gallery 浏览图片

    总叙：gallery严格意义地讲也是listView的一种，通过adapter加载数据成为了一种通用的方法。

  例子：为实现图片浏览的效果，类似于qq空间里面查看他人图片。达到如下图所示效果：

<!--StartFragment -->

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

     <LinearLayout android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <ImageView android:id="@+id/iv"
            android:layout_width="290dp"
            android:layout_height="290dp"
            android:layout_marginBottom="5dp"/>
        <Gallery android:id="@+id/gl"
            android:layout_width="fill_parent"
            android:layout_height="60dp"
            android:spacing="10dp"
            android:gravity="center_vertical"/>
    </LinearLayout>

</LinearLayout>

 即上面是imageview，下面是gallery

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

public class GalleryActivity extends Activity {
    /** Called when the activity is first created. */
   Gallery gl;
   ImageView iv;
   int imageIDs[]={
			R.drawable.a,R.drawable.b,R.drawable.c,
			R.drawable.d,R.drawable.e,R.drawable.f,
			R.drawable.g
	};//将R文件的图片id用一个数组
   MyAdapter ma;
	@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        init();//把xml文件的id传进来，初始化
        ma=new MyAdapter();//适别器
        gl.setAdapter(ma);//加载识别器
//监听事件
        gl.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

			@Override
			public void onItemSelected(AdapterView<?> arg0, View arg1,
					int arg2, long arg3) {
				// TODO Auto-generated method stub
				iv.setImageResource(imageIDs[arg2%imageIDs.length]);
             		}//一组图片的不停替换，通过一个巧妙的取余运算

			@Override
			public void onNothingSelected(AdapterView<?> arg0) {
				// TODO Auto-generated method stub
				
			}
		});
        
    }
	class MyAdapter extends BaseAdapter{

		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return Integer.MAX_VALUE;
		}//有的人可能会问为什么不是ma。size（）；是因为下面的gallery列表项无限的延伸，所以

                 //要保证position无限的大，因为getView方法就是通过，调用position的值

		@Override
		public Object getItem(int arg0) {
			// TODO Auto-generated method stub
			return null;
		}

		@Override
		public long getItemId(int arg0) {
			// TODO Auto-generated method stub
			return 0;
		}

		@Override
		public View getView(int arg0, View arg1, ViewGroup arg2) {
			// TODO Auto-generated method stub
                 /用代码实现了一个gallery列表项，相信都看的懂/
			ImageView iv=new ImageView(getApplicationContext());
			iv.setImageResource(imageIDs[arg0%imageIDs.length]);
			iv.setAlpha(200);
			iv.setScaleType(ImageView.ScaleType.FIT_XY);
			iv.setLayoutParams(new Gallery.LayoutParams(103, 106));
			return iv;
		}
		
	}
	private void init() {
		// TODO Auto-generated method stub
		gl=(Gallery)this.findViewById(R.id.gl);
		iv=(ImageView)this.findViewById(R.id.iv);
	}
}