iOS: Draw clear circle with UIBezierPath bezierPathWithOvalInRect:

问题

In my UITableViewController's cells, I want to display a circle with a number in it. I am using UIBezierPath's bezierPathWithOvalInRect: to draw the circle.

Unfortunately, while I can set the fill color to be clearColor, the unused portion of the CGRect passed to bezierPathWithOvalInRect: is black.

How do I get rid of the black area created?

Partial screenshot for reference:

(I eventually hope to get that number inside the circle)

Code:

LTTTableViewCell:

- (void)awakeFromNib {
    [super awakeFromNib];

    // Create a square view using the height of the cell
    CGRect positionFrame = CGRectMake(0, 0, self.bounds.size.height, self.bounds.size.height);
    LTTDrawBallView *drawBallView = [[LTTDrawBallView alloc] initWithFrame:positionFrame];
    [self.contentView addSubview:drawBallView];
}

LTTDrawBallView:

- (void)drawRect:(CGRect)rect
{
    // Create a new rect with some padding  
    // + create a circle from this new rect:
    CGRect box = CGRectInset(self.bounds, self.bounds.size.width * 0.1f, self.bounds.size.height * 0.1f);
    UIBezierPath *ballBezierPath = [UIBezierPath bezierPathWithOvalInRect:box];
    [[UIColor whiteColor] setStroke];
    [[UIColor greenColor] setFill]; // Green here to show the black area
    [ballBezierPath stroke];
    [ballBezierPath fill];
    [self setBackgroundColor:[UIColor clearColor]]; // Happens with and without this line
}

回答1:

In the init method of your LTTDrawBallView, include the code:

self.opaque = NO;
self.backgroundColor = [UIColor clearColor];

来源：https://stackoverflow.com/questions/18115639/ios-draw-clear-circle-with-uibezierpath-bezierpathwithovalinrect

标签

ios

objective-c

core-graphics