Question

我在flex builder中创建了一个名为loginInterface的对象。初始化此对象时，它会加载登录界面，创建按钮，输入框等。

我为这个对象创建了一个名为unload的方法。我还有一个方法，它返回接口是否已加载。现在，我想卸载对象，以便屏幕不仅有新的接口空间，而且还应该删除对象，以便重新分配该内存。

loginInterface.as类文件：

package
{
    //import required libraries
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.net.URLRequest;
    import flash.net.navigateToURL;

    public class LoginInterface extends Sprite
    {
        private var welcomeLabel:CustomLabel;
        private var versionLabel:CustomLabel;
        private var loginButton:CustomButton;
        private var registerButton:CustomButton;
        private var usernameLabel:CustomLabel;
        private var passwordLabel:CustomLabel;
        private var usernameInputBox:CustomInputBox;
        private var passwordInputBox:CustomInputBox;
        private var loaded:Boolean = false;

        public function LoginInterface()
        {
            trace("LoginInterface object loaded.");
            init(); //initialize the login interface
        }

        public function init():void //initialize the login interface
        {
            trace("LoginInterface init method was called.");

            //create objects
            welcomeLabel = new CustomLabel(200, 100, 500, 30, "Welcome to the ALPHA client."); //welcome label
            versionLabel = new CustomLabel(200, 120, 500, 30, "Version: v1.0.000", "Arial", 0x000000, 12); //version label
            loginButton = new CustomButton(300, 300, 100, 30, "Login"); //login button
            registerButton = new CustomButton(400, 300, 100, 30, "Register") //register button          
            usernameLabel = new CustomLabel(200, 200, 200, 30, "username: "); //username label      
            passwordLabel = new CustomLabel(200, 240, 200, 30, "password: "); //password label
            usernameInputBox = new CustomInputBox(300, 200, 200, 30, false, 0x6D7B8D); //username input box
            passwordInputBox = new CustomInputBox(300, 240, 200, 30, true, 0x6D7B8D); //password input box

            //add objects to the display tree
            addChild(welcomeLabel);
            addChild(versionLabel);
            addChild(loginButton);
            addChild(registerButton);
            addChild(usernameInputBox);
            addChild(usernameLabel);
            addChild(passwordInputBox);
            addChild(passwordLabel);

            //register object events
            registerButton.addEventListener(MouseEvent.CLICK, registerClicked); //register button is clicked
            loginButton.addEventListener(MouseEvent.CLICK, loginClicked); //login button is clicked

            //interface has been loaded
            loaded = true;
        }

        public function isLoaded():Boolean
        {
            if (loaded) return true;
            return false;
        }

        public function unload():void
        {
            if (!loaded) return;
            //welcomeLabel
            removeChild(welcomeLabel);
            welcomeLabel = null;
            //versionLabel
            removeChild(versionLabel);
            versionLabel = null;
            //loginButton
            loginButton.removeEventListener(MouseEvent.CLICK, loginClicked);
            removeChild(loginButton);
            loginButton = null;
            //registerButton
            registerButton.removeEventListener(MouseEvent.CLICK, registerClicked);
            removeChild(registerButton);
            registerButton = null;
            //usernameInputBox
            removeChild(usernameInputBox);
            usernameInputBox = null;
            //usernameLabel
            removeChild(usernameLabel);
            usernameLabel = null;
            //passwordInputBox
            removeChild(passwordInputBox);
            passwordInputBox = null;
            //passwordLabel
            removeChild(passwordLabel);
            passwordLabel = null;
            //set loaded to false
            loaded = false;
        }

        private function loginClicked(event:MouseEvent):void
        {
            trace("Login button has been clicked.");
            var username:String = usernameInputBox.text;
            var password:String = passwordInputBox.text;
            if (!checkLogin(username, password)) {
                new Alert("Please enter a correct username and password.");
            }
            else {
                trace("Creating socket connection.");
                var socketConnection:SocketConnection = new SocketConnection(this);
            }
        }

        private function checkLogin(username:String, password:String):Boolean
        {
            if ((username == "") || (password == "")) {
                return false;
            }
            return true;
        }

        private function registerClicked(event:MouseEvent):void
        {
            trace("Register button has been clicked.");
            var url:URLRequest = new URLRequest("http://url.com/client/register.php");
            navigateToURL(url, "_blank");
        }
    }
}

请参阅加载对象的init函数和卸载它们的卸载函数。这在视觉上是有效的。然而，它是最好的方法吗？它甚至会在一段时间后让垃圾收集器从内存中卸载这些对象吗？

Answer 1

当从父的displayList中删除一个对象（例如LoginInterface）时，只要没有其他对象包含对子对象的引用，该对象内的所有子对象都将自动从内存中删除。

因此，您实际上不需要删除添加到LoginInterface的displayList中的每个对象。您只需要删除您指定的事件侦听器。

所以，你的目标没有任何问题，但你unload方法中真正需要的只是：

loginButton.removeEventListener(MouseEvent.CLICK, loginClicked);
registerButton.removeEventListener(MouseEvent.CLICK, registerClicked);

希望有所帮助。

Answer 2

您卸载代码将按照您的意图运行。 Flash垃圾收集器使用引用计数来确定特定对象是否是垃圾收集的候选对象。运行unload（）函数后，在load（）中创建的所有CustomButton对象的引用计数都为0，最终将被垃圾回收。

在AS3中卸载垃圾收集器的对象

2 个答案: