Java Tutorial/Swing/JSplitPane

Continuously move the divider and resize its child components while the user is dragging the divider

import javax.swing.JButton;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] argv) throws Exception {
    JButton topComponent = new JButton("top");
    JButton bottomComponent = new JButton("bottom");
    JSplitPane vpane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, topComponent, bottomComponent);
    boolean b = vpane.isContinuousLayout(); // false by default
    // Set the split pane to continuously resize the child components which the divider is dragged
    vpane.setContinuousLayout(true);
  }
}

Create a left-right split pane

import javax.swing.JButton;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] argv) throws Exception {
    JButton leftComponent = new JButton("left");
    JButton rightComponent = new JButton("right");
    // Create a left-right split pane
    JSplitPane hpane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftComponent, rightComponent);
  }
}

Create a top-bottom split pane

import javax.swing.JButton;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] argv) throws Exception {
    JButton topComponent = new JButton("top");
    JButton bottomComponent = new JButton("bottom");
    JSplitPane vpane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, topComponent, bottomComponent);
  }
}

Customizing a JSplitPane Look and Feel

Property StringObject TypeSplitPane.actionMapActionMapSplitPane.activeThumbColorSplitPane.ancestorInputMapInputMapSplitPane.backgroundColorSplitPane.borderBorderSplitPane.centerOneTouchButtonsBooleanSplitPane.darkShadowColorSplitPane.dividerFocusColorColorSplitPane.dividerSizeIntegerSplitPane.foregroundColorSplitPane.highlightColorSplitPane.leftButtonTextStringSplitPane.oneTouchButtonOffsetIntegerSplitPane.oneTouchButtonSizeIntegerSplitPane.oneTouchButtonsOpaqueBooleanSplitPane.oneTouchExpandableBooleanSplitPane.oneTouchOffsetIntegerSplitPane.rightButtonTextStringSplitPane.shadowColorSplitPane.sizeIntegerSplitPane.supportsOneTouchButtonsBooleanSplitPaneDivider.borderBorderSplitPaneDivider.draggingColorColorSplitPaneDivider.oneTouchButtonSizeIntegerSplitPaneUIString

Distributing Space When a JSplitPane Container Is Resized

import javax.swing.JButton;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] argv) throws Exception {
    JButton leftComponent = new JButton("left");
    JButton rightComponent = new JButton("right");
    JSplitPane pane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftComponent, rightComponent);
    double weight = pane.getResizeWeight(); // 0.0 by default
    weight = 1D;
    pane.setResizeWeight(weight);
    weight = .5D;
    pane.setResizeWeight(weight);
  }
}

Getting the Setting the Children in a JSplitPane Container

import javax.swing.JButton;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] argv) throws Exception {
    JButton leftComponent = new JButton("left");
    JButton rightComponent = new JButton("right");
    JButton topComponent = new JButton("top");
    JButton bottomComponent = new JButton("bottom");
    JSplitPane hpane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftComponent, rightComponent);
    JSplitPane vpane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, topComponent, bottomComponent);
    leftComponent = (JButton) hpane.getLeftComponent();
    rightComponent = (JButton) hpane.getRightComponent();
    topComponent = (JButton) vpane.getTopComponent();
    bottomComponent = (JButton) vpane.getBottomComponent();
    hpane.setLeftComponent(topComponent);
    hpane.setRightComponent(bottomComponent);
    vpane.setTopComponent(leftComponent);
    vpane.setBottomComponent(rightComponent);
  }
}

JSplitPane

1. Allows you to display components in a single row or column.
2. JSplitPane can display two-and only two-components.
3. The components are of variable size and separated by a movable divider.

public JSplitPane()
JSplitPane splitPane = new JSplitPane();
public JSplitPane(int newOrientation)
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
public JSplitPane(int newOrientation, boolean newContinuousLayout)
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, true);
public JSplitPane(int newOrientation, Component newLeftComponent, Component newRightComponent)
JComponent topComponent = new JButton("Top Button");
JComponent bottomComponent = new JButton("Bottom Button");
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, topComponent, bottomComponent);
public JSplitPane(int newOrientation, boolean newContinuousLayout, Component newLeftComponent, Component newRightComponent)
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, true, topComponent, bottomComponent);

The continuousLayout property setting determines how the split pane reacts when the user drags the divider.

1. false (the default), only the divider is redrawn when dragged.
2. true, the JSplitPane resizes and redraws the components on each side of the divider as the user drags the divider.

Listening for JSplitPane Property Changes

import java.awt.BorderLayout;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JSplitPane;
public class PropertySplitPane {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Property Split");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
    splitPane.setContinuousLayout(true);
    splitPane.setOneTouchExpandable(true);
    JComponent topComponent = new JButton("A");
    splitPane.setTopComponent(topComponent);
    JComponent bottomComponent = new JButton("B");
    splitPane.setBottomComponent(bottomComponent);
    PropertyChangeListener propertyChangeListener = new PropertyChangeListener() {
      public void propertyChange(PropertyChangeEvent changeEvent) {
        JSplitPane sourceSplitPane = (JSplitPane) changeEvent.getSource();
        String propertyName = changeEvent.getPropertyName();
        if (propertyName.equals(JSplitPane.LAST_DIVIDER_LOCATION_PROPERTY)) {
          int current = sourceSplitPane.getDividerLocation();
          System.out.println("Current: " + current);
          Integer last = (Integer) changeEvent.getNewValue();
          System.out.println("Last: " + last);
          Integer priorLast = (Integer) changeEvent.getOldValue();
          System.out.println("Prior last: " + priorLast);
        }
      }
    };
    splitPane.addPropertyChangeListener(propertyChangeListener);
    frame.add(splitPane, BorderLayout.CENTER);
    frame.setSize(300, 150);
    frame.setVisible(true);
  }
}

Moving the JSplitPane Divider

Reset the divider position to that position by calling the resetToPreferredSizes() method of JSplitPane.

1. Change the dividerLocation property with setDividerLocation(newLocation).
2. 0.0 and 1.0, representing a percentage of the JSplitPane container width.

import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JSplitPane;
public class MovingJSplitPaneDivider {
  public static void main(String[] a) {
    JFrame horizontalFrame = new JFrame();
    horizontalFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JComponent topButton = new JButton("Left");
    JComponent bottomButton = new JButton("Right");
    final JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
    splitPane.setTopComponent(topButton);
    splitPane.setBottomComponent(bottomButton);
    
    horizontalFrame.add(splitPane, BorderLayout.CENTER);
    horizontalFrame.setSize(150, 150);
    horizontalFrame.setVisible(true);
    splitPane.setDividerLocation(0.5);
  }
}

With the system-provided look and feel classes, pressing the F8 key allows you to move the divider with the keyboard keys such as Home, End, or the arrows. F8 isn"t a modifier like Shift or Alt.

Nested JSplitPane

import javax.swing.JApplet;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JSplitPane;
public class NestedJSplitPane{
  
  public static void main(String[] a) {
    int HORIZSPLIT = JSplitPane.HORIZONTAL_SPLIT;
    int VERTSPLIT = JSplitPane.VERTICAL_SPLIT;
    boolean continuousLayout = true;

    JLabel label1 = new JLabel("a");
    JLabel label2 = new JLabel("b");
    JLabel label3 = new JLabel("c");
    JSplitPane splitPane1 = new JSplitPane(VERTSPLIT, continuousLayout, label1, label2);
    splitPane1.setOneTouchExpandable(true);
    splitPane1.setDividerSize(2);
    splitPane1.setDividerLocation(0.5);
    JSplitPane splitPane2 = new JSplitPane(HORIZSPLIT, splitPane1, label3);
    splitPane2.setOneTouchExpandable(true);
    splitPane2.setDividerLocation(0.4);
    splitPane2.setDividerSize(2);
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(splitPane2);
    frame.pack();
    frame.setVisible(true);
  }
}

Resizing Components and Working with a One-Touch Expandable Divider

import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JSplitPane;
public class TouchExpandableSplitPane {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Property Split");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
    splitPane.setContinuousLayout(true);
    splitPane.setOneTouchExpandable(true);
    JComponent topComponent = new JButton("A");
    splitPane.setTopComponent(topComponent);
    JComponent bottomComponent = new JButton("B");
    splitPane.setBottomComponent(bottomComponent);
    frame.add(splitPane, BorderLayout.CENTER);
    frame.setSize(300, 150);
    frame.setVisible(true);
  }
}

set Divider Location for JSplitPane

import java.awt.ruponent;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] args) {
    JFrame frame = new JFrame("SplitPaneFrame");
    JLabel leftImage = new JLabel(new ImageIcon("a.gif"));
    Component left = new JScrollPane(leftImage);
    JLabel rightImage = new JLabel(new ImageIcon("b.gif"));
    Component right = new JScrollPane(rightImage);
    JSplitPane split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, left, right);
    split.setDividerLocation(100);
    frame.getContentPane().add(split);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}

Setting Orientation: JSplitPane.VERTICAL_SPLIT or JSplitPane.HORIZONTAL_SPLIT

import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JSplitPane;
public class JSplitPaneVerticalSetLeftRight {
  public static void main(String[] a) {
    JFrame horizontalFrame = new JFrame();
    horizontalFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
    
    JComponent leftButton = new JButton("Left");
    JComponent rightButton = new JButton("Right");
    JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
    splitPane.setLeftComponent(leftButton);
    splitPane.setRightComponent(rightButton);
    
    horizontalFrame.add(splitPane, BorderLayout.CENTER);
    horizontalFrame.setSize(150, 150);
    horizontalFrame.setVisible(true);
    
  }
}

The split pane supports a one-touch-expandable capability that allows the user to conveniently move the divider to either end with a single click

import javax.swing.JButton;
import javax.swing.JSplitPane;
public class Main {
  public static void main(String[] argv) throws Exception {
    JButton topComponent = new JButton("top");
    JButton bottomComponent = new JButton("bottom");
    JSplitPane vpane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, topComponent, bottomComponent);
    boolean b = vpane.isOneTouchExpandable(); // false by default
    vpane.setOneTouchExpandable(true);
  }
}