防Iphone 拖动相片特效Gallery的简单应用.

Step 1:准备图片素材.

将icon2,icon3,icon4,icon5,icon6五张图片导入res/drawable里加上icon.png本身一共有6张图片.

Step 2:新建Android工程,命名为GalleryDemo.

Step 3:设计UI,修改main.xml代码如下:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:background="@drawable/white"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

>

<TextView

android:id="@+id/myTextView01"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/hello"

android:gravity="center_vertical|center_horizontal"

/>

<Gallery

android:id="@+id/myGallery1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:gravity="bottom"

/>

</LinearLayout>

Step 4:设计主程序类GalleryDemo.java代码如下:

 package com.android.test;

import com.android.test.R.drawable;

importandroid.app.Activity;

importandroid.content.Context;

importandroid.os.Bundle;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.BaseAdapter;

importandroid.widget.Gallery;

import android.widget.ImageView;

public class GalleryDemo extends Activity {

/**Calledwhentheactivityisfirstcreated.*/

@Override

publicvoidonCreate(BundlesavedInstanceState){

super.onCreate(savedInstanceState);

  setContentView(R.layout.main);

((Gallery)findViewById(R.id.myGallery1)).setAdapter(newImageAdapter(

this));

 }

 public class ImageAdapter extends BaseAdapter {

/*类成员myContext为Context父类*/

  private Context myContext;

  /* 使用res/drawable图片作为图片来源 */

privateint[]myImageIds={drawable.icon,drawable.icon2,

    drawable.icon3, drawable.icon4, drawable.icon5, drawable.icon6};

  /* 构造器只有一个参数，即要存储的Context */

publicImageAdapter(Contextc){

this.myContext=c;

  }

  /* 返回所有已定义的图片总数量 */

publicintgetCount(){

returnthis.myImageIds.length;

  }

  /* 利用getItem方法，取得目前容器中图像的数组ID */

publicObjectgetItem(intposition){

returnposition;

  }

  public long getItemId(int position) {

returnposition;

  }

  /* 取得目前欲显示的图像View，传入数组ID值使之读取与成像 */

publicViewgetView(intposition,ViewconvertView,ViewGroupparent){

/*创建一个ImageView对象*/

   ImageView i = new ImageView(this.myContext);

   i.setImageResource(this.myImageIds[position]);   i.setScaleType(ImageView.ScaleType.FIT_XY);

   /* 设置这个ImageView对象的宽高，单位为dip */

i.setLayoutParams(newGallery.LayoutParams(120,120));

returni;

  }

  /* 依据距离中央的位移量 利用getScale返回views的大小(0.0f to 1.0f) */

publicfloatgetScale(booleanfocused,intoffset){

/*Formula:1/(2^offset)*/

returnMath.max(0,1.0f/(float)Math.pow(2,Math.abs(offset)));

}

}

}

Step 5:run it,效果如下图: