GWT TextArea-調整大小處理程序

Question

一些瀏覽器為HTML Textareas顯示一個調整文本框大小的句柄。 有什么辦法可以對GWT中的調整大小事件做出反應？

我用以下代碼嘗試過，但未觸發事件：

TextArea textArea = new TextArea();

textArea.addHandler(new ResizeHandler() {

    @Override
    public void onResize(ResizeEvent event) {
        System.out.println("resize");

    }
}, ResizeEvent.getType());

Answer 1

“看起來您不能專門將事件附加到調整文本區域的大小 。 當調整窗口大小時，會觸發resize事件。 ”

https://stackoverflow.com/a/2096352/1467482

Answer 2

這個問題已經有兩年歷史了，但是對於由Google提出這個問題的人，我有一個解決方案。

您可以使用鼠標向下，鼠標移動和鼠標向上事件來響應調整文本區域的大小。 這是基本代碼：

TextArea textArea = new TextArea();
...
textArea.addMouseDownHandler(new MouseDownHandler() {
  private HandlerRegistration mouseMoveUpRegistration;
  private int lastWidth;
  private int lastHeight;

  @Override
  public void onMouseDown(MouseDownEvent event) {
    lastWidth = getOffsetWidth();
    lastHeight = getOffsetHeight();

    if (mouseMoveUpRegistration == null) {
      mouseMoveUpRegistration = Event.addNativePreviewHandler(new NativePreviewHandler() {
        @Override
        public void onPreviewNativeEvent(NativePreviewEvent event) {
          if (event.getTypeInt() == Event.ONMOUSEMOVE || event.getTypeInt() == Event.ONMOUSEUP) {
            int width = getOffsetWidth();
            int height = getOffsetHeight();
            if (width != lastWidth || height != lastHeight) {
              // do whatever you want to to while still resizing
              lastWidth = width;
              lastHeight = height;
            }

            if (event.getTypeInt() == Event.ONMOUSEUP) {
              // do whatever you want to do when resizing finished
              // perhaps check actual and initial size to see if the size really changed
              /* mouse up => additionally remove the handler */
              if (mouseMoveUpRegistration != null) {
                mouseMoveUpRegistration.removeHandler();
                mouseMoveUpRegistration = null;
              }
            }
          }

      });
    }
  }

}）;