android学习日记03--常用控件ListView

浏览数：33 / 时间：2015年06月11日

8、ListView
列表视图，比如游戏的排行榜。列表数据可以根据屏幕大小自适应
LIstView用到两种适配器：
1、ArrayAdapter--简单适配器，只显示文字

2、SimpleAdapter--自定义适配器，可以显示自定义内容

使用简单适配器可直接
new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
this：当前context
android.R.layout.simple_list_item_1是系统的布局文件
list：ListView的各项数据

SimpleAdapter各项参数
new SimpleAdapter(context, data, resource, from, to)
context：当前context内容
data：ListView的各项数据
resource：ListView的每项布局
from：ListView的组件索引
to：ListView的组件ID
如：
new SimpleAdapter(MainActivity.this, list, R.layout.activity_main, new String[] {"item1","item2","item3","item4","item5"}
, new int[] {R.id.iv,R.id.bigtv,R.id.smalltv,R.id.btn,R.id.cb});

但是SimpleAdapter 不能触发组件的事件，还需
自己写适配器继承BaseAdapter

BaseAdapter主要有四个方法
getCount --列表每一项的长度
getItem
getItemId
getView --绘制每一项的具体组件

例子演示自定义MyAdapter

 1 <?xml version="1.0" encoding="utf-8"?>  
 2 <LinearLayout   
 3     android:orientation="horizontal" 
 4     android:layout_width="fill_parent"   
 5     android:layout_height="fill_parent"   
 6     xmlns:android="http://schemas.android.com/apk/res/android"
 7     >  
 8     <ImageView 
 9         android:id="@+id/iv"   
10         android:layout_width="wrap_content"   
11         android:layout_height="wrap_content"   
12         />
13     <LinearLayout   
14         android:orientation="vertical" 
15         android:layout_width="wrap_content"   
16         android:layout_height="wrap_content"   
17     >  
18     <TextView 
19         android:layout_width="wrap_content"   
20         android:layout_height="wrap_content"  
21         android:textSize="20sp"
22         android:id="@+id/bigtv"
23         />
24     
25     <TextView 
26         android:layout_width="wrap_content"   
27         android:layout_height="wrap_content"  
28         android:textSize="10sp"
29         android:id="@+id/smalltv"
30         />
31     
32     </LinearLayout>
33     
34     <Button 
35         android:layout_width="wrap_content"   
36         android:layout_height="wrap_content" 
37         android:text="button"
38         android:id="@+id/btn"
39         android:focusable="false"
40         />
41     
42     <CheckBox 
43         android:layout_width="wrap_content"   
44         android:layout_height="wrap_content" 
45         android:id="@+id/cb"
46         android:focusable="false"
47         />
48         
49     
50 </LinearLayout>

View Code

布局文件要特别说明两个属性
android:textSize="10sp" 设置text的大小
android:focusable="false" 设置焦点属性不可见

  1 package com.example.listview2;
  2 
  3 import java.util.List;
  4 import java.util.Map;
  5 
  6 import android.app.AlertDialog;
  7 import android.content.Context;
  8 import android.view.LayoutInflater;
  9 import android.view.View;
 10 import android.view.View.OnClickListener;
 11 import android.view.ViewGroup;
 12 import android.widget.BaseAdapter;
 13 import android.widget.Button;
 14 import android.widget.CheckBox;
 15 import android.widget.CompoundButton;
 16 import android.widget.CompoundButton.OnCheckedChangeListener;
 17 import android.widget.ImageView;
 18 import android.widget.TextView;
 19 
 20 public class MyAdapter extends BaseAdapter {
 21 
 22     
 23     private LayoutInflater mInflater;
 24     private List<Map<String, Object>> list;
 25     private int layId;
 26     private String flag[];
 27     private int itemId[];
 28     
 29     
 30     
 31     public MyAdapter(Context context, List<Map<String, Object>> list,
 32             int layId, String[] flag, int itemId[]) {
 33         this.mInflater = LayoutInflater.from(context);
 34         this.list = list;
 35         this.layId = layId;
 36         this.flag = flag;
 37         this.itemId = itemId;
 38     }
 39 
 40     @Override
 41     public int getCount() {
 42         // TODO Auto-generated method stub
 43         return list.size();
 44     }
 45 
 46     @Override
 47     public Object getItem(int arg0) {
 48         // TODO Auto-generated method stub
 49         return null;
 50     }
 51 
 52     @Override
 53     public long getItemId(int arg0) {
 54         // TODO Auto-generated method stub
 55         return 0;
 56     }
 57 
 58     @Override
 59     public View getView(int arg0, View arg1, ViewGroup arg2) {
 60         // TODO Auto-generated method stub
 61         arg1 = mInflater.inflate(layId, null);
 62         for (int i = 0; i < flag.length; i++) {
 63             if (arg1.findViewById(itemId[i]) instanceof ImageView) {
 64                 ImageView iv = (ImageView)arg1.findViewById(itemId[i]);
 65                 iv.setBackgroundResource((Integer) list.get(arg0).get(flag[i]));
 66             }else if (arg1.findViewById(itemId[i]) instanceof TextView) {
 67                 TextView tv = (TextView)arg1.findViewById(itemId[i]);
 68                 tv.setText((String)list.get(arg0).get(flag[i]));
 69             }
 70         }
 71         
 72         ((Button) arg1.findViewById(R.id.btn))
 73             .setOnClickListener(new OnClickListener() {
 74             
 75             @Override
 76             public void onClick(View v) {
 77                 // TODO Auto-generated method stub
 78                 new AlertDialog.Builder(MainActivity.ma)
 79                 .setTitle("自定义SimpleAdapter")
 80                 .setMessage("按钮成功触发监听事件！")
 81                 .show();
 82             }
 83         });
 84         CheckBox cb = (CheckBox) arg1.findViewById(R.id.cb);
 85         
 86         cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
 87             
 88             @Override
 89             public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
 90                 // TODO Auto-generated method stub
 91                 new AlertDialog.Builder(MainActivity.ma)
 92                 .setTitle("自定义 adapter")
 93                 .setMessage("触发选择框")
 94                 .show();
 95             }
 96         });
 97         
 98         return arg1;
 99     }
100 
101 }

View Code

MyAdapter代码里
new AlertDialog.Builder(MainActivity.ma)
.setTitle("自定义 adapter")
.setMessage("触发选择框")
.show();

表示弹出对话框，与Toast不同的是该对话框要按返回才会退出，而Toast是一闪而过的
MainActivity.ma是定义在MainActivity的静态变量指向this自己

MainActivity代码

 1 package com.example.listview2;
 2 
 3 import java.util.ArrayList;
 4 import java.util.HashMap;
 5 import java.util.List;
 6 import java.util.Map;
 7 
 8 import android.app.Activity;
 9 import android.os.Bundle;
10 import android.view.Menu;
11 import android.widget.ListView;
12 import android.widget.SimpleAdapter;
13 
14 public class MainActivity extends Activity {
15     private ListView lv;
16     private List<Map<String, Object>> list;
17     //private SimpleAdapter sp;
18     public static MainActivity ma;
19     @Override
20     protected void onCreate(Bundle savedInstanceState) {
21         super.onCreate(savedInstanceState);
22         setContentView(R.layout.activity_main);
23         
24         ma = this;
25         
26         lv = new ListView(this);
27         
28         list = new ArrayList<Map<String,Object>>();
29         
30         Map<String, Object> map = new HashMap<String, Object>();
31         map.put("item1", R.drawable.ic_launcher);
32         map.put("item2", "bigtv");
33         map.put("item3", "smalltv");
34         
35         list.add(map);
36         
37         
38         //sp = new SimpleAdapter(MainActivity.this, list, R.layout.activity_main, new String[] {"item1","item2","item3","item4","item5"}, new int[] {R.id.iv,R.id.bigtv,R.id.smalltv,R.id.btn,R.id.cb});
39         //lv.setAdapter(sp);
40         
41            // --使用自定义适配器，可监听其ListView中每一项的事件监听
42         MyAdapter adapter = new MyAdapter(this, list, R.layout.activity_main, new String[] {"item1","item2","item3"}, new int[] {R.id.iv,R.id.bigtv,R.id.smalltv});
43              // 为列表视图设置适配器（将数据映射到列表视图中）
44             lv.setAdapter(adapter);
45              // //显示列表视图
46         
47         this.setContentView(lv);
48         
49     }
50 
51 
52     @Override
53     public boolean onCreateOptionsMenu(Menu menu) {
54         // Inflate the menu; this adds items to the action bar if it is present.
55         getMenuInflater().inflate(R.menu.main, menu);
56         return true;
57     }
58     
59 }