自定义圆形imageview

 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.util.AttributeSet;
 import android.widget.ImageView;

 /**
  *
  * @file_name: CircleImageView.java
  * @function：自定义圆形imageview
  */
 public class CircleImageView extends ImageView {

     private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;

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

     private static final int DEFAULT_BORDER_WIDTH = 0;
     private static final int DEFAULT_BORDER_COLOR = Color.BLACK;

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

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

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

     private Bitmap mBitmap;
     private BitmapShader mBitmapShader;
     private int mBitmapWidth;
     private int mBitmapHeight;

     private float mDrawableRadius;
     private float mBorderRadius;

     private boolean mReady;
     private boolean mSetupPending;

     public CircleImageView(Context context) {
         super(context);
     }

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

     public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
         super.setScaleType(SCALE_TYPE);

 //        TypedArray a = context.obtainStyledAttributes(attrs,
 //                R.styleable.CircleImageView, defStyle, 0);
 //
 //        mBorderWidth = a.getDimensionPixelSize(
 //                R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH);
 //        mBorderColor = a.getColor(R.styleable.CircleImageView_border_color,
 //                DEFAULT_BORDER_COLOR);

 //        a.recycle();

         mReady = true;

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

     @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 onDraw(Canvas canvas) {
         if (getDrawable() == null) {
             return;
         }

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

     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         super.onSizeChanged(w, h, oldw, oldh);
         setup();
     }

     public int getBorderColor() {
         return mBorderColor;
     }

     public void setBorderColor(int borderColor) {
         if (borderColor == mBorderColor) {
             return;
         }

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

     public int getBorderWidth() {
         return mBorderWidth;
     }

     public void setBorderWidth(int borderWidth) {
         if (borderWidth == mBorderWidth) {
             return;
         }

         mBorderWidth = borderWidth;
         setup();
     }

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

     @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();
     }

     private Bitmap getBitmapFromDrawable(Drawable drawable) {
         if (drawable == null) {
             return null;
         }

         if (drawable instanceof BitmapDrawable) {
             return ((BitmapDrawable) drawable).getBitmap();
         }

         try {
             Bitmap bitmap;

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

             Canvas canvas = new Canvas(bitmap);
             drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
             drawable.draw(canvas);
             return bitmap;
         } catch (OutOfMemoryError e) {
             return null;
         }
     }

     private void setup() {
         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();

         mBorderRect.set(0, 0, getWidth(), getHeight());
         mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2,
                 (mBorderRect.width() - mBorderWidth) / 2);

         mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width()
                 - mBorderWidth, mBorderRect.height() - mBorderWidth);
         mDrawableRadius = Math.min(mDrawableRect.height() / 2,
                 mDrawableRect.width() / 2);

         updateShaderMatrix();
         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;
             dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
         } else {
             scale = mDrawableRect.width() / (float) mBitmapWidth;
             dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
         }

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

         mBitmapShader.setLocalMatrix(mShaderMatrix);
     }

 }