2015-07-16 15:21
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在开发中,我们经常使用到ListView这个控件。Android的API也提供了许多创建ListView适配器的快捷方式。例如ArrayAdapter、SimpleAdapter和SimpleCursorAdapter等。但你是否发现,如果采用这些系统自带的适配器,对于事件的响应只能局限在一个行单位。假设一行里面有一个按钮和一个图片控件,它们之间的响应操作是不一样的。若采用系统自带的适配器,就不能精确到每个控件的响应事件。这时,我们一般采取自定义适配器来实现这个比较精确地请求。
listview的创建一般包括两部分元素
1.要映射的元素,即字符串或图片集等元素
2.适配器,把要映射的元素映射为视图(如TextView,ImageView),并添加到listview中
下面是具体的实例
1、创建数据集,一般定义如下
private List<Map<String, Object>> listItems;
元素添加方式:
Map<String, Object> map = new HashMap<String, Object>();
map.put("image", imgeIDs[i]); //图片资源
map.put("title", "物品名称:"); //物品标题
map.put("info", goodsNames[i]); //物品名称
map.put("detail", goodsDetails[i]); //物品详情
listItems.add(map); //添加一项
2、创建适配器
public class ListViewAdapter extends BaseAdapter{........} //自定义的适配器一般继承BaseAdapter类
listViewAdapter = new ListViewAdapter(this, listItems);
3、给ListView设置适配器
listView.setAdapter(listViewAdapter);
4、这里还有个关键点,如何把list_item.xml布局作为一个视图,添加到listView中:
LayoutInflater listContainer; //视图容器工厂
listContainer = LayoutInflater.from(context); //创建视图容器工厂并设置上下文
convertView = listContainer.inflate(R.layout.list_item, null); //创建list_item.xml布局文件的视图
下面是具体的代码文件
1)布局文件main.xml
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<?xml version="1.0" encoding="utf-8"?>
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<LinearLayout xmlns:Android="http://schemas./apk/res/android"
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Android:orientation="vertical"
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Android:layout_width="fill_parent"
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Android:layout_height="fill_parent">
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<!-- 结算 -->
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<LinearLayout Android:gravity="center_horizontal"
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Android:orientation="horizontal" android:layout_width="fill_parent"
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Android:layout_height="wrap_content">
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<TextView Android:text="结算: "
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:textColor="#FFFFFFFF"
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Android:textSize="20px"/>
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<ImageButton Android:id="@+id/imgbt_sum"
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Android:layout_width="40px"
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Android:layout_height="40px"
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Android:background = "@drawable/shopping" />
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</LinearLayout>
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<TextView Android:text="商品列表: "
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:textColor="#FFFFFFFF" />
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<!-- 商品列表 -->
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<ListView Android:id="@+id/list_goods"
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Android:layout_width="fill_parent"
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Android:layout_height="wrap_content" />
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</LinearLayout>
列表项布局文件list_item.xml
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<?xml version="1.0" encoding="utf-8"?>
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<LinearLayout xmlns:Android="http://schemas./apk/res/android"
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Android:orientation="horizontal" android:layout_width="fill_parent"
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Android:layout_height="fill_parent">
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<!-- 商品图片 -->
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<ImageView Android:id="@+id/imageItem"
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:layout_margin="5px"/>
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<!-- 商品信息 -->
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<LinearLayout Android:orientation="vertical"
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content">
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<TextView Android:id="@+id/titleItem"
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:textColor="#FFFFFFFF"
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Android:textSize="13px" />
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<TextView Android:id="@+id/infoItem"
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:textColor="#FFFFFFFF"
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Android:textSize="22px" />
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</LinearLayout>
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<!-- 购买和商品详情 -->
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<LinearLayout Android:gravity="right"
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Android:orientation="horizontal" android:layout_width="fill_parent"
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Android:layout_height="wrap_content">
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<CheckBox Android:id="@+id/checkItem"
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:layout_margin="5px"/>
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<Button Android:id="@+id/detailItem"
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Android:layout_width="wrap_content"
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Android:layout_height="wrap_content"
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Android:layout_margin="5px"/>
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</LinearLayout>
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</LinearLayout>
2)代码,主代码:
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package com.myAndroid.test;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import Android.app.Activity;
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import Android.app.AlertDialog;
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import Android.content.DialogInterface;
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import Android.os.Bundle;
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import Android.view.View;
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import Android.view.View.OnClickListener;
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import Android.widget.ArrayAdapter;
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import Android.widget.ImageButton;
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import Android.widget.ListView;
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public class MyListView extends Activity {
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private ListView listView;
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private ImageButton imgbt_sum;
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private ListViewAdapter listViewAdapter;
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private List<Map<String, Object>> listItems;
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private Integer[] imgeIDs = {R.drawable.cake,
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R.drawable.gift, R.drawable.letter,
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R.drawable.love, R.drawable.mouse,
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R.drawable.music};
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private String[] goodsNames = {"蛋糕", "礼物",
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"邮票", "爱心", "鼠标", "音乐CD"};
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private String[] goodsDetails = {
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"蛋糕:好好吃。",
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"礼物:礼轻情重。",
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"邮票:环游世界。",
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"爱心:世界都有爱。",
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"鼠标:反应敏捷。",
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"音乐CD:酷我音乐。"};
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/** Called when the activity is first created. */
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@Override
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public void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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setContentView(R.layout.main);
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listView = (ListView)findViewById(R.id.list_goods);
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imgbt_sum = (ImageButton) findViewById(R.id.imgbt_sum);
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imgbt_sum.setOnClickListener(new ClickEvent());
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listItems = getListItems();
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listViewAdapter = new ListViewAdapter(this, listItems); //创建适配器
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listView.setAdapter(listViewAdapter);
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}
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/**
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* 初始化商品信息
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*/
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private List<Map<String, Object>> getListItems() {
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List<Map<String, Object>> listItems = new ArrayList<Map<String, Object>>();
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for(int i = 0; i < goodsNames.length; i++) {
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Map<String, Object> map = new HashMap<String, Object>();
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map.put("image", imgeIDs[i]); //图片资源
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map.put("title", "物品名称:"); //物品标题
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map.put("info", goodsNames[i]); //物品名称
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map.put("detail", goodsDetails[i]); //物品详情
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listItems.add(map);
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}
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return listItems;
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}
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class ClickEvent implements OnClickListener{
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@Override
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public void onClick(View v) {
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// TODO Auto-generated method stub
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String goodsList = "";
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for(int i = 0; i < listItems.size(); i++) {
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goodsList += listViewAdapter.hasChecked(i)? goodsNames[i] + " ": "";
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}
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new AlertDialog.Builder(MyListView.this)
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.setTitle("购物清单:")
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.setMessage("你好,你选择了如下商品:\n" + goodsList)
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.setPositiveButton("确定", null)
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.show();
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}
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}
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}
适配器代码:
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package com.myAndroid.test;
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import java.util.List;
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import java.util.Map;
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import Android.app.AlertDialog;
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import Android.content.Context;
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import Android.util.Log;
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import Android.view.LayoutInflater;
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import Android.view.View;
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import Android.view.ViewGroup;
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import Android.widget.BaseAdapter;
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import Android.widget.Button;
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import Android.widget.CheckBox;
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import Android.widget.CompoundButton;
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import Android.widget.ImageView;
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import Android.widget.ListView;
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import Android.widget.TextView;
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public class ListViewAdapter extends BaseAdapter {
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private Context context; //运行上下文
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private List<Map<String, Object>> listItems; //商品信息集合
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private LayoutInflater listContainer; //视图容器
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private boolean[] hasChecked; //记录商品选中状态
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public final class ListItemView{ //自定义控件集合
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public ImageView image;
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public TextView title;
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public TextView info;
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public CheckBox check;
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public Button detail;
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}
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public ListViewAdapter(Context context, List<Map<String, Object>> listItems) {
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this.context = context;
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listContainer = LayoutInflater.from(context); //创建视图容器并设置上下文
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this.listItems = listItems;
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hasChecked = new boolean[getCount()];
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}
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public int getCount() {
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// TODO Auto-generated method stub
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return listItems.size();
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}
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public Object getItem(int arg0) {
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// TODO Auto-generated method stub
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return null;
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}
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public long getItemId(int arg0) {
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// TODO Auto-generated method stub
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return 0;
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}
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/**
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* 记录勾选了哪个物品
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* @param checkedID 选中的物品序号
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*/
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private void checkedChange(int checkedID) {
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hasChecked[checkedID] = !hasChecked[checkedID];
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}
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/**
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* 判断物品是否选择
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* @param checkedID 物品序号
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* @return 返回是否选中状态
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*/
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public boolean hasChecked(int checkedID) {
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return hasChecked[checkedID];
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}
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/**
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* 显示物品详情
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* @param clickID
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*/
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private void showDetailInfo(int clickID) {
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new AlertDialog.Builder(context)
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.setTitle("物品详情:" + listItems.get(clickID).get("info"))
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.setMessage(listItems.get(clickID).get("detail").toString())
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.setPositiveButton("确定", null)
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.show();
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}
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/**
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* ListView Item设置
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*/
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public View getView(int position, View convertView, ViewGroup parent) {
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// TODO Auto-generated method stub
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Log.e("method", "getView");
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final int selectID = position;
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//自定义视图
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ListItemView listItemView = null;
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if (convertView == null) {
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listItemView = new ListItemView();
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//获取list_item布局文件的视图
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convertView = listContainer.inflate(R.layout.list_item, null);
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//获取控件对象
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listItemView.image = (ImageView)convertView.findViewById(R.id.imageItem);
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listItemView.title = (TextView)convertView.findViewById(R.id.titleItem);
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listItemView.info = (TextView)convertView.findViewById(R.id.infoItem);
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listItemView.detail= (Button)convertView.findViewById(R.id.detailItem);
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listItemView.check = (CheckBox)convertView.findViewById(R.id.checkItem);
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//设置控件集到convertView
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convertView.setTag(listItemView);
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}else {
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listItemView = (ListItemView)convertView.getTag();
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}
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// Log.e("image", (String) listItems.get(position).get("title")); //测试
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// Log.e("image", (String) listItems.get(position).get("info"));
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//设置文字和图片
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listItemView.image.setBackgroundResource((Integer) listItems.get(
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position).get("image"));
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listItemView.title.setText((String) listItems.get(position)
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.get("title"));
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listItemView.info.setText((String) listItems.get(position).get("info"));
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listItemView.detail.setText("商品详情");
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//注册按钮点击时间爱你
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listItemView.detail.setOnClickListener(new View.OnClickListener() {
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@Override
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public void onClick(View v) {
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//显示物品详情
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showDetailInfo(selectID);
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}
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});
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// 注册多选框状态事件处理
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listItemView.check
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.setOnCheckedChangeListener(new CheckBox.OnCheckedChangeListener() {
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@Override
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public void onCheckedChanged(CompoundButton buttonView,
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boolean isChecked) {
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//记录物品选中状态
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checkedChange(selectID);
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}
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});
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return convertView;
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}
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}
下面是显示的效果图:
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