ios - 如何根据模拟器方向以编程方式应用约束

Question

在我的 ViewController 中，我使用自动布局以编程方式添加了一个 UIView

我在这里应用基于模拟器方向的约束，但这里基于我的代码约束仅在模拟器处于纵向模式时适用，但在横向模式下更改时约束不应用我在这里做错了什么

我的代码:

#import "MainViewController.h"

@interface MainViewController (){

    UIView * MainView;
}

@end

@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    MainView = [[UIView alloc] init];
    MainView.backgroundColor = [UIColor orangeColor];
    MainView.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:MainView];

    [self AppyingAutolayoutsAtPortraint];
}

-(void)AppyingAutolayoutsAtPortraint{

    NSDictionary * HeaderDictionary = NSDictionaryOfVariableBindings(MainView);

    //Appliying Autolayouts for MainView

    [self.view removeConstraints:self.view.constraints];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"H:|-0-[MainView]-0-|"]
                                                                      options:0
                                                                      metrics:nil
                                                                        views:HeaderDictionary]];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"V:|-0-[MainView]-0-|"]
                                                                      options:0
                                                                      metrics:nil
                                                                        views:HeaderDictionary]];

     [self.view setNeedsLayout];

}

-(void)AppyingAutolayoutsLandAtScpae{

    NSDictionary * HeaderDictionary = NSDictionaryOfVariableBindings(MainView);

    //Appliying Autolayouts for MainView

    [self.view removeConstraints:self.view.constraints];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"H:|-10-[MainView]-10-|"]
                                                                      options:0
                                                                      metrics:nil
                                                                        views:HeaderDictionary]];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"V:|-10-[MainView]-10-|"]
                                                                      options:0
                                                                      metrics:nil
                                                                        views:HeaderDictionary]];

     [self.view setNeedsLayout];
}

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
    [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context){

         UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];

        if (orientation == UIInterfaceOrientationPortrait) {

            NSLog(@"UIInterfaceOrientationPortrait");
             [self AppyingAutolayoutsAtPortraint];
        }
        else if (orientation == UIInterfaceOrientationLandscapeLeft) {


            NSLog(@"UIInterfaceOrientationLandscapeLeft");
             [self AppyingAutolayoutsLandAtScpae];

        }else if (orientation == UIInterfaceOrientationLandscapeRight){

              NSLog(@"UIInterfaceOrientationLandscapeRight");
              [self AppyingAutolayoutsLandAtScpae];
        }

     } completion:^(id<UIViewControllerTransitionCoordinatorContext> context)
     {

     }];

    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
}

@end

Answer 1

您可以根据您的要求使用尺码等级。使用大小类，在设计您的应用程序时，您现在可以创建一个适用于所有当前 iOS 设备的单一布局，而无需笨拙的特定于平台的代码。您需要做的就是打开 Storyboard，转到文件检查器并确保选中 Use Size Classes 复选框。

Here is a really nice tutorial on Size Classes.