Android自定义Drawable实现圆形和圆角

package com.customview.widget;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.Shader;import android.graphics.drawable.Drawable;import android.support.annotation.IntRange;import android.support.annotation.NonNull;import android.support.annotation.Nullable;public class CircleDrawable extends Drawable {  private Paint mPaint;  private int mWidth; //宽/高，直径  private Bitmap mBitmap;  public CircleDrawable(Bitmap bitmap) {    this.mBitmap = bitmap;    BitmapShader bitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);//着色器 水平和竖直都需要填充满    mPaint = new Paint();    mPaint.setAntiAlias(true);    mPaint.setShader(bitmapShader);    mWidth = Math.min(mBitmap.getWidth(), mBitmap.getHeight()); //宽高的最小值作为直径  }  @Override  public void draw(@NonNull Canvas canvas) {    canvas.drawCircle(mWidth/2, mWidth/2, mWidth/2, mPaint); //绘制圆形  }  @Override  public void setAlpha(@IntRange(from = 0, to = 255) int i) {    mPaint.setAlpha(i);  }  @Override  public void setColorFilter(@Nullable ColorFilter colorFilter) {    mPaint.setColorFilter(colorFilter);  }  @Override  public int getOpacity() {    return PixelFormat.TRANSLUCENT; //设置系统默认，让drawable支持和窗口一样的透明度  }  //还需要从重写以下2个方法，返回drawable实际宽高  @Override  public int getIntrinsicWidth() {    return mWidth;  }  @Override  public int getIntrinsicHeight() {    return mWidth;  }}