圆角图片RoundCornerImageView-优快云博客

本文链接：https://blog.youkuaiyun.com/sclgxt/article/details/51321700

本文介绍了一个自定义的Android ImageView组件——RoundCornerImageView，该组件能够显示带有圆角效果的图片。文章提供了完整的实现代码，并强调了使用注意事项，例如设置图片缩放类型为centerCrop以避免空白区域。

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package com.sclgxt.customimageview;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
 * Created by Sclgxt on 2016/5/5.
 * Mind:圆角图片,如果不是wrapcontent,
 * 请注意加上这句话android:scaleType="centerCrop",防止图片撑不起来而留有空
 * 请注意setRoundCorner.
 */

public class RoundCornerImageView extends ImageView {    

private Paint roundPaint;    

private Paint maskPaint;    

private int size = 0;    

public RoundCornerImageView(Context context) {        

this(context, null);    

}    

public RoundCornerImageView(Context context, AttributeSet attrs, int defStyleAttr) {       

 super(context, attrs, defStyleAttr);   

 }    

public RoundCornerImageView(Context context, AttributeSet attrs) {       

 this(context, attrs, 0);       

 init();    

}    

private void init() {        

roundPaint = new Paint();        

roundPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER));        

roundPaint.setAntiAlias(true);        

roundPaint.setColor(Color.WHITE);        

maskPaint = new Paint();        

maskPaint.setAntiAlias(true);       

maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));    

}   

 @Override    

protected void onDraw(Canvas canvas) {        

canvas.saveLayer(0, 0, getWidth(), getHeight(), 

roundPaint, Canvas.ALL_SAVE_FLAG);        

canvas.drawRoundRect(new RectF(0, 0, getWidth(), getHeight()), size, size, roundPaint);        

canvas.saveLayer(0, 0, getWidth(), getHeight(), maskPaint, Canvas.ALL_SAVE_FLAG);        

super.onDraw(canvas);    

}    

//设置圆角大小.这是一种写法,当然也可以自定义属性咯    

public void setRoundCorner(int size) {        

this.size = size;    

}

}