iOS 一一 仿写UITabBarController

效果图如下:

知识点:

1. 界面布局, 底部的button和显示的子控制器都分别使用用UIView来存放,方便后面使用.

2. 使用父子控制器知识,将所有的子控制器添加到ViewController中.

3. 通过遍历ViewController中的子控制器,来给button设置标题.

4. 当点击button的时候,将对应的子控件添加上去.并移除之前的界面( makeObjectPerformSelecter: )

//  Created by 朝阳 on 2018/2/2.
//  Copyright © 2018年 sunny. All rights reserved.
//

#import "ViewController.h"
#import "SocialViewController.h"
#import "HeadLineViewController.h"
#import "HotViewController.h"

@interface ViewController ()
/* 管理btn的stack */
@property (weak, nonatomic) IBOutlet UIStackView *btnsView;
/* 存放子控制器的View */
@property (weak, nonatomic) IBOutlet UIView *saveChildVcView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //1.添加子控制器
    [self addChildController];
    //2.给按钮设置标题
    [self setBtnTitle];
    
}

#pragma -mark 设置按钮的标题
- (void)setBtnTitle
{
    for (NSInteger i = 0; i < self.btnsView.subviews.count; ++i) {
        UIButton *btn = self.btnsView.subviews[i];
        // 获取self中的子控制器.根据子控制器来设置按钮的标题.
        UIViewController *vc = self.childViewControllers[i];
        [btn setTitle:vc.title forState:UIControlStateNormal];
    }
}

#pragma -mark 添加所有子控制器
- (void)addChildController
{
    SocialViewController *socialVC = [[SocialViewController alloc] init];
    socialVC.title = @"社会";
    [self addChildViewController:socialVC];
    
    HeadLineViewController *headLineVC = [[HeadLineViewController alloc] init];
    headLineVC.title = @"头条";
    [self addChildViewController:headLineVC];
    
    HotViewController *hotVC = [[HotViewController alloc] init];
    hotVC.title = @"热点";
    [self addChildViewController:hotVC];
    
}

- (IBAction)btnClick:(UIButton *)sender {
    
    // 当显示下一个界面时,移除之前的界面. makeObjectsPerformSelector: 使view中的所有子控制器都执行一次removeFromSuperview方法.
    [self.saveChildVcView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
//    for (UIView *vcView in self.saveChildVcView.subviews) {
//        [vcView removeFromSuperview];
//    }
    
    // 把对应子控件的view添加上去
    UIViewController *vc = self.childViewControllers[sender.tag];
    vc.view.backgroundColor = sender.backgroundColor;
    vc.view.frame = self.saveChildVcView.bounds;
    [self.saveChildVcView addSubview:vc.view];
    
}

@end