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;
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 GalleryDemo extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  ((Gallery) findViewById(R.id.myGallery1)).setAdapter(new ImageAdapter(
    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 */
  private int[] 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 */
  public ImageAdapter(Context c) {
   this.myContext = c;
  }

  /* 返回所有已定义的图片总数量 */
  public int getCount() {
   return this.myImageIds.length;
  }

  /* 利用getItem方法，取得目前容器中图像的数组ID */
  public Object getItem(int position) {
   return position;
  }

  public long getItemId(int position) {
   return position;
  }

  /* 取得目前欲显示的图像View，传入数组ID值使之读取与成像 */
  public View getView(int position, View convertView, ViewGroup parent) {
   /* 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(new Gallery.LayoutParams(120, 120));
   return i;
  }

  /* 依据距离中央的位移量 利用getScale返回views的大小(0.0f to 1.0f) */
  public float getScale(boolean focused, int offset) {
   /* Formula: 1 / (2 ^ offset) */
   return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
  }
 }
}

Step 5:run it,效果如下图: