Actionscript 3 我真的需要URLLoader的事件处理程序吗？_Actionscript 3_Flash

Actionscript 3 我真的需要URLLoader的事件处理程序吗？

actionscript-3 flash

Actionscript 3 我真的需要URLLoader的事件处理程序吗？,actionscript-3,flash,Actionscript 3,Flash,我是actionscript的新手，我正在学习Joseph Devore的教程。我知道，当我想进行网络查询时，我可以创建一个URLRequest，并使用URLLoader发送它。我希望在URLLoader.data属性中找到响应数据，但在进行查询后，在我的示例中仍然为空。然后，似乎我必须创建一个事件处理来实际访问响应。这是真的吗我编写了这个小示例代码，想知道如何（最简单的方法）访问这个get请求中的响应 package { import flash.events.Event;

我是actionscript的新手，我正在学习Joseph Devore的教程。我知道，当我想进行网络查询时，我可以创建一个URLRequest，并使用URLLoader发送它。我希望在URLLoader.data属性中找到响应数据，但在进行查询后，在我的示例中仍然为空。然后，似乎我必须创建一个事件处理来实际访问响应。这是真的吗

我编写了这个小示例代码，想知道如何（最简单的方法）访问这个get请求中的响应

package
{
    import flash.events.Event;
    import flash.net.URLLoader;
    import flash.net.URLRequest;

    public class stackQuery
    {
        public function stackQuery()
        {
        }

        public function makeQuery(): String {
            var request: URLRequest = URLRequest("http://www.google.com");
            var loader: URLLoader = new URLLoader();
            loader.addEventListener(Event.COMPLETE, handleResponse);
            try{
                loader.load(request);
            }
            if(loader.data == null){
                 return "Empty"
            }
            return "data not empty"
            }

            private function handleResponse(event:Event):void
            {
                //something with event.target.data here??
            }
    }
}

是的，当然是真的。假设您加载了1兆字节的数据。你需要时间来加载它，对吗？所以在下一行代码中不可能有这些数据

侦听器将在目标分派事件时执行—在您的情况下，当加载该MB时

这是正常的行为。

是的，当然是真的。假设您加载了1兆字节的数据。你需要时间来加载它，对吗？所以在下一行代码中不可能有这些数据

侦听器将在目标分派事件时执行—在您的情况下，当加载该MB时

这是正常的行为。

是的，当然是真的。假设您加载了1兆字节的数据。你需要时间来加载它，对吗？所以在下一行代码中不可能有这些数据

侦听器将在目标分派事件时执行—在您的情况下，当加载该MB时

这是正常的行为。

是的，当然是真的。假设您加载了1兆字节的数据。你需要时间来加载它，对吗？所以在下一行代码中不可能有这些数据

侦听器将在目标分派事件时执行—在您的情况下，当加载该MB时

这是一种正常的行为。

使用AS3进行同步加载（就像在其他一些语言中一样）没有任何好方法。您的数据为null，因为在AS3中，load命令是异步的——这意味着在加载完成之前，它不会停止应用程序的其余部分（将其锁定），它会继续执行下一行代码，并在加载完成后发送事件

下面是一个代码示例，说明您希望如何根据提供的代码处理此问题：

package
{
    import flash.events.Event;
    import flash.events.IOErrorEvent;
    import flash.events.SecurityErrorEvent;
    import flash.net.URLLoader;
    import flash.net.URLRequest;

    public class stackQuery
    {
        private var loader: URLLoader = new URLLoader(); //let's move it out to the class level so you can easily reference it from other methods (though this is purely optional)

        public function stackQuery()
        {
        }

        public function makeQuery(): String {
            var request:URLRequest = URLRequest("http://www.google.com");


            //add you listeners before loading
            loader.addEventListener(Event.COMPLETE, handleResponse);
            loader.addEventListener(IOErrorEvent.IO_ERROR, handleResponse); //it's good practice to also listen for errors
            loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, handleResponse); //this kind of error will happen if you're trying to load a local resource but have published as network only (or vice-versa)

            //load the request, any code after this will run before the load completes. 
            loader.load(request);
        }

            //this function will run once the load completes
        private function handleResponse(event:Event):void
        {
            if (event is IOErrorEvent) {
                //you had an IO error, better do something 
                return;
            }

            if (event is SecurityErrorEvent) {
                //url wasn't allowed to load
                return;
            }

            trace(loader.data); //this is what was returned from the page
                //you could also get it by referencing the currentTarget of the event
                trace(URLLoader(event.currentTarget).data);
        }
    }
}

下面是一个代码示例，说明您希望如何根据提供的代码处理此问题：

package
{
    import flash.events.Event;
    import flash.events.IOErrorEvent;
    import flash.events.SecurityErrorEvent;
    import flash.net.URLLoader;
    import flash.net.URLRequest;

    public class stackQuery
    {
        private var loader: URLLoader = new URLLoader(); //let's move it out to the class level so you can easily reference it from other methods (though this is purely optional)

        public function stackQuery()
        {
        }

        public function makeQuery(): String {
            var request:URLRequest = URLRequest("http://www.google.com");


            //add you listeners before loading
            loader.addEventListener(Event.COMPLETE, handleResponse);
            loader.addEventListener(IOErrorEvent.IO_ERROR, handleResponse); //it's good practice to also listen for errors
            loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, handleResponse); //this kind of error will happen if you're trying to load a local resource but have published as network only (or vice-versa)

            //load the request, any code after this will run before the load completes. 
            loader.load(request);
        }

            //this function will run once the load completes
        private function handleResponse(event:Event):void
        {
            if (event is IOErrorEvent) {
                //you had an IO error, better do something 
                return;
            }

            if (event is SecurityErrorEvent) {
                //url wasn't allowed to load
                return;
            }

            trace(loader.data); //this is what was returned from the page
                //you could also get it by referencing the currentTarget of the event
                trace(URLLoader(event.currentTarget).data);
        }
    }
}

下面是一个代码示例，说明您希望如何根据提供的代码处理此问题：

package
{
    import flash.events.Event;
    import flash.events.IOErrorEvent;
    import flash.events.SecurityErrorEvent;
    import flash.net.URLLoader;
    import flash.net.URLRequest;

    public class stackQuery
    {
        private var loader: URLLoader = new URLLoader(); //let's move it out to the class level so you can easily reference it from other methods (though this is purely optional)

        public function stackQuery()
        {
        }

        public function makeQuery(): String {
            var request:URLRequest = URLRequest("http://www.google.com");


            //add you listeners before loading
            loader.addEventListener(Event.COMPLETE, handleResponse);
            loader.addEventListener(IOErrorEvent.IO_ERROR, handleResponse); //it's good practice to also listen for errors
            loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, handleResponse); //this kind of error will happen if you're trying to load a local resource but have published as network only (or vice-versa)

            //load the request, any code after this will run before the load completes. 
            loader.load(request);
        }

            //this function will run once the load completes
        private function handleResponse(event:Event):void
        {
            if (event is IOErrorEvent) {
                //you had an IO error, better do something 
                return;
            }

            if (event is SecurityErrorEvent) {
                //url wasn't allowed to load
                return;
            }

            trace(loader.data); //this is what was returned from the page
                //you could also get it by referencing the currentTarget of the event
                trace(URLLoader(event.currentTarget).data);
        }
    }
}

下面是一个代码示例，说明您希望如何根据提供的代码处理此问题：

package
{
    import flash.events.Event;
    import flash.events.IOErrorEvent;
    import flash.events.SecurityErrorEvent;
    import flash.net.URLLoader;
    import flash.net.URLRequest;

    public class stackQuery
    {
        private var loader: URLLoader = new URLLoader(); //let's move it out to the class level so you can easily reference it from other methods (though this is purely optional)

        public function stackQuery()
        {
        }

        public function makeQuery(): String {
            var request:URLRequest = URLRequest("http://www.google.com");


            //add you listeners before loading
            loader.addEventListener(Event.COMPLETE, handleResponse);
            loader.addEventListener(IOErrorEvent.IO_ERROR, handleResponse); //it's good practice to also listen for errors
            loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, handleResponse); //this kind of error will happen if you're trying to load a local resource but have published as network only (or vice-versa)

            //load the request, any code after this will run before the load completes. 
            loader.load(request);
        }

            //this function will run once the load completes
        private function handleResponse(event:Event):void
        {
            if (event is IOErrorEvent) {
                //you had an IO error, better do something 
                return;
            }

            if (event is SecurityErrorEvent) {
                //url wasn't allowed to load
                return;
            }

            trace(loader.data); //this is what was returned from the page
                //you could also get it by referencing the currentTarget of the event
                trace(URLLoader(event.currentTarget).data);
        }
    }
}

虽然给出的答案是正确的，但真正的解释是ActionScript3是一种异步语言，而不是像Python这样的同步语言。在python中，加载url之类的内容后，下一行代码将不会执行，直到加载url（这可能会造成延迟或空闲执行），而在Actionscript 3中，代码执行不会等待并移动到下一行。这就是您需要使用事件（Actionscript 3是一种基于事件的语言）的原因，这样您就可以在代码仍在执行时发现等待的数据何时可用。

如果给出的答案正确，真正的解释是，ActionScript3是一种异步语言，与其他同步语言（例如Python）相反。在python中，加载url之类的内容后，下一行代码将不会执行，直到加载url（这可能会造成延迟或空闲执行），而在Actionscript 3中，代码执行不会等待并移动到下一行。这就是您需要使用事件（Actionscript 3是一种基于事件的语言）的原因，这样您就可以在代码仍在执行时发现等待的数据何时可用。

如果给出的答案正确，真正的解释是，ActionScript3是一种异步语言，与其他同步语言（例如Python）相反。在python中，加载url之类的内容后，在加载url之前，不会执行下一行代码（w