在移动应用开发过程中经常会使用到图片展示场景，例如利用多张图片说明一个产品的特点，此处就会使用到ImageSwithcher，当然也可以使用ViewFliper来实现，但使用ViewFliper的时候会资源释放的问题，需要手动进行操作，这点在以后的文章中讲述。
要使用ImageSwithcher，首先需要在界面文件中添加ImageSwithcher，然后在代码中为ImageSwithcher指定图片加载方法以及触控方法。如下为完成之后的界面：
下面讲述具体的实现方法：
界面Xml文件为：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/relativeLayout1"
android:background="#ffececec">
<ImageView
android:src="@drawable/ImgSlideLeft"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btnFeatureLeft"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true" />
<ImageSwitcher
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="1180px"
android:layout_height="638px"
android:id="@+id/SwitcherProductFeature"
android:layout_centerInParent="true" />
<ImageView
android:src="@drawable/ImgSlideRight"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btnFeatureRight"
android:layout_centerVertical="true"
android:layout_alignParentRight="true" />
</RelativeLayout>
实现代码为：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget; namespace MobileInsured.Activitys
{
[Activity (Label = "ProductFeatureActivity")]
public class ProductFeatureActivity : ContentActivity,ViewSwitcher.IViewFactory,GestureDetector.IOnGestureListener
{
private GestureDetector gestureDetector = null;
private ImageSwitcher imageSwitcher;
private int[] imgs = new int[]{
Resource.Drawable.ImgProductFeature11,
Resource.Drawable.ImgProductFeature12,
Resource.Drawable.ImgProductFeature13
};
private int currentPosition;
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle); // Create your application here
SetContent (Resource.Layout.ProductFeature);
gestureDetector = new GestureDetector(this);
var productId = Intent.GetStringExtra ("ProductId");
SetTitle ("产品特色");
imageSwitcher = FindViewById<ImageSwitcher> (Resource.Id.SwitcherProductFeature);
currentPosition = ;
imageSwitcher.SetFactory (this);
imageSwitcher.SetImageResource (Resource.Drawable.ImgProductFeature11);
} public View MakeView(){
ImageView img = new ImageView (this);
img.SetBackgroundColor (Android.Graphics.Color.Transparent);
img.SetScaleType (ImageView.ScaleType.Center);
return img;
} public override bool OnTouchEvent(MotionEvent e)
{
return gestureDetector.OnTouchEvent(e);
} public bool OnFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
{
if (e2.GetX() - e1.GetX() > ) {
currentPosition--;
if (currentPosition < )
currentPosition = imgs.Length - ;
imageSwitcher.SetInAnimation (this, Resource.Animation.LeftIn);
imageSwitcher.SetOutAnimation (this, Resource.Animation.RightOut);
imageSwitcher.SetImageResource (imgs [currentPosition]);
} else if (e2.GetX() - e1.GetX() < -) {
currentPosition++;
if (currentPosition > imgs.Length - )
currentPosition = ;
imageSwitcher.SetInAnimation (this, Resource.Animation.RightIn);
imageSwitcher.SetOutAnimation (this, Resource.Animation.LeftOut);
imageSwitcher.SetImageResource (imgs [currentPosition]);
}
return true;
} public bool OnDown(MotionEvent e)
{
return false;
} public void OnLongPress(MotionEvent e)
{
} public bool OnScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
{
return false;
} public void OnShowPress(MotionEvent e)
{
} public bool OnSingleTapUp(MotionEvent e)
{
return false;
}
}
}
如上代码所示，主要的地方时为ImageSwithcher设定Factory，声明MakeView方法，并根据需要设定具体手势判断方法。