JavaFX UI组件——ScrollBar

最新推荐文章于 2024-08-08 07:17:42 发布

转载最新推荐文章于 2024-08-08 07:17:42 发布 · 1.4k 阅读

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#java #javafx #ScrollBar #javafx滚动条 #Group

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本示例展示了如何在JavaFX中使用水平和垂直滚动条，并通过滚动条的值来动态调整画布上圆形的位置。滚动条的值变化会触发监听器，从而更新圆形的坐标。

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import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.geometry.Orientation;
import javafx.scene.Group;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.ScrollBar;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
 
/**
 * A sample showing horizontal and vertical scroll bars.
 */
public class ScrollBarApp extends Application {
    private Circle circle;
    private ScrollBar xscrollBar;
    private ScrollBar yscrollBar;
    private double xscrollValue=0;
    private double yscrollValue=15;
    private static final int xBarWidth = 393;
    private static final int xBarHeight = 15;
    private static final int yBarWidth = 15;
    private static final int yBarHeight = 393;
    private static final int circleRadius = 90;
 
    public Parent createContent() {
        Rectangle bg = new Rectangle(xBarWidth + yBarWidth,
                                     xBarHeight + yBarHeight,
                                     Color.rgb(90,90,90));
        Rectangle box = new Rectangle(100, 100, Color.rgb(150,150,150));
        box.setTranslateX(147);
        box.setTranslateY(147);
 
        // create moveable circle
        circle = new Circle(45,45, circleRadius, Color.rgb(90,210,210));
        circle.setOpacity(0.4);
        circle.relocate(0,15);
 
        // create horizontal scrollbar
        final ChangeListener<Number> xValueListener =
            (ObservableValue<? extends Number> observable,
             Number oldValue, Number newValue) -> {
                // changes the x position of the circle
                setScrollValueX(xscrollBar.getValue(), circle);
            };
        xscrollBar = horizontalScrollBar();
        xscrollBar.setUnitIncrement(20.0);
        xscrollBar.valueProperty().addListener(xValueListener);
        // create vertical scrollbar
        final ChangeListener<Number> yValueListener =
            (ObservableValue<? extends Number> observable,
             Number oldValue, Number newValue) -> {
            // changes the y position of the circle
            setScrollValueY(yscrollBar.getValue(), circle);
        };
        yscrollBar = verticalScrollBar();
        yscrollBar.setUnitIncrement(20.0);
        yscrollBar.valueProperty().addListener(yValueListener);
 
        //shift position of vertical scrollbar to right side of scene
        yscrollBar.setTranslateX(yBarHeight);
        yscrollBar.setTranslateY(yBarWidth);
        yscrollBar.setOrientation(Orientation.VERTICAL);
 
        Group group = new Group();
        group.getChildren().addAll(bg, box, circle, xscrollBar, yscrollBar);
        return group;
    }
 
    // Create a ScrollBar with given parameters
    private ScrollBar horizontalScrollBar() {
        final ScrollBar scrollBar = new ScrollBar();
        scrollBar.setMinSize(-1, -1);
        scrollBar.setPrefSize(xBarWidth, xBarHeight);
        scrollBar.setMaxSize(xBarWidth, xBarHeight);
        scrollBar.setVisibleAmount(50);
        scrollBar.setMax(xBarWidth-(2*circleRadius));
        return scrollBar;
    }
 
    // Create a ScrollBar with given parameters
    private ScrollBar verticalScrollBar() {
        final ScrollBar scrollBar = new ScrollBar();
        scrollBar.setMinSize(-1, -1);
        scrollBar.setPrefSize(yBarWidth, yBarHeight);
        scrollBar.setMaxSize(yBarWidth, yBarHeight);
        scrollBar.setVisibleAmount(50);
        scrollBar.setMax(yBarHeight-(2*circleRadius));
        return scrollBar;
    }
    // Updates x values
    private void setScrollValueX(double v, Circle circle) {
        this.xscrollValue = v;
        circle.relocate(xscrollValue, yscrollValue);
    }
    // Updates x values
    private void setScrollValueY(double v, Circle circle) {
        this.yscrollValue = v+xBarHeight;
        circle.relocate(xscrollValue, yscrollValue);
    }
 
    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setScene(new Scene(createContent()));
        primaryStage.show();
    }
 
    /**
     * Java main for when running without JavaFX launcher
     */
    public static void main(String[] args) {
        launch(args);
    }
}