Is it possible to change order of Nodes in JavaFX2 children list? I tried set()
and Collections.swap()
however both throw IllegalArgumentException
in Parent
as in some point the children list contains the same item at two positions (when node is at new position and has not been removed from the old position). There are flags inside Parent which JavaFX uses internaly in toFront()
and toBack()
which prevents the exception, however there is no way to access them from outside.
java.lang.IllegalArgumentException: Children: duplicate children added: parent = HBox@1424bf0
at javafx.scene.Parent$1.onProposedChange(Parent.java:307)
at com.sun.javafx.collections.VetoableObservableList.set(VetoableObservableList.java:156)
at com.sun.javafx.collections.ObservableListWrapper.set(ObservableListWrapper.java:281)
at java.util.Collections.swap(Collections.java:532)
JavaFX application is divided hierarchically into three main components known as Stage, Scene and nodes. We need to import javafx. application. Application class in every JavaFX application.
JavaFX Stage is a standalone application displaying window. Stage is primary element in JavaFX. We can add as many stage as we want but we have only one primary stage.
The Scene it self can only have one root Pane. So if you want 2 panes in the Scene you need 3.
The JavaFX Stage class is the top level JavaFX container. The primary Stage is constructed by the platform. Additional Stage objects may be constructed by the application. Stage objects must be constructed and modified on the JavaFX Application Thread.
You can move the child in the parent's children list by
childNode.toFront();
childNode.toBack();
ObservableList<Node> workingCollection = FXCollections.observableArrayList(pane.getChildren());
Collections.swap(workingCollection, 0, 1);
pane.getChildren().setAll(workingCollection);
Refer to this code:
package swapnode;
import java.util.Collection;
import java.util.Collections;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
/**
*
* @author reegan
*/
public class SwapNode extends Application {
@Override
public void start(Stage primaryStage) {
VBox root = new VBox(20);
/* Thid Part Swap Children of Node */
Pane pane = view();
ObservableList<Node> workingCollection = FXCollections.observableArrayList(pane.getChildren());
Collections.swap(workingCollection, 0, 1);
pane.getChildren().setAll(workingCollection);
root.getChildren().addAll(view(),pane);
Scene scene = new Scene(root, 300, 250);
primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();
}
/**
* The main() method is ignored in correctly deployed JavaFX application.
* main() serves only as fallback in case the application can not be
* launched through deployment artifacts, e.g., in IDEs with limited FX
* support. NetBeans ignores main().
*
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
public Pane view() {
HBox pane = new HBox(10);
Button button = new Button("Hello");
TextField field = new TextField("World");
pane.getChildren().addAll(button,field);
return pane;
}
}
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