自定义圆形imageview

package cn.tedu.musicclient.ui;

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;

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 = 2;
 private static final int DEFAULT_BORDER_COLOR = Color.WHITE;

 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);

  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);
 }

}