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);

     }

 }