JavaFX：如果所选选项卡的数据验证失败，则禁止选择其他选项卡 [英] JavaFX: Prevent selection of a different tab if the data validation of the selected tab fails

问题描述

我正在创建一个将数据存储在本地h2数据库中的CRUD应用程序。我是JavaFX的新手。我使用 jfxml TabPane 到3 Tab c>使用 Scene Builder 2.0 创建。每个标签包含一个 AncorPane ，它包含所有控件：标签， EditText 等等。使用一个控制器管理 TabPane 和选项卡。此函数用于创建和更新数据。它是从显示所有数据的网格调用的。一个非常基本的CRUD应用程序。

I'm creating a CRUD application that store data in a local h2 DB. I'm pretty new to JavaFX. I've created a TabPane to with 3 Tab using an jfxml created with Scene Builder 2.0. Each Tab contains an AncorPane that wrap all the controls: Label, EditText, and more. Both the TabPane and the Tabs are managed using one controller. This function is used to create and to update the data. It's called from a grid that display all the data. A pretty basic CRUD app.

我陷入了验证阶段：当用户更改选项卡时，通过选择另一个选项卡，它被称为相应选项卡的验证方法。如果选项卡的验证失败，我希望选择保留在此选项卡上。

I'm stuck in the validation phase: when the user change the tab, by selecting another tab, it's called a validation method of the corresponding tab. If the validation of the Tab fails, I want that the selection remains on this tab.

为实现此目的，我实现了以下 ChangeListener <我的 TabPane 的 SelectionModel 上的/ code>：

To achieve this I've implemented the following ChangeListener on the SelectionModel of my TabPane:

boolean processingTabValidationOnChange = false;

tabPane.getSelectionModel().selectedIndexProperty().addListener(new ChangeListener<Number>() {

            @Override
            public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
                if (processingTabValidationOnChange == false) {
                    boolean success;

                    switch (t.intValue()) {
                        case 0: success = validationTab1Passed();
                                break;
                        case 1: success = validationTab2Passed();
                                break;
                        case 1: success = validationTab3Passed();
                                break;
                        default: success = false;    
                    }
                    if (success == false) {
                        processingTabValidationOnChange = true;
                        // select the previous tab
                        tabPane.getSelectionModel().select(t.intValue());
                        processingTabValidationOnChange = false;
                    }
                }
            }
        });

我不确定这是正确的做法，因为：

I'm not sure that this is the right approach because:

1. 事件已更改被触发两次，一次用于用户选择，另一次用于 。选择（t.intValue（））。为了避免这种情况，我使用了全局字段boolean processingTabValidationOnChange ...非常脏我知道。


2. <$ c $之后c> .select（t.intValue（）） TabPane显示正确的选项卡，但选项卡的内容为空，就好像 AnchorPane 被隐藏了。我无法再次选择包含错误的选项卡，因为它已被选中。

1. The event changed is fired two times, one for the user selection and one for the .select(t.intValue()). To avoid this I've used a global field boolean processingTabValidationOnChange... pretty dirty I know.
2. After the .select(t.intValue()) the TabPane displays the correctly Tab as selected but the content of the tab is empty as if the AnchorPane was hidden. I cannot select again the tab that contains the errors because it's already selected.

任何帮助都将不胜感激。

Any help would be appreciated.

Elvis

推荐答案

正如我对詹姆斯的答案所评论的那样，我一直在寻找一种干净的解决方案。简而言之，防止用户在当前选项卡的验证失败时更改为其他选项卡。我提出了一个实现 ChangeListener 的解决方案，但正如我所解释的那样：它不是很干净而且（小细节）它不起作用！

As I commented to the James's answer, I was looking for a clean solution to the approach that I've asked. In short, to prevent the user to change to a different tab when the validation of the current tab fails. I proposed a solution implementing the ChangeListener but, as I explained: it's not very "clean" and (small detail) it doesn't work!

好的，问题是用于切换回上一个标签的代码：

Ok, the problem was that the code used to switch back the previous tab:

tabPane.getSelectionModel().select(t.intValue());

在切换标签本身完成之前被调用，因此它最终被选中..但是隐藏了。

is called before the process of switching of the tab itself it's completed, so it ends up selected... but hidden.

为了防止这种情况，我使用了 Platform.runLater（）。更改选项卡后执行代码 .select（）。完整代码变为：

To prevent this I've used Platform.runLater(). The code .select() is executed after the change of tab. The full code becomes:

//global field, to prevent validation on .select(t.intValue());
boolean skipValidationOnTabChange = false;

tabPane.getSelectionModel().selectedIndexProperty().addListener(new ChangeListener<Number>() {

    @Override
    public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
        if (skipValidationOnTabChange == false) {
            boolean success;

            switch (t.intValue()) {
                case 0:
                    success = validationTab1Passed();
                    break;
                case 1:
                    success = validationTab2Passed();
                    break;
                case 1:
                    success = validationTab3Passed();
                    break;
                default:
                    success = false;
            }
            if (success == false) {
                Platform.runLater(new Runnable() {

                    @Override
                    public void run() {
                        skipValidationOnTabChange = true;
                        tabPane.getSelectionModel().select(t.intValue());
                        skipValidationOnTabChange = false;
                    }
                });
            }
        }
    }
});

无论如何，如果有人有更好的解决方案来实现这一点，那么欢迎你。在示例中使用像 consume（）这样的方法来阻止选项卡被选中两次。这样我就可以消除全局字段 skipValidationOnTabChange 。

Anyway, if anyone has a better solution to accomplish this, you're welcome. In example using a method like consume() to prevent the tab to be selected two times. This way I can eliminated the global field skipValidationOnTabChange.

猫王

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