按变量名加载数据 (AS3)

Question

我有一个代码可以读取用户选择的语言的声音。现在，我的代码是：

if (english == true){
 helloSound = new hello_english(); 
}
if (french == true){
 helloSound = new hello_french(); 
}

因为我要添加更多的单词和更多的语言，所以我想简化我的代码。

我想做什么：

应用启动时，用户选择语言。

english.addEventListener(MouseEvent.CLICK, goEnglish, false, 0, true);
french.addEventListener(MouseEvent.CLICK, goFrench, false, 0, true);

function goEnglish(event:MouseEvent):void {
var audioChosen = "english";
}
function goFrench(event:MouseEvent):void {
var audioChosen = "french";
}

然后可以做类似的事情吗？

 helloSound = new hello_(audioChosen)();

所以，在这个例子中，将要播放的声音是：hello_english

Answer 1

使用 getDefinitionByName

要使用字符串中的 class 名称实例化一个对象，您可以使用 getDefinitionByName，如这个问题中所述：Instantiate a class from a string in ActionScript 3

// Find the relevant class:
var helloSoundFileClass:Class = getDefinitionByName("hello_english") as Class;
// Create a new instance of the class we found:
var helloSound:Sound = new helloSoundFileClass();

用法示例

下面是一个基于原始代码的示例：

var audioChosen:String;
var helloSound:Sound;
var goodbyeSound:Sound;

english.addEventListener(MouseEvent.CLICK, goEnglish, false, 0, true);
french.addEventListener(MouseEvent.CLICK, goFrench, false, 0, true);

// Set a "default" language.
audioChosen = "english"
onLanguageChanged();

// When user chooses a language:
function goEnglish(e:MouseEvent):void {
    audioChosen = "english";
    onLanguageChanged();
}
function goFrench(event:MouseEvent):void {
    audioChosen = "french";
    onLanguageChanged();
}

function onLanguageChanged() {
    // Find the relevant classes:
    var helloSoundFileClass:Class = getDefinitionByName("hello_" + audioChosen) as Class;
    var goodbyeSoundFileClass:Class = getDefinitionByName("goodbye_" + audioChosen) as Class;

    // Create a new instance of the class we found:
    helloSound = new helloSoundFileClass();
    goodbyeSound = new goodbyeSoundFileClass();
}

...

// Later, we can play the sounds:
helloSound.play();
goodbyeSound.play();

Answer 2

只是实现预期结果的另一种方法。

根据相关按钮有一个中心函数setLanguage到check/set。
加载 MP3 文件而不是使用库中的 Sound。

你可以试试：

//english.addEventListener(MouseEvent.CLICK, goEnglish, false, 0, true);
//french.addEventListener(MouseEvent.CLICK, goFrench, false, 0, true);

var helloSound :Sound;
var audioChannel :SoundChannel = new SoundChannel();
var isAudioPlaying :Boolean = false;
var audioChosen :String = "";

english.addEventListener(MouseEvent.CLICK, setLanguage);
french.addEventListener(MouseEvent.CLICK, setLanguage);
spanish.addEventListener(MouseEvent.CLICK, setLanguage);
japanese.addEventListener(MouseEvent.CLICK, setLanguage);
greek.addEventListener(MouseEvent.CLICK, setLanguage);

function setLanguage( evt :MouseEvent ) :void 
{
    //trace("clicked is : " + evt.target.name ); //# get instance name of clicked: eg... "english"
    var user_language = evt.target.name; //# will set to instance name of "evt" that triggered a "clicked" event

    //# check instance name of clicked object
    switch ( user_language )
    {
        case "english": trace("Hello World!"); audioChosen = "english"; break;
        case "french": trace("Bonjour Monde!"); audioChosen = "french"; break;
        case "spanish": trace("Hola Mundo!"); audioChosen = "spanish"; break;
        case "japanese": trace("こんにちは世界!"); audioChosen = "japanese"; break;
        case "greek": trace("γειά σου κόσμος!"); audioChosen = "greek"; break;

    }

    //# also can check with IF / ELSE version instead of the above SWITCH checking...
    //if( user_language == "english" ) { trace("Hello World!"); audioChosen = "english"; }
    //if( user_language == "japanese" ) { trace("こんにちは世界!"); audioChosen = "japanese"; }

    //# run some other function...
    do_Some_Action();
}

function do_Some_Action() :void 
{
    trace("User has chosen language: " + audioChosen);
    trace("::::::::::::::::::::::::::::::::::::::::");

    //# check if the URL is correct, example of expected: "hello_english.mp3"
    //var temp :String = "hello_" + audioChosen + ".mp3"; trace("temp is: " + temp);

    if ( audioChannel == null ) { audioChannel = new SoundChannel(); }
    if ( isAudioPlaying == true ) { audioChannel.stop(); }

    helloSound = new Sound();
    helloSound.load( new URLRequest( "hello_" + audioChosen + ".mp3" ) );
    audioChannel = helloSound.play();
    isAudioPlaying = true;
}

按变量名加载数据 (AS3)

Loading Data By Variable Name (AS3)

flash

actionscript-3

使用 getDefinitionByName

用法示例