自定义形状的ImageView

通过给定的Mask来确定显示图片的形状

直接贴上代码

/**
 * @author Momo
 * */
public class XCRoundImageView extends ImageView {
    
    
    private Paint paint;

    public XCRoundImageView(Context context) {
        this(context, null);
    }

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

    public XCRoundImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        paint = new Paint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Drawable drawable = getDrawable();
        if (null != drawable) {
            //获得原始image
            Bitmap src = ((BitmapDrawable) drawable).getBitmap();
            //创建矩阵来放大或者缩小原始图片
            //postScale（<这里面为放大或者缩小的参数>）
            Matrix matrix = new Matrix();
            float srcLength = pxTodp(Math.min(src.getWidth(),src.getHeight()));
            matrix.postScale(1 / (srcLength / 44), 1 / (srcLength / 44));
            //获得mask
            //quick_settings_personal_center_mask -->这里是mask的资源文件
            Bitmap mask = BitmapFactory.decodeResource(getResources(),R.drawable.quick_settings_personal_center_mask);
            //创建符合要求大小的原始图片
            Bitmap bitmap = Bitmap.createBitmap(((BitmapDrawable) drawable).getBitmap(), 0, 0, src.getWidth(),src.getHeight(),matrix,true);
            //设置层级
            int sr = canvas.saveLayer(0, 0, src.getWidth(),src.getHeight(), null, Canvas.ALL_SAVE_FLAG);
            canvas.drawBitmap(bitmap,0,0,paint);
            paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
            canvas.drawBitmap(mask, 0, 0, paint);
            paint.setXfermode(null);
            canvas.restoreToCount(sr);
        } else {
            super.onDraw(canvas);
        }
    }

    public int pxTodp(float px){
        final float scale = getContext().getResources().getDisplayMetrics().density;
        return (int) (px / scale + 0.5f);
    }