167

如何检测到第一次启动

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  // if very first launch than perform actionA
  // else perform actionB
}

方法？

4

17 回答 17

387 
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    if (![[NSUserDefaults standardUserDefaults] boolForKey:@"HasLaunchedOnce"])
    {
        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"HasLaunchedOnce"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
    return YES;
}
于 2012-04-01T12:31:53.540 回答
39

在Swift 3、4 中试试这个：

func isAppAlreadyLaunchedOnce()->Bool{
        let defaults = UserDefaults.standard
        
        if defaults.bool(forKey: "isAppAlreadyLaunchedOnce"){
            print("App already launched : \(isAppAlreadyLaunchedOnce)")
            return true
        }else{
            defaults.set(true, forKey: "isAppAlreadyLaunchedOnce")
            print("App launched first time")
            return false
        }
    }

在Swift 2中试试这个，

func isAppAlreadyLaunchedOnce()->Bool{
    let defaults = NSUserDefaults.standardUserDefaults()
    
    if defaults.boolForKey("isAppAlreadyLaunchedOnce"){
        print("App already launched : \(isAppAlreadyLaunchedOnce)")
        return true
    }else{
        defaults.setBool(true, forKey: "isAppAlreadyLaunchedOnce")
        print("App launched first time")
        return false
    }
}

更新：-对于OBJ-C，我使用这个，

+ (BOOL)isAppAlreadyLaunchedOnce {
    if ([[NSUserDefaults standardUserDefaults] boolForKey:@"isAppAlreadyLaunchedOnce"])
    {
        return true;
    }
    else
    {
        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"isAppAlreadyLaunchedOnce"];
        [[NSUserDefaults standardUserDefaults] synchronize];
        return false;
    }
}

OBJ-C 参考：https ://stackoverflow.com/a/9964400/3411787

于 2015-05-15T06:40:22.280 回答
34

为此，我编写了一个小型库。它让我知道这是有史以来第一次发布，还是仅针对此版本，以及用户安装的任何过去版本。它在 github 上作为 Apache 2 许可下的 cocoapod 提供：GBVersionTracking

你只需调用它application:didFinishLaunching:withOptions:

[GBVersionTracking track];

然后检查这是否是第一次启动，只需在任何地方调用它：

[GBVersionTracking isFirstLaunchEver];

同样：

[GBVersionTracking isFirstLaunchForVersion];

[GBVersionTracking currentVersion];
[GBVersionTracking previousVersion];
[GBVersionTracking versionHistory];
于 2013-01-31T10:43:48.540 回答
13

斯威夫特 3.0 - 斯威夫特 5

添加扩展名

    extension UIApplication {
        class func isFirstLaunch() -> Bool {
            if !UserDefaults.standard.bool(forKey: "hasBeenLaunchedBeforeFlag") {
                UserDefaults.standard.set(true, forKey: "hasBeenLaunchedBeforeFlag")
                UserDefaults.standard.synchronize()
                return true
            }
            return false
        }
    }

然后在你的代码中

UIApplication.isFirstLaunch()
于 2017-02-28T13:17:33.850 回答
8

您可以使用下面的静态方法来实现它：

+ (BOOL)isFirstTime{
    static BOOL flag=NO;
    static BOOL result;

    if(!flag){
        if ([[NSUserDefaults standardUserDefaults] boolForKey:@"hasLaunchedOnce"]){
            result=NO;
        }else{
            [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"hasLaunchedOnce"];
            [[NSUserDefaults standardUserDefaults] synchronize];
            result=YES;
        }

        flag=YES;
    }
    return result;
}
于 2013-03-07T15:45:45.607 回答
8

Xcode 7 和 Swift 2.0 的另一个想法是使用扩展

extension NSUserDefaults {
    func isFirstLaunch() -> Bool {
        if !NSUserDefaults.standardUserDefaults().boolForKey("HasAtLeastLaunchedOnce") {
            NSUserDefaults.standardUserDefaults().setBool(true, forKey: "HasAtLeastLaunchedOnce")
            NSUserDefaults.standardUserDefaults().synchronize()
            return true
        }
        return false
    }
}

现在您可以在应用程序的任何位置书写

if NSUserDefaults.standardUserDefaults().isFirstLaunch() {
    // do something on first launch
}

我个人更喜欢这样的 UIApplication 扩展：

extension UIApplication {
    class func isFirstLaunch() -> Bool {
        if !NSUserDefaults.standardUserDefaults().boolForKey("HasAtLeastLaunchedOnce") {
            NSUserDefaults.standardUserDefaults().setBool(true, forKey: "HasAtLeastLaunchedOnce")
            NSUserDefaults.standardUserDefaults().synchronize()
            return true
        }
        return false
    }
}

因为函数调用更具描述性：

if UIApplication.isFirstLaunch() {
    // do something on first launch
}
于 2015-12-14T02:47:42.810 回答
5

您需要在启动时保存一些内容，然后检查它是否存在。如果没有，那就是第一次。“某物”可以是文件、数据库条目、用户默认设置……

于 2012-04-01T12:32:25.147 回答
4

这样做很简单，只需要六行代码。

将此代码添加到您的应用程序启动首选项或您可能需要测试它是否第一次运行您的应用程序的任何其他地方都会很有用。

//These next six lines of code are the only ones required! The rest is just running      code when it's the first time.
//Declare an integer and a default.
NSUserDefaults *theDefaults;
int  launchCount;
//Set up the properties for the integer and default.
theDefaults = [NSUserDefaults standardUserDefaults];
launchCount = [theDefaults integerForKey:@"hasRun"] + 1;
[theDefaults setInteger:launchCount forKey:@"hasRun"];
[theDefaults synchronize];

//Log the amount of times the application has been run
NSLog(@"This application has been run %d amount of times", launchCount);

//Test if application is the first time running
if(launchCount == 1) {
    //Run your first launch code (Bring user to info/setup screen, etc.)
    NSLog(@"This is the first time this application has been run";
}

//Test if it has been run before
if(launchCount >= 2) {
    //Run new code if they have opened the app before (Bring user to home screen etc.
    NSLog(@"This application has been run before);
}

PS不要在首选项中使用 bools只使用整数。未定义时，它们默认为零。

此外，这[theDefaults synchronize];条线不是必需的，但我发现当一个应用程序在数百台设备上运行数百次时，结果并不总是可靠的，此外，这是更好的做法。

于 2013-07-12T09:55:29.133 回答
3

快速简便的功能

- (BOOL) isFirstTimeOpening {
    NSUserDefaults *theDefaults = [NSUserDefaults standardUserDefaults];
    if([theDefaults integerForKey:@"hasRun"] == 0) {
        [theDefaults setInteger:1 forKey:@"hasRun"];
        [theDefaults synchronize];
        return true;
    }
    return false;
}
于 2015-04-19T20:17:42.837 回答
3

第一次在 NSUserDefaults 中存储一个 bool 键，它将是 no，您将其更改为 yes 并保持这种状态，直到应用程序删除或重新安装它将再次是第一次。

于 2012-04-01T12:32:54.910 回答
3

为XCode 12和Swift 5更新

 extension UIApplication {
      func isFirstLaunch() -> Bool {
        if !UserDefaults.standard.bool(forKey: "HasLaunched") {
          UserDefaults.standard.set(true, forKey: "HasLaunched")
          UserDefaults.standard.synchronize()
          return true
      }
      return false
    }
}

然后你称它为

UIApplication.isFirstLaunch()
于 2020-04-12T13:23:21.540 回答
3

迅速我建议使用一个全局常量，它可以在任何范围之外非常容易地完成，例如在 App 委托之上。因此，只要应用程序未终止，它将被设置为正确的值。如果应用程序进入后台，它仍然会返回相同的值。仅当应用程序完全重新启动时，该值才会更改。

let isFirstLaunch: Bool = {
    if !UserDefaults.standard.bool(forKey: "hasBeenLaunchedBeforeFlag") {
        UserDefaults.standard.set(true, forKey: "hasBeenLaunchedBeforeFlag")
        UserDefaults.standard.synchronize()
        return true
    }
    return false
}()

但老实说，最好跟踪应用程序已至少发送到后台一次的事实。在这种情况下，我更喜欢在 UIApplication 上使用扩展并在 applicationDidEnterBackground 方法中设置标志，以便：

extension UIApplication {
    private static let isFirstLaunchKey = "isFirstLaunchKey"
    static var isFirstLaunch: Bool {
        return !UserDefaults.standard.bool(forKey: isFirstLaunchKey)
    }
    static func didEnterBackground() {
        if isFirstLaunch {
            UserDefaults.standard.set(true, forKey: isFirstLaunchKey)
            UserDefaults.standard.synchronize()
        }
    }
}

然后在您的应用程序委托或场景委托中

func sceneDidEnterBackground(_ scene: UIScene) {
        UIApplication.didEnterBackground()
    }
于 2019-11-07T13:28:38.903 回答
3

对于 Xcode 7 中的 Swift 2.0。在 AppDelegate.swift 文件中： 

import UIKit

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(application: UIApplication, willFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool
{
    return true
}


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool
{
    didFinishLaunchingOnce()
    return true
}

func didFinishLaunchingOnce() -> Bool
{
    let defaults = NSUserDefaults.standardUserDefaults()

    if let hasBeenLauncherBefore = defaults.stringForKey("hasAppBeenLaunchedBefore")
    {
        //print(" N-th time app launched ")
        return true
    }
    else
    {
        //print(" First time app launched ")
        defaults.setBool(true, forKey: "hasAppBeenLaunchedBefore")
        return false
    }
}

}
于 2015-08-21T09:12:19.583 回答
2

斯威夫特 5 iOS 13。

我喜欢Chris Fremgen的 Quick and easy 。所以我更新了它。

func isFirstTimeOpening() -> Bool {
  let defaults = UserDefaults.standard

  if(defaults.integer(forKey: "hasRun") == 0) {
      defaults.set(1, forKey: "hasRun")
      return true
  }
  return false

}
于 2019-12-30T08:39:10.193 回答
2

迅速

struct Pref {
    static let keyFirstRun = "PrefFirstRun"
    static var isFirstRun: Bool {
        get {
            return UserDefaults.standard.bool(forKey: keyFirstRun)
        }
        set {
            UserDefaults.standard.set(newValue, forKey: keyFirstRun)
        }
    }
}

在应用启动时注册默认值：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        let prefs: [String:Any] = [
            Pref.keyFirstRun: true
            ...
        ]

        UserDefaults.standard.register(defaults: prefs)

应用终止的明确价值：

func applicationWillTerminate(_ application: UIApplication) {
        Pref.isFirstRun = false

检查值：

 if Pref.isFirstRun {
    ... do whatever
于 2019-06-27T11:55:04.660 回答
0

这是一个在 swift 5.0 中工作的答案。与@Zaid Pathan 的答案相比的改进是没有隐藏的合同。如果您在调用之前没有setFirstAppLaunch()准确调用一次isFirstAppLaunch()，则会收到断言错误（仅在调试模式下）。

fileprivate struct _firstAppLaunchStaticData {
    static var alreadyCalled = false
    static var isFirstAppLaunch = true
    static let appAlreadyLaunchedString = "__private__appAlreadyLaunchedOnce"
}

func setFirstAppLaunch() {
    assert(_firstAppLaunchStaticData.alreadyCalled == false, "[Error] You called setFirstAppLaunch more than once")
    _firstAppLaunchStaticData.alreadyCalled = true
    let defaults = UserDefaults.standard

    if defaults.string(forKey: _firstAppLaunchStaticData.appAlreadyLaunchedString) != nil {
        _firstAppLaunchStaticData.isFirstAppLaunch = false
    }
    defaults.set(true, forKey: _firstAppLaunchStaticData.appAlreadyLaunchedString)
}

func isFirstAppLaunch() -> Bool {
    assert(_firstAppLaunchStaticData.alreadyCalled == true, "[Error] Function setFirstAppLaunch wasn't called")
    return _firstAppLaunchStaticData.isFirstAppLaunch
}

然后，您只需要setFirstAppLaunch()在应用程序开始时调用该函数，并且isFirstAppLaunch()无论何时您想检查您的应用程序是否已被调用。

于 2019-05-13T08:21:12.787 回答
0

NSUserDefaults + 宏

最好的方法是使用NSUserDefaults并保存一个BOOL变量。如上所述，下面的代码就可以了：

NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
[userDefaults setObject:[NSNumber numberWithBool:true] forKey:@"~applicationHasLaunchedBefore"];
[userDefaults synchronize];

您还可以创建一个如下的宏来轻松检查它是否是第一次启动

#define kApplicationHasLaunchedBefore [[NSUserDefaults standardUserDefaults] objectForKey:@"~applicationHasLaunchedBefore"]

然后就这样使用它，

if (kApplicationHasLaunchedBefore) {
    //App has previously launched
} else {
    //App has not previously launched
}
于 2016-10-24T21:38:51.363 回答