Android基础篇之ImageSwitcher与Gallery

Android基础篇之ImageSwitcher与Gallery

2011-05-19 16:16:15

自己制作一个图片浏览器的时候ImageSwitcher与Gallery组合使用是一个比较简遍的方法，现在我们蓝看一下他们的基本用法。

1.配置布局文件 main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
  <ImageSwitcher
  	android:id="@+id/imageSwitcher"
  	android:layout_width="wrap_content"
  	android:layout_height="wrap_content"
  	android:layout_centerInParent="true"/>
  <Gallery
  	android:id="@+id/gallery"
  	android:layout_width="fill_parent"
  	android:layout_height="wrap_content"
  	android:spacing="8dp"
  	android:layout_alignParentBottom="true"/>
</RelativeLayout>

2.程序主要代码 MainActivity.java

package com.yin.picture_view;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;
public class MainActivity extends Activity {
	
	//显示图片的资源
	private  static int[] images = {
			R.drawable.s0 , R.drawable.s1,
			R.drawable.s2 , R.drawable.s3,
			R.drawable.s4 , R.drawable.s5,
			R.drawable.s6 , R.drawable.s7,
			R.drawable.s8 , R.drawable.s9	
		};
	 Gallery gallery;
	 ImageSwitcher is;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        gallery = (Gallery) findViewById(R.id.gallery);
        is = (ImageSwitcher) findViewById(R.id.imageSwitcher);
        
        gallery.setAdapter(new ImageAdapter(this));
       //让选定的图片在中心显示
        gallery.setSelection(images.length/2);
        
        //为Gallery绑定监听器；
        gallery.setOnItemSelectedListener(new OnItemSelectedListener() {
			public void onItemSelected(AdapterView<?> parent, View view,
					int position, long id) {
				//当在Gallery中选定一张图片是 ImageSwitcher同步显示同一张
				//position%images.length  为了让图片循环显示
				is.setImageResource(images[position%images.length]);
				
			}
			public void onNothingSelected(AdapterView<?> parent) {
				
			}
		});
        
        
        is.setFactory(new ImageFactory(this));
    
    }
    
    private class ImageAdapter extends BaseAdapter{
    	private Context context;
		public ImageAdapter(Context context) {
			this.context = context;
		}
		//可以return images.lenght(),在这里返回Integer.MAX_VALUE
		//是为了使图片循环显示
		public int getCount() {
			return Integer.MAX_VALUE;
		}
		public Object getItem(int position) {
			return null;
		}
		public long getItemId(int position) {
			return 0;
		}
		public View getView(int position, View convertView, ViewGroup parent) {
			ImageView iv = new ImageView(context);
			iv.setImageResource(images[position%images.length]);
			iv.setLayoutParams(new Gallery.LayoutParams(90,90));
			iv.setAdjustViewBounds(true);
			return iv;
		}
    }
    
    private class ImageFactory implements ViewFactory{
    	private Context context;
    	public ImageFactory(Context context){
    		this.context = context;
    	}
		public View makeView() {
			ImageView iv = new ImageView(context);
			iv.setLayoutParams(new ImageSwitcher.LayoutParams(200,200));
			return iv;
		}
    }
}