Android：控件GridView的使用

MainActivity.java

package com.example.testgridview; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import android.app.Activity; import android.os.Bundle; import android.widget.GridView; import android.widget.SimpleAdapter; public class MainActivity extends Activity { private GridView gview; private List 
  
    > data_list; private SimpleAdapter sim_adapter; // 图片封装为一个数组 private int[] icon = { R.drawable.address_book, R.drawable.calendar, R.drawable.camera, R.drawable.clock, R.drawable.games_control, R.drawable.messenger, R.drawable.ringtone, R.drawable.settings, R.drawable.speech_balloon, R.drawable.weather, R.drawable.world, R.drawable.youtube }; private String[] iconName = { "通讯录", "日历", "照相机", "时钟", "游戏", "短信", "铃声", "设置", "语音", "天气", "浏览器", "视频" }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.test); gview = (GridView) findViewById(R.id.gview); //新建List data_list = new ArrayList 
   
     >(); //获取数据 getData(); //新建适配器 String [] from ={"image","text"}; int [] to = {R.id.image,R.id.text}; sim_adapter = new SimpleAdapter(this, data_list, R.layout.item, from, to); //配置适配器 gview.setAdapter(sim_adapter); } public List 
    
      > getData(){ //cion和iconName的长度是相同的，这里任选其一都可以 for(int i=0;i 
     
       map = new HashMap 
      
        (); map.put("image", icon[i]); map.put("text", iconName[i]); data_list.add(map); } return data_list; } } 
       
      
     
    
  

test.xml

item.xml

概述

GridView是Android的另一个列表容器，用法也跟ListView类似，它的布局是一个网格，一行可以有多个项，并且整个视图可以滚动，我们常见的应用有手机中的图库、launcher里面的应用列表、类似微信多张图片等，总的来说，ListView主要应用于单列多行的列表，然而GridView主要应用于多行多列的网状布局。

案例

GridView

上面的运行结果就是GridView的典型效果，每个item是一张固定大小的图片，这里让它自适应屏幕来填充完整个屏幕的宽度。

实现过程

相关属性解析：

子项
layout/layout_grid_item.xml

Activity代码

 package com.devilwwj.androiddevelopcourse.activities; import android.content.Context; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.BaseAdapter; import android.widget.GridView; import android.widget.ImageView; import com.devilwwj.androiddevelopcourse.R; import com.nostra13.universalimageloader.core.ImageLoader; public class GridViewTestActivity extends ActionBarActivity implements OnItemClickListener { private GridView gridView; private Context mContext; private ImageLoader imageLoader; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_gridview); mContext = GridViewTestActivity.this; imageLoader = ImageLoader.getInstance(); gridView = (GridView) this.findViewById(R.id.gridView); gridView.setAdapter(new ImageAdapter(this)); } // references to our images private Integer[] mThumbIds = { R.drawable.sample_2, R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5, R.drawable.sample_6, R.drawable.sample_7, R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2, R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5, R.drawable.sample_6, R.drawable.sample_7, R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2, R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5, R.drawable.sample_6, R.drawable.sample_7 }; @Override public void onItemClick(AdapterView 
    parent, View view, int position, long id) { // TODO: 点击列表跳转到其他页面 } private class ImageAdapter extends BaseAdapter { private Context mContext; public ImageAdapter(Context context) { this.mContext = context; } @Override public int getCount() { return mThumbIds.length; } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder = null; if (convertView == null) { convertView = LayoutInflater.from(mContext).inflate(R.layout.layout_grid_item, parent, false); viewHolder = new ViewHolder(); viewHolder.itemImg = (ImageView) convertView.findViewById(R.id.iv_head); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder) convertView.getTag(); } // 这里只是模拟，实际开发可能需要加载网络图片，可以使用ImageLoader这样的图片加载框架来异步加载图片 imageLoader.displayImage("drawable://" + mThumbIds[position], viewHolder.itemImg); return convertView; } class ViewHolder { ImageView itemImg; } } } 

在Activity中我们做了以下几件事：

1. 初始化控件
2. 定义图片资源mThumbIds
3. 定义ImageAdapter

上面代码中我们用到了ImageLoader这个图片加载框架，使用它来加载本地drawable资源，实际开发中一般不会这样用，我们传进去的uri是一个图片网络地址，具体的使用方法可以百度学习，这里简单介绍步骤：

1. 初始化ImageLoader配置
2. 获取ImageLoader实例，调用其displayImage方法异步加载图片