TextField 上的隐式强制转换错误

Question

我认为我有最常见的动作脚本错误。在下面的代码中，我有一个 MovieClip，里面有一些 TextFields，我想为它们设置动画。当我将类分配给 MovieClip 时，我收到此错误 1118: Implicit coercion of a将静态类型 Object 的值转换为可能不相关的类型 flash.text:TextField.。当我 trace 孩子时，我得到 [Object TextField] 并且如果我将它放在第一帧上并将其应用到动态文本，代码可以正常工作，所以为什么我得到这个当我尝试将此代码应用于 MovieClip 的子级时出错？

是否有可能忘记导入任何必要的库？

我已经使文本字段动态化，我已经嵌入了字符并设置了动画的抗锯齿。

package AScripts
{

import flash.display.MovieClip;
import flash.events.Event;
import flash.events.MouseEvent;
import com.greensock.*;
import com.greensock.easing.*;
import flupie.textanim.*;

public class TextFade extends MovieClip {
    private var child : Object;

    public function TextFade( )     
    {
        /*    for (var i : int = 0; i < numChildren; i++  )  {
              child = getChildAt( i );
              trace( child );  
        */
            child = getChildAt( 0 );
            var txtanim:TextAnim = new TextAnim( child ); // <-- Error
                            /* TextAnim expects a TextField as argument */
            txtanim.mode = TextAnimMode.RANDOM;
            txtanim.split = TextAnimSplit.WORDS;
            txtanim.effects = myEffect;
            txtanim.start();
    }
    function myEffect( block:TextAnimBlock ) : void
    {
        TweenLite.to( block , .5 , {alpha : 0 , delay : Math.random( ) * 1 } );
    }   
  }
}

更新：我对建议进行了更改并起作用了。

import flash.text.*;
private var child : TextField;
child = getChildAt( i ) as TextField;

Answer 1

试试这个：

try 
{
    // Need to explicitly cast the child to TextField otherwise
    // we are making an implicit cast and will get an error.
    var textField:TextField = child as TextField; 
    var txtanim:TextAnim = new TextAnim( textField); 
} 
catch (error) 
{
    // unable to cast to a textfield, handle this error if necessary.
}

Answer 2

当您获取对象或更改子变量的声明时，您可以将 child 强制转换为对象：

// cast as TextField
public function TextFade( )     
{
    child = getChildAt( 0 ) as Object;
    // ... rest of method


// change declaration of child
public class TextFade extends MovieClip {
    private var child : TextField;