ios小技巧：导航控制器相关

https://github.com/ltebean/LTNavigationBar *navBar酷炫
http://www.jianshu.com/p/b2585c37e14b
http://www.jianshu.com/p/31f177158c9e *

返回至某个VC

for (UIViewController *controller in self.navigationController.viewControllers) {
    if ([controller isKindOfClass:[AViewController class]]) {
         AViewController *A =(AViewController *)controller;
         [self.navigationController popToViewController:A animated:YES];
    }
}

获取当前导航控制器

- (UIViewController *)currentViewController
{
    UIWindow *keyWindow  = [UIApplication sharedApplication].keyWindow;
    UIViewController *vc = keyWindow.rootViewController;
    while (vc.presentedViewController)
    {
        vc = vc.presentedViewController;

        if ([vc isKindOfClass:[UINavigationController class]])
        {
            vc = [(UINavigationController *)vc visibleViewController];
        }
        else if ([vc isKindOfClass:[UITabBarController class]])
        {
            vc = [(UITabBarController *)vc selectedViewController];
        }
    }
    return vc;
}

- (UINavigationController *)currentNavigationController
{
    return [self currentViewController].navigationController;
}

毛玻璃、动态隐藏

https://www.jianshu.com/p/b2585c37e14b

判断当前VC是push还是present的方式显示的

NSArray *viewcontrollers=self.navigationController.viewControllers;

if (viewcontrollers.count > 1)
{
    if ([viewcontrollers objectAtIndex:viewcontrollers.count - 1] == self)
    {
        //push方式
       [self.navigationController popViewControllerAnimated:YES];
    }
}
else
{
    //present方式
    [self dismissViewControllerAnimated:YES completion:nil];
}

获取当前控制器（不管是push还是present方式）

- (UIViewController *)getVisibleViewControllerFrom:(UIViewController*)vc {
    if ([vc isKindOfClass:[UINavigationController class]]) {
        return [self getVisibleViewControllerFrom:[((UINavigationController*) vc) visibleViewController]];
    }else if ([vc isKindOfClass:[UITabBarController class]]){
        return [self getVisibleViewControllerFrom:[((UITabBarController*) vc) selectedViewController]];
    } else {
        if (vc.presentedViewController) {
            return [self getVisibleViewControllerFrom:vc.presentedViewController];
        } else {
            return vc;
        }
    }
}

+ (UIViewController *)jsd_getCurrentViewController{
    
    UIViewController* currentViewController = [self jsd_getRootViewController];
    BOOL runLoopFind = YES;
    while (runLoopFind) {
        if (currentViewController.presentedViewController) {
            
            currentViewController = currentViewController.presentedViewController;
        } else if ([currentViewController isKindOfClass:[UINavigationController class]]) {
            
            UINavigationController* navigationController = (UINavigationController* )currentViewController;
            currentViewController = [navigationController.childViewControllers lastObject];
            
        } else if ([currentViewController isKindOfClass:[UITabBarController class]]) {
            
            UITabBarController* tabBarController = (UITabBarController* )currentViewController;
            currentViewController = tabBarController.selectedViewController;
        } else {
            
            NSUInteger childViewControllerCount = currentViewController.childViewControllers.count;
            if (childViewControllerCount > 0) {
                
                currentViewController = currentViewController.childViewControllers.lastObject;
                return currentViewController;
            } else {
                
                return currentViewController;
            }
        }
    }
    return currentViewController;
}

+ (UIViewController *)jsd_getRootViewController{
    
    UIWindow* window = [[[UIApplication sharedApplication] delegate] window];
    NSAssert(window, @"The window is empty");
    return window.rootViewController;
}

是否允许左滑返回

    if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
        
    self.navigationController.interactivePopGestureRecognizer.enabled = NO;  
         //YES;
    }

全屏测滑返回

http://www.jianshu.com/p/bc85a3d37519

QQ.png

@interface LPNavigationController : UINavigationController

@property(nullable, nonatomic, readonly) UIGestureRecognizer *fullInteractivePopGestureRecognizer;

@end

@interface LPNavigationController () 

@property(nullable, nonatomic, readwrite) UIGestureRecognizer *fullInteractivePopGestureRecognizer;

@end

@implementation LPNavigationController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    self.interactivePopGestureRecognizer.enabled = NO;

    UIView *view = self.interactivePopGestureRecognizer.view;
    id target = self.interactivePopGestureRecognizer.delegate;
    SEL action = NSSelectorFromString(@"handleNavigationTransition:");

    self.fullInteractivePopGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:target action:action];
    self.fullInteractivePopGestureRecognizer.delaysTouchesBegan = YES;
    self.fullInteractivePopGestureRecognizer.delegate = self;
    [view addGestureRecognizer:self.fullInteractivePopGestureRecognizer];
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    // 左滑时可能与UITableView左滑删除手势产生冲突
    CGPoint translation = [(UIPanGestureRecognizer *)gestureRecognizer translationInView:gestureRecognizer.view];
    if (translation.x <= 0)
    {
        return NO;
    }

    // 跟视图控制器不响应手势
    return ([self.viewControllers count] == 1) ? NO : YES;
}

@end

导航栏渐变


-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
    if (scrollView.contentOffset.y < 0) {

        [self showView:self.navigationController.navigationBar hidden:YES];
        
    }else if(scrollView.contentOffset.y > 50) {
        [self showView:self.navigationController.navigationBar  hidden:NO];
        NSInteger barH = kScreenIphoneX?88:64;
        CGFloat alpha = MIN(1, 1 - ((50 + barH - scrollView.contentOffset.y) / barH));
        [self.navigationController.navigationBar  setBackgroundColor:[mainThemeRed colorWithAlphaComponent:alpha]];
        
    }else{
        [self showView:self.navigationController.navigationBar  hidden:NO];
        [self.navigationController.navigationBar  setBackgroundColor:[mainThemeRed colorWithAlphaComponent:0.0f]];

    }
}

-(void)showView:(UIView *)view hidden:(BOOL)hidden{
    CATransition *animation = [CATransition animation];
    animation.type = kCATransitionFade;
    animation.duration = 0.4;
    [view.layer addAnimation:animation forKey:nil];
    view.hidden = hidden;
}

导航栏颜色

[self.navigationController.navigationBar setBackgroundImage:[UIImage imageWithColor:[UIColor greenColor] size:CGSizeMake(1, 1)] forBarMetrics:UIBarMetricsDefault];

背景图

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

获取前一个控制器 *

- (UIViewController *)backViewController
{
    NSInteger myIndex = [self.navigationController.viewControllers indexOfObject:self];

    if ( myIndex != 0 && myIndex != NSNotFound ) {
        return [self.navigationController.viewControllers objectAtIndex:myIndex-1];
    } else {
        return nil;
    }
}

获取View所在的控制器

- (UIViewController *)viewController
{
  UIViewController *viewController = nil;  
  UIResponder *next = self.nextResponder;
  while (next)
  {
    if ([next isKindOfClass:[UIViewController class]])
    {
      viewController = (UIViewController *)next;      
      break;    
    }    
    next = next.nextResponder;  
  } 
    return viewController;
}

状态栏颜色设置

- (void)setStatusBarBackgroundColor:(UIColor *)color
{
    UIView *statusBar = [[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"];

    if ([statusBar respondsToSelector:@selector(setBackgroundColor:)])
    {
        statusBar.backgroundColor = color;    
    }
}

自定义navBar左按钮距左边的距离

UIBarButtonItem *leftItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"gobackItem.png"] style:UIBarButtonItemStylePlain target:self action:@selector(backViewcontroller)];

UIBarButtonItem *fixedItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
fixedItem.width = -16;  // 设置边框距离,可根据需要调节
self.navigationItem.leftBarButtonItems = @[fixedItem, leftItem];

Navbar纯透明

//第一种方法
[self.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];

//第二种方法
[[self.navigationBar subviews] objectAtIndex:0].alpha = 0;

去掉导航栏底部的黑线

self.navigationBar.shadowImage = [UIImage new];

根据滑动距离实现NavBar透明度渐变-隐藏-显示

第一种

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    //1、随滑动contentOffset控制透明度
    CGFloat offsetToShow = 200.0;
    CGFloat alpha =  (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
    [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = alpha;
    
    //2、先隐藏，滑动多少就完全显示
    CGFloat offsetToShow = 200.0;
    CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
    [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = alpha;
}

第二种

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat offsetToShow = 200.0;
    CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;

    [self.navigationController.navigationBar setShadowImage:[UIImage new]];
    [self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];
}

停止滚动时显示导航栏

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = 1;
}

根据上滑、下滑决定隐藏导航栏

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{
    NSLog(@"======== %lf", velocity.y);
    if(velocity.y > 0) {
      [self.navigationController setNavigationBarHidden:YES animated:YES];
    }else {
      [self.navigationController setNavigationBarHidden:NO animated:YES];
    }
}

velocity.y这个量，在上滑和下滑时变化极小（小数），但因为方向不同，有正负之分，这就很好处理了。

切换控制器时添加自定义动画

    ViewController *VC = [ [ViewController alloc] init];
    //创建动画
    CATransition *animation = [CATransition animation];
    //设置运动轨迹的速度
    animation.timingFunction = UIViewAnimationCurveEaseInOut;
    //设置动画类型为立方体动画
    animation.type = @"cube";
    //设置动画时长
    animation.duration =1.0f;
    //设置运动的方向
    animation.subtype =kCATransitionFromRight;
    //控制器间跳转动画
    [[UIApplication sharedApplication].keyWindow.layer addAnimation:animation forKey:nil];

   [self presentViewController:VC animated:NO completion:nil];

/*附：动画类型*/
typedef enum : NSUInteger {
    fade = 1,                   //淡入淡出
    push,                       //推挤
    reveal,                     //揭开
    moveIn,                     //覆盖
    cube,                       //立方体
    suckEffect,                 //吮吸
    oglFlip,                    //翻转
    rippleEffect,               //波纹
    pageCurl,                   //翻页
    pageUnCurl,                 //反翻页
    cameraIrisHollowOpen,       //开镜头
    cameraIrisHollowClose,      //关镜头
    curlDown,                   //下翻页
    curlUp,                     //上翻页
    flipFromLeft,               //左翻转
    flipFromRight,              //右翻转

} AnimationType;

导航栏的隐藏与显示

有的页面需要导航栏，有的页面不想要导航栏。
采用self.navigationController.navigationBar.hidden = YES/NO;
进行设置，无法达到理想需求。
正确做法如下：

第一种做法

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [self.navigationController setNavigationBarHidden:YES animated:YES];
}
- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    [self.navigationController setNavigationBarHidden:NO animated:YES];
}

第二种做法 ( 推荐 )

@interface WLHomePageController () 

@end

@implementation WLHomePageController 

#pragma mark - lifeCycle
- (void)viewDidLoad {
    [super viewDidLoad];

    self.navigationController.delegate = self;
}

#pragma mark - 导航控制器 代理方法：  将要显示控制器
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    // 判断要显示的控制器是否是自己
    BOOL isShowHomePage = [viewController isKindOfClass:[self class]];

    [self.navigationController setNavigationBarHidden:isShowHomePage animated:YES];
}

统一设置导航items数据主题

+(void)setupNavigationItemsTheme {
    UIBarButtonItem *barButtonItem = [UIBarButtonItem appearance];
    // 设置字体颜色
    [barButtonItem setTitleTextAttributes:@{
           NSForegroundColorAttributeName : [UIColor blackColor], 
           NSFontAttributeName : [UIFont systemFontOfSize:14]} 
           forState:UIControlStateNormal];

    [barButtonItem setTitleTextAttributes:@{
          NSForegroundColorAttributeName : [UIColor redColor]} 
          forState:UIControlStateHighlighted];

    [barButtonItem setTitleTextAttributes:@{
          NSForegroundColorAttributeName : [UIColor lightGrayColor]} 
          forState:UIControlStateDisabled];
}

导航栏多个item

    UIButton *addBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    [addBtn addTarget:self action:@selector(clickRightItem:) forControlEvents:UIControlEventTouchUpInside];
    [addBtn setImage:[UIImage imageNamed:@"note"] forState:UIControlStateNormal];
    addBtn.tag = 1;
    UIBarButtonItem *addBtnItem = [[UIBarButtonItem alloc] initWithCustomView:addBtn];
    
    UIButton *scanBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    [scanBtn addTarget:self action:@selector(clickRightItem:) forControlEvents:UIControlEventTouchUpInside];
    [scanBtn setImage:[UIImage imageNamed:@"scan"] forState:UIControlStateNormal];
    scanBtn.tag = 2;
    UIBarButtonItem *scanBtnItem = [[UIBarButtonItem alloc] initWithCustomView:scanBtn];
    
    UIBarButtonItem *space = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
    space.width = 20;
    
    self.navigationItem.rightBarButtonItems  = @[addBtnItem,space,scanBtnItem];