反思(JavaFx)

Question

在做了相当多的搜索之后，我把它留给你。在我的应用程序JavaFx中，我使用内省自动生成一个gridPane (然后插入到对话框中)。因此，我有TableView，当用户双击上面的按钮时，它会生成包含这个TableView列的对话框。因此，在此对话框中有TextFields，它允许修改TableView中字段的值。但是，我不能通过内省来拿回我的属性的价值，以及如何取回由于内省而创建的textFields的值？这是我的反思方法：

    public static  GridPane analyserChamp(Etudiant etu) {
    List<String> list = new ArrayList<>();
    Class<? extends Etudiant> classPixel = etu.getClass();
    Field attribut[] = classPixel.getDeclaredFields();
    GridPane gp = new GridPane();

    int i=0;
    for(Field p : attribut) {
        list.add(p.getName());
        Label lab = new Label();

        if(!p.getName().equals("classe")) {
            TextField l = new TextField();
            lab.setText(p.getName());
            gp.add(l, 1, i);

        }else {
            ComboBox<String> cb = new ComboBox<String>();
            cb.getItems().addAll("1Bi","2Bi","3Bi");
            gp.add(cb, 1, i);
        }

        gp.add(lab, 0, i);
        i++;

    }
    return gp;
}

下面是我调用内省方法的代码：

                if(e.getClickCount() == 2) {
                Dialog<Etudiant> dialog = new Dialog<>();
                Etudiant test = tableViewEtudiant.getSelectionModel().getSelectedItems().get(0);

                if(test!=null) {

                    dialog.setTitle("Editor");
                    dialog.setHeaderText("You can update your question");
                    dialog.getDialogPane().setContent(Analysateur.analyserChamp(test));

                    ButtonType buttonCancel = new ButtonType("Cancel", ButtonData.CANCEL_CLOSE);
                    ButtonType buttonOk = new ButtonType("Ok", ButtonData.OK_DONE);
                    dialog.getDialogPane().getButtonTypes().addAll(buttonOk,buttonCancel);
                    //Confirmation of the edition
                    Optional<Etudiant> result = dialog.showAndWait();
                    //Edition  of the question in the gson file
                    GridPane tmp = Analysateur.analyserChamp(test);
                    if(result.isPresent()) {

                        // Here ?????

                    }

                }

预先感谢;)

Answer 1

解决这个问题的方法有很多，例如，您可以使用userData属性来存储属性的键，这样以后可以在GridPane子节点上迭代，并在Dialog结果转换器中获得每个值。

当您回顾类Etudiant时

if(!p.getName().equals("classe")) {
            TextField l = new TextField();
            l.setUserData(p.getName()); //Store the attribute name in the TextField
            lab.setText(p.getName());
            gp.add(l, 1, i);

        }else {
            ComboBox<String> cb = new ComboBox<String>();
            cb.setUserData(p.getName()); //Store the attribute name in the ComboBox
            cb.getItems().addAll("1Bi","2Bi","3Bi");
            gp.add(cb, 1, i);
        }

当你创建Dialog时

    Dialog<Etudiant> dialog = new Dialog<>();
    ...
    GridPane content = Analysateur.analyserChamp(test); //Keep the content accesible
    ...
    dialog.getDialogPane().setContent(content);
    ...
    dialog.setResultConverter(button -> { //Convert the result
        Etudiant result = new Etudiant();
        for (Node child : content.getChildren()) { //Iterate over the GridPane children
            if (child instanceof TextField) {
                String attribute = ((TextField)child).getUserData();
                String value = ((TextField)child).getTest();
                //Set the value in the result attribute via instrospection
            }
            if (child instanceof ComboBox) {
                //Do the same with combos
            }
        }
    });

Answer 2

存储一个Supplier，用于获取Map<Field, Supplier<?>>中某个字段的输入值。通过这种方式，您可以遍历地图的条目并检索赋值：

public class ReflectionDialog<T> extends Dialog<T> {

    public ReflectionDialog(Class<T> type, Supplier<T> factory) throws IllegalAccessException {
        GridPane gp = new GridPane();
        Field[] fields = type.getDeclaredFields();

        // stores getters for result value
        final Map<Field, Supplier<?>> results = new HashMap<>();

        int i = 0;
        for (Field field : fields) {
            if (String.class.equals(field.getType())) {
                String name = field.getName();
                Node input;
                Supplier<?> getter;
                if ("classe".equals(name)) {
                    ComboBox<String> cb = new ComboBox<>();
                    cb.getItems().addAll("1Bi", "2Bi", "3Bi");
                    getter = cb::getValue;
                    input = cb;
                } else {
                    TextField l = new TextField();
                    getter = l::getText;
                    input = l;
                }
                results.put(field, getter);
                gp.addRow(i, new Label(name), input);
                i++;
            }
        }

        getDialogPane().setContent(gp);
        getDialogPane().getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);
        setResultConverter(buttonType -> {
            if (buttonType == ButtonType.OK) {
                // create & initialize new object
                final T object = factory.get();
                results.forEach((k, v) -> {
                    try {
                        k.set(object, v.get());
                    } catch (IllegalAccessException ex) {
                        throw new IllegalStateException(ex);
                    }
                });
                return object;
            } else {
                return null;
            }
        });
    }

}

public class A {

    String classe;
    String value;

    @Override
    public String toString() {
        return "A{" + "classe=" + classe + ", value=" + value + '}';
    }

}

ReflectionDialog<A> dialog = new ReflectionDialog<>(A.class, A::new);
A result = dialog.showAndWait().orElse(null);
System.out.println(result);