How to lock the divider in SplitPane JavaFX? - javafx

Question

I have a SplitPane and I need to divide the layout 25% and 75%. Also, I need to disallow dragging towards right side beyond the 25% split. However I can drag to any extent within the 25% space. Please help.

Answer 1

SplitPane will respect the min and max dimensions of the components (items) it contains. So to get the behavior you want, bind the maxWidth of the left component to splitPane.maxWidthProperty().multiply(0.25):
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.SplitPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class ConstrainedSplitPane extends Application {
#Override
public void start(Stage primaryStage) {
StackPane leftPane = new StackPane(new Label("Left"));
StackPane rightPane = new StackPane(new Label("Right"));
SplitPane splitPane = new SplitPane();
splitPane.getItems().addAll(leftPane, rightPane);
splitPane.setDividerPositions(0.25);
//Constrain max size of left component:
leftPane.maxWidthProperty().bind(splitPane.widthProperty().multiply(0.25));
primaryStage.setScene(new Scene(new BorderPane(splitPane), 800, 600));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}

Answer 2

This worked for me
private final double dividerMaxWidth = .15;
splitPane.getDividers().get(0).positionProperty().addListener((observable,oldValue,newValue) -> {
if(splitPane.getDividers().get(0).getPosition() > dividerMaxWidth)
splitPane.setDividerPosition(0, dividerMaxWidth);
});
And if you want to lock a divider into a hard position that cannot be moved
private final double absolutePosition = .15;
splitPane.getDividers().get(0).positionProperty().addListener((observable,oldValue,newValue) -> {
splitPane.setDividerPosition(0, absolutePosition);
});