UIButton setTitleColor：forState：问题

Question

为什么下面的代码起作用...

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

虽然不是吗？

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

Answer 1

我知道这是一个老问题，但是这些答案不正确。

当分别设置每一个时，您说的是state属性应该是UIControlStateHighlighted或UIControlStateDisabled，但不能同时是两个]

[按位或将它们一起表示时，必须同时在state属性中进行设置。含义在UIControlStateHighlighted属性中设置了UIControlStateDisabled和state。

下面的示例代码完美地说明了我的观点。如果您不同意自己运行它。

[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

Answer 2

因为setTitleColor：forState：方法只能接受已知的UIControlState，并且您将两个UIControlState值进行或运算。

Answer 3

可能是一个错误。尝试更改具有UIControlStateHighlighted和UIControlStateDisabled之类的意外值的位掩码，这会使所有状态颜色相同。