我对本书的一个练习感到困惑。每次单击鼠标左键时,我都需要在鼠标箭头的位置创建一个圆圈,然后如果我的鼠标刚好在这个圆圈中,我就删除这个节点,然后单击右键。将圆圈添加到窗格中是如此简单,所以我可以快速完成它但是很难将其删除,所以我被困在这个部分,有人可以添加一些代码来删除圆圈吗?
package com.company;
import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.input.MouseButton;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
import java.util.ArrayList;
public class AddOrDeletePoint extends Application {
@Override
public void start(Stage primaryStage) {
Pane pane = new Pane();
double radius = 5;
pane.setOnMouseClicked(e -> {
double X = e.getSceneX();
double Y = e.getSceneY();
Circle circle = new Circle(X, Y, radius);
circle.setFill(Color.WHITE);
circle.setStroke(Color.BLACK);
if (e.getButton() == MouseButton.PRIMARY) {
pane.getChildren().add(circle);
} else if (e.getButton() == MouseButton.SECONDARY) {
pane.getChildren().remove(circle);//this is the remove part, but it does not work!
}
});
Scene scene = new Scene(pane);
primaryStage.setScene(scene);
primaryStage.show();
}
}
答案 0 :(得分:0)
您总是创建一个圆圈。如果单击辅助按钮,则此圆圈从未添加到场景中,并且不会从pane
的子列表中删除任何内容。您需要删除现有的圈子。
将“删除圈子”听众注册到您创建的圈子:
pane.setOnMouseClicked(e -> {
if (e.getButton() == MouseButton.PRIMARY) {
double X = e.getX(); // remove pane's coordinate system here
double Y = e.getY(); // remove pane's coordinate system here
final Circle circle = new Circle(X, Y, radius);
circle.setFill(Color.WHITE);
circle.setStroke(Color.BLACK);
circle.setOnMouseClicked(evt -> {
if (evt.getButton() == MouseButton.SECONDARY) {
evt.consume();
pane.getChildren().remove(circle);
}
});
pane.getChildren().add(circle);
}
});
或者你可以使用选择结果:
pane.setOnMouseClicked(e -> {
if (e.getButton() == MouseButton.PRIMARY) {
double X = e.getX(); // remove pane's coordinate system here
double Y = e.getY(); // remove pane's coordinate system here
Circle circle = new Circle(X, Y, radius);
circle.setFill(Color.WHITE);
circle.setStroke(Color.BLACK);
pane.getChildren().add(circle);
} else if (e.getButton() == MouseButton.SECONDARY) {
// check if cicle was clicked and remove it if this is the case
Node picked = e.getPickResult().getIntersectedNode();
if (picked instanceof Circle) {
pane.getChildren().remove(picked);
}
}
});