检测应用程序重新聚焦事件 [英] Detect application refocus event

问题描述

每次用户开始使用该应用程序时我都需要知道。

I need to know each time the user is starting to use the application.

案例1（确定）：应用程序未启动。

用户从头开始申请。

我添加了一个应用程序引导程序上的监听器，我知道它什么时候开始。

I add a listener on the app's bootstrap, and I am aware when it starts.

案例2（TODO）：该应用程序已经启动，但它不再处于活动状态

用户从任务栏重新加载应用程序。

我想要知道应用程序何时从任务栏到达前台（如alt + tab）。

I want to know when the application comes from the taskbar to the foreground (like a alt+tab).

抓住这个很棘手，因为应用仍在运行，我不知道要听哪个事件。事实上，我甚至不知道如何命名这种行为。

This is tricky to catch, because the app is still running and I don't know which event to listen to. In fact, I don't even know how to name this behaviour.

推荐答案

ios-app开发者接受了帮助。他的回答非常适合我，因为它似乎很干净且可重复使用。所以我将在这里制作它：

An ios-app developper accepted to help me. His answer suits me very well, as it seem clean et reusable. So I will produce it here :

可以通过 applicationWillEnterForeground 事件捕获app come to foreground事件。
Phonegap / Cordova允许通过Cordova类调用javascript函数。 webView 对象有一个专用方法来启动js脚本。

The "app come to foreground" event can be catched through the applicationWillEnterForeground event. Phonegap/Cordova allows to call javascript functions through the Cordova classes. The webView object has a dedicated method to launch js scripts.

所以我打开了文件Projet / Classes / Cordova / AppDelegate.m：

So I opened the file Projet/Classes/Cordova/AppDelegate.m :

- (void)applicationWillEnterForeground:(UIApplication *)application {
    NSLog(@"applicationWillEnterForeground: %@", self.viewController.webView);
    [self.viewController.webView stringByEvaluatingJavaScriptFromString:@"notifyForegroundEvent();"];

}

我在根目录的某处添加了notifyForegroundEvent（）方法我的js文件：

And I added the notifyForegroundEvent() method somewhere in the root of my js files :

var notifyForegroundEvent = function() {
  console.log('notifyForegroundEvent()');
  // Do something here
}

Etvoilà

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