import <UIKit/UIKit.h>

typedef void(^TabBarDidClickAtIndex)(NSInteger buttonIndex);

@interface WNavigationTabBar : UIView

@property(nonatomic,copy)TabBarDidClickAtIndex didClickAtIndex;

-(instancetype)initWithTitles:(NSArray *)titles;

-(void)scrollToIndex:(NSInteger)index;

@property(nonatomic,strong)UIColor *sliderBackgroundColor;

@property(nonatomic,strong)UIColor *buttonNormalTitleColor;

@property(nonatomic,strong)UIColor *buttonSelectedTileColor;

@end

import "WNavigationTabBar.h"

@interface WNavigationTabBar ()

@property (nonatomic, strong) UIView *sliderView;
@property(nonatomic,strong)NSMutableArray<UIButton *> *buttonArray;
@property(nonatomic,assign)CGFloat width;
@property(nonatomic,strong)UIButton *selectedButton;

@end

@implementation WNavigationTabBar

-(instancetype)initWithTitles:(NSArray *)titles
{
if (self = [super initWithFrame:CGRectMake(0, 0, 150, 44)]) {
self.buttonNormalTitleColor = RGBA(255, 255, 255, 0.7);
self.buttonSelectedTileColor = [UIColor whiteColor];
[self setSubViewWithTitles:titles];
}
return self;
}

-(void)setSubViewWithTitles:(NSArray *)titles
{
self.buttonArray = [[NSMutableArray alloc] init];
for (int buttonIndex = 0 ; buttonIndex < titles.count; buttonIndex++) {
NSString *titleString = titles[buttonIndex];
UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
[btn setTitleColor:self.buttonNormalTitleColor forState:UIControlStateNormal];
[btn setTitleColor:self.buttonSelectedTileColor forState:UIControlStateSelected];
[btn setTitleColor:self.buttonSelectedTileColor forState:UIControlStateHighlighted | UIControlStateSelected];
[btn setTitle:titleString forState:UIControlStateNormal];
btn.titleLabel.font = [UIFont systemFontOfSize:16];
if(buttonIndex == 0) {btn.selected = YES; self.selectedButton = btn;};
[btn addTarget:self action:@selector(subButtonSelected:) forControlEvents:UIControlEventTouchUpInside];
btn.tag = 100 + buttonIndex;
[self addSubview:btn];
[self.buttonArray addObject:btn];
}

self.sliderView = [[UIView alloc] init];
self.sliderView.backgroundColor = self.buttonSelectedTileColor;
[self addSubview:self.sliderView];

}

-(void)subButtonSelected:(UIButton *)button
{
self.selectedButton.selected = NO;
button.selected = YES;
self.selectedButton = button;
[self sliderViewAnimationWithButtonIndex:button.tag - 100];
if (self.didClickAtIndex) {
self.didClickAtIndex(button.tag - 100);
}
}

-(void)scrollToIndex:(NSInteger)index
{
self.selectedButton.selected = NO;
self.buttonArray[index].selected = YES;
self.selectedButton = self.buttonArray[index];
[self sliderViewAnimationWithButtonIndex:index];

}

-(void)sliderViewAnimationWithButtonIndex:(NSInteger)buttonIndex
{
[UIView animateWithDuration:0.25 animations:^{
CGFloat buttonX = self.buttonArray[buttonIndex].center.x - (self.width /2);
self.sliderView.frame = CGRectMake(buttonX, self.frame.size.height - 2.0f, self.width - 4, 2);
}];

}

-(void)layoutSubviews
{
[super layoutSubviews];
self.width = self.frame.size.width / (self.buttonArray.count * 2);
CGFloat buttonWidth = self.frame.size.width / self.buttonArray.count;
for (int buttonIndex = 0; buttonIndex < self.buttonArray.count; buttonIndex ++) {
self.buttonArray[buttonIndex].frame = CGRectMake(buttonIndex * buttonWidth, 0, buttonWidth, 44);
}
CGFloat buttonX = self.buttonArray[0].center.x - self.width / 2;
self.sliderView.frame = CGRectMake(buttonX, self.frame.size.height - 2.0f, self.width - 4, 2);
}

@end

呼叫 建立UIPageViewController
遵循 UIPageViewController的代理 UIPageViewControllerDelegate,UIPageViewControllerDataSource

-(WNavigationTabBar *)navigationTabBar
{
if (!_navigationTabBar) {
self.navigationTabBar = [[WNavigationTabBar alloc] initWithTitles:@[@"職場",@"發現"]];
__weak typeof(self) weakSelf = self;
[self.navigationTabBar setDidClickAtIndex:^(NSInteger index){
[weakSelf navigationDidSelectedControllerIndex:index];
}];
}
return _navigationTabBar;
}

設定viewController陣列 傳入需要切換的介面
-(NSArray *)subViewControllers
{
if (!_subViewControllers) {
DiscoverViewController *controllerOne = [[DiscoverViewController alloc] init];
controllerOne.view.backgroundColor = RGB(239, 239, 239);

    BusinessController *controllerTwo = [[BusinessController alloc] init];
    controllerTwo.view.backgroundColor = RGB(239, 239, 239);
    
    
    
    self.subViewControllers = @[controllerOne,controllerTwo];
}
return _subViewControllers;

}

切記切記 遵循代理 self.delegate = self;
self.dataSource = self;

實現代理方法
[self setViewControllers:@[self.subViewControllers.firstObject]
direction:UIPageViewControllerNavigationDirectionForward
animated:YES
completion:nil];

• (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
  {
  NSInteger index = [self.subViewControllers indexOfObject:viewController];
  if(index == 0 || index == NSNotFound) {
  return nil;
  }

  return [self.subViewControllers objectAtIndex:index - 1];
  }

• (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
  {
  NSInteger index = [self.subViewControllers indexOfObject:viewController];
  if(index == NSNotFound || index == self.subViewControllers.count - 1) {
  return nil;
  }
  return [self.subViewControllers objectAtIndex:index + 1];
  }

• (void)pageViewController:(UIPageViewController *)pageViewController
  didFinishAnimating:(BOOL)finished
  previousViewControllers:(NSArray *)previousViewControllers
  transitionCompleted:(BOOL)completed {
  UIViewController *viewController = self.viewControllers[0];
  NSUInteger index = [self.subViewControllers indexOfObject:viewController];
  [self.navigationTabBar scrollToIndex:index];

}

pragma mark - PrivateMethod

• (void)navigationDidSelectedControllerIndex:(NSInteger)index {
  [self setViewControllers:@[[self.subViewControllers objectAtIndex:index]] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
  switch (index) {
  case 0:
  NSLog(@"第一個頁面");
  break;
  case 1:
  NSLog(@"第二個頁面");
  break;
  default:
  break;
  }

}