Android入门第八篇之GridView(九宫图)

GridView跟ListView都是比较常用的多控件布局，而GridView更是实现九宫图的首选!本文就是介绍如何使用GridView实现九宫 图。GridView的用法很多，网上介绍最多的方法就是自己实现一个ImageAdapter继承BaseAdapter，再供GridView使用， 类似这种的方法本文不再重复，本文介绍的GridView用法跟前文ListView的极其类似。。。。也算是我偷懒一下，嘻嘻嘻嘻。。。。

 

 

本文需要添加/修改3个文件：main.xml、night_item.xml、JAVA源代码。

main.xml源代码如下，本身是个GirdView，用于装载Item：

 <? xml   version = "1.0"   encoding = "utf-8" ?>
 < GridView   xmlns:android = "http://schemas.android.com/apk/res/android"
     android:id = "@+id/gridview"
     android:layout_width = "fill_parent"
     android:layout_height = "fill_parent"
     android:numColumns = "auto_fit"
     android:verticalSpacing = "10dp"
     android:horizontalSpacing = "10dp"
     android:columnWidth = "90dp"
     android:stretchMode = "columnWidth"
     android:gravity = "center"
 />

<?xml version="1.0" encoding="utf-8"?> <GridView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gridview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:numColumns="auto_fit" android:verticalSpacing="10dp" android:horizontalSpacing="10dp" android:columnWidth="90dp" android:stretchMode="columnWidth" android:gravity="center" />

介绍一下里面的某些属性：

android:numColumns="auto_fit" ，GridView的列数设置为自动

android:columnWidth="90dp"，每列的宽度，也就是Item的宽度
android:stretchMode="columnWidth"，缩放与列宽大小同步
android:verticalSpacing="10dp"，两行之间的边距，如：行一(NO.0~NO.2)与行二(NO.3~NO.5)间距为10dp
android:horizontalSpacing="10dp"，两列之间的边距。

 

接下来介绍 night_item.xml，这个XML跟前面ListView的ImageItem.xml很类似：

 <? xml   version = "1.0"   encoding = "utf-8" ?>
 < RelativeLayout
          xmlns:android = "http://schemas.android.com/apk/res/android"
          android:layout_height = "wrap_content"
          android:paddingBottom = "4dip"   android:layout_width = "fill_parent" >
          < ImageView
                android:layout_height = "wrap_content"
                android:id = "@+id/ItemImage"
                android:layout_width = "wrap_content"
                android:layout_centerHorizontal = "true" >
          </ ImageView >
          < TextView
                android:layout_width = "wrap_content"
                android:layout_below = "@+id/ItemImage"
                android:layout_height = "wrap_content"
                android:text = "TextView01"
                android:layout_centerHorizontal = "true"
                android:id = "@+id/ItemText" >
          </ TextView >
 </ RelativeLayout >

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_height="wrap_content" android:paddingBottom="4dip" android:layout_width="fill_parent"> <ImageView android:layout_height="wrap_content" android:id="@+id/ItemImage" android:layout_width="wrap_content" android:layout_centerHorizontal="true"> </ImageView> <TextView android:layout_width="wrap_content" android:layout_below="@+id/ItemImage" android:layout_height="wrap_content" android:text="TextView01" android:layout_centerHorizontal="true" android:id="@+id/ItemText"> </TextView> </RelativeLayout>

 

最后就是JAVA的源代码了，也跟前面的ListView的JAVA源代码很类似，不过多了“选中”的事件处理：

    public   void  onCreate(Bundle savedInstanceState) {
       super .onCreate(savedInstanceState);
       setContentView(R.layout.main);
       GridView gridview = (GridView) findViewById(R.id.gridview);

       //生成动态数组，并且转入数据
       ArrayList<HashMap<String, Object>> lstImageItem = new  ArrayList<HashMap<String, Object>>();
       for ( int  i= 0 ;i< 10 ;i++)
       {
         HashMap<String, Object> map = new  HashMap<String, Object>();
         map.put("ItemImage" , R.drawable.icon); //添加图像资源的ID
     map.put("ItemText" ,  "NO." +String.valueOf(i)); //按序号做ItemText
         lstImageItem.add(map);
       }
       //生成适配器的ImageItem <====> 动态数组的元素，两者一一对应
       SimpleAdapter saImageItems = new  SimpleAdapter( this ,  //没什么解释
                                                 lstImageItem,//数据来源
                                                 R.layout.night_item,//night_item的XML实现

                                                 //动态数组与ImageItem对应的子项
                                                 new  String[] { "ItemImage" , "ItemText" },

                                                 //ImageItem的XML文件里面的一个ImageView,两个TextView ID
                                                 new   int [] {R.id.ItemImage,R.id.ItemText});
       //添加并且显示
       gridview.setAdapter(saImageItems);
       //添加消息处理
       gridview.setOnItemClickListener(new  ItemClickListener());
   }

   //当AdapterView被单击(触摸屏或者键盘)，则返回的Item单击事件
   class   ItemClickListener  implements  OnItemClickListener
   {
 public   void  onItemClick(AdapterView<?> arg0, //The AdapterView where the click happened
                                   View arg1,//The view within the AdapterView that was clicked
                                   int  arg2, //The position of the view in the adapter
                                   long  arg3 //The row id of the item that was clicked
                                   ) {
     //在本例中arg2=arg3
     HashMap<String, Object> item=(HashMap<String, Object>) arg0.getItemAtPosition(arg2);
     //显示所选Item的ItemText
     setTitle((String)item.get("ItemText" ));
 }

   }