本文实例讲述了android编程滑动效果之倒影效果实现方法。分享给大家供大家参考，具体如下：
前面介绍了使用《android编程实现3d滑动旋转效果的方法》，现在介绍图片倒影实现，先看效果图
这里主要通过自定义gallery和imageadapter（继承自baseadapter）实现
1、倒影绘制
imageadapter继承自baseadapter，详细实现可见前面关于android gallery的用法。这里重点介绍倒影原理及实现
倒影原理：
倒影效果是主要由原图+间距+倒影三部分组成，高度大约为原图的3/2（原图为1、倒影为1/2）
原图，就是我们看到了最开始的图片
间距，是原图与倒影之间的间隙，如：reflectiongap = 4;
倒影，是原图下半部分1/2高度，通过矩阵变换matrix.prescale(1, -1); 获取倒立图片，然后再加上线性遮罩和阴影实现
倒影实现：
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/** 反射倒影 */
public boolean createreflectedimages() {
final int reflectiongap = 4;
int index = 0;
for (map<string, object> map : list) {
integer id = (integer) map.get("image");
bitmap originalimage = bitmapfactory.decoderesource(mcontext.getresources(), id); // 获取原始图片
int width = originalimage.getwidth();
int height = originalimage.getheight();
matrix matrix = new matrix();
matrix.prescale(1, -1); // 图片矩阵变换（从低部向顶部的倒影）
bitmap reflectionimage = bitmap.createbitmap(originalimage, 0, height/2, width, height/2, matrix, false); // 截取原图下半部分
bitmap bitmapwithreflection = bitmap.createbitmap(width, (height + height / 2), config.argb_8888); // 创建倒影图片（高度为原图3/2）
canvas canvas = new canvas(bitmapwithreflection); // 绘制倒影图（原图 + 间距 + 倒影）
canvas.drawbitmap(originalimage, 0, 0, null); // 绘制原图
paint paint = new paint();
canvas.drawrect(0, height, width, height + reflectiongap, paint); // 绘制原图与倒影的间距
canvas.drawbitmap(reflectionimage, 0, height + reflectiongap, null); // 绘制倒影图
paint = new paint();
lineargradient shader = new lineargradient(0, originalimage.getheight(), 0, bitmapwithreflection.getheight() + reflectiongap, 0x70ffffff, 0x00ffffff, tilemode.clamp);
paint.setshader(shader); // 线性渐变效果
paint.setxfermode(new porterduffxfermode(mode.dst_in)); // 倒影遮罩效果
canvas.drawrect(0, height, width, bitmapwithreflection.getheight() + reflectiongap, paint); // 绘制倒影的阴影效果
imageview imageview = new imageview(mcontext);
imageview.setimagebitmap(bitmapwithreflection); // 设置倒影图片
imageview.setlayoutparams(new mygallery.layoutparams(180, 240));
imageview.setscaletype(scaletype.matrix);
mimages[index++] = imageview;
}
return true;
}
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2、mygallery
自定义gallery来实现倒影图片的浏览与选择
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public class mygallery extends gallery {
private camera mcamera = new camera();
private int mmaxrotationangle = 60; // 最大旋转角度 60
private int mmaxzoom = -120;
private int mcoveflowcenter;
public mygallery(context context) {
super(context);
this.setstatictransformationsenabled(true);
}
public mygallery(context context, attributeset attrs) {
super(context, attrs);
this.setstatictransformationsenabled(true);
}
public mygallery(context context, attributeset attrs, int defstyle) {
super(context, attrs, defstyle);
this.setstatictransformationsenabled(true);
}
public int getmaxrotationangle() {
return mmaxrotationangle;
}
public void setmaxrotationangle(int maxrotationangle) {
mmaxrotationangle = maxrotationangle;
}
public int getmaxzoom() {
return mmaxzoom;
}
public void setmaxzoom(int maxzoom) {
mmaxzoom = maxzoom;
}
/** 获取gallery的中心x */
private int getcenterofcoverflow() {
return (getwidth() - getpaddingleft() - getpaddingright()) / 2 + getpaddingleft();
}
/** 获取view的中心x */
private static int getcenterofview(view view) {
return view.getleft() + view.getwidth() / 2;
}
@override
protected void onsizechanged(int w, int h, int oldw, int oldh) {
mcoveflowcenter = getcenterofcoverflow();
super.onsizechanged(w, h, oldw, oldh);
}
@override
protected boolean getchildstatictransformation(view child, transformation trans) {
final int childcenter = getcenterofview(child);
final int childwidth = child.getwidth();
int rotationangle = 0;
trans.clear();
trans.settransformationtype(transformation.type_both); // alpha 和 matrix 都变换
if (childcenter == mcoveflowcenter) { // 正中间的childview
transformimagebitmap((imageview) child, trans, 0);
} else { // 两侧的childview
rotationangle = (int) ( ( (float) (mcoveflowcenter - childcenter) / childwidth ) * mmaxrotationangle );
if (math.abs(rotationangle) > mmaxrotationangle) {
rotationangle = (rotationangle < 0) ? -mmaxrotationangle : mmaxrotationangle;
}
transformimagebitmap((imageview) child, trans, rotationangle);
}
return true;
}
private void transformimagebitmap(imageview child, transformation trans, int rotationangle) {
mcamera.save();
final matrix imagematrix = trans.getmatrix();
final int imageheight = child.getlayoutparams().height;
final int imagewidth = child.getlayoutparams().width;
final int rotation = math.abs(rotationangle);
// 在z轴上正向移动camera的视角，实际效果为放大图片; 如果在y轴上移动，则图片上下移动; x轴上对应图片左右移动。
mcamera.translate(0.0f, 0.0f, 100.0f);
// as the angle of the view gets less, zoom in
if (rotation < mmaxrotationangle) {
float zoomamount = (float) (mmaxzoom + (rotation * 1.5));
mcamera.translate(0.0f, 0.0f, zoomamount);
}
mcamera.rotatey(rotationangle); // rotationangle 为正，沿y轴向内旋转； 为负，沿y轴向外旋转
mcamera.getmatrix(imagematrix);
imagematrix.pretranslate(-(imagewidth / 2), -(imageheight / 2));
imagematrix.posttranslate((imagewidth / 2), (imageheight / 2));
mcamera.restore();
}
}
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3、activity
activity中，主要实现自定义gallery的图片填充imageadapter、mygallery选择事件监听、点击事件监听
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private void initres(){
tvtitle = (textview) findviewbyid(r.id.tvtitle);
gallery = (mygallery) findviewbyid(r.id.mygallery); // 获取自定义的mygallery控件
adapter = new imageadapter(this);
adapter.createreflectedimages(); // 创建倒影效果
gallery.setadapter(adapter);
gallery.setonitemselectedlistener(new onitemselectedlistener() { // 设置选择事件监听
@override
public void onitemselected(adapterview<?> parent, view view, int position, long id) {
tvtitle.settext(adapter.titles[position]);
}
@override
public void onnothingselected(adapterview<?> parent) {
}
});
gallery.setonitemclicklistener(new onitemclicklistener() { // 设置点击事件监听
@override
public void onitemclick(adapterview<?> parent, view view, int position, long id) {
toast.maketext(main.this, "img " + (position+1) + " selected", toast.length_short).show();
}
});
}
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main.xml布局文件中，通过实现自定义的mygallery，来显示图片集合
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<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<textview
android:id="@+id/tvtitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerhorizontal="true"
android:textsize="16sp" />
<com.homer.reflect.mygallery
android:id="@+id/mygallery"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/tvtitle"
android:layout_margintop="10dip" />
</relativelayout>
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完整实例代码点击此处本站下载。
希望本文所述对大家android程序设计有所帮助。