iOS自定义TabBar

• iOS自定义TabBar一般有两种方式：
  1. 创建一个类继承字UITabBar，在layoutSubviews方法中重新调整按钮的位置，再通过[self setValue:tabBar forKeyPath:@"tabBar"]方法，利用KVC设置TabBar，但是iOS 13后苹果粑粑不鼓励使用KVC。

  2. 这篇文章主要讲第二种方法：创建一个继承UIView的类WSTabBar，然后把系统UITabBar上的UITabBarItem移除，然后把WSTabBar加到系统TabBar的位置上，效果图如下：

     
     tabbar截图.png

一、自定义一个TabBar，其实就是自定义个UIView，然后布局5个按钮，为了方便我请设计把图片和文字都切在一起了。

#import "WSTabBar.h"

#import "WSTabBarButton.h"

@interface WSTabBar ()
/// 记录上一个按钮
@property (nonatomic, weak) UIButton *preButton;

@end

@implementation WSTabBar

+ (instancetype)tabBarWithSBNames:(NSArray *)sbNames {
    WSTabBar *tabBar = [[WSTabBar alloc] init];
    
    //创建图片对应的按钮 -- tabBarItem
    for (NSString *sbName in sbNames) {
        WSTabBarButton *btn = [WSTabBarButton buttonWithType:UIButtonTypeCustom];
        
        //记录按钮的索引
        btn.tag = tabBar.subviews.count;
        
        [tabBar addSubview:btn];
        
        //加载按钮中显示的图片
        NSString *imgName = [NSString stringWithFormat:@"TabBar_%@",sbName];
        NSString *selectedImgName = [NSString stringWithFormat:@"TabBar_%@_selected",sbName];
        
        //设置按钮的图片
        [btn setImage:[UIImage imageNamed:imgName] forState:UIControlStateNormal];
        [btn setImage:[UIImage imageNamed:selectedImgName] forState:UIControlStateSelected];
        [btn.imageView setContentMode:UIViewContentModeScaleAspectFit];
        //给按钮注册点击事件
        [btn addTarget:tabBar action:@selector(btnClick:) forControlEvents:UIControlEventTouchDown];
    }
    //让第一个按钮选中
    UIButton *btn = [tabBar.subviews firstObject];
    [tabBar btnClick:btn];
    
    return tabBar;
}

//点击按钮
- (void)btnClick:(UIButton *)sender {
    //让上一个按钮不选中
    self.preButton.selected = NO;
    //让当前按钮选中
    sender.selected = YES;
    //记录上一个按钮
    self.preButton = sender;
    
    //合适的时机调用代理方法
    if ([self.delegate respondsToSelector:@selector(tabBarDidClickedButton:selectedIndex:)]) {
        [self.delegate tabBarDidClickedButton:self selectedIndex:sender.tag];
    }
}

//设置按钮的位置
- (void)layoutSubviews {
    [super layoutSubviews];
    
    CGFloat btnW = self.bounds.size.width / self.subviews.count;
    CGFloat btnX = 0;
    CGFloat btnH;
    CGFloat btnY;
    
    for (int i = 0; i < self.subviews.count; i++) {
        UIButton *btn = self.subviews[i];
        //设置按钮的位置
        if (i == 2) { // 中间不规则按钮位置计算
            btnY = -7;
            btnH = 56;
        } else { // 普通按钮位置计算
            btnY = 0;
            btnH = self.bounds.size.height;
        }
        btnX = i * btnW;
        
        btn.frame = CGRectMake(btnX, btnY, btnW, btnH);
        
    }
}
@end

二、再自定义一个UITabBarController，将系统的UITabBarItem移除，防止重影，然后将自定义UIView加到UITabBar。

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

}

- (void)viewWillLayoutSubviews {
    [super viewWillLayoutSubviews];
    // 移除系统TabBar的UITabBarItem
    for (UIView *view in self.tabBar.subviews) {
        if (![view isKindOfClass:[WSTabBar class]]) {
            [view removeFromSuperview];
        }
    }
}

/// 自定义tabbar
- (void)configureTabbar {
    // tabbar图标名称
    NSArray *sbNames = @[
                         @"Home",
                         @"Live",
                         @"EPG",
                         @"VIP",
                         @"Mine"
                         ];
    //2 设置自定义tabBar
    WSTabBar *tabBar = [WSTabBar tabBarWithSBNames:sbNames];
    //设置代理
    tabBar.delegate = self;
    // 加到系统tabbar位置
    [self.tabBar addSubview:tabBar];
    tabBar.frame = self.tabBar.bounds;
}

#pragma mark - WSTabbarDelegate
//自定义tabBar的代理方法
- (void)tabBarDidClickedButton:(WSTabBar *)tabBar selectedIndex:(NSInteger)selectedIndex {
    //让tabBarController中的对应子控制器显示
    self.selectedIndex = selectedIndex;
}

三、去掉按钮的高亮状态，写一个继承UIButton的类WSTabBarButton

#import "WSTabBarButton.h"

@implementation WSTabBarButton

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
}
*/

- (void)setHighlighted:(BOOL)highlighted {
    
}
@end