[iOS]系统UITabBarController详解及自定义

对于UITabBarController, 大家都不陌生, 但是有时候又不那么的熟悉, 下面就来再认识一下这个熟悉的陌生人.

以下使用微信的tabBar图标;

一. 系统UITabBarController基本使用

1.1 基本用法

UITabBarController的使用, 其实很简单, 这里直接给出相应代码:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    // Override point for customization after application launch.    // 初始化UITabBarController实例对象    UITabBarController *tabBar = [[UITabBarController alloc]init];    // 创建子控制器    UIViewController *vc1 = [[UIViewController alloc]init];    vc1.view.backgroundColor = [UIColor redColor];    // 设置标题    vc1.tabBarItem.title = @"微信";    // 设置选中状态的图片    vc1.tabBarItem.selectedImage = [UIImage imageNamed:@"tabbar_mainframeHL"];    // 设置未选中状态的图片    vc1.tabBarItem.image = [UIImage imageNamed:@"tabbar_mainframe"] ;    // 设置右上角显示数字(例如: 未读消息数目)    vc1.tabBarItem.badgeValue = @"100";    // 右上角数字背景色    vc1.tabBarItem.badgeColor = [UIColor greenColor];    UIViewController *vc2 = [[UIViewController alloc]init];    vc2.view.backgroundColor = [UIColor orangeColor];    vc2.tabBarItem.title = @"联系人";    vc2.tabBarItem.selectedImage = [UIImage imageNamed:@"tabbar_contactsHL"];    vc2.tabBarItem.image = [UIImage imageNamed:@"tabbar_contacts"];    UIViewController *vc3 = [[UIViewController alloc]init];    vc3.view.backgroundColor = [UIColor cyanColor];    vc3.tabBarItem.title = @"发现";    vc3.tabBarItem.image = [UIImage imageNamed:@"tabbar_discover"];    vc3.tabBarItem.selectedImage = [UIImage imageNamed:@"tabbar_discoverHL"];    UIViewController *vc4 = [[UIViewController alloc]init];    vc4.view.backgroundColor = [UIColor whiteColor];    vc4.tabBarItem.title = @"我";    vc4.tabBarItem.image = [UIImage imageNamed:@"tabbar_me"];    vc4.tabBarItem.selectedImage = [UIImage imageNamed:@"tabbar_meHL"];    // 添加子视图到tabbar    tabBar.viewControllers = @[vc1, vc2, vc3, vc4];    // 设置为window跟视图    self.window.rootViewController = tabBar;    return YES;}

以上代码直接写在xxAppDelegate.m的上面这个方法里即可;
效果如下:

注意:这里使用的是微信的图标, 是绿色的, 设置完后变成了蓝色, 而且上面也没有设置选中及未选中文字的颜色, 这里都被默认设置了, 最主要的是没有显示我原先图标的颜色.( 这样美工是不同意的 ��).

1.2. 显示原图

根据上面的问题, 我们先来看看图标的问题, 为了不被系统渲染成蓝色, 这里我们在设置各个控制器的选中和未选中的图标的时候, 调用一下UIImage的这个方法即可imageWithRenderingMode:

// 设置选中状态的图片    vc1.tabBarItem.selectedImage = [[UIImage imageNamed:@"tabbar_mainframeHL"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];    // 设置未选中状态的图片    vc1.tabBarItem.image = [[UIImage imageNamed:@"tabbar_mainframe"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

这样就能正确显示我们原先的图片了;

1.3 修改文字颜色

但是文字的颜色并不是我们需要的, 我们可以通过下面的方法, 来修改文字的颜色:

// 未选中状态下文字颜色 [vc1.tabBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor redColor]} forState:UIControlStateNormal];// 选中状态下的文字颜色 [vc1.tabBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blueColor]} forState:UIControlStateSelected];

这是设置选中和未选中状态下的标题属性, 效果如下:

这里我只是修改了前两个控制器的文字, 后面的还是用的默认的.
上面是修改按钮标题的文字属性, 按钮右上角的角标的文字属性, 可使用下面的方法来修改:

// 未选中状态下的角标文字颜色[vc1.tabBarItem setBadgeTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]} forState:UIControlStateNormal];// 选中状态下的角标文字颜色 [vc1.tabBarItem setBadgeTextAttributes:@{NSForegroundColorAttributeName: [UIColor orangeColor]} forState:UIControlStateSelected];

以上就是系统自带UITabBarController及相关属性的设置, 对于图标规则的需求基本都能满足, 如果还有其他的需求, 系统不能满足的, 就只能自定义了.

二. 自定义tabBarController

对于自定义的tabBar, 我们一般还是定义为UITabBarController的子类:

@interface LZTabBarController : UITabBarController

这样我们可以借助UITabBarController的一些属性和方法, 例如切换控制器; 不用再去写切换的逻辑;
实际上, 我们说的自定义的tabBar, 对数情况下是自定义的底部的tabBar; 所以, 我们的重点是来设置底部视图的实现.
我们自定义的时候, 一般有两种选择:
- 一种是, 隐藏掉系统的tabBar, 完全重新布局;
- 另一种是, 使用系统的tabBar, 但是自定义tabBarItem

不管是哪一种, 都需要自定义一个tabBarItem, 所以, 先来看看怎么定义这个tabBarItem;

2.1 自定义item –LZTabBarItem

这个类, 主要做的是布局item, 及响应点击事件

我们定义一个类* LZTabBarItem*, 继承自UIView, .h声明文件如下:

////  LZTabBarItem.h//  LZTabBarController////  Created by Artron_LQQ on 2016/12/12.//  Copyright © 2016年 Artup. All rights reserved.//@protocol LZTabBarItemDelegate;@interface LZTabBarItem : UIView@property (nonatomic, copy) NSString *icon;@property (nonatomic, copy) NSString *title;@property (nonatomic, strong) UIColor *titleColor;@property (nonatomic, assign) id <LZTabBarItemDelegate> delegate;@end@protocol LZTabBarItemDelegate <NSObject>- (void)tabBarItem:(LZTabBarItem *)item didSelectIndex:(NSInteger)index;@end

这里使用代理来回调点击事件; .m实现如下:

////  LZTabBarItem.m//  LZTabBarController////  Created by Artron_LQQ on 2016/12/12.//  Copyright © 2016年 Artup. All rights reserved.//#import "LZTabBarItem.h"static NSInteger defaultTag = 100000;@interface LZTabBarItem ()@property (nonatomic, strong)UIImageView *iconImageView;@property (nonatomic, strong)UILabel *titleLabel;@end@implementation LZTabBarItem- (instancetype)init {    self = [super init];    if (self) {        self.userInteractionEnabled = YES;        UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(itemClicked:)];        [self addGestureRecognizer:tap];    }    return self;}// 重写setTag方法- (void)setTag:(NSInteger)tag {    [super setTag:tag + defaultTag];}- (UIImageView *)iconImageView {    if (_iconImageView == nil) {        _iconImageView = [[UIImageView alloc]init];        _iconImageView.contentMode = UIViewContentModeScaleAspectFit;        [self addSubview:_iconImageView];    }    return _iconImageView;}- (UILabel *)titleLabel {    if (_titleLabel == nil) {        _titleLabel = [[UILabel alloc]init];        _titleLabel.textAlignment = NSTextAlignmentCenter;        _titleLabel.font = [UIFont systemFontOfSize:10];        _titleLabel.numberOfLines = 0;        _titleLabel.textColor = [UIColor grayColor];        [self addSubview:_titleLabel];    }    return _titleLabel;}- (void)setIcon:(NSString *)icon {    _icon = icon;    self.iconImageView.image = [UIImage imageNamed:icon];}- (void)setTitle:(NSString *)title {    _title = title;    self.titleLabel.text = title;}- (void)setTitleColor:(UIColor *)titleColor {    _titleColor = titleColor;    self.titleLabel.textColor = titleColor;}- (void)layoutSubviews {    [super layoutSubviews];    CGFloat space = 6.0;    if (self.icon.length > 0 && self.title.length > 0) {        CGFloat iconHeight = (CGRectGetHeight(self.frame) - space * 3)*2/3.0 ;        self.iconImageView.frame = CGRectMake(space, space, CGRectGetWidth(self.frame) - 2 * space, iconHeight);        self.titleLabel.frame = CGRectMake(space, CGRectGetMaxY(self.iconImageView.frame) + space, CGRectGetWidth(self.frame) - 2*space, iconHeight/2.0);    } else if (self.icon.length > 0) {        self.iconImageView.frame = CGRectMake(2, 2, CGRectGetWidth(self.frame) - 4, CGRectGetHeight(self.frame) - 4);    } else if (self.title.length > 0) {        self.titleLabel.frame = CGRectMake(2, CGRectGetHeight(self.frame) - 22, CGRectGetWidth(self.frame) - 4, 20);    }}- (void)itemClicked:(UITapGestureRecognizer *)tap {    if (self.delegate && [self.delegate respondsToSelector:@selector(tabBarItem:didSelectIndex:)]) {        [self.delegate tabBarItem:self didSelectIndex:self.tag - defaultTag];    }}/*// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code}*/@end

其实, 很简单, 只是添加了一个imageView, 一个label, 和一个单击手势来响应点击事件. 这里我是在* layoutSubviews*方法里来布局子视图的, 这样当视图frame改变的时候, 其子视图会做相应的调整;
这样,tabBarItem的自定义就完成了,接下来就是自定义tabBar;
tabBar的定义, 有两种方法:
- 一个是继承自UIView, 完全自定义;
- 一个是继承自UITabBar;

2.2 继承自UIView

先来看一下继承自UIView, 完全自定义的方法:

////  LZTabBar.h//  LZTabBarController////  Created by Artron_LQQ on 2016/12/12.//  Copyright © 2016年 Artup. All rights reserved.//#import <UIKit/UIKit.h>@class LZTabBarItem;@protocol LZTabBarDelegate;@interface LZTabBar : UIView@property (nonatomic, strong)NSArray<LZTabBarItem *> *items;@property (nonatomic, assign)id <LZTabBarDelegate> delegate;@end@protocol LZTabBarDelegate <NSObject>- (void)tabBar:(LZTabBar *)tab didSelectItem:(LZTabBarItem *)item atIndex:(NSInteger)index ;@end

这里是.h文件内容, 其属性比较简单, 只设置了delegate和items;
.m的实现如下:

////  LZTabBar.m//  LZTabBarController////  Created by Artron_LQQ on 2016/12/12.//  Copyright © 2016年 Artup. All rights reserved.//#import "LZTabBar.h"#import "LZTabBarItem.h"@interface LZTabBar ()<LZTabBarItemDelegate>@property (nonatomic, strong) UIVisualEffectView *effectView;@property (nonatomic, strong) UIView *topLine;@end@implementation LZTabBar- (instancetype)init {    self = [super init];    if (self) {        self.backgroundColor = [UIColor whiteColor];    }    return self;}- (UIView *)topLine {    if (_topLine == nil) {        _topLine = [[UIView alloc]init];        _topLine.backgroundColor = [UIColor grayColor];        [self addSubview:_topLine];    }    return _topLine;}- (UIVisualEffectView *)effectView {    if (_effectView == nil) {        UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];        _effectView = [[UIVisualEffectView alloc] initWithEffect:effect];        _effectView.alpha = 1.0;        [self addSubview:_effectView];    }    return _effectView;}- (void)layoutSubviews {    [super layoutSubviews];    self.effectView.frame = self.bounds;    [self setupItems];    self.topLine.frame = CGRectMake(0, 0, CGRectGetWidth(self.frame), 0.6);}- (void)setupItems {    CGFloat width = CGRectGetWidth(self.frame)/self.items.count;    CGFloat height = CGRectGetHeight(self.frame);    for (int i = 0; i < self.items.count; i++) {        LZTabBarItem *item = [self.items objectAtIndex:i];        item.frame = CGRectMake(i*width, 0, width, height);        [self addSubview:item];        item.delegate = self;    }}- (void)tabBarItem:(LZTabBarItem *)item didSelectIndex:(NSInteger)index {    if (self.delegate && [self.delegate respondsToSelector:@selector(tabBar:didSelectItem:atIndex:)]) {        [self.delegate tabBar:self didSelectItem:item atIndex:index];    }}/*// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code}*/@end

这个类的主要作用是: 布局各个item, 在tabBar的位置, 及tabBar的一些内容.

接下来, 就是定义LZTabBarController了;

2.3 自定义LZTabBarController

这个类的主要作用是: 提供数据源, 绘制底部tabBar, 及关联viewController;

在提供数据的时候, 我单独设置了一个类类储存这些数据, 而没有直接设置为* LZTabBarController*的属性:

#pragma mark - LZTabBarConfig@interface LZTabBarConfig : NSObject/** 控制器数组, 必须设置 */@property (nonatomic, strong) NSArray *viewControllers;/** item标题数组, 选择设置 */@property (nonatomic, strong) NSArray *titles;/** 是否是导航, 默认 YES */@property (nonatomic, assign) BOOL isNavigation;/** 选中状态下的图片数组 */@property (nonatomic, strong) NSArray *selectedImages;/** 正常状态下的图片数组 */@property (nonatomic, strong) NSArray *normalImages;/** 选中状态下的标题颜色 默认: red */@property (nonatomic, strong) UIColor *selectedColor;/** 正常状态下的标题颜色 默认: gray */@property (nonatomic, strong) UIColor *normalColor;@end

提供数据源的时候, 只需要配置这个config即可;
其.m文件, 只是设置了一些默认值:

@implementation LZTabBarConfig- (instancetype)init {    self = [super init];    if (self) {        _isNavigation = YES;        _normalColor = [UIColor grayColor];        _selectedColor = [UIColor redColor];    }    return self;}@end

下面, 回到* LZTabBarController*, 其.h的声明, 就简洁许多:

#import <UIKit/UIKit.h>@class LZTabBarConfig;typedef LZTabBarConfig*(^tabBarBlock)(LZTabBarConfig *config);@interface LZTabBarController : UITabBarController/** 是否可用自动旋转屏幕 */@property (nonatomic, assign) BOOL isAutoRotation;/** 创建tabBarController @param block 配置创建tabBarController所需的参数 @return 返回tabBarController实例对象 */+ (instancetype)createTabBarController:(tabBarBlock)block;/** 获取当前的tabBarController实例, 实例创建后可通过此方法获取当前实例 @return 返回tabBarController实例对象 */+ (instancetype)defaultTabBarController;/** 隐藏底部tabBar的方法 @param isAnimation 是否需要动画 */- (void)hiddenTabBarWithAnimation:(BOOL)isAnimation;/** 显示底部tabBar的方法 @param isAnimation 是否需要动画 */- (void)showTabBarWithAnimation:(BOOL)isAnimation;@end

只是提供了创建的方法, 及获取当前实例和隐藏/显示底部tabBar的方法;
.m中的实现:

////  LZTabBarController.m//  LZTabBarController////  Created by Artron_LQQ on 2016/12/12.//  Copyright © 2016年 Artup. All rights reserved.//#import "LZTabBarController.h"#import "LZTabBar.h"static CGFloat lzTabBarHeight = 49.0;@interface LZTabBarController ()<LZTabBarDelegate>@property (nonatomic, strong) LZTabBar *customTabBar;@property (nonatomic, strong) LZTabBarConfig *config;@end@implementation LZTabBarController- (LZTabBar *)customTabBar {    if (_customTabBar == nil) {        _customTabBar = [[LZTabBar alloc]init];        _customTabBar.delegate = self;    }    return _customTabBar;}+ (instancetype)createTabBarController:(tabBarBlock)block {    static dispatch_once_t onceToken;    static LZTabBarController *tabBar;    dispatch_once(&onceToken, ^{        tabBar = [[LZTabBarController alloc]initWithBlock:block];    });    return tabBar;}+ (instancetype)defaultTabBarController {    return [LZTabBarController createTabBarController:nil];}- (void)hiddenTabBarWithAnimation:(BOOL)isAnimation {    if (isAnimation) {        [UIView animateWithDuration:0.2 animations:^{            self.customTabBar.alpha = 0;        }];    } else {        self.customTabBar.alpha = 0;    }}- (void)showTabBarWithAnimation:(BOOL)isAnimation {    if (isAnimation) {        [UIView animateWithDuration:0.2 animations:^{            self.customTabBar.alpha = 1.0;        }];    } else {        self.customTabBar.alpha = 1.0;    }}- (instancetype)initWithBlock:(tabBarBlock)block {    self = [super init];    if (self) {        LZTabBarConfig *config = [[LZTabBarConfig alloc]init];        NSAssert(block, @"Param in zhe function, can not be nil");        if (block) {            _config = block(config);        }        NSAssert(_config.viewControllers, @"Param 'viewControllers' in the 'config', can not be nil");        [self setupViewControllers];        [self setupTabBar];        _isAutoRotation = YES;    }    return self;}- (void)setupViewControllers {    if (_config.isNavigation) {        NSMutableArray *vcs = [NSMutableArray arrayWithCapacity:_config.viewControllers.count];        for (UIViewController *vc in _config.viewControllers) {            if (![vc isKindOfClass:[UINavigationController class]]) {                UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:vc];                [vcs addObject:nav];            } else {                [vcs addObject:vc];            }        }        self.viewControllers = [vcs copy];    } else {        self.viewControllers = [_config.viewControllers copy];    }}- (void)setupTabBar {    NSMutableArray *items = [NSMutableArray array];    for (int i = 0; i < _config.viewControllers.count; i++) {        LZTabBarItem *item = [[LZTabBarItem alloc]init];        if (i == 0) {            item.icon = _config.selectedImages[i];            if (_config.titles.count > 0) {                item.titleColor = _config.selectedColor;            }        } else {            item.icon = _config.normalImages[i];            if (_config.titles.count > 0) {                item.titleColor = _config.normalColor;            }        }        if (i < _config.titles.count) {            item.title = _config.titles[i];        }        [items addObject:item];        item.tag = i;    }    // 隐藏掉系统的tabBar    self.tabBar.hidden = YES;    self.customTabBar.items = [items copy];    self.customTabBar.frame = CGRectMake(0, CGRectGetHeight(self.view.frame) - lzTabBarHeight, CGRectGetWidth(self.view.frame), lzTabBarHeight);    [self.view addSubview:self.customTabBar];}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view.    self.view.backgroundColor = [UIColor whiteColor];    self.selectedIndex = 0;}#pragma mark - LZTabBarDelegate- (void)tabBar:(LZTabBar *)tab didSelectItem:(LZTabBarItem *)item atIndex:(NSInteger)index {    NSMutableArray *items = [NSMutableArray arrayWithCapacity:0];    for (UIView *view in tab.subviews) {        if ([view isKindOfClass:[LZTabBarItem class]]) {            [items addObject:view];        }    }    for (int i = 0; i < items.count; i++) {        UIView *view = items[i];        if ([view isKindOfClass:[LZTabBarItem class]]) {            LZTabBarItem *item = (LZTabBarItem *)view;            item.icon = self.config.normalImages[i];            if (self.config.titles.count > 0) {                item.titleColor = _config.normalColor;            }        }    }    item.icon = self.config.selectedImages[index];    if (self.config.titles.count > 0) {        item.titleColor = self.config.selectedColor;    }    self.selectedIndex = index;}// 屏幕旋转时调整tabbar- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];    self.customTabBar.frame = CGRectMake(0, size.height - lzTabBarHeight, size.width, lzTabBarHeight);}- (BOOL)shouldAutorotate {    return self.isAutoRotation;}- (UIInterfaceOrientationMask)supportedInterfaceOrientations {    if (self.isAutoRotation) {        return UIInterfaceOrientationMaskAllButUpsideDown;    } else {        return UIInterfaceOrientationMaskPortrait;    }}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}/*#pragma mark - Navigation// In a storyboard-based application, you will often want to do a little preparation before navigation- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {    // Get the new view controller using [segue destinationViewController].    // Pass the selected object to the new view controller.}*/@end

这里主要的其实就是, * setupTabBar*方法
和* LZTabBarDelegate*的代理方法tabBar:(LZTabBar )tab didSelectItem:(LZTabBarItem )item atIndex:(NSInteger)index, 需要处理一些状态的转换;
到此, 第一种的自定义就结束了, 效果如下:

需要注意的是:
因为我们自定义了tabBar , 所以控制器的属性hidesBottomBarWhenPushed 就失去效果了, 解决的方法可以是在合适的地方来调用隐藏/显示的方法;
如果, 还想使用系统的* hidesBottomBarWhenPushed*效果, 可在使用的时候, 调整一下方法:一般, 我们是直接将tabBarController作为window的rootvc, 然后在其子控制器分别加上导航, 我们可以做如下调整:
将tabBar作为UINavigationController的rootvc, 然后把这个导航作为window的rootvc:

// 为了能够使用hidesBottomBarWhenPushed, 不直接把tabBar设置为window的跟视图, 而是设置为导航的rootvc, 然后把导航设置为window的跟视图    // 这样, 在子控制器上就不用再添加导航了, 即设置: config.isNavigation = NO;    UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:tab];// 打开hidesBottomBarWhenPushed    nav.hidesBottomBarWhenPushed = YES;    self.window.rootViewController = nav;

这样做, 需要注意的是, 其子控制器就不用再添加导航了.

这样, 就会有上面Gif的效果;
demo地址: LZTabBarController

2.4 继承自UITabBar

继承自UITabBar的方式, 与继承自UIView, 主要的区别是LZTabBar的内容, 其他如LZTabBarItem 和LZTabBarController相关逻辑都是一样的;

#import <UIKit/UIKit.h>@class LZTabBarItem;@protocol LZTabBarDelegate;@interface LZTabBar : UITabBar@property (nonatomic, strong)NSArray<LZTabBarItem *> *lzItems;@property (nonatomic, assign)id <LZTabBarDelegate> lzDelegate;@end@protocol LZTabBarDelegate <NSObject>- (void)tabBar:(LZTabBar *)tab didSelectItem:(LZTabBarItem *)item atIndex:(NSInteger)index ;@end

.m的实现中, 主要是将系统的item移除掉, 然后添加上自定义的item:

#import "LZTabBar.h"@interface LZTabBar ()<LZTabBarItemDelegate>@end@implementation LZTabBar- (instancetype)init {    self = [super init];    if (self) {        self.backgroundColor = [UIColor whiteColor];    }    return self;}- (void)layoutSubviews {    [super layoutSubviews];    // 移除系统的tabBarItem    Class class = NSClassFromString(@"UITabBarButton");    for (UIView *item in self.subviews) {        if ([item isKindOfClass:class]) {            [item removeFromSuperview];        }    }    // 设置自定义的tabBarItem    [self setupItems];}- (void)setupItems {    CGFloat width = CGRectGetWidth(self.frame)/self.items.count;    CGFloat height = CGRectGetHeight(self.frame);    for (int i = 0; i < self.lzItems.count; i++) {        LZTabBarItem *item = [self.lzItems objectAtIndex:i];        item.frame = CGRectMake(i*width, 0, width, height);        [self addSubview:item];        item.delegate = self;    }}- (void)tabBarItem:(LZTabBarItem *)item didSelectIndex:(NSInteger)index {    if (self.lzDelegate && [self.lzDelegate respondsToSelector:@selector(tabBar:didSelectItem:atIndex:)]) {        [self.lzDelegate tabBar:self didSelectItem:item atIndex:index];    }}/*// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code}*/@end

其最终的效果是一样的, 只不过我们可以在执行push操作的时候使用控制器的* hidesBottomBarWhenPushed*属性来隐藏底部的tabBar;

(完)