Avoid Tree Resize after Section expand - swt

Question

I've got a question I couldn't resolve myself for quite a while now.
I have a RCP ViewPage containing two sections. The sections are inside a SashForm so that the user is able to resize the expanded sections. In the bottom section there is a Tree which is empty after initialization. Through user interaction (i.e. removing a filter) the tree gets filled and has a lot of data in it. If the user now collapses the bottom view and expands it again the tree gets resized which causes ScrollBars in my form. What I want is scrollbars in the tree view.
Here is how the view is build:
- ScrolledForm
- Form Body
- Sash
- Section 1
- Composite
- Some View
- Section 2
- Composite
- Tree
I hope you understand what I'm trying to achieve.
UPDATE: Here is some source code to play with. It uses a Table instead of a tree but produces the same issue.
public class MyPersonPageEditor extends FormPage {
public static final String ID = "some.ID";
TableViewer tableViewer;
public MyPersonPageEditor(FormEditor editor) {
super(editor, ID, "Some Title");
}
#Override
protected void createFormContent(IManagedForm managedForm) {
FormToolkit toolkit = managedForm.getToolkit();
ScrolledForm form = managedForm.getForm();
Composite formBody = form.getBody();
formBody.setLayout(new GridLayout());
form.setText("Some Title");
toolkit.decorateFormHeading(form.getForm());
SashForm sfForm = new SashForm(formBody, SWT.VERTICAL);
sfForm.setLayout(new GridLayout());
sfForm.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
Section topSection = new Section(sfForm, Section.TITLE_BAR | Section.EXPANDED | Section.TWISTIE);
topSection.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
topSection.setText("Section 1 Title");
Composite topSectionComposite = toolkit.createComposite(topSection);
topSectionComposite.setLayout(new GridLayout());
toolkit.createLabel(topSectionComposite, "Just some content. Doesn't need to be much");
Button btn = toolkit.createButton(topSectionComposite, "Create Table Content", SWT.PUSH);
btn.addSelectionListener(new SelectionListener() {
#Override
public void widgetSelected(SelectionEvent e) {
for (int i = 0 ; i < 10 ; i++) {
tableViewer.add("Element " + i);
}
}
#Override
public void widgetDefaultSelected(SelectionEvent e) {
}
});
topSection.setClient(topSectionComposite);
Section bottomSection = new Section(sfForm, Section.TITLE_BAR | Section.EXPANDED | Section.TWISTIE);
bottomSection.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
bottomSection.setText("Section 2 Title");
Composite bottomSectionComposite = toolkit.createComposite(bottomSection);
bottomSectionComposite.setLayout(new GridLayout());
bottomSectionComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
bottomSection.setClient(bottomSectionComposite);
Table table = toolkit.createTable(bottomSectionComposite, SWT.BORDER | SWT.MULTI | SWT.FULL_SELECTION |
SWT.V_SCROLL | SWT.H_SCROLL | SWT.RESIZE);
table.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
table.setHeaderVisible(true);
tableViewer = new TableViewer(table);
tableViewer.add("New Element");
new TableColumn(table, SWT.LEFT).setText("Spalte 1");
TableLayout layoutDefault = new TableLayout();
layoutDefault.addColumnData(new ColumnWeightData(1));
table.setLayout(layoutDefault);
form.reflow(true);
}
}
If you click the button after start the table looks like the left picture. After you collapse and expand the second section it looks like the right one.

Answer 1

Here is the code that works: you just have to tweak the size of the Tree/Table and make sure it will not span across the vertical space:
public void createPartControl(Composite parent) {
FormToolkit toolkit = new FormToolkit(parent.getDisplay());
final ScrolledForm form = toolkit.createScrolledForm(parent);
Composite formBody = form.getBody();
formBody.setLayout(new GridLayout());
form.setText("Some Title");
toolkit.decorateFormHeading(form.getForm());
SashForm sfForm = new SashForm(formBody, SWT.VERTICAL);
sfForm.setLayout(new GridLayout());
sfForm.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
//top section
Section topSection = new Section(sfForm, Section.TITLE_BAR | Section.EXPANDED | Section.TWISTIE);
topSection.setLayout(new GridLayout());
topSection.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
topSection.setText("Section 1 Title");
Composite topSectionComposite = toolkit.createComposite(topSection);
topSectionComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
topSectionComposite.setLayout(new TableWrapLayout());
toolkit.createLabel(topSectionComposite, "Just some content. Doesn't need to be much");
Button btn = toolkit.createButton(topSectionComposite, "Create Table Content", SWT.PUSH);
btn.addSelectionListener(new SelectionListener() {
#Override
public void widgetSelected(SelectionEvent e) {
for (int i = 0 ; i < 10 ; i++) {
tableViewer.add("Element " + i);
}
form.reflow(true);
}
#Override
public void widgetDefaultSelected(SelectionEvent e) {
}
});
topSection.setClient(topSectionComposite);
//bottom section
Section bottomSection = new Section(sfForm, Section.TITLE_BAR | Section.EXPANDED | Section.TWISTIE);
bottomSection.setLayout(new GridLayout());
bottomSection.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
bottomSection.setText("Section 2 Title");
Composite bottomSectionComposite = toolkit.createComposite(bottomSection);
bottomSectionComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
bottomSectionComposite.setLayout(new TableWrapLayout());
Table table = toolkit.createTable(bottomSectionComposite, SWT.BORDER | SWT.MULTI | SWT.FULL_SELECTION |
SWT.V_SCROLL | SWT.H_SCROLL | SWT.RESIZE);
TableWrapData ttd222 = new TableWrapData(TableWrapData.FILL_GRAB, TableWrapData.FILL_GRAB);
ttd222.maxHeight =200;
table.setLayoutData(ttd222);
table.setHeaderVisible(true);
tableViewer = new TableViewer(table);
tableViewer.add("New Element");
new TableColumn(table, SWT.LEFT).setText("Spalte 1");
TableLayout layoutDefault = new TableLayout();
layoutDefault.addColumnData(new ColumnWeightData(1));
table.setLayout(layoutDefault);
bottomSection.setClient(bottomSectionComposite);
form.reflow(true);
}

Answer 2

-make sure the Tree has the SWT.H_SCROLL style (if I remember correctly), that is has a minimum size (for example with GridLayout and GridData set the minHeight to X or with TableWrapLayout and TableData heightHint to X)
-if you don't manage to make it work just tell me and I'll try to make the code; also, a picture with the layout would be great