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:
?
?
?
