Android实现幻灯片式图片浏览器

<?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       }     });   }  }