Android实现动态圆环的图片头像控件

先看效果图：

现在大部分的app上难免会使用到圆形头像，所以今天我给大家分享一个单独使用的，并且周围带有圆环动画的花哨圆形头像控件，本控件是在圆形头像控件基础上实现的，只是在其周围再画一些不同大小的圆而已，就可以实现如图的效果。

圆形头像的基本原理是将设置的资源文件转化成Bitmap,然后通过BitmapShader类将Bitmap成为Paint的渲染器，然后在onDraw()中通过canvas.drawCircle(rx,ry,radius,paint);画布上画圆，而这个圆就是形成了圆形头像。

在xml中通过src设置的资源文件在ImageView的setImageDrawable(drawable)方法中可以得到Drawable类型的图像，然后再将Drawable转成Bitmap就可以了

public void setImageDrawable(Drawable drawable) {
  super.setImageDrawable(drawable);
  mBitmap = getBitmapFromDrawable(drawable);
  setup();
}
private Bitmap getBitmapFromDrawable(Drawable drawable) { 

  if (drawable == null) {
   return null;
  } 

  if (drawable instanceof BitmapDrawable) {
   //从bitmap中间裁剪出最大的正方形
   Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
   return getMaxSquareCenter(bitmap);
   //return ((BitmapDrawable) drawable).getBitmap();
  } 

  try {
   Bitmap bitmap; 

   if (drawable instanceof ColorDrawable) {
    bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION, COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
   } else {
    int min = Math.min(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
    bitmap = Bitmap.createBitmap(min, min, BITMAP_CONFIG);
   } 

   Canvas canvas = new Canvas(bitmap);
   int left,top,right,buttom;
   int width = canvas.getWidth();
   int height = canvas.getHeight();
   int abs = Math.abs(width - height);
   if(width <= height){
    left = 0;
    top = (height - abs) / 2;
    right = width;
    buttom = height - top;
   }else{
    left = (width - abs) / 2;
    top = 0;
    right = width - left;
    buttom = height;
   }
   //drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
   drawable.setBounds(left, top, right, buttom);
   drawable.draw(canvas);
   return bitmap;
  } catch (OutOfMemoryError e) {
   return null;
  }
 }
/**
  * 从bitmap中间裁剪出最大的正方形
  * @param bitmap
  * @return
  */
 private Bitmap getMaxSquareCenter(Bitmap bitmap){
  int w = bitmap.getWidth(); // 得到图片的宽，高
  int h = bitmap.getHeight();
  int cropWidth = w >= h ? h : w;// 裁切后所取的正方形区域边长
  return Bitmap.createBitmap(bitmap, (w - cropWidth)/2 , (h - cropWidth)/2, cropWidth, cropWidth, null, false);
 }

获取到Bitmap对象后就可以将Bitmap缩小一倍后，在将其画在画布上，这样就有地方来画周围的圆环了。

private void updateShaderMatrix() {
  float scale;
  float dx = 0;
  float dy = 0; 

  mShaderMatrix.set(null); 

  if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) {
   scale = mDrawableRect.height() / (float) mBitmapHeight / 2; //将图片缩放在正中间 缩小一倍
   dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
  } else {
   scale = mDrawableRect.width() / (float) mBitmapWidth / 2; //将图片缩放在正中间 缩小一倍
   dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
  } 

  mShaderMatrix.setScale(scale , scale );
 //在x轴上平移mDrawableRadius，就在正中间了
  mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth + mDrawableRadius, (int) (dy + 0.5f) + mBorderWidth); 

  mBitmapShader.setLocalMatrix(mShaderMatrix);
 }

下面就是画图片周围的圆环了，就是在图片的外围画两个圆，一个半径大点，颜色浅点，一个半径小点，颜色深点就可以了，然后通过Handler通过延时操作，不断的改变两个圆的半径大小和颜色的深浅，重绘就可以了

 private float mChangeRateBorder;//记录外圆执行动画时半径变化率
 private float mChangeRateOuter;//记录内圆执行动画时半径变化率
 private float mChangeRateInner;//记录图片边框执行动画时半径变化率
 private float mChangeRange;//变化范围，View半径的1/6
//*******执行动画*******//
 //外圆执行动画时半径变化率
 private float mRateOuter[] = {
   -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
   0,0.1f,0.2f,0.3f,0.4f,0.5f,0.6f,0.7f,0.8f,0.9f,1.0f
   ,0.92f,0.88f,0.85f,0.82f,0.76f,0.72f,0.68f,0.60f,0.54f,0.48f,
   0.40f,0.33f,0.28f,0.20f};
 //内圆执行动画时半径变化率
 private float mRateInner[] = {
   -1,-1,-1,-1,-1,
   0,0.1f,0.2f,0.3f,0.4f,0.5f,0.6f,0.7f,0.8f,0.9f,1.0f
   ,0.92f,0.88f,0.84f,0.80f,0.72f,0.67f,0.60f,0.54f,0.48f,-1f
   ,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f};
 //图片边框执行动画时半径变化率
 private float mRateBorder[] = {
   0,0.1f,0.2f,0.3f,0.4f,0.5f,0.6f,0.7f,0.8f,0.9f,1.0f
   ,0.92f,0.90f,0.84f,0.78f,0.72f,0.64f,0.58f,-1f,-1f,-1f
   ,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f
   ,-1f,-1f,-1f,-1f}; 

 private int mRateIndex;//动画变化率的索引

Handler不断改变半径的变化率和画笔的颜色

/**
  * 按住执行动画
  */
 private Handler mHandler = new Handler(){
  @Override
  public void handleMessage(Message msg) {
   super.handleMessage(msg);
   int index = mRateIndex ++;
   mChangeRateBorder = mRateBorder[(index)% mRateBorder.length];
   setPaintCorlor(mBorderPaint,mChangeRateBorder,DEFAULT_BORDER_COLOR);
   setPaintAlpha(mBorderPaint,(index)% mRateBorder.length,mRateBorder);
   mChangeRateOuter = mRateOuter[(index) % mRateOuter.length];
   setPaintCorlor(mOuterPaint,mChangeRateOuter,mOuterPaintColor);
   setPaintAlpha(mOuterPaint,(index) % mRateOuter.length,mRateOuter);
   mChangeRateInner = mRateInner[(index) % mRateInner.length];
   setPaintCorlor(mInnerPaint,mChangeRateInner,mInnerPaintColor);
   setPaintAlpha(mInnerPaint,(index) % mRateInner.length,mRateInner); 

   //System.out.println("---------mChangeRate:"+mChangeRateBorder);
   invalidate();
   mHandler.removeCallbacksAndMessages(null);
   mHandler.sendEmptyMessageDelayed(0,30);
  }
 };

每执行一次handleMessage()就会触发（invalidate()）View重绘，onDraw中不断的重绘，只需改变每个Circle的半径即可

@Override
 protected void onDraw(Canvas canvas) { 

  if (getDrawable() == null) {
   return;
  } 

  //画动画的图形
  canvas.drawCircle(getWidth() / 2,getHeight() / 2,getChangeRadiusOuter(mOuterRadius),mOuterPaint);
  canvas.drawCircle(getWidth() / 2,getHeight() / 2,getChangeRadiusInner(mInnerRadius),mInnerPaint); 

  canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius, mBitmapPaint);
  canvas.drawCircle(getWidth() / 2, getHeight() / 2, getChangeRadiusBorder(mBorderRadius), mBorderPaint);
 }

根据Handler中给的变化率来计算每个Circle的半径

private float getChangeRadiusBorder(float radius){ 

  return mChangeRateBorder * mChangeRange + radius; 

 }
 private float getChangeRadiusOuter(float radius){ 

  return mChangeRateOuter * mChangeRange + radius; 

 }
 private float getChangeRadiusInner(float radius){ 

  return mChangeRateInner * mChangeRange + radius; 

 }

这样在不断的向Handler发送消息时，也就会不断的触发重绘，不断改变外围圆的大小，形成上图所见的动画效果
如下四个方法，就是来控制圆环所展示的不同状态

/**
  * 开始动画
  */
 public void startAnim(){
 //让外围的圆环动起来
  mHandler.sendEmptyMessageDelayed(0,30); 

 }
 /**
  * 停止动画
  */
 public void stopAnim(){
 //停止外圆环的动画，展示默认的大小
  mHandler.removeCallbacksAndMessages(null);
  mChangeRateBorder = 0;
  mChangeRateOuter = 0;
  mChangeRateInner = 0; 

  initAnimColor(); 

  enterAnim();
 }
 /**
  * 进入动画
  */
 public void enterAnim(){
 //展示外圆环，显示默认大小
  mHandlerEnter.sendEmptyMessage(0);
 } 

 /**
  * 退出动画
  */
 public void exitAnim(){
 //隐藏外圆环
  mHandlerExit.sendEmptyMessage(0);
 }

好了，动态头像到这基本就实现了，进入动画和退出动画的代码就不贴出来分析了，如果发现bug或者有任何意见欢迎留言。

完整源码

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.RectF;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.widget.ImageView; 

/**
 * Created by cj_28 on 2016/10/15.
 */
public class DynamicAvatarView extends ImageView { 

 private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP; 

 private static final int COLORDRAWABLE_DIMENSION = 1;
 private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888; 

 private Bitmap mBitmap;
 private BitmapShader mBitmapShader; 

 private final Matrix mShaderMatrix = new Matrix();
 private final Paint mBitmapPaint = new Paint();
 private final Paint mBorderPaint = new Paint();
 private final Paint mOuterPaint = new Paint();
 private final Paint mInnerPaint = new Paint(); 

 private static final int DEFAULT_BORDER_WIDTH = 3;
 private static final int DEFAULT_BORDER_COLOR = Color.WHITE;
 private static final int OUTER_PAINT_COLOR = Color.parseColor("#55FFFFFF");
 private static final int INNER_PAINT_COLOR = Color.parseColor("#66FFFFFF"); 

 private int mBorderColor = DEFAULT_BORDER_COLOR;
 private int mBorderWidth = DEFAULT_BORDER_WIDTH; 

 private int mOuterPaintColor = OUTER_PAINT_COLOR;
 private int mInnerPaintColor = INNER_PAINT_COLOR; 

 private int mBitmapWidth;
 private int mBitmapHeight; 

 private final RectF mDrawableRect = new RectF();
 private final RectF mBorderRect = new RectF(); 

 private float mDrawableRadius;//显示的图片
 private float mBorderRadius;//..//显示的图片上的边框
 private float mOuterRadius;//外层动画
 private float mInnerRadius;//..//内层动画 

 private float mRealDrawableRadius;//这是View没有被缩放之前的mDrawableRadius的半径
 private float mRealBorderRadius;//.. 

 private boolean mReady;
 private boolean mSetupPending; 

 private float mChangeRateBorder;//记录外圆执行动画时半径变化率
 private float mChangeRateOuter;//记录内圆执行动画时半径变化率
 private float mChangeRateInner;//记录图片边框执行动画时半径变化率
 private float mChangeRange;//变化范围，View半径的1/6 

 //*******执行动画*******//
 //外圆执行动画时半径变化率
 private float mRateOuter[] = {
   -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
   0,0.1f,0.2f,0.3f,0.4f,0.5f,0.6f,0.7f,0.8f,0.9f,1.0f
   ,0.92f,0.88f,0.85f,0.82f,0.76f,0.72f,0.68f,0.60f,0.54f,0.48f,
   0.40f,0.33f,0.28f,0.20f};
 //内圆执行动画时半径变化率
 private float mRateInner[] = {
   -1,-1,-1,-1,-1,
   0,0.1f,0.2f,0.3f,0.4f,0.5f,0.6f,0.7f,0.8f,0.9f,1.0f
   ,0.92f,0.88f,0.84f,0.80f,0.72f,0.67f,0.60f,0.54f,0.48f,-1f
   ,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f};
 //图片边框执行动画时半径变化率
 private float mRateBorder[] = {
   0,0.1f,0.2f,0.3f,0.4f,0.5f,0.6f,0.7f,0.8f,0.9f,1.0f
   ,0.92f,0.90f,0.84f,0.78f,0.72f,0.64f,0.58f,-1f,-1f,-1f
   ,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f,-1f
   ,-1f,-1f,-1f,-1f}; 

 //private int mColor[] = {0x55FFFFFF,0x44FFFFFF,0x33FFFFFF,0x22FFFFFF,0x11FFFFFF,0x00FFFFFF,0x00FFFFFF,0x00FFFFFF,0x00FFFFFF,0x00FFFFFF};
 private int mRateIndex;//动画变化率的索引 

 //*******进入动画*******//
 //外圆执行动画时半径变化率
 private float mRateOuterEnter[] = {
   -2,-2,//外圆要缩小2个mChangeRange才会完全隐藏
   -2,-2,-2,-2,-2,
   -0.8f,-0.6f,-0.4f,-0.2f,-0.1f,
   0,0.1f,0.2f,0.3f,0.4f,0.5f
   ,0.44f,0.4f,0.35f,0.3f,0.25f
   ,0.20f,0.15f,0.1f,0.0f};
 //内圆执行动画时半径变化率
 private float mRateInnerEnter[] = {
   -1,-1,//外圆要缩小1个mChangeRange才会完全隐藏
   -0.8f,-0.6f,-0.4f,-0.2f,-0.1f,
   0,0.1f,0.2f,0.3f,0.35f,0.4f
   ,0.45f,0.5f,0.45f,0.4f,0.35f
   ,0.3f,0.25f,0.2f,0.15f,0.1f
   ,0.05f,0f,0f,0f};
 private int mRateIndexEnter;//进入动画变化率的索引 

 //*******退出动画*******//
 //外圆执行动画时半径变化率
 private float mRateOuterExit[] = { 

   0.0f,-0.2f,-0.4f,-0.6f,-0.8f
   ,-1f,-1.2f,-1.4f,-1.6f,-1.8f
   ,-2f};
 //内圆执行动画时半径变化率
 private float mRateInnerExit[] = { 

   0.0f,-0.1f,-0.2f,-0.3f,-0.4f
   ,-0.5f,-0.6f,-0.7f,-0.8f,-0.9f
   ,-1f};
 private int mRateIndexExit;//进入动画变化率的索引 

 /**
  * 按住执行动画
  */
 private Handler mHandler = new Handler(){
  @Override
  public void handleMessage(Message msg) {
   super.handleMessage(msg);
   int index = mRateIndex ++;
   mChangeRateBorder = mRateBorder[(index)% mRateBorder.length];
   setPaintCorlor(mBorderPaint,mChangeRateBorder,DEFAULT_BORDER_COLOR);
   setPaintAlpha(mBorderPaint,(index)% mRateBorder.length,mRateBorder);
   mChangeRateOuter = mRateOuter[(index) % mRateOuter.length];
   setPaintCorlor(mOuterPaint,mChangeRateOuter,mOuterPaintColor);
   setPaintAlpha(mOuterPaint,(index) % mRateOuter.length,mRateOuter);
   mChangeRateInner = mRateInner[(index) % mRateInner.length];
   setPaintCorlor(mInnerPaint,mChangeRateInner,mInnerPaintColor);
   setPaintAlpha(mInnerPaint,(index) % mRateInner.length,mRateInner); 

   //System.out.println("---------mChangeRate:"+mChangeRateBorder);
   invalidate();
   mHandler.removeCallbacksAndMessages(null);
   mHandler.sendEmptyMessageDelayed(0,30);
  }
 }; 

 private Handler mHandlerEnter = new Handler(){
  @Override
  public void handleMessage(Message msg) {
   super.handleMessage(msg);
   int index = mRateIndexEnter ++;
   if(index >= mRateOuterEnter.length) {
    mRateIndexEnter = 0;
    mHandlerEnter.removeCallbacksAndMessages(null);
    return;
   } 

   mChangeRateOuter = mRateOuterEnter[(index) % mRateOuterEnter.length]; 

   mChangeRateInner = mRateInnerEnter[(index) % mRateInnerEnter.length]; 

   invalidate();
   mHandlerEnter.removeCallbacksAndMessages(null);
   mHandlerEnter.sendEmptyMessageDelayed(0,20);
  }
 }; 

 private Handler mHandlerExit = new Handler(){
  @Override
  public void handleMessage(Message msg) {
   super.handleMessage(msg);
   int index = mRateIndexExit ++;
   if(index >= mRateOuterExit.length) {
    mRateIndexExit = 0;
    mHandlerExit.removeCallbacksAndMessages(null);
    return;
   } 

   mChangeRateOuter = mRateOuterExit[(index) % mRateOuterExit.length]; 

   mChangeRateInner = mRateInnerExit[(index) % mRateInnerExit.length]; 

   invalidate();
   mHandlerExit.removeCallbacksAndMessages(null);
   mHandlerExit.sendEmptyMessageDelayed(0,20);
  }
 }; 

 /**
  * 设置outer和inner的画笔颜色
  * @param paint
  * @param rate
  * @param color
  */
 private void setPaintCorlor(Paint paint,float rate,int color){
  if(rate < 0){
   paint.setColor(Color.TRANSPARENT);
  }else{
   paint.setColor(color);
  }
 } 

 /**
  * 设置透明度
  * @param paint
  * @param index
  * @param rate
  */
 private void setPaintAlpha(Paint paint,int index,float[] rate){
  int pre = index -1;
  if(pre >= 0 ){
   if(rate[pre] > rate[index] && rate[index] > 0){
    int color = paint.getColor(); 

    int colorTransparent = color & 0xff000000;
    int colorValue = color & 0x00ffffff;
    colorTransparent = colorTransparent >>> 7;
    paint.setColor((int)(rate[index] * colorTransparent) << 7 | colorValue); 

   }
  }
 } 

 public DynamicAvatarView(Context context) {
  this(context,null);
 } 

 public DynamicAvatarView(Context context, AttributeSet attrs) {
  this(context, attrs,0); 

 } 

 public DynamicAvatarView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  super.setScaleType(SCALE_TYPE); 

  //可以执行了
  mReady = true; 

  if (mSetupPending) {
   setup();
   mSetupPending = false;
  }
 } 

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 

  int widthMode = MeasureSpec.getMode(widthMeasureSpec);
  int widthSize = MeasureSpec.getSize(widthMeasureSpec);
  int heightMode = MeasureSpec.getMode(heightMeasureSpec);
  int heightSize = MeasureSpec.getSize(heightMeasureSpec); 

  int size = Math.min(widthSize, heightSize); 

  super.onMeasure(MeasureSpec.makeMeasureSpec(size,widthMode), MeasureSpec.makeMeasureSpec(size,heightMode));
 } 

 @Override
 protected void onLayout(boolean changed, int left, int top, int right, int bottom) { 

  super.onLayout(changed, left, top, right, bottom);
  enterAnim();
 } 

 @Override
 protected void onDraw(Canvas canvas) { 

  if (getDrawable() == null) {
   return;
  } 

  //画动画的图形
  canvas.drawCircle(getWidth() / 2,getHeight() / 2,getChangeRadiusOuter(mOuterRadius),mOuterPaint);
  canvas.drawCircle(getWidth() / 2,getHeight() / 2,getChangeRadiusInner(mInnerRadius),mInnerPaint); 

  canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius, mBitmapPaint);
  canvas.drawCircle(getWidth() / 2, getHeight() / 2, getChangeRadiusBorder(mBorderRadius), mBorderPaint);
 } 

 private float getChangeRadiusBorder(float radius){ 

  return mChangeRateBorder * mChangeRange + radius; 

 }
 private float getChangeRadiusOuter(float radius){ 

  return mChangeRateOuter * mChangeRange + radius; 

 }
 private float getChangeRadiusInner(float radius){ 

  return mChangeRateInner * mChangeRange + radius; 

 } 

 private void initAnimColor(){
  mOuterPaint.setStyle(Paint.Style.FILL);
  mOuterPaint.setAntiAlias(true);
  mOuterPaint.setColor(mOuterPaintColor);
  mInnerPaint.setStyle(Paint.Style.FILL);
  mInnerPaint.setAntiAlias(true);
  mInnerPaint.setColor(mInnerPaintColor);
  //图片边框（默认白色）
  mBorderPaint.setColor(mBorderColor); 

  mOuterRadius = mRealBorderRadius / 6 * 5;
  mInnerRadius = mRealBorderRadius / 6 * 4;
  mChangeRange = mRealBorderRadius / 6;
  mRateIndex = 0;
 } 

 /**
  * 开始动画
  */
 public void startAnim(){
  mHandler.sendEmptyMessageDelayed(0,30); 

 }
 /**
  * 停止动画
  */
 public void stopAnim(){
  mHandler.removeCallbacksAndMessages(null);
  mChangeRateBorder = 0;
  mChangeRateOuter = 0;
  mChangeRateInner = 0;
//  mBorderPaint.setColor(DEFAULT_BORDER_COLOR);
//  mOuterPaint.setColor(mOuterPaintColor);
//  mInnerPaint.setColor(mInnerPaintColor);
//  mRateIndex = 0;
  initAnimColor(); 

  //invalidate();
  enterAnim();
 }
 /**
  * 进入动画
  */
 public void enterAnim(){
  mHandlerEnter.sendEmptyMessage(0);
 } 

 /**
  * 退出动画
  */
 public void exitAnim(){
  mHandlerExit.sendEmptyMessage(0);
 } 

 /**
  * 设置外圆动画的颜色
  * @param outerPaintColor
  */
 public void setOuterPaintColor(int outerPaintColor) {
  if (outerPaintColor == mOuterPaintColor) {
   return;
  }
  mOuterPaintColor = outerPaintColor;
  mOuterPaint.setColor(mOuterPaintColor);
  invalidate();
 } 

 /**
  * 设置内圆动画的颜色
  * @param innerPaintColor
  */
 public void setInnerPaintColor(int innerPaintColor) {
  if (innerPaintColor == mInnerPaintColor) {
   return;
  }
  mInnerPaintColor = innerPaintColor;
  mInnerPaint.setColor(mInnerPaintColor);
  invalidate();
 } 

 /**
  * 设置图片边框的颜色
  * @param borderColor
  */
 public void setBorderColor(int borderColor) {
  if (borderColor == mBorderColor) {
   return;
  } 

  mBorderColor = borderColor;
  mBorderPaint.setColor(mBorderColor);
  invalidate();
 } 

 /**
  * 设置图片边框的宽度
  * @param borderWidth
  */
 public void setBorderWidth(int borderWidth) {
  if (borderWidth == mBorderWidth) {
   return;
  } 

  mBorderWidth = borderWidth;
  setup();
 } 

 @Override
 public ScaleType getScaleType() {
  return SCALE_TYPE;
 } 

 @Override
 public void setScaleType(ScaleType scaleType) {
  if (scaleType != SCALE_TYPE) {
   throw new IllegalArgumentException(String.format("ScaleType %s not supported.", scaleType));
  }
 } 

 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
  super.onSizeChanged(w, h, oldw, oldh);
  //只有在此方法中调用setup，setup中的getWidth方法得到的值才不会是0，
  setup();
 } 

 @Override
 public void setImageBitmap(Bitmap bm) {
  super.setImageBitmap(bm);
  mBitmap = getMaxSquareCenter(bm);
  setup();
 } 

 /**
  * mxl中设置src就会走此方法
  * @param drawable
  */
 @Override
 public void setImageDrawable(Drawable drawable) {
  super.setImageDrawable(drawable);
  mBitmap = getBitmapFromDrawable(drawable);
  setup();
 } 

 @Override
 public void setImageResource(int resId) {
  super.setImageResource(resId);
  mBitmap = getBitmapFromDrawable(getDrawable());
  setup();
 } 

 /**
  * 从bitmap中间裁剪出最大的正方形
  * @param bitmap
  * @return
  */
 private Bitmap getMaxSquareCenter(Bitmap bitmap){
  int w = bitmap.getWidth(); // 得到图片的宽，高
  int h = bitmap.getHeight();
  int cropWidth = w >= h ? h : w;// 裁切后所取的正方形区域边长
  return Bitmap.createBitmap(bitmap, (w - cropWidth)/2 , (h - cropWidth)/2, cropWidth, cropWidth, null, false);
 } 

 private Bitmap getBitmapFromDrawable(Drawable drawable) { 

  if (drawable == null) {
   return null;
  } 

  if (drawable instanceof BitmapDrawable) {
   //从bitmap中间裁剪出最大的正方形
   Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
   return getMaxSquareCenter(bitmap);
   //return ((BitmapDrawable) drawable).getBitmap();
  } 

  try {
   Bitmap bitmap; 

   if (drawable instanceof ColorDrawable) {
    bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION, COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
   } else {
    int min = Math.min(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
    bitmap = Bitmap.createBitmap(min, min, BITMAP_CONFIG);
   } 

   Canvas canvas = new Canvas(bitmap);
   int left,top,right,buttom;
   int width = canvas.getWidth();
   int height = canvas.getHeight();
   int abs = Math.abs(width - height);
   if(width <= height){
    left = 0;
    top = (height - abs) / 2;
    right = width;
    buttom = height - top;
   }else{
    left = (width - abs) / 2;
    top = 0;
    right = width - left;
    buttom = height;
   }
   //drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
   drawable.setBounds(left, top, right, buttom);
   drawable.draw(canvas);
   return bitmap;
  } catch (OutOfMemoryError e) {
   return null;
  }
 } 

 private void setup() {
  //只有执行过构造函数之后，所有的成员才被初始化完毕
  if (!mReady) {
   mSetupPending = true;
   return;
  } 

  if (mBitmap == null) {
   return;
  } 

  mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP); 

  mBitmapPaint.setAntiAlias(true);
  mBitmapPaint.setShader(mBitmapShader); 

  mBorderPaint.setStyle(Paint.Style.STROKE);
  mBorderPaint.setAntiAlias(true);
  mBorderPaint.setColor(mBorderColor);
  mBorderPaint.setStrokeWidth(mBorderWidth); 

  mBitmapHeight = mBitmap.getHeight();
  mBitmapWidth = mBitmap.getWidth();
  //图片边框设置的范围
  mBorderRect.set(0, 0, getWidth(), getHeight());
  mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2, (mBorderRect.width() - mBorderWidth) / 2) / 2;
  mRealBorderRadius = 2 * mBorderRadius;
  //图片显示的范围
  mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width() - mBorderWidth, mBorderRect.height() - mBorderWidth);
  //让图片显示的范围是控件大小的一半
  mDrawableRadius = Math.min(mDrawableRect.height() / 2, mDrawableRect.width() / 2) / 2;
  mRealDrawableRadius = 2 * mDrawableRadius; 

  updateShaderMatrix();
  initAnimColor();
  invalidate();
 } 

 private void updateShaderMatrix() {
  float scale;
  float dx = 0;
  float dy = 0; 

  mShaderMatrix.set(null); 

  if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) {
   scale = mDrawableRect.height() / (float) mBitmapHeight / 2; //将图片缩放在正中间
   dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
  } else {
   scale = mDrawableRect.width() / (float) mBitmapWidth / 2;
   dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
  } 

  mShaderMatrix.setScale(scale , scale );
  mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth + mDrawableRadius, (int) (dy + 0.5f) + mBorderWidth); 

  mBitmapShader.setLocalMatrix(mShaderMatrix);
 } 

} 

参考：https://github.com/hdodenhof/CircleImageView

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