public class
ImageSwitcher
extends| ↳ | ||||||
| ↳ | ||||||
| ↳ | ||||||
| ↳ | ||||||
| ↳ | ||||||
| ↳ | android.widget.ImageSwitcher |
（译者注：ImageSwitcher是Android中控制图片展示效果的一个控件，如：幻灯片效果...，颇有感觉啊，做相册一绝。）
我们在Windows 平台上要查看多张图片，最简单的办法就是通过 "Window 图片和传真查看器“在 ”下一张“ 和”上一张“之间切换，Android平台上可以通过 ImageSwitcher 类来实现这一效果。ImageSwitcher 类必须设置一个ViewFactory,主要用来将显示的图片和父窗口区分开来，因此需要实现ViewSwitcher.ViewFactory接口，通过makeView()方法来显示图片，这里会返回一个ImageView 对象，而方法 setImageResource用来指定图片资源。首先先让我们看看这个例子的运行效果。
一、重要方法
setImageURI(Uri uri)：设置图片地址
setImageResource(int resid)：设置图片资源库
setImageDrawable(Drawable drawable)：绘制图片
=========================================================
案例一：
1.定义布局文件imageswitcher.xml
2.定义java文件ImageSwitcherDemo.java
package com.test;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.view.Window;import android.view.animation.AnimationUtils;import android.widget.AdapterView;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageSwitcher;import android.widget.ImageView;import android.widget.AdapterView.OnItemClickListener;import android.widget.AdapterView.OnItemSelectedListener;import android.widget.Gallery.LayoutParams;import android.widget.ViewSwitcher.ViewFactory;public class ImageSwitcherDemo extends Activity implements OnItemSelectedListener, ViewFactory { private ImageSwitcher is; private Gallery gallery; private Integer[] mThumbIds = { R.drawable.gallery_01,R.drawable.gallery_02,R.drawable.gallery_03, R.drawable.gallery_04,R.drawable.gallery_05,R.drawable.gallery_06, }; private Integer[] mImageIds = { R.drawable.gallery_01, R.drawable.gallery_02,R.drawable.gallery_03, R.drawable.gallery_04,R.drawable.gallery_05,R.drawable.gallery_06, }; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.imageswitcher); is = (ImageSwitcher) findViewById(R.id.switcher); is.setFactory(this); is.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); is.setOutAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); gallery = (Gallery) findViewById(R.id.gallery); gallery.setAdapter(new ImageAdapter(this)); gallery.setOnItemSelectedListener(this); } @Override public View makeView() { ImageView i = new ImageView(this); i.setBackgroundColor(0xFF000000); i.setScaleType(ImageView.ScaleType.FIT_CENTER); i.setLayoutParams(new ImageSwitcher.LayoutParams( LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); return i; } public class ImageAdapter extends BaseAdapter { public ImageAdapter(Context c) { mContext = c; } public int getCount() { return mThumbIds.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { ImageView i = new ImageView(mContext); i.setImageResource(mThumbIds[position]); i.setAdjustViewBounds(true); i.setLayoutParams(new Gallery.LayoutParams( LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));// i.setBackgroundResource(R.drawable.); return i; } private Context mContext; } @Override public void onItemSelected(AdapterView parent, View view, int position, long id) { is.setImageResource(mImageIds[position]); } @Override public void onNothingSelected(AdapterView parent) { // TODO Auto-generated method stub } } 3.执行效果：
===================================================
案例二：自定义：
1.自定义一个Gallery文件：
package com.test;import java.text.AttributedCharacterIterator.Attribute;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.widget.Gallery;public class Gallery_define extends Gallery { public Gallery_define(Context context,AttributeSet attrs) { super(context,attrs); // TODO Auto-generated constructor stub } //重写onFling方法，将滑动的速率降低 @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { // TODO Auto-generated method stub return super.onFling(e1, e2, velocityX/3, velocityY); }} 2：接下来自定义一个gallery布局文件：gallery_define.xml
3：定义布局文件：gallerydemo.xml
4.java文件：ImageSwitcherGallery_define
package com.test;import java.util.HashMap;import android.annotation.SuppressLint;import android.app.Activity;import android.content.Context;import android.content.res.TypedArray;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.view.ViewGroup.LayoutParams;import android.view.Window;import android.view.animation.AnimationUtils;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.AdapterView.OnItemSelectedListener;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageSwitcher;import android.widget.ImageView;import android.widget.TextView;import android.widget.ViewSwitcher.ViewFactory;public class ImageSwitcherGallery_define extends Activity implements OnItemSelectedListener, ViewFactory { //定义ImageSwitcher类对象 private ImageSwitcher imageSwitcher; //文本资源w private String []titles={"标题A","标题B","标题C","标题D","标题E","标题F"}; //大图资源 private int[] ThumbIds= { R.drawable.gallery_01,R.drawable.gallery_02,R.drawable.gallery_03, R.drawable.gallery_04,R.drawable.gallery_05,R.drawable.gallery_06, }; //大图资源对于的小图资源 private int[] imageIds= { R.drawable.gallery_01,R.drawable.gallery_02,R.drawable.gallery_03, R.drawable.gallery_04,R.drawable.gallery_05,R.drawable.gallery_06, }; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); //设置窗体无标题 requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.gallerydemo); imageSwitcher = (ImageSwitcher)findViewById(R.id.switcher_define); imageSwitcher.setFactory(this); imageSwitcher=(ImageSwitcher)findViewById(R.id.switcher_define); //设置图片的滑动效果 imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); Gallery gallery=(Gallery)findViewById(R.id.gallery_define); //设置Gallery的适配器 gallery.setAdapter(new ImageAdapter(this,ThumbIds.length)); //Gallery中每个条目的点击事件监听 gallery.setOnItemClickListener(itemListener); //设置默认起始位置为第二张图片 gallery.setSelection(1); } OnItemClickListener itemListener = new OnItemClickListener() { @Override public void onItemClick(AdapterView arg0, View arg1, int position, long arg3) { if (curruntPos == position) { return; } else curruntPos = position; imageSwitcher.setImageResource(ThumbIds[position % ThumbIds.length]); } }; @Override public View makeView() { ImageView imageView =new ImageView(this); imageView.setBackgroundColor(TRIM_MEMORY_BACKGROUND); imageView.setScaleType(ImageView.ScaleType.FIT_CENTER); imageView.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); return imageView; } @Override public void onItemSelected(AdapterView arg0, View arg1, int arg2, long arg3) { imageSwitcher.setImageResource(ThumbIds[arg2%imageIds.length]); } @Override public void onNothingSelected(AdapterView arg0) { // TODO Auto-generated method stub } class ImageAdapter extends BaseAdapter { private int galleryItenBackgroud; //定义map存储划过的位置 private HashMap viewMaps; private int count; //定义布局加载器 private LayoutInflater inflater; public ImageAdapter(Context c,int count) { this.count=count; viewMaps = new HashMap (count); inflater=LayoutInflater.from(ImageSwitcherGallery_define.this); //定义图片的背景样式 TypedArray a=obtainStyledAttributes(R.styleable.Gallery); galleryItenBackgroud=a.getResourceId(R.styleable.Gallery_android_galleryItemBackground, 0); //定义可以重复使用，可回收 a.recycle(); } @SuppressLint("ParserError") @Override public int getCount() { // 设置循环的次数 return Integer.MAX_VALUE; } @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; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub View viewGroup=viewMaps.get(position%count); ImageView imageView=null; TextView textView = null; if(viewGroup==null) { viewGroup =inflater.inflate(R.layout.gallery_define, null); imageView=(ImageView)viewGroup.findViewById(R.id.item_gallery_image); textView = (TextView)viewGroup.findViewById(R.id.item_gallery_text); imageView.setBackgroundResource(galleryItenBackgroud); viewMaps.put(position%count, viewGroup); imageView.setImageResource(imageIds[position%imageIds.length]); textView.setText(titles[position%imageIds.length]); } return viewGroup; } } //记录当前位置 private int curruntPos=-1;} 5：效果图：
