UIButton 设置为圆形，并且使用图片（UIImage）当做背景

-(UIButton *)shareButtonWithIcon:(NSString *)iconName

{

    UIButton *button = [UIButtonbuttonWithType:UIButtonTypeCustom];

    button.frame = CGRectMake(100, 100, 2 * 50, 2 * 50);

    

    // Circle background

    UIView *circle = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 2 * 50, 2 * 50)];

    circle.backgroundColor = [UIColorblueColor];

    circle.layer.cornerRadius = 50;

    circle.layer.masksToBounds = YES;

    circle.opaque = NO;

    circle.alpha = 0.97;

    

    // Circle icon

    UIImageView *icon = [[UIImageView alloc] initWithImage:[UIImage imageNamed:iconName]];

    CGRect f = icon.frame;

    f.origin.x = (circle.frame.size.width - f.size.width) * 0.5;

    f.origin.y = (circle.frame.size.height - f.size.height) * 0.5;

    icon.frame = f;

    [circle addSubview:icon];

    

    [button setBackgroundImage:[selfimageWithView:circle] forState:UIControlStateNormal];

    

    return button;

}

 

 

-(UIImage *)imageWithView:(UIView *)view

{

    UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);

    [view.layerrenderInContext:UIGraphicsGetCurrentContext()];

    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return img;

}