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>