## Description The Selection grid component provides support to Vaadin Grid and TreeGrid to: * select a range of rows with SHIFT/CTRL Click like Vaadin 7 Table in the default mode * focus on a particular row and column and expand the hierarchy if needed The dataprovider needs to be a in-memory dataprovider for a TreeGrid: * TreeDataProvider for a TreeGrid The component is fetching the data from the server to select an item. If a user selects the first row and shift-clicks on the last row, it will fetch all the rows. That could be a problem if you are using a lazy dataprovider. ### Multi select mode In multiselect mode, a user can select multiple items by clicking them with left mouse button while holding the Ctrl key (or Meta key) pressed. If Ctrl is not held, clicking an item will select it and other selected items are deselected. The user can select a range by selecting an item, holding the Shift key pressed, and clicking another item, in which case all the items between the two are also selected. Multiple ranges can be selected by first selecting a range, then selecting an item while holding Ctrl, and then selecting another item with both Ctrl and Shift pressed. Click on a row will select it. Space on a row will toggle the selection. You can also use Arrow down and Arrow up with Shift/Ctrl. ## How to use it Create a new component SelectionGrid/SelectionTreeGrid and use it like a Grid. The API is quite similar. ## Examples ### Basic example for a multiselect grid ``` public SimpleView() { Div messageDiv = new Div(); List personList = getItems(); Grid grid = new SelectionGrid<>(); grid.setItems(personList); grid.addColumn(Person::getFirstName).setHeader("First Name"); grid.addColumn(Person::getAge).setHeader("Age"); grid.setSelectionMode(Grid.SelectionMode.MULTI); grid.asMultiSelect().addValueChangeListener(event -> { String message = String.format("Selection changed from %s to %s", event.getOldValue(), event.getValue()); messageDiv.setText(message); }); // You can pre-select items grid.asMultiSelect().select(personList.get(0), personList.get(1)); add(grid, messageDiv); } private List getItems() { PersonService personService = new PersonService(); return personService.fetchAll(); } ``` ### Focus and scroll on a particular cell To focus on a particular cell, a new function has been added: focusOnCell that requires an item and a column. ``` public FocusGridMultipleColGroupView() { List personList = getItems(); SelectionGrid grid = new SelectionGrid<>(); grid.setItems(personList); Grid.Column firstNameColumn = grid.addColumn(Person::getFirstName).setHeader("First Name").setKey("name"); Grid.Column lastNameColumn = grid.addColumn(Person::getLastName).setHeader("Last Name").setKey("lastName"); grid.addColumn(Person::getAge).setHeader("Age").setKey("age"); ComboBox personComboBox = new ComboBox<>(); personComboBox.addValueChangeListener(item -> { if (item.getValue() != null) { grid.focusOnCell(item.getValue(), lastNameColumn); } }); personComboBox.setItems(personList); HeaderRow halfheaderRow = grid.prependHeaderRow(); halfheaderRow.join(firstNameColumn, lastNameColumn).setText("Names"); add(personComboBox); addAndExpand(grid); setPadding(false); grid.focusOnCell(personList.get(0), lastNameColumn); } private List getItems() { PersonService personService = new PersonService(); return personService.fetchAll(); } ``` ### Focus and scroll on a particular cell in a Treegrid To focus on a particular cell in a TreeGrid you can use the same function `focusOnCell` It will expand the parent nodes if they are collapsed, the expand is done node by node and can be slow. ``` private DepartmentData departmentData = new DepartmentData(); public FocusTreeGridView() { SelectionTreeGrid grid = buildGrid(); ComboBox personComboBox = new ComboBox<>("Focus"); personComboBox.addValueChangeListener(item -> { if (item.getValue() != null) { grid.focusOnCell(item.getValue(),grid.getColumnByKey("name")); } }); personComboBox.setItems(departmentData.getDepartments()); add(personComboBox); addAndExpand(grid); setPadding(false); setSizeFull(); } private SelectionTreeGrid buildGrid() { SelectionTreeGrid grid = new SelectionTreeGrid<>(); grid.setItems(departmentData.getRootDepartments(), departmentData::getChildDepartments); grid.addHierarchyColumn(Department::getName).setHeader("Department Name").setKey("name"); grid.setWidthFull(); return grid; } ``` ### Allowing text selection By default, text selection is disabled to provide a more appealing visual feedback when selecting multiple rows using shift. The downside of this is, that users cannot select text parts of single rows or cells. To allow selecting text, simply add the theme variant `SelectionGridVariant.SELECTABLE_TEXT` to your SelectionGrid instance. Please note, that the text selection will still be removed, when multiple rows are selected, but, due to technical limitations of event handling there will be a short flickering of selected text. ``` SelectionGrid grid = new SelectionGrid<>(); grid.addThemeVariants(SelectionGridVariant.SELECTABLE_TEXT); // allow text selection inside the grid ``` ## Demo You can check the demo here: https://incubator.app.fi/selection-grid-flow-demo/ ## Missing features or bugs You can report any issue or missing feature on github: https://github.com/vaadin-component-factory/selection-grid-flow ### Sponsored development Major pieces of development of this add-on has been sponsored by multiple customers of Vaadin. Read more about Expert on Demand at: [Support](https://vaadin.com/support) and [Pricing](https://vaadin.com/pricing)