ActionScript:这怎么会失败？

Question

此代码抛出错误:

    if (modalMessage != null && contains(modalMessage))
    {
        removeChild(modalMessage); // the error is here
        modalMessage = null;            
    }

错误是:

[Fault] exception, information=ArgumentError: Error #2025: The supplied DisplayObject must be a child of the caller.

怎么会这样？我正在检查它是否是一个孩子.

Answer 1

contains()如果主题是调用者的后代,则返回true.对于间接后代,儿童的孩子等也会如此.

确定指定的显示对象是DisplayObjectContainer实例的子项还是实例本身.搜索包括整个显示列表,包括此DisplayObjectContainer实例.孙子,曾孙等等都归于真实.

http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/display/DisplayObjectContainer.html#contains%28%29

您可以检查父母:

if(modalMessage && modalMessage.parent && modalMessage.parent == this)

或者,对于更通用的处理解决方案:

if(modalMessage) {
    if(modalMessage.parent) DisplayObjectContainer(modalMessage.parent).removeChild(modalMessage);
    modalMessage = null;
}