在首选项页面中获取“应用”按钮+ swt eclipse

Question

I have MyPreferencePage which extends PreferencePage. Inside the PreferencePage there is a method getApplyButton() I am overriding that method to get the apply button.

I need the apply button because there are some validators that I put on the data in the preference dialog and till the all the data is not correct I dont want the apply button to be enabled.

My code

 public class DefaultColorsPreferencePage extends PreferencePage implements IWorkbenchPreferencePage {
     @Override
     protected Control createContents(Composite parent) {

    this.container = new Composite(parent, SWT.NONE);
    this.container.setLayout(new GridLayout(1, false));
    GridData gd_area = new GridData(SWT.FILL, SWT.FILL, true, true);
    this.container.setLayoutData(gd_area);

    this.defalutColoringGroup = new Group(container, SWT.NONE);
    this.defalutColoringGroup.setLayout(new GridLayout(1, false));
    this.defalutColoringGroup.setLayoutData(gd_area);
    this.defalutColoringGroup.setText(Constants.DESCRIPTION_TEXT);

    this.defaultColoringCheckBox = new Button(defalutColoringGroup, SWT.CHECK);
    this.defaultColoringCheckBox.setText(Constants.DEFAULT_COLORING_BUTTON_TEXT);

    errorLabel = new Label(defalutColoringGroup, SWT.NONE);
    errorLabel.setText("Expression is not valid, enter a valid expression and try again!");
    errorLabel.setForeground(Display.getCurrent().getSystemColor(SWT.COLOR_RED));
    errorLabel.setVisible(false);

    this.viewer = tableviewerComposite.createTableViewer(defalutColoringGroup);
    this.viewer.setContentProvider(new ArrayContentProvider());
    try {
        contentProvider = new ContentProvider();
        this.viewer.setInput(contentProvider.getScenarios());
    } catch (ParserConfigurationException | SAXException | IOException e) {
        e.printStackTrace();
    }
    return container;
    }

     @Override
     protected Button getApplyButton() {
        super.getApplyButton();
     }
 }

//Method to create columns of the table

     private void createTableColumns(final TableViewer viewer,final Composite defalutColoringGroup) {

    TableViewerColumn scenariosColumn = createTableViewerColumn(viewer,Constants.SCENARIOS_COLUMN_NAME,Constants.SCENARIOS_COLUMN_NUMBER);
    ScenariosLabelProvider scenariosLabelProvider = new ScenariosLabelProvider();
    scenariosColumn.setLabelProvider(scenariosLabelProvider);
    scenariosColumn.setEditingSupport(new ScenariosEditingSupport(viewer));

   //more columns 
  }

//Editing Support for column

public class ScenariosEditingSupport extends EditingSupport {

private final TableViewer viewer;
private final CellEditor editor;
private final DefaultColorsPreferencePage preferencePage;

public ScenariosEditingSupport(TableViewer viewer) {
    super(viewer);
    this.viewer = viewer;
    this.editor = new TextCellEditor(viewer.getTable());
    this.preferencePage = new DefaultColorsPreferencePage();
}

@Override
protected CellEditor getCellEditor(Object element) {
    return editor;
}

@Override
protected boolean canEdit(Object element) {
    return true;
}

@Override
protected Object getValue(Object element) {
    return ((Content) element).getExpression();
}

@Override
protected void setValue(Object element, Object changedExpression) {
    String expression  = String.valueOf(changedExpression);

    if(Repository.isExpressionValid(expression)){
        ((Content) element).setExpression(expression);
        viewer.update(element, null);
    }
    else{
        preferencePage.setValid(false);
        preferencePage.setErrorMessage("Expression is not valid, enter a valid expression and try again!");
        ((Content) element).setExpression(expression);
        viewer.update(element, null);
    }
 }
}

Answer 1

You don't access the Apply button to enable / disable the preference page. Instead call the

setValid(false);

method of PreferencePage to disable Apply and OK.

Call setValid(true) when the page is OK.

You might also want to call the setErrorMessage or setMessage methods to set a message while the page is invalid.