版本更新的檢測與提示的相關文章已經很多了，但是多數只能應對基本的產品需求。

我們在實際的專案開發過程中，為了更好的使用者體驗和產品升級，有時候我們希望使用者及時的更新，但是這種更新使用者是可選的；但是如果我們遇到一個比較嚴重的漏洞，正在被惡意攻擊的時候，我們希望將所有產品全部更新升級，避免損失，這個時候就需要採取強制更新（不更新軟體則無法繼續使用）的方法。

所以我們需要知道如果有新版本的時候，這個版本是選擇性升級還是強制更新。也就是說，我們只是獲取到App Store有新版本是不夠用的。這個時候，我們需要通過介面獲取版本升級是否強制這個屬性，這個屬性一定是在app的後臺管理中進行設定的，每次app更新的時候都需要進行設定，那麼我們可以不用再去App Store獲取版本資訊，直接讓後臺管理員在app有新版本的時候在後臺進行設定一下版本號和是否強制，在介面中統一獲取即可。

還有一個問題，提示使用者進行版本升級的時候，我們一般都會和使用者展示此次版本更新優化或添加了什麼功能，修改了什麼bug等，這些也是我們需要從介面中獲取的，那麼我們就在後臺新增一個文字輸入框，在介面中傳給app端一個網頁URL，app端直接呼叫webView進行展示。

這樣，後臺管理系統中可以新增一個模組 — 版本更新，裡面設定新版本版本號，是否強制升級，更新提示內容。

下面列出的是app端的頁面展示一些程式碼：

@interface ViewController ()<UIWebViewDelegate>
{

    CGFloat alertViewWith;
    CGFloat
 
 webViewDefaultHight;
    CGFloat alertViewDefaultHight;
    NSDictionary *alertData;

}

@property (nonatomic,strong)UIView *blackView;
@property (strong,nonatomic)UIView * alertview;
@property (strong,nonatomic)UIWebView *webView;
@property (strong,nonatomic)UILabel *alertTitleLabel;

@end

#pragma mark - 彈出框提示更新版本
 


- (void)addAlertWebViewWithVersion:(NSString *)version {

    alertViewWith = SCREENWIDTH -20;
    webViewDefaultHight = SCREENHEIGHT/2;
    alertViewDefaultHight = SCREENHEIGHT/2;

    //背景遮蓋
    _blackView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, SCREENWIDTH, SCREENHEIGHT)];
    _blackView.backgroundColor = [UIColor blackColor];
    _blackView.alpha = 0.5;
    [[UIApplication sharedApplication].windows.firstObject addSubview:_blackView];

    //建立alert
    self.alertview = [[UIView alloc]initWithFrame:CGRectMake(0, 0, alertViewWith, alertViewDefaultHight)];
    self.alertview.center = self.view.center;
    self.alertview.layer.cornerRadius = 17;
    self.alertview.clipsToBounds = YES;
    self.alertview.backgroundColor = [UIColor whiteColor];

    //設定彈出框
    [self setupAlertViewWithVersion:[alertData objectForKey:@"nowbanben"]];

    [[UIApplication sharedApplication].windows.firstObject addSubview:_alertview];
    [self exChangeOut:self.alertview dur:0.6];
}

-(void)setupAlertViewWithVersion:(NSString *) versionStr{

    _alertTitleLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 5, alertViewWith, 44)];
    _alertTitleLabel.font = [UIFont systemFontOfSize:18];
    _alertTitleLabel.textColor = [UIColor blackColor];
    _alertTitleLabel.textAlignment = NSTextAlignmentCenter;
    _alertTitleLabel.text = [NSString stringWithFormat:@"有新版本釋出%@",versionStr];
    [self.alertview addSubview:_alertTitleLabel];

    UIView *lineView = [[UIView alloc]initWithFrame:CGRectMake(0, _alertTitleLabel.bottom, alertViewWith, 1)];
    lineView.backgroundColor = [UIColor colorWithRed:226/255.0 green:226/255.0 blue:226/255.0 alpha:1];
    [self.alertview addSubview:lineView];

    _webView = [[UIWebView alloc]initWithFrame:CGRectMake(5, lineView.bottom, alertViewWith - 10, webViewDefaultHight)];
    _webView.delegate = self;
    [_webView loadHTMLString:[alertData objectForKey:@"remark"] baseURL:[NSURL URLWithString:ImgDuanKou]];
    //    NSURLRequest *request =[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]];
    //    [_webView loadRequest:request];
    [self.alertview addSubview:_webView];

}

-(void)chooseClick {
    NSDictionary *infoDict = [[NSBundle mainBundle] infoDictionary];
    NSString *currentVersion = [infoDict objectForKey:@"CFBundleVersion"];
    [[NSUserDefaults standardUserDefaults] setObject:currentVersion forKey:@"version"];
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:APP_URL]];
}

#pragma mark - alertView 彈出或隱藏

-(void)exChangeOut:(UIView *)changeOutView dur:(CFTimeInterval)dur {

    CAKeyframeAnimation * animation;

    animation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
    animation.duration = dur;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;
    NSMutableArray *values = [NSMutableArray array];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(0.1, 0.1, 1.0)]];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.2, 1.2, 1.0)]];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(0.9, 0.9, 0.9)]];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.0, 1.0, 1.0)]];
    animation.values = values;
    animation.timingFunction = [CAMediaTimingFunction functionWithName: @"easeInEaseOut"];
    [changeOutView.layer addAnimation:animation forKey:nil];
}

- (void)cancleView{

    [UIView animateWithDuration:0.3 animations:^{
        self.alertview.alpha = 0.0;
    } completion:^(BOOL finished) {
        [self.alertview removeFromSuperview];
        [self.blackView removeFromSuperview];
        self.alertview = nil;
        self.blackView = nil;
    }];
}

#pragma mark - UIWebViewDelegate

-(void)webViewDidFinishLoad:(UIWebView *)webView{

    //計算web載入完後的高度，重新整理介面高度
    [self changeWebViewHeight:webView.scrollView.contentSize.height];
}


-(void)changeWebViewHeight:(CGFloat)webViewHeight {
    CGFloat showHeight = 0;
    if (webViewHeight > webViewDefaultHight) {

        showHeight = webViewDefaultHight;
    }else{
        showHeight = webViewHeight;
    }

    _webView.frame = CGRectMake(_webView.frame.origin.x, _webView.frame.origin.y, _webView.frame.size.width, showHeight);
    _alertview.size = CGSizeMake(alertViewWith, showHeight+88);
    _alertview.center = self.view.center;

    UIView *lineViewSecond = [[UIView alloc]initWithFrame:CGRectMake(0, _webView.bottom, alertViewWith, 1)];
    lineViewSecond.backgroundColor = [UIColor colorWithRed:226/255.0 green:226/255.0 blue:226/255.0 alpha:1];
    [self.alertview addSubview:lineViewSecond];

    UIButton *chooseBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    chooseBtn.frame = CGRectMake(alertViewWith/ 2, self.alertview.frame.size.height - 44, alertViewWith/ 2, 44);
    [chooseBtn setBackgroundColor:[UIColor whiteColor]];
    chooseBtn.titleLabel.textAlignment = NSTextAlignmentCenter;
    [chooseBtn setTitle:@"馬上更新" forState:UIControlStateNormal];
    [chooseBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [chooseBtn addTarget:self action:@selector(chooseClick) forControlEvents:UIControlEventTouchUpInside];
    [self.alertview addSubview:chooseBtn];

    NSInteger flog = [[alertData objectForKey:@"ismust"] integerValue];
    if (flog == 0) {//非必須更新
        UIButton *cancelBtn = [UIButton buttonWithType:UIButtonTypeCustom];
        cancelBtn.frame = CGRectMake(0, self.alertview.frame.size.height - 44, alertViewWith/ 2, 44);
        [cancelBtn setBackgroundColor:[UIColor whiteColor]];
        cancelBtn.titleLabel.textAlignment = NSTextAlignmentCenter;
        [cancelBtn setTitle:@"以後再說" forState:UIControlStateNormal];
        [cancelBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
        [cancelBtn addTarget:self action:@selector(cancleView) forControlEvents:UIControlEventTouchUpInside];
        [self.alertview addSubview:cancelBtn];

        UIView *lineViewThird = [[UIView alloc]initWithFrame:CGRectMake(alertViewWith / 2 - 1, lineViewSecond.bottom + 5, 1, 30)];
        lineViewThird.backgroundColor = [UIColor colorWithRed:226/255.0 green:226/255.0 blue:226/255.0 alpha:1];
        [self.alertview addSubview:lineViewThird];
    }else{//必須更新
        CGRect rect = chooseBtn.frame;
        rect.origin.x = 0;
        rect.size.width = alertViewWith;
        chooseBtn.frame = rect;
    }
}