java - 单击 GWT 会触发多个单击事件

Question

我有一个 FlexTable 并有一个与之关联的点击事件。有时会多次触发事件。有时单击一次最多 10 次。我已经检查了多个事件处理程序，但我只有一个。从案例中可以明显看出，它有时每次点击只运行一次。

有没有人知道它为什么会发生。

这是示例片段，我尝试对其进行调试，发现点击处理程序被触发了多次。

        private FlexTable flex = new FlexTable(); //it is a global variable
        function A(){
          flex.clear();
          flex.removeAllRows();
          flex.removeAllRows();
          flex.setBorderWidth(2);
          flex.setCellPadding(2);
          flex.setCellSpacing(2);
          flex.getRowFormatter().addStyleName(0, "historyTableHeader");
          flex.setText(0, 0, "ID");
          flex.setText(0, 1, "TIME);
          flex.addClickHandler(new ClickHandler() {
              public void onClick(ClickEvent event) {
                  //some code which might result into call of function B
              }
       }

      //function A is being called multiple times by say function B

Answer 1

您已经回答了您的问题:

flex.addClickHandler(new ClickHandler() {
    public void onClick(ClickEvent event) {
       //some code which might result into call of function B
    }
}
//function A is being called multiple times by say function B

在这种情况下，ClickHandler 存在多次。您可以将代码更改为:

private FlexTable flex = new FlexTable(); //it is a global variable
private ClickHandler handler = null;

private void A(){
    flex.clear();
    //
    if(handler == null){
        handler = new ClickHandler(){}...
        flex.addHandler(handler);
    }

更好:

private FlexTable flex = new FlexTable(); //it is a global variable
private HandlerRegistration handler = null;

private void A(){
    flex.clear();
    //
    if(handler != null){
        handler.removeHandler(); 
    }
    handler = flex.addClickHandler(new ClickHandler() {
    public void onClick(ClickEvent event) {
       //some code which might result into call of function B
    }
}

但我建议在创建 FlexTable 之后直接添加处理程序，并且只添加一次。