我用编程方式组装了一个简单的视图控制器,上面只有两个按钮.如果我去学校并为布局设置框架大小,那么一切都很好.但是,如果我对布局使用自动布局约束,则按钮显示完美,但它们不响应按下.他们甚至没有强调.我的loadview方法在下面的形式,使按钮不起作用.如果取消注释框架设置代码并添加注释的约束,则按钮开始按预期响应按下.有谁知道发生了什么事？我希望将我的代码库中所有旧的硬编码布局转换为基于约束的,但似乎是在第一个障碍下降.
- (void)loadView {
self.view = [UIView new];
self.view.translatesAutoresizingMaskIntoConstraints = NO;
self.navigationItem.title = @"Landing Page";
UIButton *buildExercisesButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
self.buildExercisesButton = buildExercisesButton;
// buildExercisesButton.frame = CGRectMake(20,312,164,44);
self.buildExercisesButton.translatesAutoresizingMaskIntoConstraints = NO;
[self.buildExercisesButton setTitle:@"Build Exercises" forState:UIControlStateNormal];
[self.buildExercisesButton addTarget:self action:@selector(buildExercisesButtonPressed) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.buildExercisesButton];
UIButton *organiseExercisesButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
self.organiseExercisesButton = organiseExercisesButton;
// organiseExercisesButton.frame = CGRectMake(192,44);
self.organiseExercisesButton.translatesAutoresizingMaskIntoConstraints = NO;
[self.organiseExercisesButton setTitle:@"Organise Exercises" forState:UIControlStateNormal];
[self.organiseExercisesButton addTarget:self action:@selector(organiseExercisesButtonPressed) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.organiseExercisesButton];
NSDictionary *variables = NSDictionaryOfVariableBindings(buildExercisesButton,organiseExercisesButton);
NSArray *constraints =
[NSLayoutConstraint constraintsWithVisualFormat:@"|-[buildExercisesButton(organiseExercisesButton)]-[organiseExercisesButton]-|"
options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom
metrics:nil
views:variables];
[self.view addConstraints:constraints];
constraints =
[NSLayoutConstraint constraintsWithVisualFormat:@"V:[buildExercisesButton]-|"
options:0
metrics:nil
views:variables];
[self.view addConstraints:constraints];
}
在viewDidAppear中,我打印出按钮的帧.他们给出了奇怪的价值,我不知道它是否相关.实际上,按钮在屏幕中央彼此并排显示.
buildExercisesButton: {{20,-63},{164,44}}
organiseExercisesButton: {{192,44}}
