android自定义控件ImageView实现圆形图片

android开发中常常涉及到一种情况，就是将用户上传的图片以圆形样式显示，但是用户上传的图片可以有直角、圆角、正方形等多种不确定样式，这时就用到了自定义ImageView控件，在安卓客户端使接收到的图片全部以圆形样式显示

CircleImageView.java

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 = 2;
 // 圆形边框的厚度默认值。
 // 如果是0，则没有天蓝色渐变的边框。
 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;
 private final Paint mFlagBackgroundPaint = new Paint();
 private final TextPaint mFlagTextPaint = new TextPaint();
 private String mFlagText;
 private boolean mShowFlag = false;
 private Rect mFlagTextBounds = new Rect();
 Shader mSweepGradient = null;
 public CircleImageView(Context context) {
 super(context);
 init();
 }

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

 public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 init();
 }

 private void init() {
 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
 public void setAdjustViewBounds(boolean adjustViewBounds) {
 if (adjustViewBounds) {
  throw new IllegalArgumentException(
   "adjustViewBounds not supported.");
 }
 }

 @Override
 protected void onDraw(Canvas canvas) {
 if (getDrawable() == null) {
  return;
 }
 canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius,
  mBitmapPaint);
 if (mBorderWidth != 0) {
  canvas.save();
  canvas.rotate(20, getWidth() / 2, getHeight() / 2);
  canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius,
   mBorderPaint);
  canvas.restore();
 }
 if (mShowFlag && mFlagText != null) {
  canvas.drawArc(mBorderRect, 40, 100, false, mFlagBackgroundPaint);
  mFlagTextPaint.getTextBounds(mFlagText, 0, mFlagText.length(),
   mFlagTextBounds);
  canvas.drawText(mFlagText, getWidth() / 2,
   (float) ((3 + Math.cos((float) (Math.PI * 5 / 18)))
      * getHeight() / 4 + mFlagTextBounds.height() / 3),
   mFlagTextPaint);
 }
 }

 @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;
 }

 /**
 * @param borderWidth
 *  圆形的边框厚度。
 */
 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();
 }

 @Override
 public void setImageURI(Uri uri) {
 super.setImageURI(uri);
 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);

 mFlagBackgroundPaint.setColor(Color.BLACK & 0x66FFFFFF);
 mFlagBackgroundPaint.setFlags(TextPaint.ANTI_ALIAS_FLAG);

 mFlagTextPaint.setFlags(TextPaint.ANTI_ALIAS_FLAG);
 mFlagTextPaint.setTextAlign(Align.CENTER);
 mFlagTextPaint.setColor(Color.WHITE);
 mFlagTextPaint
  .setTextSize(getResources().getDisplayMetrics().density * 18);

 mSweepGradient = new SweepGradient(getWidth() / 2, getHeight() / 2,
  new int[] { Color.rgb(255, 255, 255), Color.rgb(1, 209, 255) },
  null);

 mBorderPaint.setShader(mSweepGradient);

 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);
 }

 public void setShowFlag(boolean show) {
 mShowFlag = show;
 invalidate();
 }

 public void setFlagText(String text) {
 mFlagText = text;
 invalidate();
 }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  >
  <com.example.view.CircleImageView
   android:layout_width="match_parent"
  android:layout_height="match_parent"/>
<／LinearLayout>

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