Android支援展開/收縮功能的清單控制項

最近在做一個Rss閱讀器，看了下別人做的閱讀器中的清單控制項可以展開、收縮，我就在網上搜尋了一下。下面就我找到的一個小例子，給大家分享一下。

ActivityMain .java

  package study.com.android;
 
import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ExpandableListView.ExpandableListContextMenuInfo;
 
public class ActivityMain extends ExpandableListActivity {
 
    private ExpandableListAdapter mAdapter;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setTitle("ExpandableList");
        mAdapter = new MyExpandableListAdapter(this);
        setListAdapter(mAdapter);
        registerForContextMenu(this.getExpandableListView());
    }
 
    // 為列表的每一項建立操作功能表（即長按後 呼出的菜單）
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
            ContextMenuInfo menuInfo) {
        menu.setHeaderTitle("ContexMenu");
        menu.add(0, 0, 0, "ContextMenu");
    }
 
    // 單擊操作功能表後的邏輯
    @Override
    public boolean onContextItemSelected(MenuItem item) {
 
        ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item
                .getMenuInfo();
        String title = ((TextView) info.targetView).getText().toString();
 
        int type = ExpandableListView
                .getPackedPositionType(info.packedPosition);
        if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
 
            int groupPos = ExpandableListView
                    .getPackedPositionGroup(info.packedPosition);
            int childPos = ExpandableListView
                    .getPackedPositionChild(info.packedPosition);
            Toast.makeText(
                    this,
                    title + "-Group Index" + groupPos + "Child Index:"
                            + childPos, Toast.LENGTH_SHORT).show();
            return true;
        }
        return false;
    }
}

MyExpandableListAdapter.java

 ckage study.com.android;
 
import android.content.Context;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
 
public class MyExpandableListAdapter extends BaseExpandableListAdapter {
 
    private Context mContext;
 
    // 父列表資料
    private String[] groups = { "group1", "group2", "group3", "group4", ""};
 
    // 子列表資料
    private String[][] children = { { "child1" }, { "child1", "child2" },
            { "child1", "child2", "child3" },
            { "child1", "child2", "child3", "child4" }, };
 
    MyExpandableListAdapter(Context context) {
        mContext = context;
    }
 
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return children[groupPosition][childPosition];
    }
 
    @Override
    public long getChildId(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return childPosition;
    }
 
    // 取子列表中的某一項的view
    @Override
    public View getChildView(int groupPosition, int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {
        TextView textView = getGenericView();
        ;
        textView.setText(getChild(groupPosition, childPosition).toString());
        return textView;
    }
 
    @Override
    public int getChildrenCount(int groupPosition) {
        // TODO Auto-generated method stub
        return children[groupPosition].length;
    }
 
    @Override
    public Object getGroup(int groupPosition) {
        return groups[groupPosition];
    }
 
    @Override
    public int getGroupCount() {
        // TODO Auto-generated method stub
        return groups.length;
    }
 
    @Override
    public long getGroupId(int groupPosition) {
        // TODO Auto-generated method stub
        return groupPosition;
    }
 
    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        TextView textView = getGenericView();
        textView.setText(getGroup(groupPosition).toString());
 
        return textView;
    }
 
    @Override
    public boolean hasStableIds() {
        // TODO Auto-generated method stub
        return true;
    }
 
    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return true;
    }
 
    // 擷取某一項的view的邏輯
    private TextView getGenericView() {
        AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
                ViewGroup.LayoutParams.FILL_PARENT, 48);
        TextView textView = new TextView(mContext);
        textView.setLayoutParams(lp);
        textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
        textView.setPadding(32, 0, 0, 0);
        return textView;
    }
 
}

啟動並執行結果如下：