轻量级应用开发之介绍，UINavigationController导航控制器

UINavigationController是iOS开发中常用的基础控制器之一。它是一种容器控制器，可以用于管理页面的导航栈，并提供页面之间的切换、协调、和管理功能，让用户可以更加方便的进行页面的跳转操作。

简单来说，UINavigationController的作用就是协调导航控制器内的各个视图控制器，以一种层级的方式进行视图展示和切换，为用户提供便利的操作。在应用中，我们可以通过UINavigationController来实现页面间的无缝切换，提升用户体验。

使用UINavigationController的方法：

1. 创建UINavigationController对象

在创建UINavigationController对象时，我们需要把需要展示的UIViewController对象添加到导航栈中。如下代码所示：

```

UIViewController *firstVC = [[UIViewController alloc] init];

UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:firstVC];

[self presentViewController:navController animated:YES completion:nil];

```

其中，initWithRootViewController:方法用于设置导航栈中的第一个视图控制器，即根视图控制器。

2. 添加子视图控制器

可以使用pushViewController:animated:方法向导航栈中添加新的视图控制器，如下所示：

```

UIViewController *secondVC = [[UIViewController alloc] init];

[navController pushViewController:secondVC animated:YES];

```

其中，animated参数用于控制视图控制器的转场动画。

3. 返回上一级视图控制器

可以使用popViewControllerAnimated:方法返回到上一个视图控制器，如下所示：

```

[navController popViewControllerAnimated:YES];

```

也可以使用popToViewController:animated:方法返回到指定的视图控制器：

```

[navController popToViewController:firstVC animated:YES];

```

4. 设置导航栏

可以通过UINavigationBar和UIToolbar来定制导航栏和工具栏的样式和内容。例如，可以设置导航栏的背景色、标题、左右按钮等，如下所示：

```

[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor], NSFontAttributeName:[UIFont systemFontOfSize:17]}];

[self.navigationController.navigationBar setTintColor:[UIColor whiteColor]];

[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"navBg"] forBarMetrics:UIBarMetricsDefault];

```

5. 自定义转场动画

可以通过UIViewControllerTransitioningDelegate和UIViewControllerAnimatedTransitioning协议来自定义转场动画。具体实现可以参考下面的示例代码：

```

//第一个视图控制器

@interface FirstViewController ()

@end

@implementation FirstViewController

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor yellowColor];

self.title = @"First";

self.navigationController.delegate = self;

}

/**

实现UINavigationControllerDelegate代理

为当前控制器添加转场动画

*/

- (nullable id )navigationController:(UINavigationController *)navigationController

animationControllerForOperation:(UINavigationControllerOperation)operation

fromViewController:(UIViewController *)fromVC

toViewController:(UIViewController *)toVC

{

TransitionAnimator *animator = [[TransitionAnimator alloc] init];

animator.animationType = operation;

return animator;

}

/**

跳转到第二个控制器

*/

- (void)goToSecondVC {

SecondViewController *secondVC = [[SecondViewController alloc] init];

[self.navigationController pushViewController:secondVC animated:YES];

}

@end

//第二个视图控制器

@interface SecondViewController ()

@end

@implementation SecondViewController

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor blueColor];

self.title = @"Second";

}

@end

//自定义转场动画

@interface TransitionAnimator : NSObject

@property (nonatomic, assign) UINavigationControllerOperation animationType;

@end

@implementation TransitionAnimator

- (NSTimeInterval)transitionDuration:(nullable id )transitionContext {

return 0.5;

}

- (void)animateTransition:(id )transitionContext {

//获取需要展示的视图控制器，即目标控制器(toVC)和前一个控制器(fromVC)

UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];

UIView * containerView = transitionContext.containerView;

NSTimeInterval duration = [self transitionDuration:transitionContext];

CGRect fromVCRect = [transitionContext initialFrameForViewController:fromVC];

CGRect toVCRect = [transitionContext finalFrameForViewController:toVC];

//判断是Push还是Pop操作，执行不同的操作动画

if (self.animationType == UINavigationControllerOperationPush) {

toVC.view.frame = CGRectOffset(toVCRect, CGRectGetWidth(toVCRect), 0);

[containerView addSubview:toVC.view];

[UIView animateWithDuration:duration animations:^{

fromVC.view.frame = CGRectOffset(fromVCRect, -CGRectGetWidth(fromVCRect), 0);

toVC.view.frame = toVCRect;

} completion:^(BOOL finished) {

[transitionContext completeTransition:YES];

}];

} else {

[containerView insertSubview:toVC.view belowSubview:fromVC.view];

[UIView animateWithDuration:duration animations:^{

fromVC.view.frame = CGRectOffset(fromVCRect, CGRectGetWidth(fromVCRect), 0);

toVC.view.frame = toVCRect;

} completion:^(BOOL finished) {

[transitionContext completeTransition:YES];

}];

}

}

@end

```

以上是UINavigationController的基础知识和使用方法，接下来我们来看看UINavigationController在实际开发中的应用案例。

案例1：

一个简单的导航栏应用，有两个视图控制器，通过按钮来实现跳转。

```

//第一个视图控制器

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor yellowColor];

self.title = @"First";

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 100, 50)];

[button setTitle:@"Go" forState:UIControlStateNormal];

[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];

[button addTarget:self action:@selector(goToSecondVC) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button];

}

/**

跳转到第二个控制器

*/

- (void)goToSecondVC {

SecondViewController *secondVC = [[SecondViewController alloc] init];

[self.navigationController pushViewController:secondVC animated:YES];

}

//第二个视图控制器

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor blueColor];

self.title = @"Second";

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 100, 50)];

[button setTitle:@"Back" forState:UIControlStateNormal];

[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];

[button addTarget:self action:@selector(goToFirstVC) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button];

}

/**

返回到第一个控制器

*/

- (void)goToFirstVC {

[self.navigationController popViewControllerAnimated:YES];

}

```

案例2：

一个简单的图片浏览应用，通过滑动来实现图片间的切换。

```

//第一个视图控制器

@interface ViewController ()

@property (nonatomic, strong) UIScrollView *scrollView; //滚动视图

@property (nonatomic, strong) NSArray *imageArray; //存储图片的数组

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor blackColor];

self.title = @"Photos";

//初始化图片数组

self.imageArray = @[@"image1",@"image2",@"image3",@"image4",@"image5",@"image6"];

//初始化UIScrollView

self.scrollView = [[UIScrollView alloc] initWithFrame:[UIScreen mainScreen].bounds];

self.scrollView.delegate = self;

self.scrollView.contentSize = CGSizeMake(CGRectGetWidth(self.view.frame) * self.imageArray.count, CGRectGetHeight(self.view.frame));

self.scrollView.pagingEnabled = YES;

[self.view addSubview:self.scrollView];

//添加UIImageView

for (int i = 0; i < self.imageArray.count; i++) {

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(self.view.frame.size.width * i, 0, self.view.frame.size.width, self.view.frame.size.height)];

imageView.backgroundColor = [UIColor clearColor];

imageView.contentMode = UIViewContentModeScaleAspectFit;

imageView.image = [UIImage imageNamed:self.imageArray[i]];

[self.scrollView addSubview:imageView];

}

}

#pragma mark - UIScrollViewDelegate

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

NSUInteger index = scrollView.contentOffset.x / CGRectGetWidth(self.view.frame);

self.title = [NSString stringWithFormat:@"Photos %d/%d",index + 1, (int)self.imageArray.count];

}

@end

```

以上是UINavigationController的详细介绍和使用方法，通过UINavigationController的使用，我们可以轻松实现应用中的页面导航和转场动画。如果你有更好的实践和体会，欢迎留言分享。 如果你喜欢我们三七知识分享网站的文章， 欢迎您分享或收藏知识分享网站文章 欢迎您到我们的网站逛逛喔！https://www.37seo.cn/