自定义Drawable实现圆角图片和圆形图片

1 自定义圆角图片

a 继承drawable，重写里面的几个方法
b 通过构造方法传入Bitmap对象，初始化一个BitmapShader，将其传递给我们的画笔

public RoundImageDrawable(Bitmap bitmap) {
mBitmap = bitmap;
BitmapShader bitmapShader = new BitmapShader(bitmap, TileMode.CLAMP,
TileMode.CLAMP);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setShader(bitmapShader);
}

c 在setBounds（）初始化一个 ReactF

@Override
public void setBounds(int left, int top, int right, int bottom) {
super.setBounds(left, top, right, bottom);
rectF = new RectF(left, top, right, bottom);
}

d 在draw（）方法里面调用
canvas.draw（）传入我们的矩形对象和画笔

canvas.drawRoundRect(rectF, 30, 30, mPaint);

效果图如下



源码如下：

package com.xujun.administrator.customdrawable.view;

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.RectF;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.Drawable;

public class RoundImageDrawable extends Drawable {

private Paint mPaint;
private Bitmap mBitmap;

private RectF rectF;

public RoundImageDrawable(Bitmap bitmap) {
mBitmap = bitmap;
BitmapShader bitmapShader = new BitmapShader(bitmap, TileMode.CLAMP,
TileMode.CLAMP);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setShader(bitmapShader);
}
@Override
public void setBounds(int left, int top, int right, int bottom) {
super.setBounds(left, top, right, bottom);
rectF = new RectF(left, top, right, bottom);
}

@Override
public void draw(Canvas canvas) {
//圆角的 半斤可以通过参数传递进来，这里写死了
canvas.drawRoundRect(rectF, 30, 30, mPaint);

}

@Override
public int getIntrinsicWidth() {
return mBitmap.getWidth();
}

@Override
public int getIntrinsicHeight() {
return mBitmap.getHeight();
}

@Override
public void setAlpha(int alpha) {
mPaint.setAlpha(alpha);
}

@Override
public void setColorFilter(ColorFilter cf) {
mPaint.setColorFilter(cf);
}

@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}

}

2 自定义圆形图片

a 继承drawable，重写里面的几个方法
b 通过构造方法传入Bitmap对象，初始化一个BitmapShader，将其传递给我们的画笔

public CircleImageDrawable(Bitmap bitmap) {
mBitmap = bitmap;
BitmapShader bitmapShader = new BitmapShader(bitmap, TileMode.CLAMP,
TileMode.CLAMP);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setShader(bitmapShader);
//        选择我们的半径为较小的那个
mWidth = Math.min(mBitmap.getWidth(), mBitmap.getHeight());
}

c 在Draw（）方法里面调用
canvas.draw（）传入我们的矩形对象和画笔

canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2, mPaint);

效果图如下






例子源码下载地址：

https://github.com/gdutxiaoxu/CustomDrawable