程式碼如下：

[button setBackgroundImage:[UIImage imageNamed:@"pic1"] forState:UIControlStateNormal] 

[button setBackgroundImage:[UIImage imageNamed:@"pic2"] forState:UIControlStateHighlighted];

如果想使用純色為背景色
可以使用如下程式碼：

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

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

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

    return image;
}