可展开（收缩）的列表ListView(ExpandableListView)

1、首先创建我们的Activity，继承 android.app.ExpandableListActivity，直接看代码吧。

package com.ideasandroid.sample; import android.app.ExpandableListActivity; import android.os.Bundle; import com.ideasandroid.sample.adapter.IdeasExpandableListAdapter; /** * 可展开(收缩)列表示例 */ public class IdeasExpandableListView extends ExpandableListActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //设置列表适配器IdeasExpandableListAdapter setListAdapter(new IdeasExpandableListAdapter(this)); } }

2、创建适配器，继承android.widget.BaseExpandableListAdapter。

package com.ideasandroid.sample.adapter; import java.util.ArrayList; import java.util.List; 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; /** * 可展开(收缩)列表示例 */ public class IdeasExpandableListAdapter extends BaseExpandableListAdapter { private Context mContext = null; // 测试数据，开发时可能来自数据库，网络.... private String[] groups = { "家人", "朋友", "同事" }; private String[] familis = { "老爸", "老妈", "妹妹" }; private String[] friends = { "小李", "张三", "李四" }; private String[] colleagues = { "陈总", "李工", "李客户" }; private List<String> groupList = null; private List<List<String>> itemList = null; public IdeasExpandableListAdapter(Context context) { this.mContext = context; groupList = new ArrayList<String>(); itemList = new ArrayList<List<String>>(); initData(); } /** * 初始化数据，将相关数据放到List中，方便处理 */ private void initData() { for (int i = 0; i < groups.length; i++) { groupList.add(groups[i]); } List<String> item1 = new ArrayList<String>(); for (int i = 0; i < familis.length; i++) { item1.add(familis[i]); } List<String> item2 = new ArrayList<String>(); for (int i = 0; i < friends.length; i++) { item2.add(friends[i]); } List<String> item3 = new ArrayList<String>(); for (int i = 0; i < colleagues.length; i++) { item3.add(colleagues[i]); } itemList.add(item1); itemList.add(item2); itemList.add(item3); } public boolean areAllItemsEnabled() { return false; } /* * 设置子节点对象，在事件处理时返回的对象，可存放一些数据 */ public Object getChild(int groupPosition, int childPosition) { return itemList.get(groupPosition).get(childPosition); } public long getChildId(int groupPosition, int childPosition) { return childPosition; } /* * 字节点视图，这里我们显示一个文本对象 */ public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { TextView text = null; if (convertView == null) { text = new TextView(mContext); } else { text = (TextView) convertView; } // 获取子节点要显示的名称 String name = (String) itemList.get(groupPosition).get(childPosition); // 设置文本视图的相关属性 AbsListView.LayoutParams lp = new AbsListView.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, 40); text.setLayoutParams(lp); text.setTextSize(18); text.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT); text.setPadding(45, 0, 0, 0); text.setText(name); return text; } /* * 返回当前分组的字节点个数 */ public int getChildrenCount(int groupPosition) { return itemList.get(groupPosition).size(); } /* * 返回分组对象，用于一些数据传递，在事件处理时可直接取得和分组相关的数据 */ public Object getGroup(int groupPosition) { return groupList.get(groupPosition); } /* * 分组的个数 */ public int getGroupCount() { return groupList.size(); } public long getGroupId(int groupPosition) { return groupPosition; } /* * 分组视图，这里也是一个文本视图 */ public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { TextView text = null; if (convertView == null) { text = new TextView(mContext); } else { text = (TextView) convertView; } String name = (String) groupList.get(groupPosition); AbsListView.LayoutParams lp = new AbsListView.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, 40); text.setLayoutParams(lp); text.setTextSize(18); text.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT); text.setPadding(36, 0, 0, 0); text.setText(name); return text; } /* * 判断分组是否为空，本示例中数据是固定的，所以不会为空，我们返回false * 如果数据来自数据库，网络时，可以把判断逻辑写到这个方法中，如果为空 * 时返回true */ public boolean isEmpty() { return false; } /* * 收缩列表时要处理的东西都放这儿 */ public void onGroupCollapsed(int groupPosition) { } /* * 展开列表时要处理的东西都放这儿 */ public void onGroupExpanded(int groupPosition) { } /* * Indicates whether the child and group IDs are stable across changes to * the underlying data. */ public boolean hasStableIds() { return false; } /* * Whether the child at the specified position is selectable. */ public boolean isChildSelectable(int groupPosition, int childPosition) { return true; } }