Android学习之——GridView

背景知识

    GridView在Android开发中和ListView一样经常被使用。如我们经常使用的快图浏览，里面就有将图片的布局改为网格（即GridView）的选项。还有约X神器——陌陌的搜索界也是用了GridView。

定义

   GridView is a ViewGroup that displays items in a two-dimensional, scrollable grid. The grid items are automatically inserted to the layout using a ListAdapter

   网格视图是一个二维的可滚动的网格中展示网格项的视图集合。网格项使用ListAdapter自动插入到布局中。

Demo

 1.使用SimpleAdapter适配

MainActivity

 1 package com.johntsai.gridviewdemo;
 2
 3 import java.util.ArrayList;
 4 import java.util.HashMap;
 5
 6 import android.app.Activity;
 7 import android.content.Intent;
 8 import android.os.Bundle;
 9 import android.view.View;
10 import android.widget.AdapterView;
11 import android.widget.AdapterView.OnItemClickListener;
12 import android.widget.GridView;
13 import android.widget.SimpleAdapter;
14 import android.widget.Toast;
15
16 public class MainActivity extends Activity {
17     private int ids[]={
18         R.drawable.aaa,
19         R.drawable.bbb,
20         R.drawable.ccc,
21         R.drawable.ddd,
22         R.drawable.eee,
23         R.drawable.fff,
24         R.drawable.ggg,
25         R.drawable.hhh,
26         R.drawable.aaa
27     };
28     private GridView gridView;
29     @Override
30     protected void onCreate(Bundle savedInstanceState) {
31         super.onCreate(savedInstanceState);
32         setContentView(R.layout.activity_main);
33
34         gridView = (GridView)findViewById(R.id.gridview);
35
36         ArrayList<HashMap<String, Object>> images = new ArrayList<HashMap<String,Object>>();
37         for(int i=0;i<ids.length;i++){
38             HashMap<String, Object>map = new HashMap<String, Object>();
39             map.put("Image", ids[i]);
40             map.put("Id", "Android"+i+"号");
41             images.add(map);
42         }
43
44         SimpleAdapter adapter = new SimpleAdapter(this,
45                 images, R.layout.gridview_item,
46                 new String[]{"Image","Id"}, new int[]{R.id.imageItem,R.id.idItem});
47         gridView.setAdapter(adapter);
48
49         gridView.setOnItemClickListener(new OnItemClickListener() {
50
51             @Override
52             public void onItemClick(AdapterView<?> parent, View view,
53                     int position, long id) {
54                  Toast.makeText(getApplicationContext(),
55                          "你点击了" + position+"号", Toast.LENGTH_LONG).show();
56
57             }
58         });
59     }
60 }

 主界面布局文件

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/gridview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:columnWidth="90dp"
    android:numColumns="auto_fit"
    android:stretchMode="columnWidth"
    android:gravity="center"
/>
<!--
  android:columnWidth="90dp" 列宽设置为90dp
  android:numColumns="auto_fit"列数设置为自动
  android:stretchMode="columnWidth" 缩放与列的宽度同步
  -->

GridView项布局文件

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:paddingBottom="4dip">
 6
 7     <ImageView
 8         android:id="@+id/imageItem"
 9         android:layout_height="70dp"
10         android:layout_width="70dp"
11         android:layout_centerHorizontal="true"
12         />
13     <TextView
14         android:id="@+id/idItem"
15         android:layout_height="wrap_content"
16         android:layout_width="70dp"
17         android:layout_centerHorizontal="true"
18         android:layout_below="@id/imageItem"
19         />
20 </RelativeLayout>

运行效果：

     2.使用继承自BaseAdapter的ImageAdapter适配

 1 package com.johntsai.gridviewdemo;
 2
 3 import android.content.Context;
 4 import android.view.View;
 5 import android.view.ViewGroup;
 6 import android.widget.BaseAdapter;
 7 import android.widget.GridView;
 8 import android.widget.ImageView;
 9
10 public class ImageAdapter extends BaseAdapter {
11     public Integer [] ImagesIds = {
12         R.drawable.aaa,
13         R.drawable.bbb,
14         R.drawable.ccc,
15         R.drawable.ddd,
16         R.drawable.eee,
17         R.drawable.fff,
18         R.drawable.ggg,
19         R.drawable.hhh
20     };
21     private Context context;
22     //构造方法
23     public ImageAdapter(Context c) {
24           context = c;
25     }
26     @Override
27     public int getCount() {
28         return ImagesIds.length;
29     }
30
31     @Override
32     public Object getItem(int position) {
33         return null;
34     }
35
36     @Override
37     public long getItemId(int position) {
38         return 0;
39     }
40
41     @Override
42     public View getView(int position, View convertView, ViewGroup parent) {
43         ImageView imageView;
44         if (convertView == null) {
45                   imageView = new ImageView(context);
46                   imageView.setLayoutParams(new GridView.LayoutParams(100, 100));
47                   imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
48                   imageView.setPadding(0, 0, 0, 0);
49                   } else {
50                       imageView = (ImageView) convertView;
51                   }
52
53                   imageView.setImageResource(ImagesIds[position]);
54                   return imageView;
55     }
56
57 }

MainActivity

 1 public class MainActivity extends Activity {
 2     private GridView gridView;
 3     @Override
 4     protected void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6         setContentView(R.layout.activity_main);
 7
 8         gridView = (GridView)findViewById(R.id.gridview);
 9         gridView.setAdapter(new ImageAdapter(getApplicationContext()));
10
11         gridView.setOnItemClickListener(new OnItemClickListener() {
12
13             @Override
14             public void onItemClick(AdapterView<?> parent, View view,
15                     int position, long id) {
16                  Toast.makeText(getApplicationContext(),
17                          "你点击了" + position+"号", Toast.LENGTH_LONG).show();
18
19             }
20         });
21     }
22 }

原文地址：http://www.cnblogs.com/JohnTsai/p/4155117.html