SWT: Nested Layouts with ScrolledComposite exceeds available space

Question

Hi,

I want to build a Master-Detail layout for one of my applications using SWT.

Container, Content, Sidebar and Part1 are Composite instances. Scrolled is a ScrolledComposite

The desired layout is something like:

+--Container-------------------------------------+
|+--Content----------------------++--Sidebar----+|
||                               ||+--Part1----+||
||                               |||           |||
||                               |||           |||
||                               |||           |||
||                               |||           |||
||                               |||           |||
||                               ||+-----------+||
||                               ||+--Scrolled-+||
||                               |||           |||
||                               |||           |||
||                               |||           |||
||                               |||           |||
||                               |||           |||
||                               ||+-----------+||
|+-------------------------------++-------------+|
+------------------------------------------------+

The Content should grab all the space horizontally and vertically that is available.

The sidebar is basically a container for Part1 and Scrolled which should be of equal height.

Scrolled is the container for a Composite containing a dynamic number of sub items which are arranged in the content composite. Because there can be a large variation of the number of sub-items, this Composite should be scrollable.

I have now implemented this in the following way:

• Container has a GridLayout with 2 colums.

• Inside of that the content has FILL_BOTH behaviour and grabs also all HORIZONTAL/VERTICAL space.

• The sidebar has a FillLayout(SWT.VERTICAL) and contains the Part1 and Scrolled Childs.

Problem: When putting a lot of items into the scrolled composite and the layout just overflows the available space and there is no scrolling available where it should be.

When I use a FillLayout(SWT.HORIZONTAL) for the container the behaviour is as desired, since there is a scrolling and everything is "inside bounds".

Is there a way to achieve this behaviour also when using a GridLayout because I want the content to grab most of the space.

Attached the current test SWT snippet:

public class Scrolled {
    public static void main(String[] args) {
     Display display = new Display();
     Shell shell = new Shell(display);
     shell.setLayout(new GridLayout(2,false));
     //shell.setLayout(new FillLayout(SWT.HORIZONTAL));

     Composite content = new Composite(shell, SWT.BORDER);
     content.setLayoutData(new GridData(SWT.LEFT,SWT.CENTER,false,false));

     Composite sidebar = new Composite(shell, SWT.BORDER);
     sidebar.setLayout(new FillLayout(SWT.VERTICAL));
     sidebar.setLayoutData(new GridData(SWT.LEFT,SWT.CENTER,false,false));

     Composite cc = new Composite(sidebar, SWT.BORDER);

     ScrolledComposite sc = new ScrolledComposite(sidebar, SWT.BORDER
       | SWT.V_SCROLL | SWT.H_SCROLL);
     sc.setLayout(new GridLayout(1,true));

     Composite c = new Composite(sc, SWT.NONE);
     c.setSize(400, 400);
     c.setLayout(new GridLayout(1, true));

     for(int i = 0; i < 1000; i++){
      new Button(c, SWT.PUSH).setText("Text");
     }

     sc.setMinSize(c.computeSize(SWT.DEFAULT, SWT.DEFAULT));
     sc.setContent(c);
     sc.setExpandHorizontal(true);
     sc.setExpandVertical(true);
     sc.setAlwaysShowScrollBars(true);

     shell.open();
     while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
       display.sleep();
     }
     display.dispose();
    }
}

Answer 1

Hi,

seems like I found the solution.

Seems to be the case that a Composite has to take "GRAB_EXCESS_VERTICAL" to be limited to available width. Otherwise the component gets assigned the preffered height which is the maximum height to display all at once.

The following code changes did the trick:

content.setLayoutData(new GridData(SWT.FILL,SWT.FILL,true,**true**));

sidebar.setLayoutData(new GridData(SWT.FILL,SWT.FILL,false,**true**));