All geek questions in one place

JToolBar IllegalArgumentException Error When Returning to GridBagLayout

Why does this code generate IllegalArgumentExceptionwhen the toolbar is pulled out of the GUI and then closed (to return it to the GUI)?

I could understand why it would be wrong to add a component without restrictions, but in this case the initial addition of a toolbar to a panel (which uses GridBagLayout) without limitation does not cause such a problem. Why should this happen with the second and subsequent addition of time?

The code is adapted from this answer , but both codes show the same problem.

code

import java.awt.*;
import javax.swing.*;

public class GridBagToolBarOddity {

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                JPanel gui = new JPanel(new GridBagLayout());
                JToolBar tb = new JToolBar();
                tb.add(new JLabel("Drag me off, then drop me back!"));
                gui.add(tb);

                gui.setPreferredSize(new Dimension(300, 100));
                gui.setBackground(Color.RED);

                JFrame f = new JFrame("Demo");
                f.add(gui);
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                f.setLocationByPlatform(true);

                f.pack();
                f.setVisible(true);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

Exception

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: 
    cannot add to layout: constraints must be a GridBagConstraint
        at java.awt.GridBagLayout.addLayoutComponent(GridBagLayout.java:702)
        at java.awt.Container.addImpl(Container.java:1120)
        at java.awt.Container.add(Container.java:966)
        at javax.swing.plaf.basic.BasicToolBarUI$FrameListener.windowClosing(BasicToolBarUI.java:1265)
        at java.awt.Window.processWindowEvent(Window.java:2051)
        at javax.swing.JDialog.processWindowEvent(JDialog.java:681)
        at java.awt.Window.processEvent(Window.java:2009)
        at java.awt.Component.dispatchEventImpl(Component.java:4861)
        at java.awt.Container.dispatchEventImpl(Container.java:2287)
        at java.awt.Window.dispatchEventImpl(Window.java:2719)
        at java.awt.Component.dispatchEvent(Component.java:4687)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
        at java.awt.EventQueue.access$200(EventQueue.java:103)
        at java.awt.EventQueue$3.run(EventQueue.java:694)
        at java.awt.EventQueue$3.run(EventQueue.java:692)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:708)
        at java.awt.EventQueue$4.run(EventQueue.java:706)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)
+4
2

BasicToolBarUI

    public void windowClosing(WindowEvent w) {
        if (toolBar.isFloatable()) {
            if (dragWindow != null)
                dragWindow.setVisible(false);
            floating = false;
            if (floatingToolBar == null)
                floatingToolBar = createFloatingWindow(toolBar);
            if (floatingToolBar instanceof Window) ((Window)floatingToolBar).setVisible(false);
            floatingToolBar.getContentPane().remove(toolBar);
            String constraint = constraintBeforeFloating;
            if (toolBar.getOrientation() == JToolBar.HORIZONTAL) {
                if (constraint == "West" || constraint == "East") {
                    constraint = "North";
                }
            } else {
                if (constraint == "North" || constraint == "South") {
                    constraint = "West";
                }
            }
            if (dockingSource == null)
                dockingSource = toolBar.getParent();
            if (propertyListener != null)
                UIManager.removePropertyChangeListener(propertyListener);
            dockingSource.add(toolBar, constraint);

, constraintBeforeFloating String , GridBagLayout GridBagConstraints.

constraintBeforeFloating = calculateConstraint();


private String calculateConstraint() {
    String constraint = null;
    LayoutManager lm = dockingSource.getLayout();
    if (lm instanceof BorderLayout) {
        constraint = (String)((BorderLayout)lm).getConstraints(toolBar);
    }
    return (constraint != null) ? constraint : constraintBeforeFloating;
}

, , curretn (String) GridBagLayout .

+3

Source: https://habr.com/ru/post/1525283/

More articles:


All Articles