Android自定义View之绘制圆形头像功能

public class RoundImageView extends ImageView {
  public RoundImageView(Context context) {
    super(context);
  }
  public RoundImageView(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
  }
  public RoundImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
  }
}

com.example.roundimageview D/RoundImageView: RoundImageView: 两个参数的构造方法

roundImageView = RoundImageView(this@MainActivity)
roundImageView = RoundImageView(this@MainActivity, null)
roundImageView = RoundImageView(this@MainActivity, null,0)

drawable = this.getDrawable();

if (drawable == null) {
  throw new Resources.NotFoundException("Image resource not set");
}

bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(),
    Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),
    drawable.getIntrinsicHeight());
drawable.draw(canvas);

circleBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);

Paint paint = new Paint();
Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
canvas.drawRect(rect,paint);
RectF rectF = new RectF(rect);

float roundRa = 0.0f;
if (bitmap.getWidth() > bitmap.getHeight()) {
  roundRa = bitmap.getHeight() / 2.0f;
} else {
  roundRa = bitmap.getWidth() / 2.0f;
}

paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.WHITE);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

canvas.drawBitmap(bitmap, rect, rect, paint);

* 获取圆形裁剪的bitmap
 *
 * @param bitmap 原bitmap
 */
private Bitmap getCircleBitmap(Bitmap bitmap) {
  circleBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
  Canvas canvas = new Canvas(circleBitmap);
  Paint paint = new Paint();
  Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
  RectF rectF = new RectF(rect);
  float roundRa = 0.0f;
  if (bitmap.getWidth() > bitmap.getHeight()) {
    roundRa = bitmap.getHeight() / 2.0f;
  } else {
    roundRa = bitmap.getWidth() / 2.0f;
  }
  paint.setAntiAlias(true);
  canvas.drawARGB(0, 0, 0, 0);
  paint.setColor(Color.GRAY);
  canvas.drawRoundRect(rectF, roundRa, roundRa, paint);
  paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
  canvas.drawBitmap(bitmap, rect, rect, paint);
  return circleBitmap;
}

 setImageBitmap(getCircleBitmap(bitmap));