先看效果圖：
現在大部分的app上難免會使用到圓形頭像，所以今天我給大家分享一個單獨使用的，并且周圍帶有圓環動畫的花哨圓形頭像控件，本控件是在圓形頭像控件基礎上實現的，只是在其周圍再畫一些不同大小的圓而已，就可以實現如圖的效果。
圓形頭像的基本原理是將設置的資源文件轉化成Bitmap,然后通過BitmapShader類將Bitmap成為Paint的渲染器，然后在onDraw()中通過canvas.drawCircle(rx,ry,radius,paint);畫布上畫圓，而這個圓就是形成了圓形頭像。
在xml中通過src設置的資源文件在ImageView的setImageDrawable(drawable)方法中可以得到Drawable類型的圖像，然后再將Drawable轉成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) { //從bitmap中間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; } } /** * 從bitmap中間裁剪出最大的正方形 * @param bitmap * @return */ private Bitmap getMaxSquareCenter(Bitmap bitmap){ int w = bitmap.getWidth(); // 得到圖片的寬，高 int h = bitmap.getHeight(); int cropWidth = w >= h ? h : w;// 裁切后所取的正方形區域邊長 return Bitmap.createBitmap(bitmap, (w - cropWidth)/2 , (h - cropWidth)/2, cropWidth, cropWidth, null, false); } 獲取到Bitmap對象后就可以將Bitmap縮小一倍后，在將其畫在畫布上，這樣就有地方來畫周圍的圓環了。
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; //將圖片縮放在正中間 縮小一倍 dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f; } else { scale = mDrawableRect.width() / (float) mBitmapWidth / 2; //將圖片縮放在正中間 縮小一倍 dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f; } mShaderMatrix.setScale(scale , scale ); //在x軸上平移mDrawableRadius，就在正中間了 mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth + mDrawableRadius, (int) (dy + 0.5f) + mBorderWidth); mBitmapShader.setLocalMatrix(mShaderMatrix); } 下面就是畫圖片周圍的圓環了，就是在圖片的外圍畫兩個圓，一個半徑大點，顏色淺點，一個半徑小點，顏色深點就可以了，然后通過Handler通過延時操作，不斷的改變兩個圓的半徑大小和顏色的深淺，重繪就可以了
private float mChangeRateBorder;//記錄外圓執行動畫時半徑變化率 private float mChangeRateOuter;//記錄內圓執行動畫時半徑變化率 private float mChangeRateInner;//記錄圖片邊框執行動畫時半徑變化率 private float mChangeRange;//變化范圍，View半徑的1/6 //*******執行動畫*******// //外圓執行動畫時半徑變化率 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}; //內圓執行動畫時半徑變化率 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}; //圖片邊框執行動畫時半徑變化率 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;//動畫變化率的索引 Handler不斷改變半徑的變化率和畫筆的顏色
/** * 按住執行動畫 */ 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); } }; 每執行一次handleMessage()就會觸發（invalidate()）View重繪，onDraw中不斷的重繪，只需改變每個Circle的半徑即可
@Override protected void onDraw(Canvas canvas) { if (getDrawable() == null) { return; } //畫動畫的圖形 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); } 根據Handler中給的變化率來計算每個Circle的半徑
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; } 這樣在不斷的向Handler發送消息時，也就會不斷的觸發重繪，不斷改變外圍圓的大小，形成上圖所見的動畫效果
如下四個方法，就是來控制圓環所展示的不同狀態
/** * 開始動畫 */ public void startAnim(){ //讓外圍的圓環動起來 mHandler.sendEmptyMessageDelayed(0,30); } /** * 停止動畫 */ public void stopAnim(){ //停止外圓環的動畫，展示默認的大小 mHandler.removeCallbacksAndMessages(null); mChangeRateBorder = 0; mChangeRateOuter = 0; mChangeRateInner = 0; initAnimColor(); enterAnim(); } /** * 進入動畫 */ public void enterAnim(){ //展示外圓環，顯示默認大小 mHandlerEnter.sendEmptyMessage(0); } /** * 退出動畫 */ public void exitAnim(){ //隱藏外圓環 mHandlerExit.sendEmptyMessage(0); } 好了，動態頭像到這基本就實現了，進入動畫和退出動畫的代碼就不貼出來分析了，如果發現bug或者有任何意見歡迎留言。
完整源碼
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;//顯示的圖片 private float mBorderRadius;//..//顯示的圖片上的邊框 private float mOuterRadius;//外層動畫 private float mInnerRadius;//..//內層動畫 private float mRealDrawableRadius;//這是View沒有被縮放之前的mDrawableRadius的半徑 private float mRealBorderRadius;//.. private boolean mReady; private boolean mSetupPending; private float mChangeRateBorder;//記錄外圓執行動畫時半徑變化率 private float mChangeRateOuter;//記錄內圓執行動畫時半徑變化率 private float mChangeRateInner;//記錄圖片邊框執行動畫時半徑變化率 private float mChangeRange;//變化范圍，View半徑的1/6 //*******執行動畫*******// //外圓執行動畫時半徑變化率 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}; //內圓執行動畫時半徑變化率 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}; //圖片邊框執行動畫時半徑變化率 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;//動畫變化率的索引 //*******進入動畫*******// //外圓執行動畫時半徑變化率 private float mRateOuterEnter[] = { -2,-2,//外圓要縮小2個mChangeRange才會完全隱藏 -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}; //內圓執行動畫時半徑變化率 private float mRateInnerEnter[] = { -1,-1,//外圓要縮小1個mChangeRange才會完全隱藏 -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;//進入動畫變化率的索引 //*******退出動畫*******// //外圓執行動畫時半徑變化率 private float mRateOuterExit[] = { 0.0f,-0.2f,-0.4f,-0.6f,-0.8f ,-1f,-1.2f,-1.4f,-1.6f,-1.8f ,-2f}; //內圓執行動畫時半徑變化率 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;//進入動畫變化率的索引 /** * 按住執行動畫 */ 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); } }; /** * 設置outer和inner的畫筆顏色 * @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); } } /** * 設置透明度 * @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); //可以執行了 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; } //畫動畫的圖形 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); //圖片邊框（默認白色） mBorderPaint.setColor(mBorderColor); mOuterRadius = mRealBorderRadius / 6 * 5; mInnerRadius = mRealBorderRadius / 6 * 4; mChangeRange = mRealBorderRadius / 6; mRateIndex = 0; } /** * 開始動畫 */ public void startAnim(){ mHandler.sendEmptyMessageDelayed(0,30); } /** * 停止動畫 */ 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(); } /** * 進入動畫 */ public void enterAnim(){ mHandlerEnter.sendEmptyMessage(0); } /** * 退出動畫 */ public void exitAnim(){ mHandlerExit.sendEmptyMessage(0); } /** * 設置外圓動畫的顏色 * @param outerPaintColor */ public void setOuterPaintColor(int outerPaintColor) { if (outerPaintColor == mOuterPaintColor) { return; } mOuterPaintColor = outerPaintColor; mOuterPaint.setColor(mOuterPaintColor); invalidate(); } /** * 設置內圓動畫的顏色 * @param innerPaintColor */ public void setInnerPaintColor(int innerPaintColor) { if (innerPaintColor == mInnerPaintColor) { return; } mInnerPaintColor = innerPaintColor; mInnerPaint.setColor(mInnerPaintColor); invalidate(); } /** * 設置圖片邊框的顏色 * @param borderColor */ public void setBorderColor(int borderColor) { if (borderColor == mBorderColor) { return; } mBorderColor = borderColor; mBorderPaint.setColor(mBorderColor); invalidate(); } /** * 設置圖片邊框的寬度 * @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); //只有在此方法中調用setup，setup中的getWidth方法得到的值才不會是0， setup(); } @Override public void setImageBitmap(Bitmap bm) { super.setImageBitmap(bm); mBitmap = getMaxSquareCenter(bm); setup(); } /** * mxl中設置src就會走此方法 * @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(); } /** * 從bitmap中間裁剪出最大的正方形 * @param bitmap * @return */ private Bitmap getMaxSquareCenter(Bitmap bitmap){ int w = bitmap.getWidth(); // 得到圖片的寬，高 int h = bitmap.getHeight(); int cropWidth = w >= h ? h : w;// 裁切后所取的正方形區域邊長 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) { //從bitmap中間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() { //只有執行過構造函數之后，所有的成員才被初始化完畢 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(); //圖片邊框設置的范圍 mBorderRect.set(0, 0, getWidth(), getHeight()); mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2, (mBorderRect.width() - mBorderWidth) / 2) / 2; mRealBorderRadius = 2 * mBorderRadius; //圖片顯示的范圍 mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width() - mBorderWidth, mBorderRect.height() - mBorderWidth); //讓圖片顯示的范圍是控件大小的一半 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; //將圖片縮放在正中間 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); } } 參考：https://github.com/hdodenhof/CircleImageView
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