设置 Button 的背景颜色(利用 BackgroundImage 属性).m

- (void)setBackgroundColor:(UIColor *)backgroundColor forState:(UIControlState)state {
	[self setBackgroundImage:[UIButton imageWithColor:backgroundColor] forState:state];
}

+ (UIImage *)imageWithColor:(UIColor *)color {
	CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
	UIGraphicsBeginImageContext(rect.size);
	CGContextRef context = UIGraphicsGetCurrentContext();

	CGContextSetFillColorWithColor(context, [color CGColor]);
	CGContextFillRect(context, rect);

	UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();

	return image;
}