。
    }
}
 

希望这有助于！

修改

这都应该走到一起，像这样：

 公共类List_Exp延伸活动{
    @覆盖
    公共无效onActivityCreated（包savedInstanceState）{
        super.onActivityCreated（savedInstanceState）;
        mDbHelper =新YourDB（getActivity（））;
        mDbHelper.open（）;
        fillData（）;
    }

    私人无效fillData（）{
        //设置列表在这里适配器
    }

    公共类MyExpandableListAdapter扩展SimpleCursorTreeAdapter {
        //你的适配器
    }
}
 

编辑2

要赶点击，集听众对你的活动：

  lv.setOnChildClickListener（新ExpandableListView.OnChildClickListener（）{
    @覆盖
    公共布尔onChildClick（ExpandableListView父，视图V，
        INT groupPosition，诠释childPosition，长ID）{
        //你的孩子点击code在这里
        返回true;
    }
}）;

lv.setOnGroupClickListener（新ExpandableListView.OnGroupClickListener（）{
    @覆盖
    公共布尔onGroupClick（ExpandableListView父，视图V，
        INT groupPosition，诠释groupPosition，长ID）{
        //你的组点击code在这里
        返回true;
    }
}）;
 

I have two tables in my database - rooms and devices. Each room can have many devices. I want to make an expandable listview with room name as group and devices name and state as children (on or off).

Can any one give me a simple idea because I am kind of new with Android and all tutorials are hard to make

This is my database:

public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table if not exists rooms (
                                    id_room integer primary key autoincrement, "
                + "name_room text not null" 
                + ");");    
        db.execSQL("create table if not exists devices (
                                    id_device integer primary key autoincrement, "
                + "name_device text not null," 
                + "state_device text not null,"
                + "id_room references rooms"
                + ");");
    }

解决方案

Following is a very simple, no frills expandable list implementation.

You need two methods in your db helper class to gather the cursors you will need.

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);
}

Then you need to set up your adapter (in your activity):

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;
    }
}

And finally call the adapter and set it to your list (in your activity):

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.
    }
}

Hope this helps!

EDIT

It should all come together like so:

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
    }
}

EDIT 2

To catch clicks, set listeners in you activity:

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;
    }
});

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