UIButton 标题文字变色

Question

I have a UIButton in a custom UIView. In the view, I have a function setDisabled:(BOOL)disabled which is called when I want to change the appearance of the UIView.

\\ Method 1
- (void) setDisabled:(BOOL)disabled
{
   myUIButton.titleLabel.textColor = disabled ? [UIColor systemGrayColor] : [UIColor systemBlueColor];
}

\\ Method 2
- (void) setDisabled:(BOOL)disabled
{
   [myUIButton setTitleColor: disabled ? [UIColor systemGrayColor] : [UIColor systemBlueColor] forState: UIControlStateNormal];
}

I have used this UIView for cells in UITable view. Using Method 1 , the change is not immediately reflected (reflected when i scroll through UITableView) whereas using Method 2 , the color change is immediately reflected. In this apple documentation, it is mentioned to not use Method 1 . However I could not find the reason. Any leads would be helpful.

Answer 1

Do NOT use "Method 1"...

UIKit controls - such as UIButton - have a lot of code that does work "behind the scenes."

For example, if your button has a normal color of Red, and a Highlighted color of LightGray, and then you execute:

myUIButton.titleLabel.textColor = [UIColor systemBlueColor];

The button itself does not know that you did that. It still has Red as its normal color property.

As soon as UIKit updates that button - a tap or a layout change, etc - the text color will be set back to the normal color property.