我想将 TableViewCell 中的 CheckBox 绑定到 BooleanBinding。下面的示例由一个带有列的 TableViewname和isEffectiveRequired. 列中的复选框绑定到表达式：
isRequired.or(name.isEqualTo("X"))
因此，当行中的项目是必需的或名称是 X 时，该项目是“有效必需的”，那么表达式应该为真。不幸的是，CheckBox 没有反映更改。为了调试，我添加了一个文本字段，显示nameProperty和requiredProperty计算的effectiveRequiredProperty。
有趣的是，当只返回 isRequiredProperty 而不是绑定时，复选框起作用。
public ObservableBooleanValue effectiveRequiredProperty() {
// Bindings with this work:
// return isRequired;
// with this not
return isRequired.or(name.isEqualTo(SPECIAL_STRING));
}
那么就 CheckBox 而言，Property 和 ObservableValue 有什么区别？
public class TableCellCBBinding extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) throws Exception {
init(primaryStage);
primaryStage.show();
}
private void init(Stage primaryStage) {
primaryStage.setScene(new Scene(buildContent()));
}
private Parent buildContent() {
TableView<ViewModel> tableView = new TableView<>();
tableView.setItems(sampleEntries());
tableView.setEditable(true);
tableView.getColumns().add(buildRequiredColumn());
tableView.getColumns().add(buildNameColumn());
// Add a Textfield to show the values for the first item
// As soon as the name is set to "X", the effectiveRequiredProperty should evaluate to true and the CheckBox should reflect this but it does not
TextField text = new TextField();
ViewModel firstItem = tableView.getItems().get(0);
text.textProperty()
.bind(Bindings.format("%s | %s | %s", firstItem.nameProperty(), firstItem.isRequiredProperty(), firstItem.effectiveRequiredProperty()));
return new HBox(text, tableView);
}
private TableColumn<ViewModel, String> buildNameColumn() {
TableColumn<ViewModel, String> nameColumn = new TableColumn<>("Name");
nameColumn.setCellValueFactory(new PropertyValueFactory<>("name"));
nameColumn.setCellFactory(TextFieldTableCell.forTableColumn());
nameColumn.setEditable(true);
return nameColumn;
}
private TableColumn<ViewModel, Boolean> buildRequiredColumn() {
TableColumn<ViewModel, Boolean> requiredColumn = new TableColumn<>("isEffectiveRequired");
requiredColumn.setMinWidth(50);
// This is should bind my BindingExpression from to ViewModel to the CheckBox
requiredColumn.setCellValueFactory( p -> p.getValue().effectiveRequiredProperty());
requiredColumn.setCellFactory( CheckBoxTableCell.forTableColumn(requiredColumn));
return requiredColumn;
}
private ObservableList<ViewModel> sampleEntries() {
return FXCollections.observableArrayList(
new ViewModel(false, "A"),
new ViewModel(true, "B"),
new ViewModel(false, "C"),
new ViewModel(true, "D"),
new ViewModel(false, "E"));
}
public static class ViewModel {
public static final String SPECIAL_STRING = "X";
private final StringProperty name;
private final BooleanProperty isRequired;
public ViewModel(boolean isRequired, String name) {
this.name = new SimpleStringProperty(this, "name", name);
this.isRequired = new SimpleBooleanProperty(this, "isRequired", isRequired);
this.name.addListener((observable, oldValue, newValue) -> System.out.println(newValue));
}
public StringProperty nameProperty() {return name;}
public final String getName(){return name.get();}
public final void setName(String value){
name.set(value);}
public boolean isRequired() {
return isRequired.get();
}
public BooleanProperty isRequiredProperty() {
return isRequired;
}
public void setRequired(final boolean required) {
this.isRequired.set(required);
}
public ObservableBooleanValue effectiveRequiredProperty() {
// Bindings with this work:
// return isRequired;
// with this not
return isRequired.or(name.isEqualTo(SPECIAL_STRING));
}
}
}
在名称中键入 X 时，应选中该行中的复选框。
在名称中键入 X 时，不会选中该行中的复选框。它从来没有被检查过，就像它根本没有被绑定一样。