Question

我目前正在尝试向我的应用添加一个扩展的启动画面，一旦完成下载RSS源并在该Feed中找到有效的高分辨率图像，就会自动删除它自己的缩略图（在第一次启动时）应用程序，这可能需要5秒以上，让用户留下空白屏幕）。

不幸的是，MSDN Extended Splash Screen示例并不是很有用，因为他们通过按下按钮而不是等待各种嵌套函数完成来解雇他们。我发现的其他示例跳过重要的细节，这对于对应用程序编程相对较新的人没有帮助。

app.onactivated = function (args) {
    if (args.detail.kind === activation.ActivationKind.launch) {
        if (args.detail.previousExecutionState !== activation.ApplicationExecutionState.terminated) {
            // TODO: This application has been newly launched. Initialize
            // your application here.
        } else {
            // TODO: This application has been reactivated from suspension.
            // Restore application state here.
        }

        performSetupTasks();
        // Retrieve splash screen object.
        var splash = args.detail.splashScreen;
        // Display the extended splash screen.
        displayExtendedSplash(splash);

        args.setPromise(WinJS.UI.processAll().then(removeExtendedSplash()));            
    }
};

相反，上面的代码会立即删除扩展的启动画面;我需要在报告performSetupTasks()的代码中添加任何内容吗？

Answer 1

问题是您可能正在使用performSetupTasks();方法执行异步操作。

重构您的代码以返回该承诺，因此只有在履行承诺后才会删除启动画面：

function removeExtendedSplash() {
    var promise = WinJS.xhr(...);
    promise.then(function(result) { ... });
    return promise;
}

args.setPromise(removeExtendedSplash());

您还可以尝试这种扩展的启动画面实现：https://gist.github.com/petertakacs/5330117

Answer 2

在进入应用程序之前暂停启动画面显示的脚本...

1。）“app.onactivated = function（args）{ if（args.detail.kind === activation.ActivationKind.launch）{“在default.js中添加以下代码

    pauseDisplayOfSplashScreen(2500);

2.）在app.oncheckpoint = function（args）之上，添加以下功能。

    function pauseDisplayOfSplashScreen(milliseconds) {
    milliseconds += new Date().getTime();
    while (new Date() < milliseconds) { }
}

为了清楚地理解这里是完整的启动画面暂停工作default.js：

   // For an introduction to the Blank template, see the following documentation:
   // http://go.microsoft.com/fwlink/?LinkId=232509
  (function () {
    "use strict";

     WinJS.Binding.optimizeBindingReferences = true;

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

app.onactivated = function (args) {
    if (args.detail.kind === activation.ActivationKind.launch) {

        //pause for two seconds
        pauseDisplayOfSplashScreen(2500);

        if (args.detail.previousExecutionState !==   activation.ApplicationExecutionState.terminated) {
            // TODO: This application has been newly launched. Initialize
            // your application here.
        } else {
            // TODO: This application has been reactivated from suspension.
            // Restore application state here.
        }
        args.setPromise(WinJS.UI.processAll());
    }
};


function pauseDisplayOfSplashScreen(milliseconds) {
    milliseconds += new Date().getTime();
    while (new Date() < milliseconds) { }
}
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();

 })();

希望这能解决您的问题：）

Windows 8：等到设置任务完成后再拆除扩展的启动画面

2 个答案: