Android开发之组件GridView简单使用方法示例

<?xml version="1.0" encoding="utf-8"? 
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context=".MainActivity"  
 <!--定义一个GridView组件-- 
 <GridView
  android:id="@+id/grid01"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:horizontalSpacing="1pt"
  android:verticalSpacing="1pt"
  android:numColumns="3"
  android:gravity="center"/ 
 <!--定义一个ImageView组件-- 
 <ImageView
  android:id="@+id/image_view"
  android:layout_width="240dp"
  android:layout_height="240dp"
  android:layout_gravity="center_horizontal"/ 
</LinearLayout 

public class MainActivity extends Activity {
private GridView gridView;
//定义字符串数组作为提示的文本
private ImageView imageView;
private int[] photoId = new int[]{
R.drawable.huangjindiao, R.drawable.piaopiao,
R.drawable.xiaochouyu, R.drawable.paodangyu,
R.drawable.addphoto, R.drawable.huangjinxiahu
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//创建一个list对象，list对象的元素是Map
List<Map<String,Object   listItems = new ArrayList<Map<String,Object  ();
for (int i = 0 ; i < photoId.length ; i ++ ){
Map<String,Object  photolist = new HashMap<String, Object ();
photolist.put("image",photoId[i]);
listItems.add(photolist);
}
//获取图片的imageView
imageView = (ImageView) findViewById(R.id.image_view);
//创建一个SimpleAdapter
SimpleAdapter simpleAdapter = new SimpleAdapter(this,listItems,
//arry_list只有一个ImageView放图片 代码下面给出
R.layout.array_list,
new String[]{"image"}, new int[]{R.id.image});
gridView = (GridView) findViewById(R.id.grid01);
//为gridview设置adapter
gridView.setAdapter(simpleAdapter);
//添加列表项中被选中的监听器
gridView.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?  parent, View view, int position, long id) {
//显示当前被选中的图片
imageView.setImageResource(photoId[position]);
}
@Override
public void onNothingSelected(AdapterView<?  parent) {
}
});
//添加列表中被单击的监听器
gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?  parent, View view, int position, long id) {
//显示被单击的图片
imageView.setImageResource(photoId[position]);
}
});
//点击图片保存
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String[] PERMISSIONS = {
"android.permission.READ_EXTERNAL_STORAGE",
"android.permission.WRITE_EXTERNAL_STORAGE" };
//检测是否有写的权限
int permission = ContextCompat.checkSelfPermission(MainActivity.this,
"android.permission.WRITE_EXTERNAL_STORAGE");
if (permission != PackageManager.PERMISSION_GRANTED) {
// 没有写的权限，去申请写的权限，会弹出对话框
ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS,1);
}
try {
//创建savephoto类保存图片
SavePhoto savePhoto = new SavePhoto(MainActivity.this);
savePhoto.SaveBitmapFromView(imageView);
} catch (ParseException e) {
e.printStackTrace();
}
}
});
}
}

<?xml version="1.0" encoding="utf-8"? 
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/image"
android:layout_width="100dp"
android:layout_height="100dp"
android:scaleType="fitXY" 
</ImageView