app引导页实现

应用开机引导页并不是每次运行都显示的；首先需要判断应用是否是安装后首次运行或者升级后首次运行。

需要用到一个方法：

获取应用版本号：key值：CFBundleShortVersionString，也有人使用通过获取应用的build版本号判断的，这里我使用的是前者

定义一个实例方法，在方法中：
获取应用版本号：

NSString *currentVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];//获取应用版本号

定义一个标识：

NSString *key = @"APP_LASTLANUCH_VERSION";

首先判断这个标识是否有值：

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *lastLaunchVersion = [defaults objectForKey:key];

判断：

if (lastLaunchVersion == nil) {
        //第一次运行
        [defaults setObject:currentVersion forKey:key];
        return YES;
    }else if (![lastLaunchVersion isEqualToString:currentVersion]){
        //升级后第一次
        [defaults setObject:currentVersion forKey:key];
        return YES;
    }

其他结果均返回NO

---

在AppDelegate的

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    BOOL isFirst = [self isFirstLoad];
    
    if (isFirst) {
        GuideView *guideView = [[GuideView alloc] initWithFrame:[UIScreen mainScreen].bounds];
        [self.window.rootViewController.view addSubview:guideView];
    }
    return YES;
}

方法中调用之前定义的那个实例方法.

新建一个添加引导页内容的GuideView类：
初始化：

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self createView];
    }
    return self;
}

定义的createView方法：

NSArray *imagesArray = @[@"guide1", @"guide2", @"guide3", @"guide4", @"guide5", @"guide6"];//我从网上随便找了几张图  并不是我项目中的原图。项目中 存在“登录/注册”和“立即体验”两个按钮，这里只有最后一张图有个“Go”按钮
    
    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.bounds];
    [self addSubview:scrollView];
    
    //设置是否有橡皮筋效果
    scrollView.bounces = NO;//默认YES
    
    //设置是否使用分页属性
    scrollView.pagingEnabled = YES;//默认NO
    
    //设置是否允许滚动属性
    scrollView.scrollEnabled = YES;//默认为YES
    
    //设置是否显示水平、竖直滚动条属性 默认均为YES
    scrollView.showsHorizontalScrollIndicator = NO;
    scrollView.showsVerticalScrollIndicator = NO;
    
    scrollView.delegate = self;//设置代理
    
    //设置内容范围属性
    scrollView.contentSize = CGSizeMake(self.frame.size.width * (imagesArray.count + 1), self.frame.size.height);
    
    //为每一页添加数组数据
    for (int i = 0; i < imagesArray.count; i ++) {
        UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(i * scrollView.frame.size.width, 0, scrollView.frame.size.width, scrollView.frame.size.height)];
        imgView.tag = 2016 + i;
        imgView.userInteractionEnabled = YES;
        imgView.image = [UIImage imageNamed:imagesArray[i]];
        [scrollView addSubview:imgView];
    }

scrollView代理方法：

#pragma mark -UIScrollViewDelegate
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    NSInteger pageIndex = scrollView.contentOffset.x / scrollView.frame.size.width;
    
    if (pageIndex == 5) {
        if (_btn == nil) {
            _btn = [UIButton buttonWithType:UIButtonTypeCustom];
            _btn.backgroundColor = [UIColor clearColor];
            [_btn addTarget:self action:@selector(btnClickAction) forControlEvents:UIControlEventTouchUpInside];
            
            UIImageView *imgView = (UIImageView *)[scrollView viewWithTag:2021];
            [imgView addSubview:_btn];
            
            //这里不一定正好遮住Go按钮哈 -_- 偷懒
            __weak typeof(self) weakSelf = self;
            [_btn mas_makeConstraints:^(MASConstraintMaker *make) {
                make.leading.equalTo(weakSelf.mas_centerX).offset(-75);
                make.bottom.mas_equalTo(-60);
                make.width.mas_equalTo(160);
                make.height.mas_equalTo(60);
            }];
        }
        
    }else {
        if (_btn) {
            [_btn removeFromSuperview];
            _btn = nil;
        }
    }
    
    if (pageIndex < 6) {
        //
    }else {
        [self performSelector:@selector(removeFromSuperview) withObject:nil afterDelay:0.5];
    }
}

移除方法：

- (void)btnClickAction
{
    [self performSelector:@selector(removeFromSuperview) withObject:nil];
}

Demo地址：https://github.com/talent129/GuideDemo.git