以编程方式更改 Scroller 容器的位置（通过 HGroup 索引）

Question

我正在尝试更改事件上 Scroller 容器的可见索引。 Scroller 包含一个带有图像的 HGroup，因此在发生事件时我想通过指定 HGroup 索引来更改哪些图像在 Scroller 中可见。这可能吗？

容器代码：

<s:Scroller id="test" includeIn="startState" x="53" y="20" width="170"
            height="200" depth="2" scrollSnappingMode="leadingEdge">
    <s:HGroup gap="0" width="170" height="200">
        <s:Image id="BrigadeEmblem1" width="170" height="200" smooth="true"
                 smoothingQuality="high" source="assets/1st Stryker Brigade.png"
                 verticalAlign="middle"/>
        <s:Image id="BrigadeEmblem4" width="170" height="200" smooth="true"
                 smoothingQuality="high" source="assets/4th Stryker Brigade.png"
                 verticalAlign="middle"/>
    </s:HGroup>
</s:Scroller>

因此，例如，如果“BrigadeEmblem1”在滚动条中可见，我想在听到特定事件时以编程方式将可见图像更改为“BrigadeEmblem4”。

Answer 1

正是如此！

    setTimeout(image1,3000); // in 3 seconds this event will call for the function(image1)

    function image1(){
    myMovieClip .visible = false;
    }

Answer 2

是的，实际上这是可能的。

我通过扩展 Scroller 类并创建此方法来完成此操作：

public function ensureIndexIsVisible(index:int):void {

        if (!viewport || !(viewport is GroupBase) || !(viewport as GroupBase).layout) {
            return;
        }

        var spDelta:Point = GroupBase(viewport).layout.getScrollPositionDeltaToElement(index);

        // if spDelta is null, no scrolling is required.
        if (spDelta) {
            GroupBase(viewport).horizontalScrollPosition += spDelta.x;
            GroupBase(viewport).verticalScrollPosition += spDelta.y;
        }
    }

因此，当您想要第二个图像时：

myScroller.ensureIndexIsVisible(1);

Answer 3

答案有点晚了，但我希望这对某人有用。我编写了一些自动滚动 Scroller 的代码，以便聚焦的组件完全可见。您可以用它来解决您的问题

 private var _focusedComponentPaddingTop:int = 10;
 private var _focusedComponentPaddingBottom:int = 10;
 private var _focusedComponentPaddingLeft:int = 5;
 private var _focusedComponentPaddingRight:int = 5;

 public function makeFocusedItemVisible(event:FocusEvent):void {
    // Target is the actual object that has focus.
    var target:DisplayObject = DisplayObject(event.target);

    if (target != null && contains(target)) {
       // The container's viewable area
       var visibleArea:Rectangle = getVisibleArea();
       var changed:Boolean = false;

       // Calculate the position of the target in the container.
       var topLeft:Point = new Point(0, 0);
       topLeft = target.localToGlobal(topLeft);
       topLeft = globalToLocal(topLeft);

       var bottomRight:Point =
             new Point(target.width, target.height);
       bottomRight = target.localToGlobal(bottomRight);
       bottomRight = globalToLocal(bottomRight);

       // Check if the component is visible and move the scrollbars if not
       if (bottomRight.x > visibleArea.right) {
          var deltaX:Number = bottomRight.x - visibleArea.right;
          viewport.horizontalScrollPosition += deltaX + _focusedComponentPaddingRight;
          topLeft.x -= deltaX;
          changed = true;
       }

       if (topLeft.x < visibleArea.left) {
          viewport.horizontalScrollPosition -=
                visibleArea.left - topLeft.x + _focusedComponentPaddingLeft;
          changed = true;
       }

       if (bottomRight.y > visibleArea.bottom) {
          var deltaY:Number = bottomRight.y - visibleArea.bottom;
          viewport.verticalScrollPosition += deltaY + focusedComponentPaddingBottom;
          topLeft.y -= deltaY;
          changed = true;
       }

       if (topLeft.y < visibleArea.top) {
          viewport.verticalScrollPosition -=
                visibleArea.top - topLeft.y + focusedComponentPaddingTop;
          changed = true;
       }

       // Call validateNow() to get the container move the component 
       if (changed) {
          validateNow();
       }
    }
 }

 private function getVisibleArea():Rectangle {
    var area:Rectangle = new Rectangle();

    area.x = x;
    area.y = y;
    area.width = width;
    area.height = height;

    return area;
 }