android图片倒影控件ReflectionImage

 
ReflectionImage是从android.widget.ImageView继承而来,使用方法和其他的Android控件一样 

实现思路是从某个网站上剽窃过来的。 

实现起来很简单,详细的解释写到注释里面,总体思路就是在Canvas里面重新把原始图片画一次,反转图片用Matrix来做,透明处理实际上是加了一层渐变的蒙板. 

import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.LinearGradient;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.PorterDuffXfermode;import android.graphics.Bitmap.Config;import android.graphics.PorterDuff.Mode;import android.graphics.Shader.TileMode;import android.graphics.drawable.BitmapDrawable;import android.util.AttributeSet;import android.widget.ImageView;public class ReflectionImage extends ImageView {//是否为Reflection模式private boolean mReflectionMode = true;public ReflectionImage(Context context) {super(context);}public ReflectionImage(Context context, AttributeSet attrs) {super(context, attrs);//取得原始图片的bitmap并重画Bitmap originalImage = ((BitmapDrawable)this.getDrawable()).getBitmap();DoReflection(originalImage);}public ReflectionImage(Context context, AttributeSet attrs,int defStyle) {super(context, attrs, defStyle);Bitmap originalImage = ((BitmapDrawable)this.getDrawable()).getBitmap();DoReflection(originalImage);}public void setReflectionMode(boolean isRef) {mReflectionMode = isRef;}public boolean getReflectionMode() {return mReflectionMode;}//偷懒了,只重写了setImageResource,和构造函数里面干了同样的事情@Overridepublic void setImageResource(int resId) {Bitmap originalImage = BitmapFactory.decodeResource(getResources(), resId);DoReflection(originalImage);//super.setImageResource(resId);}private void DoReflection(Bitmap originalImage) {final int reflectionGap = 4;//原始图片和反射图片中间的间距int width = originalImage.getWidth();int height = originalImage.getHeight();//反转Matrix matrix = new Matrix();matrix.preScale(1, -1);  //reflectionImage就是下面透明的那部分,可以设置它的高度为原始的3/4,这样效果会更好些Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,0, width, height, matrix, false);//创建一个新的bitmap,高度为原来的两倍Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height), Config.ARGB_8888);Canvas canvasRef = new Canvas(bitmapWithReflection);//先画原始的图片canvasRef.drawBitmap(originalImage, 0, 0, null);//画间距Paint deafaultPaint = new Paint();canvasRef.drawRect(0, height, width, height + reflectionGap, deafaultPaint);//画被反转以后的图片canvasRef.drawBitmap(reflectionImage, 0, height + reflectionGap, null);// 创建一个渐变的蒙版放在下面被反转的图片上面Paint paint = new Paint();LinearGradient shader = new LinearGradient(0,originalImage.getHeight(), 0, bitmapWithReflection.getHeight()+ reflectionGap, 0x80ffffff, 0x00ffffff, TileMode.CLAMP);// Set the paint to use this shader (linear gradient)paint.setShader(shader);// Set the Transfer mode to be porter duff and destination inpaint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));// Draw a rectangle using the paint with our linear gradientcanvasRef.drawRect(0, height, width, bitmapWithReflection.getHeight()+ reflectionGap, paint);  //调用ImageView中的setImageBitmapthis.setImageBitmap(bitmapWithReflection);}}