objective-c - 如何将 swift NSLayoutConstraint activateConstraints 翻译成 objective-c ？

Question

我在 swift 中成功地创建了一个项目，我按下 viewController 中的按钮将其他 viewControllers 或 xib 文件加载到容器中。只是给你一个想法:

它工作得很好，但我很难将它翻译成 objective-c ，这是实际需要代码的地方。这是按下按钮时 swift 代码的样子:

let sub3 = UINib(nibName: "thirdXib", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! UIView

containerOutlet.addSubview(sub3)

NSLayoutConstraint.activate([
    sub3.leadingAnchor.constraint(equalTo: containerOutlet.leadingAnchor),
    sub3.trailingAnchor.constraint(equalTo: containerOutlet.trailingAnchor),
    sub3.topAnchor.constraint(equalTo: containerOutlet.topAnchor),
    sub3.bottomAnchor.constraint(equalTo: containerOutlet.bottomAnchor)
        ])

现在，我希望所有代码都在 objective-c 中。在 objective-c 中，我已经完成了第一部分，我认为这是正确的:

UINib *nib = [UINib nibWithNibName:@"SecondView" bundle:nil];
[nib instantiateWithOwner:self options:nil];

[containerOutlet addSubview:((UIView*)nib)];

但我对最后一部分有问题，NSLayoutConstraint activateConstraints

[NSLayoutConstraint activateConstraints:@[
        [nib.lead],
        [nib.centerXAnchor constraintEqualToAnchor:self.view.centerXAnchor],
        ]
 ];

编译器说 property lead not found on object of type UIBib 和下面的代码一样。我已经尝试了这些的变体，但没有做对。如何在我的 xib 上设置尾随、前导、底部和顶部约束？我需要在 .h` 文件中添加 #import SecondView.xib"吗？顺便说一句？




Answer 1

你可以试试

UINib *nib = [UINib nibWithNibName:@"SecondView" bundle:nil]; 
UIView *sub3 = [nib instantiateWithOwner:self options:nil][0]; 
[containerOutlet addSubview:sub3];


[NSLayoutConstraint activateConstraints:@[
   [sub3.leadingAnchor constraintEqualToAnchor:scontainerOutlet.leadingAnchor],
   [sub3.trailingAnchor constraintEqualToAnchor:containerOutlet.trailingAnchor],
   [sub3.topAnchor constraintEqualToAnchor:containerOutlet.topAnchor],
   [sub3.bottomAnchor constraintEqualToAnchor:containerOutlet.bottomAnchor]
]];