java - 如何调用 GWT 中单个事件处理程序类中编写的相应 Java 方法(针对每个按钮)？

Question

我想在单击不同按钮时调用不同的方法(位于单个 GWT 事件处理程序类中)？是这样的:

假设我的 UI 中有 3 个按钮:

1. 按钮1
2. 按钮2
3. 按钮3

而且，我为它们每个附加了相同的(点击)EventHandler:ButtonClicker

在 OnClick() 方法中，我想调用与所单击的按钮相对应的方法。下面是一些示例代码，可以更好地说明我想要做的事情:

public class ButtonClicker implements ClickHandler 
{
    public void onClick(ClickEvent event)
    {
        PushButton clickedButton = (PushButton) event.getSource();

        // I could call the corresponding method using if-else condition but I do not want to do that. 
        // Instead, I want some code here, may be using JSNI (using eval in some way) or something like that to call the corresponding method.
        ......      
    }

    private void Button1Click()
    {
        // Code to handle Button1 Click 
    }

    private void Button2Click()
    {
        // Code to handle Button2 Click
    }

    private void Button3Click()
    {
        // Code to handle Button3 Click
    }
}

提前致谢。

Answer 1

我想你有充分的理由走这条复杂的路线，所以这里有一个建议，不包括任何判断:

JavaScriptObject map = createMap(this);

private static native JavaScriptObject createMap(ButtonClicker o) /*-{
   // Note: does not use $entry() as this will be called from GWT code
   return {
       "button1": function() { o.@foo.ButtonClicker::Button1Click()(); },
       "button2": function() { o.@foo.ButtonClicker::Button2Click()(); },
       "button3": function() { o.@foo.ButtonClicker::Button3Click()(); }
     };
}-*/;

private static native void call(JavaScriptObject map, String id) /*-{
  var fn = map[id];
  // TODO: add null-check / fallback behavior
  fn();
}-*/;

@Override
public void onClick(ClickEvent event) {
  call(map, ((UIObject) event.getSource()).getElement().getId());
}