Iphone 带圆角矩形和阴影的UIView：阴影显示在矩形上方

我有一个uiview子类，我试图画一个带阴影的圆形矩形。虽然它同时绘制了两个元素，但我可以通过圆角矩形填充看到阴影。我是CG新手，所以我可能遗漏了一些简单的东西（虽然它似乎不是设置为1的填充的alpha）。这是DrawRect代码

- (void)drawRect:(CGRect)rect {
    // get the contect
 CGContextRef context = UIGraphicsGetCurrentContext();

 //for the shadow, save the state then draw the shadow
 CGContextSaveGState(context);
    CGContextSetShadow(context, CGSizeMake(4,-5), 10);



 //now draw the rounded rectangle
 CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);
 CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);

 //since I need room in my rect for the shadow, make the rounded rectangle a little smaller than frame
 CGRect rrect = CGRectMake(CGRectGetMinX(rect), CGRectGetMinY(rect), CGRectGetWidth(rect)-30, CGRectGetHeight(rect)-30);
 CGFloat radius = self.cornerRadius;
 // the rest is pretty much copied from Apples example
 CGFloat minx = CGRectGetMinX(rrect), midx = CGRectGetMidX(rrect), maxx = CGRectGetMaxX(rrect);
 CGFloat miny = CGRectGetMinY(rrect), midy = CGRectGetMidY(rrect), maxy = CGRectGetMaxY(rrect);

 // Start at 1
 CGContextMoveToPoint(context, minx, midy);
 // Add an arc through 2 to 3
 CGContextAddArcToPoint(context, minx, miny, midx, miny, radius);
 // Add an arc through 4 to 5
 CGContextAddArcToPoint(context, maxx, miny, maxx, midy, radius);
 // Add an arc through 6 to 7
 CGContextAddArcToPoint(context, maxx, maxy, midx, maxy, radius);
 // Add an arc through 8 to 9
 CGContextAddArcToPoint(context, minx, maxy, minx, midy, radius);
 // Close the path
 CGContextClosePath(context);
 // Fill & stroke the path
 CGContextDrawPath(context, kCGPathFillStroke);

 //for the shadow
  CGContextRestoreGState(context);
}

---

我认为你不可能一次就做到这一点。嗯，我改变了你的代码如下，这似乎是工作

- (void)drawRect:(CGRect)rect
{
    // get the contect
    CGContextRef context = UIGraphicsGetCurrentContext();

    //now draw the rounded rectangle
    CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);
    CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 0.0);

    //since I need room in my rect for the shadow, make the rounded rectangle a little smaller than frame
    CGRect rrect = CGRectMake(CGRectGetMinX(rect), CGRectGetMinY(rect), CGRectGetWidth(rect)-30, CGRectGetHeight(rect)-30);
    CGFloat radius = 45;
    // the rest is pretty much copied from Apples example
    CGFloat minx = CGRectGetMinX(rrect), midx = CGRectGetMidX(rrect), maxx = CGRectGetMaxX(rrect);
    CGFloat miny = CGRectGetMinY(rrect), midy = CGRectGetMidY(rrect), maxy = CGRectGetMaxY(rrect);

    {
        //for the shadow, save the state then draw the shadow
        CGContextSaveGState(context);

        // Start at 1
        CGContextMoveToPoint(context, minx, midy);
        // Add an arc through 2 to 3
        CGContextAddArcToPoint(context, minx, miny, midx, miny, radius);
        // Add an arc through 4 to 5
        CGContextAddArcToPoint(context, maxx, miny, maxx, midy, radius);
        // Add an arc through 6 to 7
        CGContextAddArcToPoint(context, maxx, maxy, midx, maxy, radius);
        // Add an arc through 8 to 9
        CGContextAddArcToPoint(context, minx, maxy, minx, midy, radius);
        // Close the path
        CGContextClosePath(context);

        CGContextSetShadow(context, CGSizeMake(4,-5), 10);
        CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);

        // Fill & stroke the path
        CGContextDrawPath(context, kCGPathFillStroke);

        //for the shadow
        CGContextRestoreGState(context);
    }

    {
        // Start at 1
        CGContextMoveToPoint(context, minx, midy);
        // Add an arc through 2 to 3
        CGContextAddArcToPoint(context, minx, miny, midx, miny, radius);
        // Add an arc through 4 to 5
        CGContextAddArcToPoint(context, maxx, miny, maxx, midy, radius);
        // Add an arc through 6 to 7
        CGContextAddArcToPoint(context, maxx, maxy, midx, maxy, radius);
        // Add an arc through 8 to 9
        CGContextAddArcToPoint(context, minx, maxy, minx, midy, radius);
        // Close the path
        CGContextClosePath(context);

        CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);
        CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);       

        // Fill & stroke the path
        CGContextDrawPath(context, kCGPathFillStroke);
    }
}

---

导入

QuartzCore/QuartzCore.h

yourView.layer.shadowColor = [[UIColor blackColor] CGColor];
yourView.layer.shadowOffset = CGSizeMake(10.0f, 10.0f);
yourView.layer.shadowOpacity = 1.0f;
yourView.layer.shadowRadius = 10.0f;

---

太好了，谢谢。很有意义：你画了一个矩形，画了一个阴影，它在圆角矩形的上方，所以你最后再画一次矩形。关于代码的一个注释。我在init语句中已将视图的背景设置为清晰。上面的代码适用于任何其他背景，但对于清晰的背景，我必须在第一个矩形被笔划和填充之前设置填充颜色。我了解到，您可以扩展渲染层的区域，这样它就不会被图幅剪裁。用法：layer.bounds=CGRectMake（-1，-1102102）。。。如果您的视图为100x100，阴影为像素偏移等，您就明白了。使用maskToBounds和setCornerRadius对圆角不起作用。请尝试添加视图。layer.shouldRasterize=YES；为了帮助提高性能…或者，将layer.shadowPath设置为shouldRasterize的替代方案。如何准确设置阴影路径？我不确定我到底应该在这里放什么..这里的一个警告是确保您的视图的背景设置为[UIColor clearColor]，否则您将在视图的框架周围绘制阴影，忽略圆角。在drawRect:中设置图层属性是无用且多余的，因为除非你改变它们，否则它们不会改变。取消这些调用（例如，在init…）阅读此博客文章。这里介绍的解决方案最适合我，因为它向我展示了如何使用自定义图像（maskToBounds=YES）以及阴影。谢谢@约翰：非常感谢你的链接，伙计。。。帮助我开始。：）

- (void)drawRect:(CGRect)rect
{
    self.layer.masksToBounds = NO;
    self.layer.shadowColor = [[UIColor whiteColor] CGColor];
    self.layer.shadowOffset = CGSizeMake(0,2);
    self.layer.shadowRadius = 2;
    self.layer.shadowOpacity = 0.2;

    UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(20, 20)];
    [[UIColor blackColor] setFill];

    [path fill];
}