一:首先查看一下关于UITabBarController的定义
NS_CLASS_AVAILABLE_IOS(2_0) @interface UITabBarController : UIViewController <UITabBarDelegate, NSCoding> //设置控制器数组 @property(nullable, nonatomic,copy) NSArray<__kindof UIViewController *> *viewControllers; //设置控制器数组 动画 - (void)setViewControllers:(NSArray<__kindof UIViewController *> * __nullable)viewControllers animated:(BOOL)animated; //选中的控制器 @property(nullable, nonatomic, assign) __kindof UIViewController *selectedViewController; //选中索引值 @property(nonatomic) NSUInteger selectedIndex; //当item超过五个时 就会有一个更多 @property(nonatomic, readonly) UINavigationController *moreNavigationController; @property(nullable, nonatomic, copy) NSArray<__kindof UIViewController *> *customizableViewControllers; //tab条 @property(nonatomic,readonly) UITabBar *tabBar NS_AVAILABLE_IOS(3_0); //委托 @property(nullable, nonatomic,weak) id<UITabBarControllerDelegate> delegate; @end
UITabBarController和UINavigationController一样是用来管理试图控制器的,与导航控制器不同,tabBarController控制器使用数组管理子试图控制器的,并且子试图之间是平等关系,导航控制器所管理的试图控制器之间是在出桟和入桟的关系;
知识点1:在Application的中编码,平时项目要使用继承一个于UITabBarController的控制器里面
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]]; self.window.backgroundColor = [UIColor whiteColor]; //初始化一个tabBar控制器 UITabBarController *tb = [[UITabBarController alloc]init]; //设置UIWindow的rootViewController为UITabBarController self.window.rootViewController = tb; //创建相应的子控制器 UIViewController *vc1 = [[UIViewController alloc]init]; vc1.view.backgroundColor = [UIColor greenColor]; vc1.tabBarItem.title = @"首页"; vc1.tabBarItem.image = [[UIImage imageNamed:@"Home_normal"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]; vc1.tabBarItem.selectedImage = [[UIImage imageNamed:@"Home_selected"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]; UIViewController *vc2 = [[UIViewController alloc]init]; vc2.view.backgroundColor = [UIColor blueColor]; vc2.tabBarItem.title = @"分类"; vc2.tabBarItem.image = [[UIImage imageNamed:@"List_normal"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]; vc2.tabBarItem.selectedImage = [[UIImage imageNamed:@"List_selected"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]; [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor colorWithRed:102.0/255 green:102.0/255 blue:102.0/255 alpha:1.0],NSForegroundColorAttributeName, [UIFont systemFontOfSize:10.0],NSFontAttributeName,nil] forState:UIControlStateNormal]; [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor colorWithRed:255.0/255 green:73.0/255 blue:87.0/255 alpha:1.0],NSForegroundColorAttributeName, [UIFont systemFontOfSize:10.0],NSFontAttributeName,nil] forState:UIControlStateSelected]; //把子控制器添加到UITabBarController //[tb addChildViewController:c1]; //[tb addChildViewController:c2]; //或者 tb.viewControllers = @[vc1,vc2]; [self.window makeKeyAndVisible]; return YES; }
知识点2:moreNavigationController
UITabBar上最多可以显示5个Tab,当我们往UITabBarController中添加超过的viewController超过5个时候,最后一个一个就会自动变成更多,按照设置的viewControlles的顺序,显示前四个viewController的tabBarItem,后面的tabBarItem将不再显示。当点击more时候将会弹出一个标准的navigationViewController,里面放有其它未显示的的viewController,并且带有一个edit按钮,通过点击该按钮可以进入类似与ipod程序中设置tabBar的编辑界面。编辑界面中默认所有的viewController都是可以编辑的,我们可以通过设置UITabBarController的customizableViewControllers属性来指定viewControllers的一个子集,即只允许一部分viewController是可以放到tabBar中显示的。但是这块儿要注意一个问题就是每当UITabBarController的viewControllers属性发生变化的时候,customizableViewControllers就会自动设置成跟viewControllers一致,即默认的所有的viewController都是可以编辑的,如果我们要始终限制只是某一部分可编辑的话,记得在每次viewControlles发生改变的时候,重新设置一次customizableViewControllers。
二:UITabBarControllerDelegate委托内容
1、视图将要切换时调用,viewController为将要显示的控制器,如果返回的值为NO,则无法点击其它分栏了(viewController指代将要显示的控制器) - (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController 例如1: - (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController { NSLog(@"被选中的控制器将要显示的按钮"); //return NO;不能显示选中的控制器 return YES; } 2、视图已经切换后调用,viewController 是已经显示的控制器 - (void)tabBarController:(UITabBarController *)tabBarControllerdidSelectViewController:(UIViewController *)viewController 例如2: - (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController { NSLog(@"视图显示后调用"); } 3、将要开始自定义item的顺序 - (void)tabBarController:(UITabBarController *)tabBarController willBeginCustomizingViewControllers:(NSArray<__kindof UIViewController *> *)viewControllers 例如3 - (void)tabBarController:(UITabBarController *)tabBarController willBeginCustomizingViewControllers:(NSArray<__kindof UIViewController *> *)viewControllers { NSLog(@"将要开始自定义item时调用"); NSLog(@"%@",viewControllers); } 4、将要结束自定义item的顺序 - (void)tabBarController:(UITabBarController *)tabBarController willEndCustomizingViewControllers:(NSArray<__kindof UIViewController *> *)viewControllers changed:(BOOL)changed 例如4 - (void)tabBarController:(UITabBarController *)tabBarController willEndCustomizingViewControllers:(NSArray<__kindof UIViewController *> *)viewControllers changed:(BOOL)changed { NSLog(@"将要结束自定义item时调用"); NSLog(@"%@",viewControllers); }
5、结束自定义item的顺序
- (void)tabBarController:(UITabBarController *)tabBarController didEndCustomizingViewControllers:(NSArray<__kindof UIViewController *> *)viewControllers changed:(BOOL)changed
例如5:
- (void)tabBarController:(UITabBarController *)tabBarController didEndCustomizingViewControllers:(NSArray<__kindof UIViewController *> *)viewControllers changed:(BOOL)changed
{
NSLog(@"已经结束自定义item顺序时调用");
NSLog(@"%@",viewControllers);
}
三:UIViewController (UITabBarControllerItem)分类
@interface UIViewController (UITabBarControllerItem) //当前视图的UITabBarItem对象 @property(null_resettable, nonatomic, strong) UITabBarItem *tabBarItem; //如果视图控制器是一个标签栏控制器的子控制器,则返回它。否则返回nil @property(nullable, nonatomic, readonly, strong) UITabBarController *tabBarController; @end
四:关于UITabBar的定义
NS_CLASS_AVAILABLE_IOS(2_0) @interface UITabBar : UIView //委托 @property(nullable,nonatomic,assign) id<UITabBarDelegate> delegate; //UITabBarItem集合 @property(nullable,nonatomic,copy) NSArray<UITabBarItem *> *items; //被选中的item @property(nullable,nonatomic,assign) UITabBarItem *selectedItem; //批量设置items - (void)setItems:(nullable NSArray<UITabBarItem *> *)items animated:(BOOL)animated; - (void)beginCustomizingItems:(NSArray<UITabBarItem *> *)items; - (BOOL)endCustomizingAnimated:(BOOL)animated; - (BOOL)isCustomizing; //渲染色 @property(null_resettable, nonatomic,strong) UIColor *tintColor NS_AVAILABLE_IOS(5_0); //背景色 @property(nullable, nonatomic,strong) UIColor *barTintColor NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //被选中的图片选染色 @property(nullable,nonatomic,strong) UIColor *selectedImageTintColor NS_DEPRECATED_IOS(5_0,8_0,"Use tintColor") UI_APPEARANCE_SELECTOR; //背景图 @property(nullable, nonatomic,strong) UIImage *backgroundImage NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; //选中指示图 @property(nullable, nonatomic,strong) UIImage *selectionIndicatorImage NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; //阴影图 @property(nullable, nonatomic,strong) UIImage *shadowImage NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR; @property(nonatomic) UITabBarItemPositioning itemPositioning NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //元素宽度 @property(nonatomic) CGFloat itemWidth NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //item间隔 @property(nonatomic) CGFloat itemSpacing NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //风格 @property(nonatomic) UIBarStyle barStyle NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; //是否透明 @property(nonatomic,getter=isTranslucent) BOOL translucent NS_AVAILABLE_IOS(7_0); @end
UITabBar包含多个UITabBarItem,每?个UITabBarItem对应?个UIViewController。UITabBar的?度是49;系统最多只显?5个UITabBarItem,当UITabBarItem超过5个时系统会?动增加?个更多按钮,点击更多按钮没有在底部出现的按钮会以列表的形式显?出来.
五:UITabBarDelegate内容
@protocol UITabBarDelegate<NSObject> @optional - (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item; // called when a new view is selected by the user (but not programatically) - (void)tabBar:(UITabBar *)tabBar willBeginCustomizingItems:(NSArray<UITabBarItem *> *)items; - (void)tabBar:(UITabBar *)tabBar didBeginCustomizingItems:(NSArray<UITabBarItem *> *)items; - (void)tabBar:(UITabBar *)tabBar willEndCustomizingItems:(NSArray<UITabBarItem *> *)items changed:(BOOL)changed; - (void)tabBar:(UITabBar *)tabBar didEndCustomizingItems:(NSArray<UITabBarItem *> *)items changed:(BOOL)changed; @end
对于点击哪个UITabBarItem响应事件则是在这个委托里面进行;由于UITabBarController已经遵守了UITabBarDelegate协议,如果有继承UITabBarController已经可以直接运用UITabBarDelegate里面的内容;
知识点1:iOS 点击UITabBar触发刷新
平常我们在切换UITabBarController底部菜单时,它是不会有刷新的功能;如果要实现刷新的效果可以如下实现;原理如下,在监听UITabBar点击的方法中判断本次点击的UITabBarItem和上次点击的是否一样,如果一样就发出通知,首先需要自定义一个UITabBarController (比如LLTabBarController);要判断本次点击的UITabBarItem和上次点击的是否一样,就需要定义一个属性记录下来上次点击的UITabBarItem,并在viewWillAppear:方法中给该属性赋值默认的UITabBarItem
/** 之前被选中的UITabBarItem */ @property (nonatomic, strong) UITabBarItem *lastItem; - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; // 将默认被选中的tabBarItem保存为属性 self.lastItem = self.tabBar.selectedItem; } - (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item { // 判断本次点击的UITabBarItem是否和上次的一样 if (item == self.lastItem) { // 一样就发出通知 [[NSNotificationCenter defaultCenter] postNotificationName:@"LLTabBarDidClickNotification" object:nil userInfo:nil]; } // 将这次点击的UITabBarItem赋值给属性 self.lastItem = item; }
在需要实现点击UITabBar触发刷新功能的控制器中监听通知
- (void)viewDidLoad { [super viewDidLoad]; // 监听UITabBarItem被重复点击时的通知 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(tabBarDidClick) name:@"LLTabBarDidClickNotification" object:nil]; } - (void)tabBarDidClick { // 如果本控制器的view显示在最前面,就下拉刷新 if ([self.view isShowingOnKeyWindow]) { // 判断一个view是否显示在根窗口上,该方法在UIView的分类中实现 [self.tableView.header beginRefreshing]; // MJRefresh } }
判断一个view是否显示在根窗口上
/** 该方法在UIView的分类中实现 */ - (BOOL)isShowingOnKeyWindow { UIWindow *keyWindow = [UIApplication sharedApplication].keyWindow; // 把这个view在它的父控件中的frame(即默认的frame)转换成在window的frame CGRect convertFrame = [self.superview convertRect:self.frame toView: keyWindow]; CGRect windowBounds = keyWindow.bounds; // 判断这个控件是否在主窗口上(即该控件和keyWindow有没有交叉) BOOL isOnWindow = CGRectIntersectsRect(convertFrame, windowBounds); // 再判断这个控件是否真正显示在窗口范围内(是否在窗口上,是否为隐藏,是否透明) BOOL isShowingOnWindow = (self.window == keyWindow) && !self.isHidden && (self.alpha > 0.01) && isOnWindow; return isShowingOnWindow; }
在控制器销毁时要移除通知
- (void)dealloc { // 移除通知 [[NSNotificationCenter defaultCenter] removeObserver:self]; }
六:UITabBarItem的定义
NS_CLASS_AVAILABLE_IOS(2_0) @interface UITabBarItem : UIBarItem - (instancetype)init NS_DESIGNATED_INITIALIZER; //初始化几中方式 - (nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER; - (instancetype)initWithTitle:(nullable NSString *)title image:(nullable UIImage *)image tag:(NSInteger)tag; //初始化 标是 图标 选中图标 - (instancetype)initWithTitle:(nullable NSString *)title image:(nullable UIImage *)image selectedImage:(nullable UIImage *)selectedImage NS_AVAILABLE_IOS(7_0); - (instancetype)initWithTabBarSystemItem:(UITabBarSystemItem)systemItem tag:(NSInteger)tag; //给当前的分栏控制器的item设置一个选中状态的图片 @property(nullable, nonatomic,strong) UIImage *selectedImage NS_AVAILABLE_IOS(7_0); //角标 @property(nullable, nonatomic, copy) NSString *badgeValue; //IOS7以后过期 - (void)setFinishedSelectedImage:(nullable UIImage *)selectedImage withFinishedUnselectedImage:(nullable UIImage *)unselectedImage NS_DEPRECATED_IOS(5_0,7_0,"Use initWithTitle:image:selectedImage: or the image and selectedImage properties along with UIImageRenderingModeAlwaysOriginal"); //IOS7以后过期 - (nullable UIImage *)finishedSelectedImage NS_DEPRECATED_IOS(5_0,7_0); //IOS7以后过期 - (nullable UIImage *)finishedUnselectedImage NS_DEPRECATED_IOS(5_0,7_0); //文字的偏移 @property (nonatomic, readwrite, assign) UIOffset titlePositionAdjustment NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; @end
知识点1:tabBarItem相关属性运用
1) 用来控制一组控制器的切换,类似选项卡,每个Tab控制一个试图控制器,点击哪个tab就显示对应的试图控制器,当前的试图控制器 2) 每个tabBarItem都可以设置title、image/selectedImages、badgeValue 例如: (1).给当前的分栏控制器的item设置一个标题 self.tabBarItem.title = @"我的"; (2).给当前的分栏控制器的item设置一个图片 self.tabBarItem.image = [UIImage imageNamed:@"[email protected]"]; (3).给当前的分栏控制器的item设置一个选中状态的图片 self.tabBarItem.selectedImage = [UIImage imageNamed:@"[email protected]"];//@2x表示给高清屏 30*30的效果好 self.tabBarItem.badgeValue = @"new";//在小图标的上面家字体加字体 3) 设置选中的颜色 分栏控制器.tabBar.tintColor self.tabBarController.tabBar.tintColor = [UIColor redColor]; 3) TabBar只能显示五个tab Item,如果超过五个则会自动生成个Morede 标签显示剩余的Tab,这些Tab可以通过编辑显示在UITabBar上(打开页面后自动显示在界面,点击tabBar右边) 4) 自定义Item [UITabBarItem alloc]initWithTitle: image: tag: [UITabBarItem alloc]initWithTabBarSystemItem:tag: