界面搭建 移除系统自带tabbar上的按钮

修改导航栏上的背景和字体颜色
移除系统tabbar上的按钮
按钮的选中与取消

界面搭建一般都是三级控制器，标签控制器-->导航控制器-->视图控制器

这里，因为每个标签项管理的视图有的是一样的，所以我们可以用继承的办法

以阿里星球项目为例, 其他控制器都继承BaseViewController，一些相同的内容都写在这里

@interface DynamicViewController : BaseViewController

修改导航栏上的背景

//1.设置导航栏的背景图片
    [self.navigationBar setBackgroundImage:[UIImage imageNamed:@"nav_bg"] forBarMetrics:UIBarMetricsDefault];
    
    //2.设置导航栏标题的字体颜色
    NSDictionary *dic = @{NSForegroundColorAttributeName:[UIColor whiteColor],
                          NSFontAttributeName:[UIFont systemFontOfSize:16]};
    
    [self.navigationBar setTitleTextAttributes:dic];

移除系统tabbar上的按钮

/**
 *  自定义TabbarController
 
 1.设置tabbarController 的viewControllers
 2.移除系统的按钮和tabbar
 3.创建 自定义的tabbar
 
 */
@implementation AliTabbarController

- (void)viewDidLoad {
    [super viewDidLoad];

    //1.设置tabbarController 的viewControllers
    [self creatViewControllers];
    
    //2.移除系统自带的tabbar的子视图
    [self removeSystemTabbarSubviews];
    
    //3.自定义tabbar 上控件
    [self creatSubViews];
    
    
    
}

#pragma mark - 1.设置viewController
-(void)creatViewControllers {
    
    //1.创建视图控制器
    DynamicViewController *dynamic = [[DynamicViewController alloc] init];
    DIscoverViewController *discover = [[DIscoverViewController alloc] init];
    MessageViewController *message = [[MessageViewController alloc] init];
    MineViewController *mine = [[MineViewController alloc] init];
    
    //2.给每一个视图控制器添加导航控制器
    NSArray *controllers = @[dynamic,discover,message,mine];
    
    NSMutableArray *navis = [[NSMutableArray alloc] initWithCapacity:4];
    
    for (UIViewController *viewController in controllers) {
        
        //创建导航控制器
        BaseNavigationController *navigation = [[BaseNavigationController alloc] initWithRootViewController:viewController];
        
        [navis addObject:navigation];
    }
    
    self.viewControllers = navis;
}

#pragma mark - 2.移除系统自带的tabbar的子视图
-(void)removeSystemTabbarSubviews {
    
    for (UIView *view in self.tabBar.subviews) {
        NSLog(@"%@",view);
        //判断子视图 是否属于这类 UITabBarButton
        
        //1.[类名 class] 得出这个类
        //2.NSClassFromString(NSString) 使用字符串转换得出一个类
        
        if ([view isKindOfClass:NSClassFromString(@"UITabBarButton")]) {
            
            [view removeFromSuperview];
        }
    }
}

#pragma mark - 3.自定义tabbar子视图
-(void)creatSubViews {
    //1.创建tabbar背景图片视图

    UIImageView *bjImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, kScreenW, kTabbar)];
    
    
    bjImageView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"tabBarViewBg"]];
    
    [self.tabBar addSubview:bjImageView];
    
    
    
    
    CGFloat itemWidth = kScreenW / 4.0;
    
    
    NSArray *imageNames = @[@"trends",@"find",@"message",@"my"];
    
    
    //2.创建四个按钮
    for (int  i = 0; i <self.viewControllers.count; i++) {
        
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        
        //设置按钮frame
        button.frame = CGRectMake(i * itemWidth, 0, itemWidth, kTabbar);
        
        //设置图片
        NSString *imageNormal = [NSString stringWithFormat:@"trends_%@_normal",imageNames[i]];
        NSString *imageSelected = [NSString stringWithFormat:@"trends_%@_click",imageNames[i]];
        
        [button setImage:[UIImage imageNamed:imageNormal] forState:UIControlStateNormal];
        [button setImage:[UIImage imageNamed:imageSelected] forState:UIControlStateSelected];
        
        
        button.tag = 1000 + i;
        
        //设置第一个按钮为选中状态
        if (button.tag == 1000) {
            button.selected = YES;
        }
        
        [button addTarget:self
                   action:@selector(clickBtn:)
         forControlEvents:UIControlEventTouchUpInside];
        
        
        [self.tabBar addSubview:button];
        
    }

}

-(void)clickBtn:(UIButton *)sender {
    
    
    NSInteger index = sender.tag - 1000;
    
    //1.切换视图控制器
    self.selectedIndex = index;
    
    //2.修改按钮的旋钮的选中状态
    for (int i = 0; i < self.viewControllers.count; i++) {
        
        UIButton *btn = (UIButton *)[self.tabBar viewWithTag:1000 + i];
        
        btn.selected = NO;
    }
    
    sender.selected = !sender.selected;
    
    
}