UINavigationController这一篇就够了
zhaobin545
7年前
<h2>（一）UINavigationController及其相关控件之间的关系</h2> <pre> <code class="language-objectivec">@interface UINavigationController : UIViewController @property(nonatomic,readonly) UINavigationBar *navigationBar; @interface UIViewController (UINavigationControllerItem) @property(nonatomic,readonly,strong) UINavigationItem *navigationItem; @interface UINavigationBar : UIView @property(nullable, nonatomic,readonly,strong) UINavigationItem *topItem; @property(nullable, nonatomic,readonly,strong) UINavigationItem *backItem; @property(nullable,nonatomic,copy) NSArray<UINavigationItem *> *items; @interface UINavigationItem : NSObject @property(nullable,nonatomic,strong) UIBarButtonItem *backBarButtonItem @property(nullable,nonatomic,copy) NSArray<UIBarButtonItem *> *leftBarButtonItems; @property(nullable,nonatomic,copy) NSArray<UIBarButtonItem *> *rightBarButtonItems; @property(nullable, nonatomic,strong) UIBarButtonItem *leftBarButtonItem; @property(nullable, nonatomic,strong) UIBarButtonItem *rightBarButtonItem; @interface UIBarButtonItem : UIBarItem @property(nullable, nonatomic) SEL action; @interface UIBarItem : NSObject @property(nullable, nonatomic,copy) NSString *title; @property(nullable, nonatomic,strong) UIImage *image;</code></pre> <p>通过对上述几个类的属性的罗列，我们可以做个总结</p> <p>基本介绍</p> <ul> <li>UIBarItem<br> 一个可以放置在Bar之上的所有小控件类的抽象类,可以设置标题，图片等</li> <li>UIBarButtonItem<br> 继承UIBarItem，增加了动作以及目标等button的属性。相当于放在UIToolBar或者UINavigationBar上的特殊的button。</li> <li>UINavigationItem<br> 包含了title,prompt,titleView,leftBarButtonItem,rightBarButtonItem,backBarButonItem等当前页面上所有的信息</li> <li>UINavigationBar<br> NavigaitonBar就是导航栏 主要对UINavigationItem进行栈管理 展示导航栏的外观背景</li> <li>UINavigationController<br> 包含了viewcontrollers、navigationbar、toolbar</li> </ul> <p>关系综述</p> <ul> <li>UINavigationController是一个容器类，对ViewController进行栈管理，包含navigationBar。</li> <li>UINavigationBar 即UINavigationController顶部的导航栏，主要负责外观背景的展示，并对navigationItem进行栈管理</li> <li>UINavigationItem是导航栏上显示的具体的元素的一个抽象类,UINavigationController 通过Category的方法为ViewController添加了一个navigationItem,把UINavigationItem交由ViewController管理 <p>// Created on-demand so that a view controller may customize its navigation appearance.</p> </li> </ul> <p>这里引用 叶落寒 的一段介绍，更加的通俗易懂</p> <p>通俗地说就是，UINavigationController是个容器，里面可以装很多UIViewController。装这么多UIViewController让用户怎么控制它们呢？总得有个工具吧，这个工具就是UINavigationBar。一个容器就这么一个bar，相当于控制台吧。但是管理那么多UIViewController，控制台上得按钮啊、标题啊，都千篇一律是不是看起来太无聊了。为了解决这个问题，UINavigationController为每个UIViewController生成一个UINavigationItem，通过这个UINavigationItem可以改变控制台“上面”的按钮和标题。如果你不自定义UINavigationItem，UINavigationController会使用默认的;</p> <h2>（二）UINavigationController及其相关控件的属性和方法</h2> <h3>1. UIBarButtonItem</h3> <pre> <code class="language-objectivec">//初始化方法 - (instancetype)init; - (nullable instancetype)initWithCoder:(NSCoder *)aDecoder; - (instancetype)initWithImage:(nullable UIImage *)image landscapeImagePhone:(nullable UIImage *)landscapeImagePhone style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action; - (instancetype)initWithTitle:(nullable NSString *)title style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action; - (instancetype)initWithBarButtonSystemItem:(UIBarButtonSystemItem)systemItem target:(nullable id)target action:(nullable SEL)action; - (instancetype)initWithCustomView:(UIView *)customView; @property(nonatomic) UIBarButtonItemStyle style; //类型 @property(nonatomic) CGFloat width; @property(nullable, nonatomic,copy) NSSet<NSString *> *possibleTitles; @property(nullable, nonatomic,strong) __kindof UIView *customView; @property(nullable, nonatomic) SEL action; @property(nullable, nonatomic,weak) id target; @property(nullable, nonatomic,strong) UIColor *tintColor //为任意style的button设置背景图片 - (void)setBackgroundImage:(nullable UIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics - (nullable UIImage *)backgroundImageForState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics //为特定style的button设置背景图片 - (void)setBackgroundImage:(nullable UIImage *)backgroundImage forState:(UIControlState)state style:(UIBarButtonItemStyle)style barMetrics:(UIBarMetrics)barMetrics - (nullable UIImage *)backgroundImageForState:(UIControlState)state style:(UIBarButtonItemStyle)style barMetrics:(UIBarMetrics)barMetrics //设置背景图片垂直方向的偏移量 - (void)setBackgroundVerticalPositionAdjustment:(CGFloat)adjustment forBarMetrics:(UIBarMetrics)barMetrics - (CGFloat)backgroundVerticalPositionAdjustmentForBarMetrics:(UIBarMetrics)barMetrics //设置标题的偏移量 - (void)setTitlePositionAdjustment:(UIOffset)adjustment forBarMetrics:(UIBarMetrics)barMetrics - (nullable UIImage *)backButtonBackgroundImageForState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics //设置返回按钮标题偏移量 - (void)setBackButtonTitlePositionAdjustment:(UIOffset)adjustment forBarMetrics:(UIBarMetrics)barMetrics - (UIOffset)backButtonTitlePositionAdjustmentForBarMetrics:(UIBarMetrics)barMetrics //设置返回按钮背景图片在垂直方向上的偏移量 - (void)setBackButtonBackgroundVerticalPositionAdjustment:(CGFloat)adjustment forBarMetrics:(UIBarMetrics)barMetrics - (CGFloat)backButtonBackgroundVerticalPositionAdjustmentForBarMetrics:(UIBarMetrics)barMetrics</code></pre> <pre> <code class="language-objectivec">typedef NS_ENUM(NSInteger, UIBarButtonSystemItem) { UIBarButtonSystemItemDone,//显示完成 UIBarButtonSystemItemCancel,//显示取消 UIBarButtonSystemItemEdit, //显示编辑 UIBarButtonSystemItemSave, //显示保存 UIBarButtonSystemItemAdd,//显示加号 UIBarButtonSystemItemFlexibleSpace,//什么都不显示，占位一个空间位置 UIBarButtonSystemItemFixedSpace,//和上一个类似 UIBarButtonSystemItemCompose,//显示写入按钮 UIBarButtonSystemItemReply,//显示循环按钮 UIBarButtonSystemItemAction,//显示活动按钮 UIBarButtonSystemItemOrganize,//显示组合按钮 UIBarButtonSystemItemBookmarks,//显示图书按钮 UIBarButtonSystemItemSearch,//显示查找按钮 UIBarButtonSystemItemRefresh,//显示刷新按钮 UIBarButtonSystemItemStop,//显示停止按钮 UIBarButtonSystemItemCamera,//显示相机按钮 UIBarButtonSystemItemTrash,//显示移除按钮 UIBarButtonSystemItemPlay,//显示播放按钮 UIBarButtonSystemItemPause,//显示暂停按钮 UIBarButtonSystemItemRewind,//显示退后按钮 UIBarButtonSystemItemFastForward,//显示前进按钮 UIBarButtonSystemItemUndo,//显示消除按钮 UIBarButtonSystemItemRedo ,//显示重做按钮 UIBarButtonSystemItemPageCurl ,//在tool上有效 };</code></pre> <h3>2.UINavigationItem</h3> <pre> <code class="language-objectivec">NS_CLASS_AVAILABLE_IOS(2_0) @interface UINavigationItem : NSObject <NSCoding> //初始化 - (instancetype)initWithTitle:(NSString *)title NS_DESIGNATED_INITIALIZER; - (nullable instancetype)initWithCoder:(NSCoder *)coder NS_DESIGNATED_INITIALIZER; //设置导航栏中间的内容标题 @property(nullable, nonatomic,copy) NSString *title; //设置导航栏中间的内容视图 @property(nullable, nonatomic,strong) UIView *titleView; //提示 @property(nullable,nonatomic,copy) NSString *prompt; //返回 @property(nullable,nonatomic,strong) UIBarButtonItem *backBarButtonItem; //是否隐藏返回Button @property(nonatomic,assign) BOOL hidesBackButton; - (void)setHidesBackButton:(BOOL)hidesBackButton animated:(BOOL)animated; //左边数组Item @property(nullable,nonatomic,copy) NSArray<UIBarButtonItem *> *leftBarButtonItems NS_AVAILABLE_IOS(5_0); //右边数组Item @property(nullable,nonatomic,copy) NSArray<UIBarButtonItem *> *rightBarButtonItems NS_AVAILABLE_IOS(5_0); - (void)setLeftBarButtonItems:(nullable NSArray<UIBarButtonItem *> *)items animated:(BOOL)animated NS_AVAILABLE_IOS(5_0); - (void)setRightBarButtonItems:(nullable NSArray<UIBarButtonItem *> *)items animated:(BOOL)animated NS_AVAILABLE_IOS(5_0); //通过指定该属性为YES，可以让leftBarButtonItem和backBarButtonItem同时显示，其中leftBarButtonItem显示在backBarButtonItem的右边 默认值为NO @property(nonatomic) BOOL leftItemsSupplementBackButton NS_AVAILABLE_IOS(5_0); //左边Item @property(nullable, nonatomic,strong) UIBarButtonItem *leftBarButtonItem; //右边Item @property(nullable, nonatomic,strong) UIBarButtonItem *rightBarButtonItem; - (void)setLeftBarButtonItem:(nullable UIBarButtonItem *)item animated:(BOOL)animated; - (void)setRightBarButtonItem:(nullable UIBarButtonItem *)item animated:(BOOL)animated; @end</code></pre> <p>prompt 是一个NSString类型描述，注意添加该描述以后NavigationBar的高度会增加30，总的高度会变成74(不管当前方向是Portrait还是Landscape，此模式下navgationbar都使用高度44加上prompt30的方式进行显示)。</p> <p>如：</p> <pre> <code class="language-objectivec">self.navigationItem.prompt=@"这是什么？"; self.title=@"HAH";</code></pre> <p style="text-align:center"><img src="https://simg.open-open.com/show/ff7a6fab5861aaa4d0e570e799fe7caa.png"></p> <p>prompt.png</p> <h3>3.UINavigationBar</h3> <pre> <code class="language-objectivec">NS_CLASS_AVAILABLE_IOS(2_0) @interface UINavigationBar : UIView <NSCoding, UIBarPositioning> //UIBarStyleDefault 灰色背景 白色文字 UIBarStyleBlack 纯黑色背景 白色文字 @property(nonatomic,assign) UIBarStyle barStyle; @property(nullable,nonatomic,weak) id<UINavigationBarDelegate> delegate; //Translucent设置成透明度,设置成YES会有一种模糊效果 @property(nonatomic,assign,getter=isTranslucent) BOOL translucent NS_AVAILABLE_IOS(3_0) UI_APPEARANCE_SELECTOR; //UINavigationBar上面不只是简单的显示标题，它也将标题进行了堆栈的管理，每一个标题抽象为的对象在iOS系统中是UINavigationItem对象，我们可以通过push与pop操作管理item组。 //向栈中添加一个item，上一个item会被推向导航栏的左侧，变为pop按钮，会有一个动画效果 - (void)pushNavigationItem:(UINavigationItem *)item animated:(BOOL)animated; //pop一个item - (nullable UINavigationItem *)popNavigationItemAnimated:(BOOL)animated; //当前push到最上层的item @property(nullable, nonatomic,readonly,strong) UINavigationItem *topItem; //仅次于最上层的item，一般式被推向导航栏左侧的item @property(nullable, nonatomic,readonly,strong) UINavigationItem *backItem; //获取堆栈中所有item的数组 @property(nullable,nonatomic,copy) NSArray<UINavigationItem *> *items; //设置一组item - (void)setItems:(nullable NSArray<UINavigationItem *> *)items animated:(BOOL)animated; //系统类型按钮文字颜色 @property(null_resettable, nonatomic,strong) UIColor *tintColor; //通过barTintColor来设置背景色 @property(nullable, nonatomic,strong) UIColor *barTintColor NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //设置工具栏背景和阴影图案 - (void)setBackgroundImage:(nullable UIImage *)backgroundImage forBarPosition:(UIBarPosition)barPosition barMetrics:(UIBarMetrics)barMetrics NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; - (nullable UIImage *)backgroundImageForBarPosition:(UIBarPosition)barPosition barMetrics:(UIBarMetrics)barMetrics NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //通过背景图片来设置导航栏的外观 - (void)setBackgroundImage:(nullable UIImage *)backgroundImage forBarMetrics:(UIBarMetrics)barMetrics NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; - (nullable UIImage *)backgroundImageForBarMetrics:(UIBarMetrics)barMetrics NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; //背景阴影图片 - 即分割线 @property(nullable, nonatomic,strong) UIImage *shadowImage NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR; //标题的富文本 @property(nullable,nonatomic,copy) NSDictionary<NSString *,id> *titleTextAttributes NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; //标题垂直偏移 - (void)setTitleVerticalPositionAdjustment:(CGFloat)adjustment forBarMetrics:(UIBarMetrics)barMetrics NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; - (CGFloat)titleVerticalPositionAdjustmentForBarMetrics:(UIBarMetrics)barMetrics NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; //设置返回按钮的图片 @property(nullable,nonatomic,strong) UIImage *backIndicatorImage NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; @property(nullable,nonatomic,strong) UIImage *backIndicatorTransitionMaskImage NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; @end</code></pre> <h3>4.UINavigationController</h3> <pre> <code class="language-objectivec">NS_CLASS_AVAILABLE_IOS(2_0) @interface UINavigationController : UIViewController //UINavigationController初始化,自定义NavigationBar,自定义toolbar - (instancetype)initWithNavigationBarClass:(nullable Class)navigationBarClass toolbarClass:(nullable Class)toolbarClass NS_AVAILABLE_IOS(5_0); //UINavigationController初始化,导航控制器的根控制器 - (instancetype)initWithRootViewController:(UIViewController *)rootViewController; //压栈：将目标控制器压入栈中 - (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated; //弹栈：将栈顶控制器从栈中弹出 - (nullable UIViewController *)popViewControllerAnimated:(BOOL)animated; //弹栈：弹到指定的目标控制器 - (nullable NSArray<__kindof UIViewController *> *)popToViewController:(UIViewController *)viewController animated:(BOOL)animated; //弹栈：弹到根控制器 - (nullable NSArray<__kindof UIViewController *> *)popToRootViewControllerAnimated:(BOOL)animated; //导航栈的栈顶视图 只读 就是某个导航栈的栈顶视图，和导航息息相关 @property(nullable, nonatomic,readonly,strong) UIViewController *topViewController; //当前显示的控制器 只读 visibleViewController和哪个导航栈没有关系，只是当前显示的控制器，也就是说任意一个导航的visibleViewController所返回的值应该是一样的 @property(nullable, nonatomic,readonly,strong) UIViewController *visibleViewController; //栈里的视图控制器数组 @property(nonatomic,copy) NSArray<__kindof UIViewController *> *viewControllers; //替换栈中的视图控制器数组 - (void)setViewControllers:(NSArray<UIViewController *> *)viewControllers animated:(BOOL)animated NS_AVAILABLE_IOS(3_0); //是否隐藏导航栏 @property(nonatomic,getter=isNavigationBarHidden) BOOL navigationBarHidden; //设置导航栏隐藏 是否有动画 - (void)setNavigationBarHidden:(BOOL)hidden animated:(BOOL)animated; //导航栏 @property(nonatomic,readonly) UINavigationBar *navigationBar; //toolbar是否隐藏 @property(nonatomic,getter=isToolbarHidden) BOOL toolbarHidden NS_AVAILABLE_IOS(3_0); //toolbar是否隐藏 是否有动画 - (void)setToolbarHidden:(BOOL)hidden animated:(BOOL)animated NS_AVAILABLE_IOS(3_0); //toolbar对象 @property(null_resettable,nonatomic,readonly) UIToolbar *toolbar NS_AVAILABLE_IOS(3_0); //委托 @property(nullable, nonatomic, weak) id<UINavigationControllerDelegate> delegate; //边缘侧滑返回手势 @property(nullable, nonatomic, readonly) UIGestureRecognizer *interactivePopGestureRecognizer NS_AVAILABLE_IOS(7_0); //展示视图控制器 - (void)showViewController:(UIViewController *)vc sender:(nullable id)sender NS_AVAILABLE_IOS(8_0); // Interpreted as pushViewController:animated: //输入键盘出现时将导航栏隐藏 IOS8特性 @property (nonatomic, readwrite, assign) BOOL hidesBarsWhenKeyboardAppears NS_AVAILABLE_IOS(8_0); //滚动页面时隐藏Bar IOS8特性 @property (nonatomic, readwrite, assign) BOOL hidesBarsOnSwipe NS_AVAILABLE_IOS(8_0); //获取能够隐藏navigationBar的滑动手势 只读 @property (nonatomic, readonly, strong) UIPanGestureRecognizer *barHideOnSwipeGestureRecognizer NS_AVAILABLE_IOS(8_0); //当设置为true时，横向方向时隐藏NavigationBar @property (nonatomic, readwrite, assign) BOOL hidesBarsWhenVerticallyCompact NS_AVAILABLE_IOS(8_0); //当设置为true时，如果有没处理的点击手势就会隐藏和现实navigationBar @property (nonatomic, readwrite, assign) BOOL hidesBarsOnTap NS_AVAILABLE_IOS(8_0); //获取能够隐藏navigationBar的点击手势 只读 @property (nonatomic, readonly, assign) UITapGestureRecognizer *barHideOnTapGestureRecognizer NS_AVAILABLE_IOS(8_0); @end</code></pre> <pre> <code class="language-objectivec">@interface UIViewController (UINavigationControllerItem) //导航栏上面用户自定义视图 @property(nonatomic,readonly,strong) UINavigationItem *navigationItem; //推送时隐藏bottom @property(nonatomic) BOOL hidesBottomBarWhenPushed; //下级视图的导航控制器 @property(nullable, nonatomic,readonly,strong) UINavigationController *navigationController; @end</code></pre> <pre> <code class="language-objectivec">@interface UIViewController (UINavigationControllerContextualToolbarItems) //属性设置工具条中包含的按钮 @property (nullable, nonatomic, strong) NSArray<__kindof UIBarButtonItem *> *toolbarItems NS_AVAILABLE_IOS(3_0); - (void)setToolbarItems:(nullable NSArray<UIBarButtonItem *> *)toolbarItems animated:(BOOL)animated NS_AVAILABLE_IOS(3_0); @end</code></pre> <h2>（三）实际开发过程中的一些问题</h2> <h3>1.UINavigationBar的背景颜色</h3> <pre> <code class="language-objectivec">-(void)changeNavigationBarBackgroundColor { //背景色 self.navigationBar.barTintColor = [UIColor blueColor]; //title字体 //[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor lightGrayColor],NSFontAttributeName:[UIFont systemFontOfSize:17]}]; //修改UIBarButtonItem 图片 title颜色 self.navigationBar.tintColor = [UIColor greenColor]; //是否半透明 当为YES时 设置的导航栏背景颜色会和实际rgb值有误差 self.navigationBar.translucent = NO; //如果想要半透明效果 颜色没有色差 可以通过设置背景图片的方法 背景图片会覆盖barTintColor //- (void)setBackgroundImage:(nullable UIImage *)backgroundImage forBarMetrics:(UIBarMetrics)barMetrics }</code></pre> <h3>2.UINavigationBar底部的shadowImage</h3> <p>Apple官方对shadowImage有这样的介绍：</p> <p>/ <em>Default is nil. When non-nil, a custom shadow image to show instead of the default shadow image. For a custom shadow to be shown, a custom background image must also be set with -setBackgroundImage:forBarMetrics: (if the default background image is used, the default shadow image will be used).</em> /</p> <p>设置shadowImage必须先setBackgroundImage，否则无法实现效果</p> <pre> <code class="language-objectivec">-(void)changeNavigationBarBottonLine { //设置底部line颜色时需要同时设置backgroundImage即导航栏的背景图片 否则没有效果 [self.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault]; [self.navigationBar setShadowImage:[self imageWithColor:[UIColor redColor]]]; //此处设置透明颜色的image,底部line即可隐藏，但此种方法隐藏，没有办法再显示 下面方法通过找到该view 控制其hidden属性 //[self reducibilityHiddenNavogationBarLine]; }</code></pre> <p>找到该imageView设置起Hidden为YES</p> <pre> <code class="language-objectivec">-(void)reducibilityHiddenNavogationBarLine { UIImageView * imageView = [self findLineImageViewUnder:self.navigationBar]; if (imageView) { imageView.hidden = YES; } }</code></pre> <p>找到该imageView</p> <pre> <code class="language-objectivec">-(UIImageView *)findLineImageViewUnder:(UIView *)view { if ([view isKindOfClass:[UIImageView class]] && view.bounds.size.height <= 1.0) { return (UIImageView *)view; } for (UIView * subView in view.subviews) { UIImageView * imageView = [self findLineImageViewUnder:subView]; if (imageView) { return imageView; } } return nil; }</code></pre> <h3>3.自定义导航栏的返回按钮</h3> <pre> <code class="language-objectivec">@property(nonatomic,readonly) UINavigationBar *navigationBar;// The navigation bar managed by the controller. Pushing, popping or setting navigation items on a managed navigation bar is not supported.</code></pre> <p>受controller管理的navigationBar 不支持对navigation items操作,所以此处对返回按钮的操作是在ViewController完成的，以下代码中self表示ViewController</p> <p>Apple官方对setBackIndicatorImage和setBackIndicatorTransitionMaskImage做了如下解释，必须同时设置才能生效</p> <pre> <code class="language-objectivec">/* The back indicator image is shown beside the back button. The back indicator transition mask image is used as a mask for content during push and pop transitions Note: These properties must both be set if you want to customize the back indicator image. */</code></pre> <p>1.自定义文字+图片</p> <pre> <code class="language-objectivec">-(void)createCustomBackBarItem { //修改图片文字颜色 self.navigationController.navigationBar.tintColor = [UIColor whiteColor]; //替换图片 [self.navigationController.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"erwema"]]; [self.navigationController.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"erwema"]]; //设置文字 UIBarButtonItem * backBarItem = [[UIBarButtonItem alloc]initWithTitle:@"返回" style:UIBarButtonItemStylePlain target:nil action:nil]; self.navigationItem.backBarButtonItem = backBarItem; }</code></pre> <p>注意：</p> <p>对backBarButtonItem的修改是在当前viewController前一个页面完成的，在当前页面修改针对下一个viewController的navigationItem生效</p> <p>2.不显示文字</p> <p>设置Title在Y方向上的偏移量，使其移除屏幕，该方法在第一次进入时会有个文字移动的动画效果，效果不好，不推荐使用</p> <pre> <code class="language-objectivec">[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -100) forBarMetrics:UIBarMetricsDefault];</code></pre> <p>3.使用leftBarButtonItem替代backBarButtonItem</p> <p>使用这种方法，不能使用边缘滑动返回手势，且不能同时设置图片和标题</p> <pre> <code class="language-objectivec">-(void)setLeftBarItemBack { UIBarButtonItem *leftBarBtnItem = [[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"back"] style:UIBarButtonItemStylePlain target:self action:@selector(clickLeftBarBtnItem:)]; [self.navigationItem setLeftBarButtonItem:leftBarBtnItem animated:YES]; self.navigationItem.leftBarButtonItem.tintColor = NavigationLeftBackColor; } /** * 导航条leftBarBtn事件 */ - (void)clickLeftBarBtnItem:(UIBarButtonItem *)sender { [self.navigationController popViewControllerAnimated:YES]; }</code></pre> <p>4.使用CustomView的方法</p> <p>此方法不适于backBarButtonItem，只能用于leftBarButtonItem</p> <p>注意：</p> <p>1.如果B视图有一个自定义的左侧按钮（leftBarButtonItem），则会显示这个自定义按钮；</p> <p>2.如果B没有自定义按钮，但是A视图的backBarButtonItem属性有自定义项，则显示这个自定义项；</p> <p>3.如果前2条都没有，则默认显示一个后退按钮，后退按钮的标题是A视图的标题；</p> <p>此处注意:</p> <p>5.0中新增加了一个属性leftItemsSupplementBackButton，通过指定该属性为YES，可以让leftBarButtonItem和backBarButtonItem同时显示，其中leftBarButtonItem显示在backBarButtonItem的右边。</p> <p>使用3、4方法，边缘返回会失效，此时加上这句代码依然可以实现边缘滑动返回</p> <pre> <code class="language-objectivec">self.navigationController.interactivePopGestureRecognizer.delegate = self;</code></pre> <p>这里推荐使用 <a href="/misc/goto?guid=4959635476022877280" rel="nofollow,noindex">FDFullscreenPopGesture</a> 全屏滑动手势返回，减少工作量。</p> <h3>4.navigationBar偶尔显示上一个页面的navigationBar</h3> <p>一般情况下都是正常的。但是在偶然情况下，会出现在进入新界面后，新界面的navigationBar会突然消失，出现的还是上一个界面的 navigationBar。从此以后，navigationBar 全乱了， kill 掉重新进，恢复正常。</p> <p>原因：</p> <p>一般我们会打点调用navigationBarHidden的属性来设置导航栏是否隐藏，这种方法是不带动画效果的。这样偶尔就会导致错乱，这应该是一个系统的bug,所以应尽量使用</p> <pre> <code class="language-objectivec">[self.navigationController setNavigationBarHidden:YES animated:YES];</code></pre> <p>来设置navigationBar的Hidden属性。</p> <h3>5.修改系统navigationBar的高度</h3> <pre> <code class="language-objectivec">UINavigationBar * navigatioBar = self.navigationController.navigationBar; CGFloat navBarHeight = 100.f; CGRect frame = CGRectMake(0.0f, 0.0f, 320.0f, navBarHeight); [navigatioBar setFrame:frame];</code></pre> <p>此种方法经测试只有在非rootViewController中才能生效，这样在第一次进入根视图的时候navigationBar并不会变高，不知有没有人知道该如何解决，欢迎赐教。</p> <h3>6.易混淆知识点</h3> <p>1.self.title、self.navigationItem.title、self.tabBarItem.title之间的关系</p> <p>一目了然</p> <pre> <code class="language-objectivec">self.navigationItem.title = @"my title"; //sets navigation bar title. self.tabBarItem.title = @"my title"; //sets tab bar title. self.title = @"my title"; //sets both of these.</code></pre> <ol> <li>如果当前VC通过 self.navigationItem.titleView指定了自定义的titleView，系统将会显示指定的titleView,设置self.title、self.navigationItem.title不会改变导航栏的标题。</li> <li>如果当前VC没有指定titleView，系统则会根据当前VC的title或者当前VC的navigationItem.title的内容创建一个UILabel并显示。</li> <li>self.title会重写navigationItem和tabBarItem的title。</li> </ol> <p>2.self.navigationItem,self.navigationController.navigationItem的关系</p> <p>navigationItem是UIViewController的一个属性，navigationController继承UIViewController，自然会继承viewControoler的navigationItem属性。此处self.navigationController.navigationItem是应该被忽视的。navigationItem直接由viewController管理。</p> <p>3.UIBarMetrics和UIBarPosition</p> <pre> <code class="language-objectivec">typedef NS_ENUM(NSInteger, UIBarMetrics) { UIBarMetricsDefault, //横屏 UIBarMetricsCompact,//竖屏 UIBarMetricsDefaultPrompt = 101, //横屏且设置了prompt属性 Applicable only in bars with the prompt property, such as UINavigationBar and UISearchBar UIBarMetricsCompactPrompt, //竖屏且设置了prompt属性 }; typedef NS_ENUM(NSInteger, UIBarPosition) { UIBarPositionAny = 0, //Bar在任何位置 UIBarPositionBottom = 1, //Bar在底部 UIBarPositionTop = 2, //Bar在顶部 UIBarPositionTopAttached = 3, //Bar在顶部，且他的背景扩展到statusBar的区域 } NS_ENUM_AVAILABLE_IOS(7_0);</code></pre> <p>不正之处，还望多多指教！</p> <p>参考文章</p> <p><a href="/misc/goto?guid=4959738041375763830" rel="nofollow,noindex">你真的了解UINavigationController吗?</a></p> <p><a href="/misc/goto?guid=4959738041465447592" rel="nofollow,noindex">UINavigationItem UINavigationBar 关系分析</a></p> <p> </p> <p>来自：http://www.jianshu.com/p/69b4e7bed7d4</p> <p> </p>