javafx - TableView 不会在焦点丢失事件上提交值

Question

我想创建一个具有以下功能的表:

• 按键编辑
• 输入键 = 下一行
• Tab 键 = 下一列
• 退出键 = 取消编辑

下面是实现这些功能的代码。值(value)观应该致力于失去焦点。问题:他们没有 promise 。焦点更改事件被触发，根据控制台输出，这些值将是正确的，但最终表格单元格中的值是旧的。

有谁知道如何防止这种情况以及如何获取当前的 EditingCell 对象以便我可以手动调用提交？毕竟应该调用某种验证器，以防止在值不正确时更改焦点。

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.value.ObservableValue;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableColumn.CellEditEvent;
import javafx.scene.control.TablePosition;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;
import javafx.util.Callback;

public class TableViewInlineEditDemo extends Application {

    private final TableView<Person> table = new TableView<>();
    private final ObservableList<Person> data =
            FXCollections.observableArrayList(
            new Person("Jacob", "Smith", "jacob.smith@example.com"),
            new Person("Isabella", "Johnson", "isabella.johnson@example.com"),
            new Person("Ethan", "Williams", "ethan.williams@example.com"),
            new Person("Emma", "Jones", "emma.jones@example.com"),
            new Person("Michael", "Brown", "michael.brown@example.com"));

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setWidth(450);
        stage.setHeight(550);

        final Label label = new Label("Address Book");
        label.setFont(new Font("Arial", 20));

        table.setEditable(true);

        Callback<TableColumn<Person, String>, TableCell<Person, String>> cellFactory = (TableColumn<Person, String> p) -> new EditingCell();

        TableColumn<Person, String> firstNameCol = new TableColumn<>("First Name");
        TableColumn<Person, String> lastNameCol = new TableColumn<>("Last Name");
        TableColumn<Person, String> emailCol = new TableColumn<>("Email");

        firstNameCol.setMinWidth(100);
        firstNameCol.setCellValueFactory(new PropertyValueFactory<>("firstName"));
        firstNameCol.setCellFactory(cellFactory);
        firstNameCol.setOnEditCommit((CellEditEvent<Person, String> t) -> {
            ((Person) t.getTableView().getItems().get(t.getTablePosition().getRow())).setFirstName(t.getNewValue());
        });

        lastNameCol.setMinWidth(100);
        lastNameCol.setCellValueFactory(new PropertyValueFactory<>("lastName"));
        lastNameCol.setCellFactory(cellFactory);
        lastNameCol.setOnEditCommit((CellEditEvent<Person, String> t) -> {
            ((Person) t.getTableView().getItems().get(t.getTablePosition().getRow())).setLastName(t.getNewValue());
        });

        emailCol.setMinWidth(200);
        emailCol.setCellValueFactory(new PropertyValueFactory<>("email"));
        emailCol.setCellFactory(cellFactory);
        emailCol.setOnEditCommit((CellEditEvent<Person, String> t) -> {
            ((Person) t.getTableView().getItems().get(t.getTablePosition().getRow())).setEmail(t.getNewValue());
        });

        table.setItems(data);
        table.getColumns().addAll(firstNameCol, lastNameCol, emailCol);


        // edit mode on keypress
        table.addEventFilter(KeyEvent.KEY_PRESSED, new EventHandler<KeyEvent>() {
            @Override
            public void handle(KeyEvent e) {

                if( e.getCode() == KeyCode.TAB) { // commit should be performed implicitly via focusedProperty, but isn't
                    table.getSelectionModel().selectNext();
                    e.consume();
                    return;
                }
                else if( e.getCode() == KeyCode.ENTER) { // commit should be performed implicitly via focusedProperty, but isn't
                    table.getSelectionModel().selectBelowCell();
                    e.consume();
                    return;
                }

                // switch to edit mode on keypress, but only if we aren't already in edit mode
                if( table.getEditingCell() == null) {
                    if( e.getCode().isLetterKey() || e.getCode().isDigitKey()) {  

                        TablePosition focusedCellPosition = table.getFocusModel().getFocusedCell();
                        table.edit(focusedCellPosition.getRow(), focusedCellPosition.getTableColumn());

                    }
                }

            }
        });

        // single cell selection mode
        table.getSelectionModel().setCellSelectionEnabled(true);
        table.getSelectionModel().selectFirst();


        final VBox vbox = new VBox();
        vbox.getChildren().addAll(label, table);

        ((Group) scene.getRoot()).getChildren().addAll(vbox);

        stage.setScene(scene);
        stage.show();
    }


    class EditingCell extends TableCell<Person, String> {

        private TextField textField;

        public EditingCell() {
        }

        @Override
        public void startEdit() {
            if (!isEmpty()) {
                super.startEdit();
                createTextField();
                setText(null);
                setGraphic(textField);
                textField.requestFocus(); // must be before selectAll() or the caret would be in wrong position
                textField.selectAll();
            } 
        }

        @Override
        public void cancelEdit() {
            super.cancelEdit();
            setText((String) getItem());
            setGraphic(null);
        }

        @Override
        public void updateItem(String item, boolean empty) {
            super.updateItem(item, empty);

            if (empty) {
                setText(null);
                setGraphic(null);
            } else {
                if (isEditing()) {
                    if (textField != null) {
                        textField.setText(getString());
                    }
                    setText(null);
                    setGraphic(textField);
                } else {
                    setText(getString());
                    setGraphic(null);
                }
            }
        }

        private void createTextField() {

            textField = new TextField(getString());
            textField.setMinWidth(this.getWidth() - this.getGraphicTextGap() * 2);

            // commit on focus lost
            textField.focusedProperty().addListener((ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) -> {

                if( oldValue = true && newValue == false) {

                    System.out.println( "Focus lost, current value: " + textField.getText());

                    commitEdit();

                }
            });

            // cancel edit on ESC
            textField.addEventFilter(KeyEvent.KEY_RELEASED, e -> {

                if( e.getCode() == KeyCode.ESCAPE) {
                    cancelEdit();
                }

            });

        }

        private String getString() {
            return getItem() == null ? "" : getItem().toString();
        }

        private boolean commitEdit() {
            super.commitEdit(textField.getText());
            return true; // TODO: add verifier and check if commit was possible
        }
    }

    public static class Person {

        private final SimpleStringProperty firstName;
        private final SimpleStringProperty lastName;
        private final SimpleStringProperty email;

        private Person(String fName, String lName, String email) {
            this.firstName = new SimpleStringProperty(fName);
            this.lastName = new SimpleStringProperty(lName);
            this.email = new SimpleStringProperty(email);
        }

        public String getFirstName() {
            return firstName.get();
        }

        public void setFirstName(String fName) {
            firstName.set(fName);
        }

        public String getLastName() {
            return lastName.get();
        }

        public void setLastName(String fName) {
            lastName.set(fName);
        }

        public String getEmail() {
            return email.get();
        }

        public void setEmail(String fName) {
            email.set(fName);
        }
    }

}

非常感谢!

编辑:我已经缩小了范围。问题似乎是当焦点改变时，JavaFX 代码取消了编辑模式。这很糟糕。

public Cell() {
    setText(null); // default to null text, to match the null item
    // focusTraversable is styleable through css. Calling setFocusTraversable
    // makes it look to css like the user set the value and css will not 
    // override. Initializing focusTraversable by calling set on the 
    // CssMetaData ensures that css will be able to override the value.
    ((StyleableProperty<Boolean>)(WritableValue<Boolean>)focusTraversableProperty()).applyStyle(null, Boolean.FALSE);
    getStyleClass().addAll(DEFAULT_STYLE_CLASS);

    /**
     * Indicates whether or not this cell has focus. For example, a
     * ListView defines zero or one cell as being the "focused" cell. This cell
     * would have focused set to true.
     */
    super.focusedProperty().addListener(new InvalidationListener() {
        @Override public void invalidated(Observable property) {
            pseudoClassStateChanged(PSEUDO_CLASS_FOCUSED, isFocused()); // TODO is this necessary??

            // The user has shifted focus, so we should cancel the editing on this cell
            if (!isFocused() && isEditing()) {
                cancelEdit();
            }
        }
    });

    // initialize default pseudo-class state
    pseudoClassStateChanged(PSEUDO_CLASS_EMPTY, true);
}

Answer 1

我很好奇并做了一些背景研究。

您面临着 JavaFX 中一个众所周知的错误问题。

背景

当您调用 commitEdit(textField.getText()) 时，它所做的第一件事是检查 isEditing() 的值，如果该值为 false，无需提交。

public void commitEdit(T newValue) {
    if (! isEditing()) return;

    ... // Rest of the things
}

为什么返回 false？

您可能已经发现，一旦您按 TAB 或 ENTER 更改您的选择，就会调用 cancelEdit()将 TableCell.isEditing() 设置为 false。当调用 textField 焦点属性监听器内的 commitEdit() 时，isEditing() 已经返回 false。

解决方案/技巧

JavaFX 社区对此主题的讨论一直在进行。那里的人已经发布了黑客，非常欢迎您查看。

• TableView, TreeView, ListView - Clicking outside of the edited cell, node, or entry should commit the value
• TableCell - commit on focus lost not possible in every case

a SO thread 中显示了一个黑客攻击，这似乎完成了工作，尽管我还没有尝试过。