actionscript-3 - Actionscript 3.0 中的 MovieClip 与 Sprite

Question

如果我用 MovieClip 而不是 Sprite 来扩展 MainClass 还能做些什么。我知道 MovieClip 扩展了 Sprite 并且在它下面定义了时间轴。但是我仍然可以通过 MovieClip 使用它吗？

package  {
    import flash.display.Sprite;
    import flash.text.TextField;
    import flash.text.TextFormat;
    import flash.display.MovieClip;
    import flash.text.TextFieldType;

    public class MainClass extends Sprite{      
        public function MainClass() {   

            var m:Module=new Module("Admin","John");

            var tf:TextField=new TextField();
            tf.text=m.info;
            tf.border=true;
            tf.type=TextFieldType.INPUT;

            var myFormat:TextFormat = new TextFormat();
            myFormat.size = 3;
            tf.defaultTextFormat=myFormat;

            addChild(tf);   
            this.width=500;
            this.height=300;
            this.x=0;
            this.y=10;
        }
    }       
}


class Module{
        private var m_mName:String;
        private var m_owner:String;

        public function Module(mName:String,owner:String):void{
            m_mName=mName;
            m_owner=owner;
        }
        public function get info():String{
            return owner+' is owner of '+mName;
        }
        public function get mName():String{
            return m_mName;
        }
        public function get owner():String{
            return m_owner;
        }       
    }

另一个小问题，如果我用 MovieClip 替换 Sprite，如何使用 Timeline？

Answer 1

引自 an AS3 book :

Prior to ActionScript 3.0, the MovieClip class was used as an all-purpose graphics container (much like ActionScript 3.0s Sprite class is used). As of ActionScript 3.0, MovieClip is used only to control instances of movieclip symbols created in the Flash authoring tool. Because ActionScript 3.0 does not provide a way to create timeline elements such as frames and tweens, there is no need to create new empty movieclips at runtime in ActionScript 3.0. Instead, all programmatically created graphics should be instances of the appropriate core display class (Bitmap, Shape, Sprite, TextField, etc).

MovieClip 是一个动态类，它保留了与 AS2 的向后兼容性。这意味着，如果虽然不推荐，但需要您向 MovieClip 添加属性，您可以简单地说 myMC.myCustomProperty = "someValue" ，而对于 Sprite，这将引发错误。

出于这个原因，他们还说使用 Sprites 在性能方面更有效。您可以在 this Adobe Forum post 中找到有关此问题的讨论。 .