android 的 Gallery 的简单使用

Gallery 的用法很简单，百度一下一大堆。现在就结合1个效果的例子。



这个效果其实很简单，设置未被选中的项，的透明度 周围的看起来就会有点模糊

android:unselectedAlpha="0.5"

设置好每个item的间隔

android:spacing="15dip"

每个item 的样子 就需要自己设置。比如利用 渲染器等各种效果

实现思路就是 在 onItemSelected 中监听 选中状态 动态的去改变 每个item的样子

部分代码：

public class BitmapUtil {

   
	public static Bitmap createTxtImage(String txt, int txtSize) {

    	/**
    	 * 未选中的 item 进行字体的设置
    	 */
        Bitmap btimap = Bitmap.createBitmap(txt.length() * txtSize + 6,
                txtSize + 6, Config.ARGB_8888);
        Canvas canvas = new Canvas(btimap);
        Paint p = new Paint();
        p.setAntiAlias(true);
        p.setColor(Color.WHITE);
        p.setTextSize(txtSize);
        canvas.drawText(txt, 3, txtSize - 3, p);
        return btimap;

    }

    
    
    /**
     * 图片倒影的效果
     */  
    public static Bitmap createReflectedImage(Bitmap bitmap) {
        
        //中间
    	final int reflectionGap = 0 ;
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        
        //整个 bitmap
        Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
                (height + height/2 + 20 ), Config.ARGB_8888);
        
        Matrix matrix = new Matrix();
        matrix.preScale(1, -1);
        Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 
        		          0 , height / 2, width , height / 2, matrix, false);
        
        Canvas canvas = new Canvas(bitmapWithReflection);
            //正面的
            canvas.drawBitmap(bitmap,0 , 20, null);
	        // draw 倒影
	        Paint  defaultPaint = new Paint();
	        canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);
	        canvas.drawBitmap(reflectionImage, 0, height + reflectionGap + 20 , null);
    
        
        
        Paint paint = new Paint();
       
        //线性渲染器
        LinearGradient shader = new LinearGradient(0,
        		bitmap.getHeight()+30, 0, bitmapWithReflection.getHeight()
                             + reflectionGap,0x70ffffff, 0x00ffffff, TileMode.CLAMP);

        paint.setShader(shader);
       
        paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
        canvas.drawRect(0, height + 20, width, bitmapWithReflection.getHeight()
                                                              + reflectionGap, paint);

        return bitmapWithReflection;

    }

}

adapter

public class GalleryAdapter extends BaseAdapter{

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

        ImageView imageView = new ImageView(context);
        	
        	  if (select == position) {
                  Entity en = entity_list.get(position % entity_list.size());           
                  imageView.setImageBitmap(BitmapUtil.createReflectedImage(BitmapUtil
                                .createTxtImage(en.getName(), 30)));

              } else {

              	  Entity en  = entity_list.get(position % entity_list.size());
                  imageView.setImageBitmap(BitmapUtil.createTxtImage(en.getName(),
                          25));
              }
        	  
        return imageView;
    }
}

public class MyGalleryWight extends Gallery {

    public MyGalleryWight(Context context, AttributeSet attrs) {

        super(context, attrs);
    }
    
    // 这个是为了不让他一下滑动好多  你也可以不重写这个方法
    public boolean onFling (MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
    	return false;

    }

}

主要访法

@Override
		public void onItemSelected(AdapterView<?> arg0, View view, int position,
				long arg3) {
			// TODO Auto-generated method stub
			adapter.notifyDataSetChanged(position);//arg2会返回当前选中项的位置，调用此方法，通知更新
		}

代码： http://download.csdn.net/detail/kongbaidepao/6640881