gwt - 允许/禁止 GWT 中 TabPanel 的选项卡选择

Question

我有 4 个标签。我想阻止用户（使用 window.alert 示例）进入另一个选项卡，因为它尚未完成填充当前选项卡。用户填写完所有字段后，当前选项卡内会出现一个文本（说他可以移动到下一个选项卡）。他将能够单击下面的选项卡。

我应该使用 BeforeSelectionEvent 处理程序还是 SelectionHandler？

Answer 1

我做这个代码来回答我的问题，但太长了

is there a possibility to turn it into a short function ?
 this.addBeforeSelectionHandler(new BeforeSelectionHandler<Integer>() {
              public void onBeforeSelection(BeforeSelectionEvent<Integer> event) {
                if (Application.get().getChampsObligatoire().values().contains("Fiche")) {
                    if (event.getItem().intValue() > 0){
                    event.cancel();
                    Window.alert("You must fill all fields before proceeding to the next step.");
                    }

                    }
                if (Application.get().getChampsObligatoire().values().contains("projet")) {
                    if (event.getItem().intValue() > 1){
                    event.cancel();
                    Window.alert("You must fill all fields before proceeding to the next step.");
                    }
                }
                    if (Application.get().getChampsObligatoire().values().contains("cibles")) {
                        if (event.getItem().intValue() > 2){
                        event.cancel();
                        Window.alert("You must fill all fields before proceeding to the next step.");
                        }

                        }

                    if (Application.get().getChampsObligatoire().values().contains("Ressources")) {
                        if (event.getItem().intValue() > 3){
                        event.cancel();
                        Window.alert("You must fill all fields before proceeding to the next step.");
                        }

                        }
                    if (Application.get().getChampsObligatoire().values().contains("Contrôle")) {
                        if (event.getItem().intValue() > 4){
                        event.cancel();
                        Window.alert("You must fill all fields before proceeding to the next step.");
                        }

                        }



              }

            }); 

Answer 2

对于 GWT 选项卡面板：

@Override
public boolean onBeforeTabSelected(SourcesTabEvents sender, int tabIndex)
{
    String currentTabName = widget.getTabHTML(widget.getSelectedTab()); // for reference
    String tabNameYouTryingToSelect = widget.getTabHTML(tabIndex);  // for reference

    // check some external self-written method and return true or false to allow/disallow selection
    if (isCurrentlyActiveTabBuilt()){
        return true;
    } else {
        Window.alert("You must fill all fields before proceeding to the next step.");
        return false;
    }
}