如何使用Autolayouts以编程方式在UIView上添加UI按钮

Question

嗨，我是初学者，在我的项目目标中，我必须使用自动布局以编程方式添加UIview上的按钮，我尝试了我的关卡，但结果还没来，请帮助我一些其他人

这是我的代码

 UIView * myView;
 myView = [UIView new];
    myView.translatesAutoresizingMaskIntoConstraints = NO;
    myView.backgroundColor = [UIColor colorWithRed:0.95 green:0.47 blue:0.48 alpha:1.0];
    [self.view addSubview:myView];

UIButton *mainButton;
mainButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[mainButton setTitle:@"MainButton" forState:UIControlStateNormal];
[mainButton sizeToFit];
mainButton.backgroundColor = [UIColor blackColor];
mainButton.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:mainButton];

//在UIview上添加myview

constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.0f constant:30.0f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0f constant:100.0f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:100.0f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:100.0f];
    [self.view addConstraint:constraint];

//在myview上添加按钮： -

constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:myView attribute:NSLayoutAttributeLeading multiplier:1.0f constant:20.f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:myView attribute:NSLayoutAttributeTop multiplier:1.0f constant:30.0f];
    [self.view addConstraint:constraint];

但结果不是仅仅添加myview但是按钮没有添加到我的视图上我希望结果如下图像formate 请帮助我一些

Answer 1

我认为你应该将UIButton作为子视图添加到myView，而不是self.view。