android自定义控件ImageView实现圆形图片

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();  } }

<?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>