将color转为UIImage

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    //建立图片
    UIImageView *imageView=[[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 200, 200)];
    imageView.image=[self createImageWithColor:[UIColor yellowColor]];
    [self.view addSubview:imageView];
    
    
}
//将color转为UIImage
- (UIImage *)createImageWithColor:(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 *theImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return theImage;
}