Javafx点击Circle并获得它的参考 [英] Javafx click on a Circle and get it's reference
本文介绍了Javafx点击Circle并获得它的参考的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我在舞台上有一组节点,圈子。
我希望能够点击其中一个并选择它(只需获取它的参考,这样我就可以移动它,改变颜色等。)
I have a set of Nodes, Circles, on the stage. I want to be able to click on one of them and 'select it' (just get a reference to it so I can move it around, change color etc.)
Pane root = new Pane();
root.getChildren().addAll( /* an array of Circle objects */ );
Scene scene = new Scene(root, 500, 500, BACKGROUND_COLOR);
scene.setOnMouseClicked(new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent mouseEvent) {
// how do I get which Circle I clicked on?
}
});
stage.setTitle(TITLE);
stage.setScene(scene);
stage.show();
推荐答案
我只想在每个圆圈中注册一个监听器。然后你已经有了监听者注册的圈子的引用。
I would simply register a listener with each circle itself. Then you already have the reference to the circle with which the listener was registered.
这个例子推动了可用性的限制,因为它有10,000个圆圈显示全部曾经,但它演示了这种技术:
This example pushes the limit a little as to usability, because it has 10,000 circles shown all at once, but it demonstrates the technique:
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.css.PseudoClass;
import javafx.geometry.Point2D;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
public class GridOfCircles extends Application {
private static final PseudoClass SELECTED_P_C = PseudoClass.getPseudoClass("selected");
private final int numColumns = 100 ;
private final int numRows = 100 ;
private final double radius = 4 ;
private final double spacing = 2 ;
private final ObjectProperty<Circle> selectedCircle = new SimpleObjectProperty<>();
private final ObjectProperty<Point2D> selectedLocation = new SimpleObjectProperty<>();
@Override
public void start(Stage primaryStage) {
selectedCircle.addListener((obs, oldSelection, newSelection) -> {
if (oldSelection != null) {
oldSelection.pseudoClassStateChanged(SELECTED_P_C, false);
}
if (newSelection != null) {
newSelection.pseudoClassStateChanged(SELECTED_P_C, true);
}
});
Pane grid = new Pane();
for (int x = 0 ; x < numColumns; x++) {
double gridX = x*(spacing + radius + radius) + spacing ;
grid.getChildren().add(new Line(gridX, 0, gridX, numRows*(spacing + radius + radius)));
}
for (int y = 0; y < numRows ; y++) {
double gridY = y*(spacing + radius + radius) + spacing ;
grid.getChildren().add(new Line(0, gridY, numColumns*(spacing + radius + radius), gridY));
}
for (int x = 0 ; x < numColumns; x++) {
for (int y = 0 ;y < numRows ; y++) {
grid.getChildren().add(createCircle(x, y));
}
}
Label label = new Label();
label.textProperty().bind(Bindings.createStringBinding(() -> {
Point2D loc = selectedLocation.get();
if (loc == null) {
return "" ;
}
return String.format("Location: [%.0f, %.0f]", loc.getX(), loc.getY());
}, selectedLocation));
BorderPane root = new BorderPane(new ScrollPane(grid));
root.setTop(label);
Scene scene = new Scene(root);
scene.getStylesheets().add("grid.css");
primaryStage.setScene(scene);
primaryStage.show();
}
private Circle createCircle(int x, int y) {
Circle circle = new Circle();
circle.getStyleClass().add("intersection");
circle.setCenterX(x * (spacing + radius + radius) + spacing);
circle.setCenterY(y * (spacing + radius + radius) + spacing);
circle.setRadius(radius);
circle.addEventHandler(MouseEvent.MOUSE_CLICKED, e -> {
selectedCircle.set(circle);
selectedLocation.set(new Point2D(x, y));
});
return circle ;
}
public static void main(String[] args) {
launch(args);
}
}
文件grid.css:
with the file grid.css:
.intersection {
-fx-fill: blue ;
}
.intersection:selected {
-fx-fill: gold ;
}
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