第一章:初进Android大门(Gallery拖动相片特效)

<?xml version="1.0" encoding="utf-8"?><AbsoluteLayoutandroid:id="@+id/widget0"android:layout_width="fill_parent"android:layout_height="fill_parent"xmlns:android="http://schemas.android.com/apk/res/android"><Galleryandroid:id="@+id/image"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_x="43px"android:layout_y="142px"></Gallery></AbsoluteLayout>

package gallery.test;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageView;public class GalleryTest extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        /** 获得 Gallery对象组件*/        ((Gallery)findViewById(R.id.image)).setAdapter(new ImageAdapter(this));    }    public class ImageAdapter extends BaseAdapter{    	private Context myContext;    	/** 定义图片*/    	private int[] myImages={    			android.R.drawable.btn_minus,    			android.R.drawable.btn_radio,    			android.R.drawable.ic_lock_idle_low_battery,    			android.R.drawable.ic_menu_camera,    	};    	/** 存储Context*/    	public ImageAdapter(Context c){    		this.myContext=c;    		    	}    	/** 获得图片数量*/		public int getCount() {			// TODO Auto-generated method stub			return this.myImages.length;		}		/** 获得目前图像数组ID*/		@Override		public Object getItem(int position) {			// TODO Auto-generated method stub			return position;		}		@Override		public long getItemId(int position) {			// TODO Auto-generated method stub			return position;		}		/**取得显示图像View,传入数组ID值读取数组图像*/		@Override		public View getView(int position, View convertView, ViewGroup parent) {			/**实例化ImageView对象*/			ImageView i=new ImageView(this.myContext);			/**设置图片*/			i.setImageResource(this.myImages[position]);			/**设置View的大小*/			i.setScaleType(ImageView.ScaleType.FIT_XY);			/**设置ImageView对象宽度和高度*/			i.setLayoutParams(new Gallery.LayoutParams(120,120));			return i;		}		/**距离中央距离位移梁 利用getScale返回View大小*/    	public float getScale(boolean flg,int offset){    		return Math.max(0,1.0f/(float)Math.pow(2, Math.abs(offset)));    	}    	    }}