UIButton setTitleColor:forState: 问题

UIButton setTitleColor:forState: question(UIButton setTitleColor:forState: 问题)

问题描述

为什么下面的代码会起作用...

Why does the following code work...

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

虽然没有?

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

推荐答案

我知道这是一个老问题，但这些答案并不正确.

I know this is an old question, but these answers aren't correct.

当您分别设置每个时，您是在说 state 属性应该是 UIControlStateHighlighted 或 UIControlStateDisabled 但不能同时是两者

When you set each separately you are saying the state property should be UIControlStateHighlighted OR UIControlStateDisabled but NOT both

当你按位或它们在一起时，你说明它们必须在 state 属性中设置.含义 UIControlStateHighlighted 和 UIControlStateDisabled 在 state 属性中设置.

When you bitwise or them together you are stating they must BOTH be set in the state property. Meaning UIControlStateHighlighted AND UIControlStateDisabled are set in the state property.

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.

The example code below perfectly illustrates my point. If you disagree run it for yourself.

[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

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