自定义控件-----ReflectionImage

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ReflectionImage是一个有倒影效果的图片.先来看看长什么样子的吧...

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,因为很久了记不到网站了,这里就不贴了...搜一下吧

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.

源码如下

[java] view plaincopy

package com.myview;
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
@Override
public 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 in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
// Draw a rectangle using the paint with our linear gradient
canvasRef.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint);
//调用ImageView中的setImageBitmap
this.setImageBitmap(bitmapWithReflection);
}
}

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