Flex 当 mxml 描述的组件初始化它的 mxml 描述的属性时

发布于 2024-11-10 10:07:38 字数 263 浏览 6 评论 0原文

我正在尝试覆盖 Button 类，我有一些属性，我希望直接使用组件的 mxml 描述进行初始化，例如：

<sl:TMyButton id="btnX" x="168" y="223" width="290" label="Button" myproperty1="10" myproperty2="101" myproperty3="4"/>

当具有 mxml 描述的所有属性完全初始化时，会触发哪个函数（以便覆盖它）他们的价值观？

原文

I am trying to override a Button class, i have a few properties which i wish directly initialise with the mxml description of the component, like :

<sl:TMyButton id="btnX" x="168" y="223" width="290" label="Button" myproperty1="10" myproperty2="101" myproperty3="4"/>

which function is triggered ( in order to override it ) when all properties with mxml description is fully initialised with their values ?

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月隐月明月朦胧 2024-11-17 10:07:38

Flex 组件在 中有 4 个方法protected 命名空间应被覆盖以解决不同的任务：

createChildren() — 调用一次以创建和添加子组件。
在布局过程中调用measure()来计算组件尺寸。
updateDisplayList() 将真实组件未缩放的宽度和高度作为参数。显然这种方法对于儿童的定位来说是很方便的。
commitProperties() 是我建议您重写的方法，以便应用不需要应用组件大小的属性值。

因此，在您的情况下，它可以是 updateDisplayList() 或 commitProperties()。我向您推荐以下代码片段：

private var myproperty1Dirty:Boolean;
private var _myproperty1:String;
public function set myproperty1(value:String):void
{
    if (_myproperty1 == value)
        return;
    _myproperty1 = value;
    myproperty1Dirty = true;
    // Postponed cumulative call of updateDisplayList() to place elements
    invalidateDisplayList();
}

private var myproperty2Dirty:Boolean;
private var _myproperty2:String;
public function set myproperty2(value:String):void
{
    if (_myproperty2 == value)
        return;
    _myproperty2 = value;
    myproperty2Dirty = true;
    // Postponed cumulative call of commitProperties() to apply property value
    invalidatePropertues();
}

override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
{
    super.updateDisplayList(unscaledWidth, unscaledHeight);
    if (myproperty1Dirty)
    {
        // Perform children placing which depends on myproperty1 changes
        myproperty1Dirty = false;
    }
}

override protected function commitProperties():void
{
    super.commitProperties();
    if (myproperty2Dirty)
    {
        // Apply changes of myproperty2
        myproperty2Dirty = false;
    }
}

希望这有帮助！

Flex components have 4 methods in protected namespace which should be overridden to solve different tasks:

createChildren() — calls one time to create and add subcomponents.
measure() called in process of lay outing to calculate components size.
updateDisplayList() has real component unscaled width and height as parameter. It is obvious this method is convenient for positioning of children.
commitProperties() is the method I suggest you to override in order to apply properties values which don't need component size to apply.

So in your case it can be updateDisplayList() or commitProperties(). I recommend you the following code snippets:

private var myproperty1Dirty:Boolean;
private var _myproperty1:String;
public function set myproperty1(value:String):void
{
    if (_myproperty1 == value)
        return;
    _myproperty1 = value;
    myproperty1Dirty = true;
    // Postponed cumulative call of updateDisplayList() to place elements
    invalidateDisplayList();
}

private var myproperty2Dirty:Boolean;
private var _myproperty2:String;
public function set myproperty2(value:String):void
{
    if (_myproperty2 == value)
        return;
    _myproperty2 = value;
    myproperty2Dirty = true;
    // Postponed cumulative call of commitProperties() to apply property value
    invalidatePropertues();
}

override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
{
    super.updateDisplayList(unscaledWidth, unscaledHeight);
    if (myproperty1Dirty)
    {
        // Perform children placing which depends on myproperty1 changes
        myproperty1Dirty = false;
    }
}

override protected function commitProperties():void
{
    super.commitProperties();
    if (myproperty2Dirty)
    {
        // Apply changes of myproperty2
        myproperty2Dirty = false;
    }
}

Hope this helps!

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