【Android开发】范例2-实现幻灯片式图片浏览器

效果图如图

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:orientation="vertical"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"  
    android:id="@+id/layout1"
    android:gravity="center_horizontal"
    >  
    <ImageSwitcher
        android:id="@+id/imageSwitcher"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="30px"
        android:layout_weight="2"/>
    <Gallery
        android:id="@+id/gallery1"
        android:spacing="5px"
        android:layout_weight="1"
        android:unselectedAlpha="0.6"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>  

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="Gallery">
    	<attr name="android:galleryItemBackground"/>
    </declare-styleable>
</resources>

package com.example.test;  
  
import android.app.Activity;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.animation.AnimationUtils;
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 {  
	//定义并初始化保存图片id的数组
      private int[] imageId=new int[]{R.drawable.img1,R.drawable.img2,R.drawable.img3,R.drawable.img4,
    		  R.drawable.img5,R.drawable.img6,R.drawable.img7,R.drawable.img8,R.drawable.img9};
      //声明一个图像切换器对象
      private ImageSwitcher imageSwitcher;
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
         
        Gallery gallery=(Gallery)findViewById(R.id.gallery1);//获取gallery组件
        
        imageSwitcher=(ImageSwitcher)findViewById(R.id.imageSwitcher);//获取图像切换器
        //设置动画效果
        imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
        		android.R.anim.fade_in));//设置淡入动画
        imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this, 
        		android.R.anim.fade_out));//设置淡出动画
        imageSwitcher.setFactory(new ViewFactory(){


			@Override
			public View makeView() {
				ImageView imageView=new ImageView(MainActivity.this);//实例化一个imageView类的对象
				imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);//设置保持纵横比居中缩放图像
				imageView.setLayoutParams(new ImageSwitcher.LayoutParams(
						LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
				return imageView;//返回imageView对象
			}
        });
        
        BaseAdapter adapter=new BaseAdapter(){


        	@Override
			public View getView(int position, View convertView, ViewGroup parent) {
				ImageView imageView;//声明ImageView的对象
				if(convertView==null){
					imageView=new ImageView(MainActivity.this);//实例化ImageView的对象
					imageView.setScaleType(ImageView.ScaleType.FIT_XY);//设置缩放方式
					imageView.setLayoutParams(new Gallery.LayoutParams(180,135));
					//设置gallery每一项图片的背景资源(使用的是attr.xml的自定义样式)
					TypedArray typedArray=obtainStyledAttributes(R.styleable.Gallery);
					imageView.setBackgroundResource(typedArray.getResourceId(
							R.styleable.Gallery_android_galleryItemBackground, 0));
					
					imageView.setPadding(5, 0, 5, 0);//设置imageView的内边距
				}else{
					imageView=(ImageView)convertView;
				}
				imageView.setImageResource(imageId[position]);//为imageView设置要显示的图片
				return imageView;//返回ImageView
			}
        	
        	//功能:获得当前选项的id
			@Override
			public long getItemId(int position) {
				return position;
			}
			
			//功能：获得当前选项
			@Override
			public Object getItem(int position) {
				return position;
			}
			
			//获得数量
			@Override
			public int getCount() {
				return imageId.length;
			}
        };
        
        gallery.setAdapter(adapter);//将适配器与Gallery关联
        gallery.setSelection(imageId.length/2);//选中中间的图片
        gallery.setOnItemSelectedListener(new OnItemSelectedListener() {


			@Override
			public void onItemSelected(AdapterView<?> parent, View v,
					int position, long id) {
				imageSwitcher.setImageResource(imageId[position]);//显示选中的图片
			}


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

这样单击某张图片，可以选中该图片，并且让其居中显示，也可以用手指拖动图片来移动图片，并且让选中的图片在上方显示,

如图是切换瞬间的效果

转载请注明出处：http://blog.csdn.net/acmman/article/details/44994443