JavaFX 2.2：挂钩滑块拖动事件 [英] JavaFX 2.2: Hooking Slider Drag n Drop Events

问题描述

我正在抓住JavaFX上的事件滑块，特别是指示拖曳停止并被释放的滑块。起初我使用这样的模型代码 valueProperty

I am trying to catch the events on the JavaFX Slider especially the one which indicates that the drag stopped and was released. At first I used the valueProperty with mock-up code like this

slider.valueProperty().addListener(new ChangeListener<Number>() {
    @Override
    public void changed(ObservableValue<? extends Number> ov, Number oldValue, Number newValue) {
        log.fine(newValue.toString());
    }
});

但是，它更新太频繁。所以我在SceneBuilder和AP​​I中进行了搜索，发现了一些像

but with this it update too often. So I searched within SceneBuilder and the API and found some interessting like

slider.setOnMouseDragReleased(new EventHandler<MouseDragEvent>() {
    @Override
    public void handle(MouseDragEvent event) {
        System.out.println("setOnMouseDragReleased");
    }
});

但他们从未被解雇。只有一些喜欢 setOnMouseReleased 我得到一些输出，但是例如对于整个节点，像标签等一样。

but they never get fired. There only some like setOnMouseReleased I get some output, but this for example count for the whole Node like the labels etc.

所以我的问题是，这是正确的钩子，知道值不再改变（如果可能的话，释放鼠标，如拖动手势），也许与

推荐答案

将更改侦听器添加到滑块的 valueChangingProperty 知道滑块的值是否在更改，并采取任何

Add a change listener to the slider's valueChangingProperty to know when the slider's value is changing, and take whatever action you want on the value change.

下面的示例将在开始更改时记录滑块的值，并在其完成更改时再次记录。

The sample below will log the slider's value when it starts to change and again when it finishes changing.

import javafx.application.Application;
import javafx.beans.value.*;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class SliderChangeLog extends Application {
    private final ListView<String> startLog = new ListView<>();
    private final ListView<String> endLog   = new ListView<>();

    @Override public void start(Stage stage) throws Exception {
        Pane logsPane = createLogsPane();
        Slider slider = createMonitoredSlider();

        VBox layout = new VBox(10);
        layout.setAlignment(Pos.CENTER);
        layout.setPadding(new Insets(10));
        layout.getChildren().setAll(
                slider,
                logsPane
        );
        VBox.setVgrow(logsPane, Priority.ALWAYS);

        stage.setTitle("Slider Value Change Logger");
        stage.setScene(new Scene(layout));
        stage.show();
    }

    private Slider createMonitoredSlider() {
        final Slider slider = new Slider(0, 1, 0.5);
        slider.setMajorTickUnit(0.5);
        slider.setMinorTickCount(0);
        slider.setShowTickMarks(true);
        slider.setShowTickLabels(true);
        slider.setMinHeight(Slider.USE_PREF_SIZE);

        slider.valueChangingProperty().addListener(new ChangeListener<Boolean>() {
            @Override
            public void changed(
                    ObservableValue<? extends Boolean> observableValue,
                    Boolean wasChanging,
                    Boolean changing) {
                String valueString = String.format("%1$.3f", slider.getValue());

                if (changing) {
                    startLog.getItems().add(
                            valueString
                    );
                } else {
                    endLog.getItems().add(
                            valueString
                    );
                }
            }
        });
        return slider;
    }

    private HBox createLogsPane() {
        HBox logs = new HBox(10);
        logs.getChildren().addAll(
                createLabeledLog("Start", startLog),
                createLabeledLog("End",   endLog)
        );
        return logs;
    }

    public Pane createLabeledLog(String logName, ListView<String> log) {
        Label label = new Label(logName);
        label.setLabelFor(log);

        VBox logPane = new VBox(5);
        logPane.getChildren().setAll(
                label,
                log
        );

        logPane.setAlignment(Pos.TOP_LEFT);

        return logPane;
    }

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

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