在開發中,我們經常使用到ListView這個控件。Android的API也提供了許多創建ListView適配器的快捷方式。例如ArrayAdapter、SimpleAdapter和SimpleCursorAdapter等。但你是否發現,如果採用這些系統自帶的適配器,對於事件的響應只能侷限在一個行單位。假設一行裏面有一個按鈕和一個圖片控件,它們之間的響應操作是不一樣的。若採用系統自帶的適配器,就不能精確到每個控件的響應事件。這時,我們一般採取自定義適配器來實現這個比較精確地請求。
ListView的創建,一般要具備兩大元素:
1)數據集,即要映射的字符串、圖片信息之類。
2)適配器,實現把要映射的字符串、圖片信息映射成視圖(如Textview、Image等組件),再添加到ListView中。
下面是一個實操例子:
實現細節:
1、創建數據集,一般定義如下
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]); //圖片資源
map.put("title", "物品名稱:"); //物品標題
map.put("info", goodsNames[i]); //物品名稱
map.put("detail", goodsDetails[i]); //物品詳情
listItems.add(map); //添加一項
2、創建適配器
public class ListViewAdapter extends BaseAdapter{........} //自定義的適配器一般繼承BaseAdapter類
listViewAdapter = new ListViewAdapter(this, listItems);
3、給ListView設置適配器
listView.setAdapter(listViewAdapter);
4、這裏還有個關鍵點,如何把list_item.xml佈局作爲一個視圖,添加到listView中:
LayoutInflater listContainer; //視圖容器工廠
listContainer = LayoutInflater.from(context); //創建視圖容器工廠並設置上下文
convertView = listContainer.inflate(R.layout.list_item, null); //創建list_item.xml佈局文件的視圖
實例視圖如下:
1)佈局文件main.xml
<?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">
<!-- 結算 -->
<LinearLayout android:gravity="center_horizontal"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView android:text="結算: "
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFFFF"
android:textSize="20px"/>
<ImageButton android:id="@+id/imgbt_sum"
android:layout_width="40px"
android:layout_height="40px"
android:background = "@drawable/shopping" />
</LinearLayout>
<TextView android:text="商品列表: "
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFFFF" />
<!-- 商品列表 -->
<ListView android:id="@+id/list_goods"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
列表項佈局文件list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!-- 商品圖片 -->
<ImageView android:id="@+id/imageItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5px"/>
<!-- 商品信息 -->
<LinearLayout android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView android:id="@+id/titleItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFFFF"
android:textSize="13px" />
<TextView android:id="@+id/infoItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFFFF"
android:textSize="22px" />
</LinearLayout>
<!-- 購買和商品詳情 -->
<LinearLayout android:gravity="right"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="wrap_content">
<CheckBox android:id="@+id/checkItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5px"/>
<Button android:id="@+id/detailItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5px"/>
</LinearLayout>
</LinearLayout>
2)代碼,主代碼:
package com.myandroid.test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.ImageButton;
import android.widget.ListView;
public class MyListView extends Activity {
private ListView listView;
private ImageButton imgbt_sum;
private ListViewAdapter listViewAdapter;
private List<Map<String, Object>> listItems;
private Integer[] imgeIDs = {R.drawable.cake,
R.drawable.gift, R.drawable.letter,
R.drawable.love, R.drawable.mouse,
R.drawable.music};
private String[] goodsNames = {"蛋糕", "禮物",
"郵票", "愛心", "鼠標", "音樂CD"};
private String[] goodsDetails = {
"蛋糕:好好吃。",
"禮物:禮輕情重。",
"郵票:環遊世界。",
"愛心:世界都有愛。",
"鼠標:反應敏捷。",
"音樂CD:酷我音樂。"};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView = (ListView)findViewById(R.id.list_goods);
imgbt_sum = (ImageButton) findViewById(R.id.imgbt_sum);
imgbt_sum.setOnClickListener(new ClickEvent());
listItems = getListItems();
listViewAdapter = new ListViewAdapter(this, listItems); //創建適配器
listView.setAdapter(listViewAdapter);
}
/**
* 初始化商品信息
*/
private List<Map<String, Object>> getListItems() {
List<Map<String, Object>> listItems = new ArrayList<Map<String, Object>>();
for(int i = 0; i < goodsNames.length; i++) {
Map<String, Object> map = new HashMap<String, Object>();
map.put("image", imgeIDs[i]); //圖片資源
map.put("title", "物品名稱:"); //物品標題
map.put("info", goodsNames[i]); //物品名稱
map.put("detail", goodsDetails[i]); //物品詳情
listItems.add(map);
}
return listItems;
}
class ClickEvent implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String goodsList = "";
for(int i = 0; i < listItems.size(); i++) {
goodsList += listViewAdapter.hasChecked(i)? goodsNames[i] + " ": "";
}
new AlertDialog.Builder(MyListView.this)
.setTitle("購物清單:")
.setMessage("你好,你選擇瞭如下商品:/n" + goodsList)
.setPositiveButton("確定", null)
.show();
}
}
}
適配器:
package com.myandroid.test;
import java.util.List;
import java.util.Map;
import android.app.AlertDialog;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
public class ListViewAdapter extends BaseAdapter {
private Context context; //運行上下文
private List<Map<String, Object>> listItems; //商品信息集合
private LayoutInflater listContainer; //視圖容器
private boolean[] hasChecked; //記錄商品選中狀態
public final class ListItemView{ //自定義控件集合
public ImageView image;
public TextView title;
public TextView info;
public CheckBox check;
public Button detail;
}
public ListViewAdapter(Context context, List<Map<String, Object>> listItems) {
this.context = context;
listContainer = LayoutInflater.from(context); //創建視圖容器並設置上下文
this.listItems = listItems;
hasChecked = new boolean[getCount()];
}
public int getCount() {
// TODO Auto-generated method stub
return listItems.size();
}
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}
/**
* 記錄勾選了哪個物品
* @param checkedID 選中的物品序號
*/
private void checkedChange(int checkedID) {
hasChecked[checkedID] = !hasChecked[checkedID];
}
/**
* 判斷物品是否選擇
* @param checkedID 物品序號
* @return 返回是否選中狀態
*/
public boolean hasChecked(int checkedID) {
return hasChecked[checkedID];
}
/**
* 顯示物品詳情
* @param clickID
*/
private void showDetailInfo(int clickID) {
new AlertDialog.Builder(context)
.setTitle("物品詳情:" + listItems.get(clickID).get("info"))
.setMessage(listItems.get(clickID).get("detail").toString())
.setPositiveButton("確定", null)
.show();
}
/**
* ListView Item設置
*/
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Log.e("method", "getView");
final int selectID = position;
//自定義視圖
ListItemView listItemView = null;
if (convertView == null) {
listItemView = new ListItemView();
//獲取list_item佈局文件的視圖
convertView = listContainer.inflate(R.layout.list_item, null);
//獲取控件對象
listItemView.image = (ImageView)convertView.findViewById(R.id.imageItem);
listItemView.title = (TextView)convertView.findViewById(R.id.titleItem);
listItemView.info = (TextView)convertView.findViewById(R.id.infoItem);
listItemView.detail= (Button)convertView.findViewById(R.id.detailItem);
listItemView.check = (CheckBox)convertView.findViewById(R.id.checkItem);
//設置控件集到convertView
convertView.setTag(listItemView);
}else {
listItemView = (ListItemView)convertView.getTag();
}
// Log.e("image", (String) listItems.get(position).get("title")); //測試
// Log.e("image", (String) listItems.get(position).get("info"));
//設置文字和圖片
listItemView.image.setBackgroundResource((Integer) listItems.get(
position).get("image"));
listItemView.title.setText((String) listItems.get(position)
.get("title"));
listItemView.info.setText((String) listItems.get(position).get("info"));
listItemView.detail.setText("商品詳情");
//註冊按鈕點擊時間愛你
listItemView.detail.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//顯示物品詳情
showDetailInfo(selectID);
}
});
// 註冊多選框狀態事件處理
listItemView.check
.setOnCheckedChangeListener(new CheckBox.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
//記錄物品選中狀態
checkedChange(selectID);
}
});
return convertView;
}
}