第八课：Activity 及其子类的使用二：ExpandableListActivity

最新推荐文章于 2020-05-16 17:09:56 发布

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#android #Activity #ExpandableListActivi

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本文介绍了如何使用ExpandableListActivity在Android应用中实现可展开列表的功能，包括XML布局方式和代码实现。通过实例演示了如何创建可展开的神族、虫族和人族兵种列表。

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例1：使用 ExpandableListActivity 实现可展开的 Activity

public class ExpandableListActivityTest extends ExpandableListActivity
{
	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		ExpandableListAdapter adapter = new BaseExpandableListAdapter()
		{
			int[] logos = new int[]
			{
				R.drawable.p,
				R.drawable.z,
				R.drawable.t
			};
 			private String[] armTypes = new String[]
				{ "神族兵种", "虫族兵种", "人族兵种"};
			private String[][] arms = new String[][]
			{
				{ "狂战士", "龙骑士", "黑暗圣堂", "电兵" },
				{ "小狗", "刺蛇", "飞龙", "自爆飞机" },
				{ "机枪兵", "护士MM" , "幽灵" }
			};
			//获取指定组位置、指定子列表项处的子列表项数据
			@Override
			public Object getChild(int groupPosition, int childPosition)
			{
				return arms[groupPosition][childPosition];
			}
			@Override
			public long getChildId(int groupPosition, int childPosition)
			{
				return childPosition;
			}
			@Override
			public int getChildrenCount(int groupPosition)
			{
				return arms[groupPosition].length;
			}
			private TextView getTextView()
			{
				AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
						ViewGroup.LayoutParams.MATCH_PARENT, 64);
				TextView textView = new TextView(ExpandableListActivityTest.this);
				textView.setLayoutParams(lp);
				textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
				textView.setPadding(36, 0, 0, 0);
				textView.setTextSize(20);
				return textView;
			}
			//该方法决定每个子选项的外观
			@Override
			public View getChildView(int groupPosition, int childPosition,
					boolean isLastChild, View convertView, ViewGroup parent)
			{
				TextView textView = getTextView();
				textView.setText(getChild(groupPosition, childPosition).toString());
				return textView;
			}
			//获取指定组位置处的组数据
			@Override
			public Object getGroup(int groupPosition)
			{
				return armTypes[groupPosition];
			}
			@Override
			public int getGroupCount()
			{
				return armTypes.length;
			}
			@Override
			public long getGroupId(int groupPosition)
			{
				return groupPosition;
			}
			//该方法决定每个组选项的外观
			@Override
			public View getGroupView(int groupPosition, boolean isExpanded,
					View convertView, ViewGroup parent)
			{
				LinearLayout ll = new LinearLayout(ExpandableListActivityTest.this);
				ll.setOrientation(0);
				ImageView logo = new ImageView(ExpandableListActivityTest.this);
				logo.setImageResource(logos[groupPosition]);
				ll.addView(logo);
				TextView textView = getTextView();
				textView.setText(getGroup(groupPosition).toString());
				ll.addView(textView);
				return ll;
			}
			@Override
			public boolean isChildSelectable(int groupPosition, int childPosition)
			{
				return true;
			}
			@Override
			public boolean hasStableIds()
			{
				return true;
			}
		};
		// 设置该窗口显示列表
		setListAdapter(adapter);
	}
}

例2：xml布局的方式使用 ExpandableListActivity

1.首先在main.xml添加ExpandableListView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <ExpandableListView
    	android:id="@id/android:list"   //ExpandableListView的ID为Android自定义，不可改变
    	android:layout_width="fill_parent"
    	android:layout_height="fill_parent"
		android:background="@drawable/background"/>
</LinearLayout>

2.为父目录创建布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content">
  <TextView
  	android:id="@+id/parent_group"
  	android:layout_width="wrap_content"
  	android:layout_height="wrap_content"
  	android:paddingTop="8px"
  	android:paddingLeft="50px"
  	android:paddingBottom="6px"
  	android:textColor="#ff00ff"
  	android:textStyle="bold"/>
</LinearLayout>

3.为子目录创建布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:paddingLeft="20dp"
  android:orientation="horizontal">
  <ImageView
  	android:layout_width="wrap_content"
  	android:layout_height="wrap_content"
  	android:paddingLeft="20px"
 	android:paddingTop="4dp"
  	android:background="@drawable/child_image"/>
  <LinearLayout
  	android:orientation="vertical"
  	android:layout_width="wrap_content"
  	android:layout_height="wrap_content">
  	<TextView
  		android:id="@+id/child_group"
  		android:textSize="20sp"
  		android:layout_width="wrap_content"
  		android:layout_height="wrap_content"/>
  	<TextView
  	  	android:layout_width="wrap_content"
  		android:layout_height="wrap_content"
  		android:text="地址：xx省xx市xx"/>
  	</LinearLayout>
</LinearLayout>

4.DisplayExpandableList.java

package com.yin;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.SimpleExpandableListAdapter;
public class DisplayExpandableList extends ExpandableListActivity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		List<HashMap<String, String>> parent_groups = new ArrayList<HashMap<String, String>>();
		String[] parent_group_names = {"我的好友","初中同学","高中同学","大学同学","黑名单"};
		parent_groups = this.addParentItems(parent_groups, parent_group_names);
		List<List<HashMap<String, String>>> child_groups = new ArrayList<List<HashMap<String, String>>>();
		List<HashMap<String, String>> child_lists = new ArrayList<HashMap<String, String>>();
		child_groups = this.addChildsItems(child_groups, child_lists,
				"小华");
		/**
		 * SimpleExpandableListAdapter的参数那是相当的多啊
		 * 参数   1：context  
		 * 		2：父级目录的数据
		 * 		3：父级目录的布局文件
		 * 		4: 夫级目录的数据来源
		 * 		5：指定父级目录显示数据的控件
		 * 		6：子级目录的数据
		 * 		7：子级目录的布局文件
		 * 		8：子级目录的数据来源
		 * 		9：指定子级目录显示数据的控件
		 */
		SimpleExpandableListAdapter adapter = new SimpleExpandableListAdapter(
				this, parent_groups, R.layout.parent_layout,
				new String[]{"parent_group"}, new int[]{R.id.parent_group},
				child_groups, R.layout.child_layout, new String[]{"child_group"},
				new int[]{R.id.child_group});
		setListAdapter(adapter);
	}
	//为每个父母目录下子目录添加数据
	public List<List<HashMap<String, String>>> addChildsItems(
			List<List<HashMap<String, String>>> child_groups,
			List<HashMap<String, String>> child_list, String item) {
		
		child_groups = new ArrayList<List<HashMap<String, String>>>();
		child_list = new ArrayList<HashMap<String, String>>();
		HashMap<String, String> map = new HashMap<String, String>();
		map.put("child_group", item);
		child_list.add(map);
		child_groups.add(child_list);
		return child_groups;
	}
	//为父级目录分组，添加标识
	public List<HashMap<String, String>> addParentItems(
			List<HashMap<String, String>> parent_groups, String[] parent_group_names) {
		parent_groups = new ArrayList<HashMap<String, String>>();
	
		for(int i=0;i<parent_group_names.length;i++){
			HashMap<String, String> groups = new HashMap<String, String>();
			groups.put("parent_group", parent_group_names[i]);
			parent_groups.add(groups);
		}
		
		return parent_groups;
	}
}

后续链接： Activity 及其子类的使用三：PreferenceActivity

源代码下载