AJ分享，必须精品

这里实现了大多数app都会有的软件新特性的功能，用的是UICollectionViewController实现的

这里用了UICollectionViewController实现，就是做一个没有间隙，每个cell都是一个屏幕的UICollectionViewController，自定义的。然后把下面的UIPageControl 还有最后一页的开始以及分享按钮放入就OK了。

调用的时候，首先获取当前的app的版本号，然后再获取上一个版本。进行两个版本的比较。当前版本和上一个版本不同，当前版本是从infoDictionary中拿到的，上一个版本是从自己存的NSUserDefaults 中的NYVersionKey拿到的，并且苹果允许上传小于当前版本的app，如果是第一个版本时候，上一个版本还没有值，也会不同。
根据结果设置window的不同根控制器。

自定义UICollectionViewController步骤：
要注意：
1.初始化的时候设置布局参数
2.collertionView必须注册cell
3.自定义cell

调用部分代码：AppDelegate

 //1,获取当前的版本号
    NSString *currentVersion = [NSBundle mainBundle].infoDictionary[@"CFBundleVersion"];

    //2，获取上一次的版本号
    NSString *lastVersion = [[NSUserDefaults standardUserDefaults]objectForKey:NYVersionKey];

    NYLog(@"currentVersion == %@ , lastVersion == %@ ",currentVersion, lastVersion);
    //判断是否有新的版本
    if ([currentVersion isEqualToString:lastVersion]) {
        //如果没有新的版本(当前版本和上一个版本不同，当前版本是从infoDictionary中拿到的，上一个版本是从自己存的NSUserDefaults 中的NYVersionKey拿到的，并且苹果允许上传小于当前版本的app，如果是第一个版本时候，上一个版本还没有值，也会不同。)

        //创建tabBarVC
        NYTabBarController *tabBarVC = [[NYTabBarController alloc]init];

        //设置窗口跟控制器
        self.window.rootViewController = tabBarVC;
    }else{//如果有新的版本

        //进入新特性界面
        NYNewFeatureController *newFeatureVC = [[NYNewFeatureController alloc]init];

        newFeatureVC.view.backgroundColor = [UIColor redColor];

        self.window.rootViewController = newFeatureVC;

        //用偏好设置，保存当前版本。
        [[NSUserDefaults standardUserDefaults]setObject:currentVersion forKey:NYVersionKey];

    }

---

自定义的collectionViewController

NYNewFeatureController.m

//
//  NYNewFeatureController.m

//  Created by apple on 15-8-1.
//  Copyright (c) 2015年 znycat. All rights reserved.
//

#import "NYNewFeatureController.h"
#import "NYNewFeatureCell.h"

@interface NYNewFeatureController ()

@property (nonatomic, weak) UIPageControl *control;

@end

@implementation NYNewFeatureController

static NSString * const reuseIdentifier = @"cell";

- (void)viewDidLoad {
    [super viewDidLoad];

    //注册cell，默认就会创建这个类型的cell
    [self.collectionView registerClass:[NYNewFeatureCell class] forCellWithReuseIdentifier:reuseIdentifier];

    //分页
    self.collectionView.pagingEnabled = YES;
    //取消弹簧效果
    self.collectionView.bounces = NO;
    //不显示滚动条
    self.collectionView.showsHorizontalScrollIndicator = NO;

    // 添加pageController
    [self setUpPageControl];
    // Do any additional setup after loading the view.
}
// 添加pageController
- (void)setUpPageControl
{
    // 添加pageController,只需要设置位置，不需要管理尺寸
    UIPageControl *control = [[UIPageControl alloc] init];

    control.numberOfPages = 4;
    control.pageIndicatorTintColor = [UIColor blackColor];
    control.currentPageIndicatorTintColor = [UIColor redColor];

    // 设置center
    control.center = CGPointMake(self.view.width * 0.5, self.view.height);
    _control = control;
    [self.view addSubview:control];
}

/*使用UICollectionViewController要注意：
1.初始化的时候设置布局参数
2.collertionView必须注册cell
3.自定义cell
*/

-(instancetype)init
{

    //
    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc]init];

    //设置cell的尺寸
    layout.itemSize = [UIScreen mainScreen].bounds.size;

    //清空cell间隔的行距
    layout.minimumLineSpacing = 0;

    //设置cell的滑动方向
    layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;

    return [super initWithCollectionViewLayout:layout];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - UICollectionView代理和数据源
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {

    return 1;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return 4;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    // dequeueReusableCellWithReuseIdentifier
    // 1.首先从缓存池里取cell
    // 2.看下当前是否有注册Cell,如果注册了cell，就会帮你创建cell
    // 3.没有注册，报错

    NYNewFeatureCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];

    // 拼接图片名称 3.5 320 480
    CGFloat screenH = [UIScreen mainScreen].bounds.size.height;
    NSString *imageName = [NSString stringWithFormat:@"new_feature_%ld",indexPath.row + 1];
    if (screenH > 480) { // 5 , 6 , 6 plus
        imageName = [NSString stringWithFormat:@"new_feature_%ld-568h",indexPath.row + 1];
    }

    cell.image = [UIImage imageNamed:imageName];

    [cell setIndexPath:indexPath count:4];

    return cell;
}
#pragma mark - UIScrollView代理
// 只要一滚动就会调用
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // 获取当前的偏移量，计算当前第几页
    int page = scrollView.contentOffset.x / scrollView.bounds.size.width + 0.5;

    // 设置页数
    _control.currentPage = page;
}

@end

自定义的cell

NYNewFeatureCell.h

//
//  NYNewFeatureCell.h

//  Created by apple on 15-8-1.
//  Copyright (c) 2015年 znycat. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface NYNewFeatureCell : UICollectionViewCell

@property (nonatomic, strong) UIImage *image;

// 判断是否是最后一页
- (void)setIndexPath:(NSIndexPath *)indexPath count:(int)count;

@end

NYNewFeatureCell.m

//
//  NYNewFeatureCell.m

//  Created by apple on 15-8-1.
//  Copyright (c) 2015年 znycat. All rights reserved.
//

#import "NYNewFeatureCell.h"
#import "NYTabBarController.h"

@interface NYNewFeatureCell()

@property (nonatomic, weak) UIImageView *imageView;
//分享按钮
@property (nonatomic, weak) UIButton *shareButton;
//开始按钮
@property (nonatomic, weak) UIButton *startButton;
@end

@implementation NYNewFeatureCell

//分享按钮懒加载
- (UIButton *)shareButton
{
    if (_shareButton == nil) {

        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        [btn setTitle:@"分享给大家" forState:UIControlStateNormal];
        [btn setImage:[UIImage imageNamed:@"new_feature_share_false"] forState:UIControlStateNormal];
        [btn setImage:[UIImage imageNamed:@"new_feature_share_true"] forState:UIControlStateSelected];
        [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
        [btn sizeToFit];

        [self.contentView addSubview:btn];

        _shareButton = btn;

    }
    return _shareButton;
}

//开始按钮懒加载
- (UIButton *)startButton
{
    if (_startButton == nil) {
        UIButton *startBtn = [UIButton buttonWithType:UIButtonTypeCustom];
        [startBtn setTitle:@"开始微博" forState:UIControlStateNormal];
        [startBtn setBackgroundImage:[UIImage imageNamed:@"new_feature_finish_button"] forState:UIControlStateNormal];
        [startBtn setBackgroundImage:[UIImage imageNamed:@"new_feature_finish_button_highlighted"] forState:UIControlStateHighlighted];
        [startBtn sizeToFit];
        [startBtn addTarget:self action:@selector(start) forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:startBtn];
        _startButton = startBtn;

    }
    return _startButton;
}

-(UIImageView *)imageView
{
    if (_imageView == nil) {
        UIImageView *imageV = [[UIImageView alloc]init];

        _imageView = imageV;

        // 注意:一定要加载contentView
        [self.contentView addSubview:imageV];
    }
    return _imageView;
}

// 布局子控件的frame
-(void)layoutSubviews
{
    [super layoutSubviews];

    self.imageView.frame = self.bounds;

    // 分享按钮
    self.shareButton.center = CGPointMake(self.width * 0.5, self.height * 0.8);

    // 开始按钮
    self.startButton.center = CGPointMake(self.width * 0.5, self.height * 0.9);
}

-(void)setImage:(UIImage *)image
{
    _image = image;
    self.imageView.image = image;
}

// 判断当前cell是否是最后一页
-(void)setIndexPath:(NSIndexPath *)indexPath count:(int)count
{
    if (indexPath.row == count - 1) { // 最后一页,显示分享和开始按钮
        self.shareButton.hidden = NO;
        self.startButton.hidden = NO;

    }else{ // 非最后一页，隐藏分享和开始按钮
        self.shareButton.hidden = YES;
        self.startButton.hidden = YES;

    }
}

// 点击开始微博的时候调用
- (void)start
{
    // 进入tabBarVc
    NYTabBarController *tabBarVc = [[NYTabBarController alloc] init];

    // 切换根控制器:可以直接把之前的根控制器清空
    NYKeyWindow.rootViewController = tabBarVc;

}
@end