(转)gallary和imageswitcher

public class AndroidImageSwitcher  extends Activity implements ViewFactory { 

 private ImageSwitcher is;   

     private Gallery gallery;   

     private int downX,upX;   

     private ArrayList<Integer> imgList=new ArrayList<Integer>();//图像ID   

        


     protected void onCreate(Bundle savedInstanceState) {   

         // TODO Auto-generated method stub   

         super.onCreate(savedInstanceState);   

         setContentView(R.layout.imageswitchview);   

         //用反射机制来获取资源中的图片ID   

         Field[] fields = R.drawable.class.getDeclaredFields();   

         for (Field field : fields)   

         {   

             if (!"icon".equals(field.getName()))//除了icon之外的图片   

             {      

                 int index = 0;   

                 try {   

                     index = field.getInt(R.drawable.class);   

                 } catch (IllegalArgumentException e) {   

                     // TODO Auto-generated catch block   

                     e.printStackTrace();   

                 } catch (IllegalAccessException e) {   

                     // TODO Auto-generated catch block   

                     e.printStackTrace();   

                 }   

                 //保存图片ID   

                 imgList.add(index);   

             }   

         }   

            

         //设置ImageSwitcher控件   

         is = (ImageSwitcher) findViewById(R.id.switcher);   

         is.setFactory(this);   

         is.setInAnimation(AnimationUtils.loadAnimation(this,   

                 android.R.anim.fade_in));   

         is.setOutAnimation(AnimationUtils.loadAnimation(this,   

                 android.R.anim.fade_out));   

         is.setOnTouchListener(new OnTouchListener(){   

             /*  

              * 在ImageSwitcher控件上滑动可以切换图片  

              */  

       

             public boolean onTouch(View v, MotionEvent event) {   

                 if(event.getAction()==MotionEvent.ACTION_DOWN)   

                 {   

                     downX=(int) event.getX();//取得按下时的坐标   

                     return true;   

                 }   

                 else if(event.getAction()==MotionEvent.ACTION_UP)   

                 {   

                     upX=(int) event.getX();//取得松开时的坐标   

                     int index=0;   

                     if(upX-downX>100)//从左拖到右，即看前一张   

                     {   

                         //如果是第一，则去到尾部   

                         if(gallery.getSelectedItemPosition()==0)   

                            index=gallery.getCount()-1;   

                         else  

                             index=gallery.getSelectedItemPosition()-1;   

                     }   

                     else if(downX-upX>100)//从右拖到左，即看后一张   

                     {   

                         //如果是最后，则去到第一   

                         if(gallery.getSelectedItemPosition()==(gallery.getCount()-1))   

                             index=0;   

                         else  

                             index=gallery.getSelectedItemPosition()+1;   

                     }   

                     //改变gallery图片所选，自动触发ImageSwitcher的setOnItemSelectedListener   

                     gallery.setSelection(index, true);   

                     return true;   

                 }   

                 return false;   

             }   

                

         });   

            

         //设置gallery控件   

         gallery = (Gallery) findViewById(R.id.gallery);   

         gallery.setAdapter(new ImageAdapter(this));   

         gallery.setOnItemSelectedListener(new OnItemSelectedListener(){   


             public void onItemSelected(AdapterView<?> arg0, View arg1,   

                     int position, long arg3) {   

                 is.setImageResource(imgList.get(position));   

             }   

             

             public void onNothingSelected(AdapterView<?> arg0) {   

                 // TODO Auto-generated method stub   

             }   

                

         });   

     }   

     //设置ImgaeSwitcher   

   

     public View makeView() {   

         ImageView i = new ImageView(this);   

         i.setBackgroundColor(0xFF000000);   

         i.setScaleType(ImageView.ScaleType.CENTER);//居中   

         i.setLayoutParams(new ImageSwitcher.LayoutParams(//自适应图片大小   

                 LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));   

         return i;   

     }   

     public class ImageAdapter extends BaseAdapter {   

         public ImageAdapter(Context c) {   

             mContext = c;   

         }   

         public int getCount() {   

             return imgList.size();   

         }   

         public Object getItem(int position) {   

             return position;   

         }   

         public long getItemId(int position) {   

             return position;   

         }   

         public View getView(int position, View convertView, ViewGroup parent) {   

             ImageView i = new ImageView(mContext);   

             i.setImageResource(imgList.get(position));   

             i.setAdjustViewBounds(true);   

             i.setLayoutParams(new Gallery.LayoutParams(   

                     LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));   

             return i;   

         }   

         private Context mContext;   

     }