圆形头像的实现

这里参考：http://www.jianshu.com/p/6b5eef0f6f3d
注意： // canvas.drawColor(Color.YELLOW); 这里稍微设置一下，否则可能肉眼看不出裁剪的效果！！！
我的效果图：

image.png

package com.example.liqing.mytextview.widget;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;

/**

• Created by liqing on 17/6/2.
  */

public class CirecleImageView extends android.support.v7.widget.AppCompatImageView {

private static String TAG = " CirecleImageView :";
private int mRadius;   // 圆角的半径
private float mScale; // 缩放比例

// private Paint mPaint=new Paint();
private Paint mPaint;

public CirecleImageView(Context context) {
    super(context);


}

public CirecleImageView(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);

}

public CirecleImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);


}

//
// public CirecleImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
// super(context, attrs, defStyleAttr, defStyleRes);
// }

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    Log.d(TAG, "onMeasure: ");
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int size = Math.min(getMeasuredWidth(), getMeasuredHeight());
    int he=getMeasuredHeight();
    int wid =getMeasuredWidth();
    Log.d(TAG, "onMeasure: he ="+he +"  wid="+wid);
    mRadius = size / 2;
    //setMeasuredDimension(2,2);
    setMeasuredDimension(size, size);
}

@Override
protected void onDraw(Canvas canvas) {
    Log.d(TAG, "onDraw: ");
    super.onDraw(canvas);
    mPaint = new Paint();
    Bitmap bp = drwableToBitmap(getDrawable());
    // BitmapShader 渲染
    BitmapShader bitmapShader = new BitmapShader(bp, Shader.TileMode.CLAMP, Shader.TileMode.MIRROR);
    mScale = (mRadius * 2.0f) / Math.min(bp.getWidth(), bp.getHeight());
    //Matrix控制变换 可以 平移、旋转角度 、倾斜、 缩放
    Matrix matrix = new Matrix();
    matrix.setScale(mScale, mScale);
    // 设置shader的本地矩阵,如果localM为空将重置shader的本地矩阵。
    bitmapShader.setLocalMatrix(matrix);
    mPaint.setShader(bitmapShader);

            mPaint.setAntiAlias(false);                       //设置画笔为无锯齿
    mPaint.setColor(Color.BLACK);                    //设置画笔颜色
   // canvas.drawColor(Color.YELLOW);                  //白色背景
    //"#50000000"

    mPaint.setStrokeWidth((float) 3.0);              //线宽

    //指定画的圆的 圆心x/y r
    Log.d(TAG, "onDraw:   canvas.drawCircle  mRadius =" +mRadius );

   canvas.drawCircle(mRadius,mRadius,mRadius,mPaint);

// mPaint.setAntiAlias(false); //设置画笔为无锯齿
// mPaint.setColor(Color.BLACK); //设置画笔颜色
// canvas.drawColor(Color.WHITE); //白色背景
// mPaint.setStrokeWidth((float) 3.0); //线宽
// mPaint.setStyle(Paint.Style.STROKE); //空心效果
// initPaint();
//
// canvas.drawCircle(50, 50, 10, mPaint); //绘制圆形
// canvas.drawCircle(100, 100, 20, mPaint); //绘制圆形
// canvas.drawCircle(150, 150, 30, mPaint); //绘制圆形
// canvas.drawCircle(200, 200, 40, mPaint); //绘制圆形
// canvas.drawCircle(250, 250, 50, mPaint); //绘制圆形
// canvas.drawCircle(300, 300, 60, mPaint); //绘制圆形
// canvas.drawCircle(350, 350, 70, mPaint); //绘制圆形
}

// 2.初始化画笔
private void initPaint() {

    mPaint.setColor(Color.BLACK);       //设置画笔颜色
    mPaint.setStyle(Paint.Style.FILL);  //设置画笔模式为填充
    mPaint.setStrokeWidth(10f);         //设置画笔宽度为10px
}
//把drawable 转为bitmap
public Bitmap drwableToBitmap(Drawable drawable) {
    if (drawable instanceof BitmapDrawable) {
        //BtimapDrawable是Drawable的子类
        Log.d(TAG, "drwableToBitmap:  BitmapDrawable exsit!");
        BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
        return bitmapDrawable.getBitmap();// 最终 这里的bitmapDrawable就是Bitmap对象了

    }
    int width = drawable.getIntrinsicWidth();
    int height = drawable.getIntrinsicHeight();
    Log.d(TAG, "drwableToBitmap: width:"+width+ ", height "+height);
    //图片压缩 最后一个参数是色彩信息，也是影响图片占有空间的
    Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    //   Canvas();创建一个空画布，它必须绑定bitmap才有效，一般以bitmap来创建一个bitmap的操作，
    // 当canvas进行绘图，他绘制的内容都绘在bitmap上。
    Canvas canvas = new Canvas(bitmap);
   // drawable.setBounds(0, 0, width, height);
    Log.d(TAG, "drwableToBitmap:    drawable.draw(canvas);");
    drawable.draw(canvas);
    return bitmap;
}

}