Android入门第十三篇之Gallery + ImageSwitcher

       本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

       上次讲了如何使用Gallery控件，这次就讲Gallery 与ImageSwitcher的结合使用，本文实现一个简单的浏览图片的功能。先贴出程序运行截图：

除了Gallery可以拖拉切换图片，我在ImageSwitcher控件加入了setOnTouchListener事件实现，使得ImageSwitcher也可以在拖拉中切换图片。本例子依然使用JAVA的反射机制来自动读取资源中的图片。

 

main.xml的源码如下:

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <ImageSwitcher android:id="@+id/switcher" android:layout_width="match_parent" android:layout_height="match_parent"/> <Gallery android:id="@+id/gallery" android:background="#55000000" android:layout_width="match_parent" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:gravity="center_vertical" android:spacing="16dp" android:layout_height="100dp"/></RelativeLayout>

 

程序的源码如下:

package com.testImageView;import java.lang.reflect.Field;import java.util.ArrayList;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;import android.view.ViewGroup;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.OnItemSelectedListener;import android.widget.Gallery.LayoutParams;import android.widget.ViewSwitcher.ViewFactory;public class testImageView extends Activity implements ViewFactory {private ImageSwitcher is;private Gallery gallery;private int downX,upX; private ArrayList<Integer> imgList=new ArrayList<Integer>();//图像ID @Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.main); //用反射机制来获取资源中的图片ID Field[] fields = R.drawable.class.getDeclaredFields(); for (Field field : fields) { if (!"icon".equals(field.getName()))//除了icon之外的图片 { int index = 0;try {index = field.getInt(R.drawable.class);} catch (IllegalArgumentException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();} //保存图片ID imgList.add(index); } } //设置ImageSwitcher控件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));is.setOnTouchListener(new OnTouchListener(){/* * 在ImageSwitcher控件上滑动可以切换图片 */@Overridepublic boolean onTouch(View v, MotionEvent event) {if(event.getAction()==MotionEvent.ACTION_DOWN){downX=(int) event.getX();//取得按下时的坐标return true;}else if(event.getAction()==MotionEvent.ACTION_UP){upX=(int) event.getX();//取得松开时的坐标int index=0;if(upX-downX>100)//从左拖到右，即看前一张{//如果是第一，则去到尾部if(gallery.getSelectedItemPosition()==0) index=gallery.getCount()-1;elseindex=gallery.getSelectedItemPosition()-1;}else if(downX-upX>100)//从右拖到左，即看后一张{//如果是最后，则去到第一if(gallery.getSelectedItemPosition()==(gallery.getCount()-1))index=0;elseindex=gallery.getSelectedItemPosition()+1;}//改变gallery图片所选，自动触发ImageSwitcher的setOnItemSelectedListenergallery.setSelection(index, true);return true;}return false;}});//设置gallery控件gallery = (Gallery) findViewById(R.id.gallery);gallery.setAdapter(new ImageAdapter(this));gallery.setOnItemSelectedListener(new OnItemSelectedListener(){@Overridepublic void onItemSelected(AdapterView<?> arg0, View arg1,int position, long arg3) {is.setImageResource(imgList.get(position));}@Overridepublic void onNothingSelected(AdapterView<?> arg0) {// TODO Auto-generated method stub}});}//设置ImgaeSwitcher@Overridepublic View makeView() {ImageView i = new ImageView(this);i.setBackgroundColor(0xFF000000);i.setScaleType(ImageView.ScaleType.CENTER);//居中i.setLayoutParams(new ImageSwitcher.LayoutParams(//自适应图片大小LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));return i;}public class ImageAdapter extends BaseAdapter {public ImageAdapter(Context c) {mContext = c;}public int getCount() {return imgList.size();}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(imgList.get(position));i.setAdjustViewBounds(true);i.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));return i;}private Context mContext;}}