Question

我有一个用HTML / JS / CSS构建的简单UWP应用程序。它本质上是一个网站，它将一些数据加载到webview等等，没什么特别的。

我挣扎的是应用程序生命周期及其“恢复”状态，应用程序已经在哪里运行，用户再次打开应用程序，然后重新呈现整个应用程序，所有html + js都到达再次运行导致基本上重新加载（就像通过F5）。我该如何预防？

这是非常基本的main.js文件，请注意我将上一个执行状态与应用程序执行状态“running”进行比较的行。我认为我应该做些什么来防止重新加载我的应用程序（或换句话说重新渲染），所以它不会再次经历初始化过程。它看起来很糟糕，因为所有资源都被重新加载。

   (function () {
    "use strict";

    var app = WinJS.Application;
    var activation = Windows.ApplicationModel.Activation;
    var isFirstActivation = true;

    app.onactivated = function (args) {
        if (args.detail.kind === activation.ActivationKind.voiceCommand) {
            // TODO: Handle relevant ActivationKinds. For example, if your app can be started by voice commands,
            // this is a good place to decide whether to populate an input field or choose a different initial view.
        }
        else if (args.detail.kind === activation.ActivationKind.launch) {
            // A Launch activation happens when the user launches your app via the tile
            // or invokes a toast notification by clicking or tapping on the body.
            if (args.detail.arguments) {
                // TODO: If the app supports toasts, use this value from the toast payload to determine where in the app
                // to take the user in response to them invoking a toast notification.
            }
            else if (args.detail.previousExecutionState === activation.ApplicationExecutionState.terminated) {
                // TODO: This application had been suspended and was then terminated to reclaim memory.
                // To create a smooth user experience, restore application state here so that it looks like the app never stopped running.
                // Note: You may want to record the time when the app was last suspended and only restore state if they've returned after a short period.
            }
            else if (args.detail.previousExecutionState === activation.ApplicationExecutionState.running) {
                isFirstActivation = false;
            }
        }

        if (!args.detail.prelaunchActivated) {
            // TODO: If prelaunchActivated were true, it would mean the app was prelaunched in the background as an optimization.
            // In that case it would be suspended shortly thereafter.
            // Any long-running operations (like expensive network or disk I/O) or changes to user state which occur at launch
            // should be done here (to avoid doing them in the prelaunch case).
            // Alternatively, this work can be done in a resume or visibilitychanged handler.
        }

        if (isFirstActivation) {
            // TODO: The app was activated and had not been running. Do general startup initialization here.
            document.addEventListener("visibilitychange", onVisibilityChanged);
            args.setPromise(WinJS.UI.processAll().then(function(){ WinJS.UI.enableAnimations();}));
        }

        isFirstActivation = false;
    };

    function onVisibilityChanged(args) {
        if (!document.hidden) {
            // TODO: The app just became visible. This may be a good time to refresh the view.
        }
    }

    app.oncheckpoint = function (args) {
        // TODO: This application is about to be suspended. Save any state that needs to persist across suspensions here.
        // You might use the WinJS.Application.sessionState object, which is automatically saved and restored across suspension.
        // If you need to complete an asynchronous operation before your application is suspended, call args.setPromise().
    };

    app.start();

})();

Answer 1

好的，经过一段时间的调试并重新编写应用程序前后，我已经意识到这里的罪魁祸首是＆＃34; StartPage＆＃34;在应用程序清单中。

应用程序出现问题＆＃34;重新加载＆＃34;即使它之前处于运行状态是由＆＃34; app.Start（）＆＃34;每次用户重新打开应用程序后触发。但来自UWP样品套件的样品并没有受到这种行为的影响，我已经注意到＆＃34; app.Start（）＆＃34;当应用程序实际启动时，仅触发一次。每个后续的开放都不再像我的应用程序那样（到＃34; app.Start（）＆＃34;）。

以前，我有此值设置StartPage =＆＃34; ms-appx-web：///index.html"由于Content Security Policy问题。但是将这个值与样本进行比较，他们使用＆＃34; StartPage = index.html＆＃34;让我觉得这可能是问题而我是对的。我花了几个小时来确保我没有得到任何与内容安全策略相关的错误（内联脚本被替换），但它最终有效。

我无法解释为什么＆＃34; StartPage =＆＃39; ms-appx-web：///index.html'＆＃34;导致应用程序每次重新启动，而＆＃34; StartPage =＆＃39; index.html＆＃39;＆＃34;正确地保持其状态，但它确实解决了我的问题。

Windows UWP应用程序生命周期：如何防止在JS / HTML / CSS应用程序中重新加载

1 个答案: