iphone - UIButton setTitleColor :forState: question

Question

为什么下面的代码可以工作...

[signInBtn setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted];
[signInBtn setTitleColor:[UIColor blackColor] forState:UIControlStateDisabled];

虽然这不是？

[signInBtn setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted|UIControlStateDisabled];

Answer 1

我知道这是一个老问题，但这些答案并不正确。

当你分别设置每一个时，你说的是 state 属性应该是 UIControlStateHighlighted 或 UIControlStateDisabled 但不能两者都是

当您按位或将它们放在一起时，您声明它们必须在 state 属性中设置。意思是 UIControlStateHighlighted 和 UIControlStateDisabled 在 state 属性中设置。

下面的示例代码完美地说明了我的观点。如果您不同意，请自行运行。

[button setTitle:@"highlighted and selected" forState:UIControlStateHighlighted | UIControlStateSelected];
[button setTitle:@"Highlighted only" forState:UIControlStateHighlighted];
[button setTitle:@"Selected only" forState:UIControlStateSelected];
[button setTitle:@"Normal" forState:UIControlStateNormal];

NSLog(@"Normal title: %@", [[button titleLabel] text]); // prints title: Normal

[button setSelected:YES];

NSLog(@"Selected title: %@", [[button titleLabel] text]); // prints title: Selected only 

[button setSelected:NO];
[button setHighlighted:YES];

NSLog(@"highlighted title: %@", [[button titleLabel] text]); // prints title: Highlighted only

[button setSelected:YES];

NSLog(@"highlighted and selected title: %@", [[button titleLabel] text]); // prints title: highlighted and selected