--- title: Grid order: 24 layout: page --- [[components.grid]] = [classname]#Grid# ifdef::web[] [.sampler] image:{live-demo-image}[alt="Live Demo", link="http://demo.vaadin.com/sampler/#ui/grids-and-trees/grid"] endif::web[] ((("[classname]#Grid#"))) [classname]#Grid# is many things, and perhaps the most versatile and powerful component in Vaadin. Like [classname]#Table#, it allows presenting and editing tabular data, but escapes many of [classname]#Table#'s limitations. Efficient lazy loading of data while scrolling greatly improves performance. Grid is scalable, mobile friendly, and extensible. [[components.grid.overview]] == Overview [classname]#Grid# is for displaying and editing tabular data laid out in rows and columns. At the top, a __header__ can be shown, and a __footer__ at the bottom. In addition to plain text, the header and footer can contain HTML and components. Having components in the header allows implementing filtering easily. The grid data can be sorted by clicking on a column header; shift-clicking a column header enables secondary sorting criteria. [[figure.components.grid.features]] .A [classname]#Grid# Component image::img/grid-features.png[] The data area can be scrolled both vertically and horizontally. The leftmost columns can be frozen, so that they are never scrolled out of the view. The data is loaded lazily from the server, so that only the visible data is loaded. The smart lazy loading functionality gives excellent user experience even with low bandwidth, such as mobile devices. The grid data can be edited with a row-based editor after double-clicking a row. The fields are generated with a field factory, or set explicitly, and bound to data with a field group. Grid is fully themeable with CSS and style names can be set for all grid elements. For data rows and cells, the styles can be generated with a row or cell style generator. Finally, [classname]#Grid# is designed to be extensible and used just as well for client-side development - its GWT API is nearly identical to the server-side API, including data binding. [[components.grid.overview.table]] === Differences to Table In addition to core features listed above, [classname]#Grid# has the following API-level and functional differences to Table: * Grid is not a [interfacename]#Container# itself, even though it can be bound to a container data source. Consequently, columns are defined differently, and so forth. * Rows can be added with [methodname]#addRow()# shorthand (during initialization) instead of [methodname]#addItem()#. * Use [methodname]#setHeightByRows()# and [methodname]#setHeightMode()# instead of [methodname]#setPageLength()# to set the height in number of rows. * Grid does not extend [classname]#AbstractSelect# and is not a field, but has its own selection API. [methodname]#addSelectionListener()# is called to define a [interfacename]#SelectionListener#. The listener also receives a collection of deselected items. * Grid does not support having all cells in editable mode, it only supports row-based editing, with a row mini-editor that allows saving or discarding the changes. * Grid has no generated columns. Instead, the container data source can be wrapped around a [classname]#GeneratedPropertyContainer#. * No column icons; you can implement them in a column with an [classname]#ImageRenderer#. * Components can not be shown in Grid cells; instead the much more efficient renderers can be used for the most common cases, and row editor for editing values. * Limited support for drag and drop: the user can drag columns to reorder them. In addition, Grid has the following visual changes: * Multiple selection is indicated with check boxes in addition to highlighting. * Grid does not show the row loading indicator like Table does. [[components.grid.data]] == Binding to Data [classname]#Grid# is normally used by binding it to a container data source, described in <>. The container must implement [interfacename]#Container.Indexed# interface. By default, it is bound to an [classname]#IndexedContainer#; Grid offers some shorthand methods to operate on the default container, as described later. You can set the container in the constructor or with [methodname]#setContainerDataSource()#. For example, if you have a collection of beans, you could wrap them in a Vaadin [classname]#BeanContainer# or [classname]#BeanItemContainer#, and bind to a [classname]#Grid# as follows [source, java] ---- // Have some data Collection people = Lists.newArrayList( new Person("Nicolaus Copernicus", 1543), new Person("Galileo Galilei", 1564), new Person("Johannes Kepler", 1571)); // Have a container of some type to contain the data BeanItemContainer container = new BeanItemContainer(Person.class, people); // Create a grid bound to the container Grid grid = new Grid(container); grid.setColumnOrder("name", "born"); layout.addComponent(grid); ---- Note that you need to override [methodname]#equals()# and [methodname]#hashcode()# for the bean ([classname]#Person#) class to make the [classname]#BeanItemContainer# work properly. [[components.grid.basic.manual]] === Default Data Source and Shorthands Sometimes, when you have just a few fixed items that you want to display, you can define the grid columns and add data rows manually. [classname]#Grid# is by default bound to a [classname]#IndexedContainer#. You can define new columns (container properties) with [methodname]#addColumn()# and then add rows (items) with [methodname]#addRow()#. The types in the row data must match the defined column types. For example: [source, java] ---- // Create a grid Grid grid = new Grid(); // Define some columns grid.addColumn("name", String.class); grid.addColumn("born", Integer.class); // Add some data rows grid.addRow("Nicolaus Copernicus", 1543); grid.addRow("Galileo Galilei", 1564); grid.addRow("Johannes Kepler", 1571); layout.addComponent(grid); ---- Or, if you have the data in an array: [source, java] ---- // Have some data Object[][] people = { {"Nicolaus Copernicus", 1543}, {"Galileo Galilei", 1564}, {"Johannes Kepler", 1571}}; for (Object[] person: people) grid.addRow(person); ---- Note that you can not use [methodname]#addRow()# to add items if the container is read-only or has read-only columns, such as generated columns. [[components.grid.selection]] == Handling Selection Changes Selection in [classname]#Grid# is handled a bit differently from other selection components, as it is not an [classname]#AbstractSelect#. Grid supports both single and multiple selection, defined by the __selection mode__. Selection events can be handled with a [interfacename]#SelectionListener#. [[components.grid.selection.mode]] === Selection Mode A [classname]#Grid# can be set to be in [literal]#++SINGLE++# (default), [literal]#++MULTI++#, or [literal]#++NONE++# selection mode, defined in the [classname]#Grid.SelectionMode# enum. [source, java] ---- // Use single-selection mode (default) grid.setSelectionMode(SelectionMode.SINGLE); ---- Empty (null) selection is allowed by default, but can be disabled with [methodname]#setDeselectAllowed()# in single-selection mode. The selection is handled with a different selection model object in each respective selection mode: [classname]#SingleSelectionModel#, [classname]#MultiSelectionModel#, and [classname]#NoSelectionModel# (in which selection is always empty). [source, java] ---- // Pre-select an item SingleSelectionModel selection = (SingleSelectionModel) grid.getSelectionModel(); selection.select( // Select 3rd item grid.getContainerDataSource().getIdByIndex(2)); ---- [[components.grid.selection.single]] === Handling Selection Changes in the selection can be handled with a [interfacename]#SelectionListener#. You need to implement the [methodname]#select()# method, which gets a [classname]#SelectionEvent# as parameter. In addition to selection, you can handle clicks on rows or cells with a [interfacename]#ItemClickListener#. You can get the new selection from the selection event with [methodname]#getSelected()#, which returns a set of item IDs, or more simply from the grid or the selection model with [methodname]#getSelectedRow()#, which returns the single selected item ID. For example: [source, java] ---- grid.addSelectionListener(selectionEvent -> { // Java 8 // Get selection from the selection model Object selected = ((SingleSelectionModel) grid.getSelectionModel()).getSelectedRow(); if (selected != null) Notification.show("Selected " + grid.getContainerDataSource().getItem(selected) .getItemProperty("name")); else Notification.show("Nothing selected"); }); ---- The current selection can be obtained from the [classname]#Grid# object by [methodname]#getSelectedRow()# or [methodname]#getSelectedRows()#, which return one (in single-selection mode) or all (in multi-selection mode) selected items. [WARNING] ==== Note that changes to the item set of the container data source are not automatically reflected in the selection model and may cause the selection model to refer to stale item IDs. This always occurs, for example, when you delete the selected item or items. So, if you modify the item set of the container, you should synchronize or reset the selection with the container, such as by calling [methodname]#reset()# on the selection model. ==== [[components.grid.selection.multi]] === Multiple Selection In the multiple selection mode, a user can select multiple items by clicking on the checkboxes in the leftmost column, or by using the kbd:[Space] to select/deselect the currently focused row. Space bar is the default key for toggling the selection, but it can be customized. [[figure.components.grid.selection.multi]] .Multiple Selection in [classname]#Grid# image::img/grid-selection-multi.png[] The selection is managed through the [classname]#MultiSelectionMode# class. The currently selected rows can be set with [methodname]#setSelected()# by a collection of item IDs, or you can use [methodname]#select()# to add items to the selection. [source, java] ---- // Grid in multi-selection mode Grid grid = new Grid(exampleDataSource()); grid.setSelectionMode(SelectionMode.MULTI); // Pre-select some items MultiSelectionModel selection = (MultiSelectionModel) grid.getSelectionModel(); selection.setSelected( // Items 2-4 grid.getContainerDataSource().getItemIds(2, 3)); ---- The current selection can be read with [methodname]#getSelectedRows()#; either in the [classname]#MultiSelectionMode# object or in the [classname]#Grid#. [source, java] ---- // Allow deleting the selected items Button delSelected = new Button("Delete Selected", e -> { // Delete all selected data items for (Object itemId: selection.getSelectedRows()) grid.getContainerDataSource().removeItem(itemId); // Otherwise out of sync with container grid.getSelectionModel().reset(); // Disable after deleting e.getButton().setEnabled(false); }); delSelected.setEnabled(grid.getSelectedRows().size() > 0); ---- Changes in the selection can be handled with a [interfacename]#SelectionListener#. The selection event object provides [methodname]#getAdded()# and [methodname]#getRemoved()# to allow determining the differences in the selection change. [source, java] ---- // Handle selection changes grid.addSelectionListener(selection -> { // Java 8 Notification.show(selection.getAdded().size() + " items added, " + selection.getRemoved().size() + " removed."); // Allow deleting only if there's any selected deleteSelected.setEnabled( grid.getSelectedRows().size() > 0); }); ---- [[components.grid.selection.clicks]] === Focus and Clicks In addition to selecting rows, you can focus individual cells. The focus can be moved with arrow keys and, if editing is enabled, pressing kbd:[Enter] opens the editor. Normally, pressing kbd:[Tab] or kbd:[Shift+Tab] moves the focus to another component, as usual. When editing or in unbuffered mode, kbd:[Tab] or kbd:[Shift+Tab] moves the focus to the next or previous cell. The focus moves from the last cell of a row forward to the beginning of the next row, and likewise, from the first cell backward to the end of the previous row. Note that you can extend [classname]#DefaultEditorEventHandler# to change this behavior. With the mouse, you can focus a cell by clicking on it. The clicks can be handled with an [interfacename]#ItemClickListener#. The [classname]#ItemClickEvent# object contains various information, most importantly the ID of the clicked row and column. [source, java] ---- grid.addItemClickListener(event -> // Java 8 Notification.show("Value: " + container.getContainerProperty(event.getItemId(), event.getPropertyId()).getValue().toString())); ---- The clicked grid cell is also automatically focused. The focus indication is themed so that the focused cell has a visible focus indicator style by default, while the row doesn't. You can enable row focus, as well as disable cell focus, in a custom theme. See <>. [[components.grid.columns]] == Configuring Columns Columns are normally defined in the container data source. The [methodname]#addColumn()# method can be used to add columns to a container that supports it, such as the default [classname]#IndexedContainer#. Column configuration is defined in [classname]#Grid.Column# objects, which can be obtained from the grid with [methodname]#getColumn()# by the column (property) ID. [source, java] ---- Grid.Column bornColumn = grid.getColumn("born"); bornColumn.setHeaderCaption("Born"); ---- In the following, we describe the basic column configuration. [[components.grid.columns.order]] === Column Order You can set the order of columns with [methodname]#setColumnOrder()# for the grid. Columns that are not given for the method are placed after the specified columns in their natural order. [source, java] ---- grid.setColumnOrder("firstname", "lastname", "born", "birthplace", "died"); ---- Note that the method can not be used to hide columns. You can hide columns with the [methodname]#removeColumn()#, as described later, or by hiding them in a [classname]#GeneratedPropertyContainer#. [[components.grid.columns.removing]] === Hiding Columns Columns can be hidden by removing them with [methodname]#removeColumn()#. You can remove all columns with [methodname]#removeAllColumns()#. The removed columns are only removed from the grid, not from the container data source. To restore a previously removed column, you can call [methodname]#addColumn()# with the property ID. Instead of actually adding another column to the data source, it merely restores the previously removed one. However, column settings such as header or editor are not restored, but must be redone. You can also hide columns at container-level. At least [classname]#GeneratedpropertyContainer# allows doing so, as described in <>. [[components.grid.columns.captions]] === Column Captions Column captions are displayed in the grid header. The default captions are generated automatically from the property ID. You can set the header caption explicitly through the column object with [methodname]#setHeaderCaption()#. [source, java] ---- Grid.Column bornColumn = grid.getColumn("born"); bornColumn.setHeaderCaption("Born"); ---- This is equivalent to setting it with [methodname]#setText()# for the header cell; the [classname]#HeaderCell# also allows setting the caption in HTML or as a component, as well as styling it, as described later in <>. [[components.grid.columns.width]] === Column Widths Columns have by default undefined width, which causes automatic sizing based on the widths of the displayed data. You can set column widths explicitly by pixel value with [methodname]#setWidth()#, or relatively using expand ratios with [methodname]#setExpandRatio()#. When using expand ratios, the columns with a non-zero expand ratio use the extra space remaining from other columns, in proportion to the defined ratios. You can specify minimum and maximum widths for the expanding columns with [methodname]#setMinimumWidth()# and [methodname]#setMaximumWidth()#, respectively. The user can resize columns by dragging their separators with the mouse. When resized manually, all the columns widths are set to explicit pixel values, even if they had relative values before. [[components.grid.columns.frozen]] === Frozen Columns You can set the number of columns to be frozen with [methodname]#setFrozenColumnCount()#, so that they are not scrolled off when scrolling horizontally. [source, java] ---- grid.setFrozenColumnCount(2); ---- Setting the count to [parameter]#0# disables frozen data columns; setting it to [parameter]#-1# also disables the selection column in multi-selection mode. [[components.grid.generatedcolumns]] == Generating Columns Columns with values computed from other columns or in some other way can be generated with a container or data model that generates the property values. The [classname]#GeneratedPropertyContainer# can be used for this purpose. It wraps around any indexed container to extend its properties with read-only generated properties. The generated properties can have same IDs as the original ones, thereby replacing them with formatted or converted values. See <> for a detailed description of using it. Generated columns are read-only, so you can not add grid rows with [methodname]#addRow()#. In editable mode, editor fields are not generated for generated columns. Note that, while [classname]#GeneratedPropertyContainer# implements [interfacename]#Container.Sortable#, the wrapped container might not, and also sorting on the generated properties requires special handling. In such cases, generated properties or the entire container might not actually be sortable. [[components.grid.renderer]] == Column Renderers A __renderer__ is a feature that draws the client-side representation of a data value. This allows having images, HTML, and buttons in grid cells. [[figure.components.grid.renderer]] .Column Renderers: Image, Date, HTML, and Button image::img/grid-renderers.png[] Renderers implement the [interfacename]#Renderer# interface. You set the column renderer in the [classname]#Grid.Column# object as follows: [source, java] ---- grid.addColumn("born", Integer.class); ... Grid.Column bornColumn = grid.getColumn("born"); bornColumn.setRenderer(new NumberRenderer("born in %d AD")); ---- Renderers require a specific data type for the column. To convert to a property type to a type required by a renderer, you can pass an optional [interfacename]#Converter# to [methodname]#setRenderer()#, as described later in this section. A converter can also be used to (pre)format the property values. The converter is run on the server-side, before sending the values to the client-side to be rendered with the renderer. The following renderers are available, as defined in the server-side [package]#com.vaadin.ui.renderers# package: [classname]#ButtonRenderer#:: Renders the data value as the caption of a button. A [interfacename]#RendererClickListener# can be given to handle the button clicks. ifdef::web[] Typically, a button renderer is used to display buttons for operating on a data item, such as edit, view, delete, etc. It is not meaningful to store the button captions in the data source, rather you want to generate them, and they are usually all identical. + [source, java] ---- BeanItemContainer people = new BeanItemContainer<>(Person.class); people.addBean(new Person("Nicolaus Copernicus", 1473)); people.addBean(new Person("Galileo Galilei", 1564)); people.addBean(new Person("Johannes Kepler", 1571)); // Generate button caption column GeneratedPropertyContainer gpc = new GeneratedPropertyContainer(people); gpc.addGeneratedProperty("delete", new PropertyValueGenerator() { @Override public String getValue(Item item, Object itemId, Object propertyId) { return "Delete"; // The caption } @Override public Class getType() { return String.class; } }); // Create a grid Grid grid = new Grid(gpc); // Render a button that deletes the data row (item) grid.getColumn("delete") .setRenderer(new ButtonRenderer(e -> // Java 8 grid.getContainerDataSource() .removeItem(e.getItemId()))); ---- endif::web[] [classname]#ImageRenderer#:: Renders the cell as an image. The column type must be a [interfacename]#Resource#, as described in <>; only [classname]#ThemeResource# and [classname]#ExternalResource# are currently supported for images in [classname]#Grid#. ifdef::web[] [source, java] ---- grid.addColumn("picture", Resource.class) .setRenderer(new ImageRenderer()); ... // Add some data rows grid.addRow(new ThemeResource("img/copernicus-128px.jpg"), "Nicolaus Copernicus", 1543); grid.addRow(new ThemeResource("img/galileo-128px.jpg"), "Galileo Galilei", 1564); ---- + Instead of creating the resource objects explicitly, as was done above, you could generate them dynamically from file name strings using a [interfacename]#Converter# for the column. + [source, java] ---- // Define some columns grid.addColumn("picture", String.class); // Filename grid.addColumn("name", String.class); // Set the image renderer grid.getColumn("picture").setRenderer(new ImageRenderer(), new Converter() { @Override public String convertToModel(Resource value, Class targetType, Locale l) throws Converter.ConversionException { return "not needed"; } @Override public Resource convertToPresentation(String value, Class targetType, Locale l) throws Converter.ConversionException { return new ThemeResource("img/" + value); } @Override public Class getModelType() { return String.class; } @Override public Class getPresentationType() { return Resource.class; } }); // Add some data rows grid.addRow("copernicus-128px.jpg", "Nicolaus Copernicus"); grid.addRow("galileo-128px.jpg", "Galileo Galilei"); grid.addRow("kepler-128px.jpg", "Johannes Kepler"); ---- + You also need to define the row heights so that the images fit there. You can set it in the theme for all data cells or for the column containing the images. + For the latter way, first define a CSS style name for grid and the column: + [source, java] ---- grid.setStyleName("gridwithpics128px"); grid.setCellStyleGenerator(cell -> "picture".equals(cell.getPropertyId())? "imagecol" : null); ---- ifdef::web[] + Then, define the style in CSS (Sass): endif::web[] + [source, css] ---- .gridwithpics128px .imagecol { height: 128px; background: black; text-align: center; } ---- endif::web[] [classname]#DateRenderer#:: Formats a column with a [classname]#Date# type using string formatter. The format string is same as for [methodname]#String.format()# in Java API. The date is passed in the parameter index 1, which can be omitted if there is only one format specifier, such as " [literal]#++%tF++#". ifdef::web[] [source, java] ---- Grid.Column bornColumn = grid.getColumn("born"); bornColumn.setRenderer( new DateRenderer("%1$tB %1$te, %1$tY", Locale.ENGLISH)); ---- + Optionally, a locale can be given. Otherwise, the default locale (in the component tree) is used. endif::web[] [classname]#HTMLRenderer#:: Renders the cell as HTML. This allows formatting cell content, as well as using HTML features such as hyperlinks. ifdef::web[] First, set the renderer in the [classname]#Grid.Column# object: + [source, java] ---- grid.addColumn("link", String.class) .setRenderer(new HtmlRenderer()); ---- ifdef::web[] + Then, in the grid data, give the cell content: endif::web[] + [source, java] ---- grid.addRow("Nicolaus Copernicus", 1543, "info"); ---- + You could also use a [interfacename]#PropertyFormatter# or a generated column to generate the HTML for the links. endif::web[] [classname]#NumberRenderer#:: Formats column values with a numeric type extending [classname]#Number#: [classname]#Integer#, [classname]#Double#, etc. The format can be specified either by the subclasses of [classname]#java.text.NumberFormat#, namely [classname]#DecimalFormat# and [classname]#ChoiceFormat#, or by [methodname]#String.format()#. ifdef::web[] For example: + [source, java] ---- // Define some columns grid.addColumn("name", String.class); grid.addColumn("born", Integer.class); grid.addColumn("sletters", Integer.class); grid.addColumn("rating", Double.class); // Use decimal format grid.getColumn("born").setRenderer(new NumberRenderer( new DecimalFormat("in #### AD"))); // Use textual formatting on numeric ranges grid.getColumn("sletters").setRenderer(new NumberRenderer( new ChoiceFormat("0#none|1#one|2#multiple"))); // Use String.format() formatting grid.getColumn("rating").setRenderer(new NumberRenderer( "%02.4f", Locale.ENGLISH)); // Add some data rows grid.addRow("Nicolaus Copernicus", 1473, 2, 0.4); grid.addRow("Galileo Galilei", 1564, 0, 4.2); grid.addRow("Johannes Kepler", 1571, 1, 2.3); ---- endif::web[] [classname]#ProgressBarRenderer#:: Renders a progress bar in a column with a [classname]#Double# type. The value must be between 0.0 and 1.0. ifdef::web[] For example: + [source, java] ---- // Define some columns grid.addColumn("name", String.class); grid.addColumn("rating", Double.class) .setRenderer(new ProgressBarRenderer()); // Add some data rows grid.addRow("Nicolaus Copernicus", 0.1); grid.addRow("Galileo Galilei", 0.42); grid.addRow("Johannes Kepler", 1.0); ---- endif::web[] [classname]#TextRenderer#:: Displays plain text as is. Any HTML markup is quoted. [[components.grid.renderer.custom]] === Custom Renderers Renderers are component extensions that require a client-side counterpart. See <> for information on implementing custom renderers. [[components.grid.renderer.converter]] === Converting for Rendering Optionally, you can give a [interfacename]#Converter# in the [methodname]#setRenderer()#, or define it for the column, to convert the data value to an intermediary representation that is rendered by the renderer. For example, when using an [classname]#ImageRenderer#, you could store the image file name in the data column, which the converter would convert to a resource, which would then be rendered by the renderer. In the following example, we use a converter and [classname]#HTMLRenderer# to display boolean values as [classname]#FontAwesome# icons [source, java] ---- // Have a column for hyperlink paths to Wikipedia grid.addColumn("truth", Boolean.class); Grid.Column truth = grid.getColumn("truth"); truth.setRenderer(new HtmlRenderer(), new StringToBooleanConverter( FontAwesome.CHECK_CIRCLE_O.getHtml(), FontAwesome.CIRCLE_O.getHtml())); ... ---- In this example, we use a converter to format URL paths to complete HTML hyperlinks with [classname]#HTMLRenderer#: [source, java] ---- // Have a column for hyperlink paths to Wikipedia grid.addColumn("link", String.class); Grid.Column linkColumn = grid.getColumn("link"); linkColumn.setRenderer(new HtmlRenderer(), new Converter(){ @Override public String convertToModel(String value, Class targetType, Locale locale) throws Converter.ConversionException { return "not implemented"; } @Override public String convertToPresentation(String value, Class targetType, Locale locale) throws Converter.ConversionException { return "more info"; } @Override public Class getModelType() { return String.class; } @Override public Class getPresentationType() { return String.class; } }); // Data with a hyperlink path in the third column grid.addRow("Nicolaus Copernicus", 1473, "Nicolaus_Copernicus"); ... ---- A [classname]#GeneratedPropertyContainer# could be used for much the same purpose. [[components.grid.headerfooter]] == Header and Footer A grid by default has a header, which displays column names, and can have a footer. Both can have multiple rows and neighbouring header row cells can be joined to feature column groups. [[components.grid.headerfooter.adding]] === Adding and Removing Header and Footer Rows A new header row is added with [methodname]#prependHeaderRow()#, which adds it at the top of the header, [methodname]#appendHeaderRow()#, which adds it at the bottom of the header, or with [methodname]#addHeaderRowAt()#, which inserts it at the specified 0-base index. All of the methods return a [classname]#HeaderRow# object, which you can use to work on the header further. [source, java] ---- // Group headers by joining the cells HeaderRow groupingHeader = grid.prependHeaderRow(); ... // Create a header row to hold column filters HeaderRow filterRow = grid.appendHeaderRow(); ... ---- Similarly, you can add footer rows with [methodname]#appendFooterRow()#, [methodname]#prependFooterRow()#, and [methodname]#addFooterRowAt()#. [[components.grid.headerfooter.joining]] === Joining Header and Footer Cells You can join two or more header or footer cells with the [methodname]#join()# method. For header cells, the intention is usually to create column grouping, while for footer cells, you typically calculate sums or averages. [source, java] ---- // Group headers by joining the cells HeaderRow groupingHeader = grid.prependHeaderRow(); HeaderCell namesCell = groupingHeader.join( groupingHeader.getCell("firstname"), groupingHeader.getCell("lastname")).setText("Person"); HeaderCell yearsCell = groupingHeader.join( groupingHeader.getCell("born"), groupingHeader.getCell("died"), groupingHeader.getCell("lived")).setText("Dates of Life"); ---- [[components.grid.headerfooter.content]] === Text and HTML Content You can set the header caption with [methodname]#setText()#, in which case any HTML formatting characters are quoted to ensure security. [source, java] ---- HeaderRow mainHeader = grid.getDefaultHeaderRow(); mainHeader.getCell("firstname").setText("First Name"); mainHeader.getCell("lastname").setText("Last Name"); mainHeader.getCell("born").setText("Born In"); mainHeader.getCell("died").setText("Died In"); mainHeader.getCell("lived").setText("Lived For"); ---- To use raw HTML in the captions, you can use [methodname]#setHtml()#. [source, java] ---- namesCell.setHtml("Names"); yearsCell.setHtml("Years"); ---- [[components.grid.headerfooter.components]] === Components in Header or Footer You can set a component in a header or footer cell with [methodname]#setComponent()#. Often, this feature is used to allow filtering, as described in <>, which also gives an example of the use. [[components.grid.filtering]] == Filtering The ability to include components in the grid header can be used to create filters for the grid data. Filtering is done in the container data source, so the container must be of type that implements [interfacename]#Container.Filterable#. [[figure.components.grid.filtering]] .Filtering Grid image::img/grid-filtering.png[] The filtering illustrated in <> can be created as follows: [source, java] ---- // Have a filterable container IndexedContainer container = exampleDataSource(); // Create a grid bound to it Grid grid = new Grid(container); grid.setSelectionMode(SelectionMode.NONE); grid.setWidth("500px"); grid.setHeight("300px"); // Create a header row to hold column filters HeaderRow filterRow = grid.appendHeaderRow(); // Set up a filter for all columns for (Object pid: grid.getContainerDataSource() .getContainerPropertyIds()) { HeaderCell cell = filterRow.getCell(pid); // Have an input field to use for filter TextField filterField = new TextField(); filterField.setColumns(8); // Update filter When the filter input is changed filterField.addTextChangeListener(change -> { // Can't modify filters so need to replace container.removeContainerFilters(pid); // (Re)create the filter if necessary if (! change.getText().isEmpty()) container.addContainerFilter( new SimpleStringFilter(pid, change.getText(), true, false)); }); cell.setComponent(filterField); } ---- [[components.grid.sorting]] == Sorting A user can sort the data in a grid on a column by clicking the column header. Clicking another time on the current sort column reverses the sort direction. Clicking on other column headers while keeping the Shift key pressed adds a secondary or more sort criteria. [[figure.components.grid.sorting]] .Sorting Grid on Multiple Columns image::img/grid-sorting.png[] Defining sort criteria programmatically can be done with the various alternatives of the [methodname]#sort()# method. You can sort on a specific column with [methodname]#sort(Object propertyId)#, which defaults to ascending sorting order, or [methodname]#sort(Object propertyId, SortDirection direction)#, which allows specifying the sort direction. [source, java] ---- grid.sort("name", SortDirection.DESCENDING); ---- To sort on multiple columns, you need to use the fluid sort API with [methodname]#sort(Sort)#, which allows chaining sorting rules. Sorting rules are created with the static [methodname]#by()# method, which defines the primary sort column, and [methodname]#then()#, which can be used to specify any secondary sort columns. They default to ascending sort order, but the sort direction can be given with an optional parameter. [source, java] ---- // Sort first by city and then by name grid.sort(Sort.by("city", SortDirection.ASCENDING) .then("name", SortDirection.DESCENDING)); ---- The container data source must support sorting. At least, it must implement [interfacename]#Container.Sortable#. Note that when using [classname]#GeneratedPropertyContainer#, as described in <>, even though the container implements the interface, the wrapped container must also support it. Also, the generated properties are not normally sortable, but require special handling to enable sorting. [[components.grid.editing]] == Editing Grid supports line-based editing, where double-clicking a row opens the row editor. In the editor, the input fields can be edited, as well as navigated with kbd:[Tab] and kbd:[Shift+Tab] keys. If validation fails, an error is displayed and the user can correct the inputs. To enable editing, you need to call [methodname]#setEditorEnabled(true)# for the grid. [source, java] ---- Grid grid = new Grid(GridExample.exampleDataSource()); grid.setEditorEnabled(true); ---- Grid supports two row editor modes - buffered and unbuffered. The default mode is buffered. The mode can be changed with [methodname]#setBuffered(false)# [[components.grid.editing.buffered]] === Buffered Mode The editor has a [guibutton]#Save# button that commits the data item to the container data source and closes the editor. The [guibutton]#Cancel# button discards the changes and exits the editor. A row under editing is illustrated in <>. [[figure.components.grid.editing]] .Editing a Grid Row image::img/grid-editor-basic.png[] [[components.grid.editing.unbuffered]] === Unbuffered Mode The editor has no buttons and all changed data is committed directly to the container. If another row is clicked, the editor for the current row is closed and a row editor for the clicked row is opened. [[components.grid.editing.fields]] === Editor Fields The editor fields are by default generated with a [interfacename]#FieldFactory# and bound to the container data source with a [classname]#FieldGroup#, which also handles tasks such as validation, as explained later. To disable editing in a particular column, you can call [methodname]#setEditable()# in the [classname]#Column# object with [parameter]#false# parameter. [[components.grid.editing.editorfields]] === Customizing Editor Fields The editor fields are normally created by the field factory of the editor's field group, which creates the fields according to the data types of their respective columns. To customize the editor fields of specific properties, such as to style them or to set up validation, you can provide them with [methodname]#setEditorField()# in the respective columns. In the following example, we configure a field with validation and styling: [source, java] ---- TextField nameEditor = new TextField(); // Custom CSS style nameEditor.addStyleName("nameeditor"); // Custom validation nameEditor.addValidator(new RegexpValidator( "^\\p{Alpha}+ \\p{Alpha}+$", "Need first and last name")); grid.getColumn("name").setEditorField(nameEditor); ---- Setting an editor field to [parameter]#null# deletes the currently existing editor field, whether it was automatically generated or set explicitly with the setter. It will be regenerated with the factory the next time it is needed. ifdef::web[] [[components.grid.editing.captions]] === Customizing Editor Buttons In the buffered mode, the editor has two buttons: [guibutton]#Save# and [guibutton]#Cancel#. You can set their captions with [methodname]#setEditorSaveCaption()# and [methodname]#setEditorCancelCaption()#, respectively. In the following example, we demonstrate one way to translate the captions: [source, java] ---- // Captions are stored in a resource bundle ResourceBundle bundle = ResourceBundle.getBundle( MyAppCaptions.class.getName(), Locale.forLanguageTag("fi")); // Finnish // Localize the editor button captions grid.setEditorSaveCaption( bundle.getString(MyAppCaptions.SaveKey)); grid.setEditorCancelCaption( bundle.getString(MyAppCaptions.CancelKey)); ---- endif::web[] [[components.grid.editing.fieldgroup]] === Binding to Data with a Field Group Data binding to the item under editing is handled with a [classname]#FieldGroup#, which you need to set with [methodname]#setEditorFieldGroup#. This is mostly useful when using special-purpose field groups, such as [classname]#BeanFieldGroup# to enable bean validation. For example, assuming that we want to enable bean validation for a bean such as the following: [source, java] ---- public class Person implements Serializable { @NotNull @Size(min=2, max=10) private String name; @Min(1) @Max(130) private int age; ...] ---- We can now use a [classname]#BeanFieldGroup# in the [classname]#Grid# as follows: [source, java] ---- Grid grid = new Grid(exampleBeanDataSource()); grid.setColumnOrder("name", "age"); grid.setEditorEnabled(true); // Enable bean validation for the data grid.setEditorFieldGroup( new BeanFieldGroup(Person.class)); // Have some extra validation in a field TextField nameEditor = new TextField(); nameEditor.addValidator(new RegexpValidator( "^\\p{Alpha}+ \\p{Alpha}+$", "Need first and last name")); grid.setEditorField("name", nameEditor); ---- To use bean validation as in the example above, you need to include an implementation of the Bean Validation API in the classpath, as described in <>. ifdef::web[] [[components.grid.editing.validation]] === Handling Validation Errors The input fields are validated when the value is updated. The default error handler displays error indicators in the invalid fields, as well as the first error in the editor. [[figure.components.grid.errors]] .Editing a Grid Row image::img/grid-editor-errors.png[] You can modify the error handling by implementing a custom [interfacename]#EditorErrorHandler# or by extending the [classname]#DefaultEditorErrorHandler#. endif::web[] [[components.grid.editing.fieldfactory]] === Editor Field Factory The fields are generated by the [classname]#FieldFactory# of the field group; you can also set it with [methodname]#setEditorFieldFactory()#. Alternatively, you can create the editor fields explicitly with [methodname]#setEditorField()#. [[components.grid.scrolling]] == Programmatic Scrolling You can scroll to first item with [methodname]#scrollToStart()#, to end with [methodname]#scrollToEnd()#, or to a specific row with [methodname]#scrollTo()#. [[components.grid.stylegeneration]] == Generating Row or Cell Styles You can style entire rows with a [interfacename]#RowStyleGenerator# or individual cells with a [interfacename]#CellStyleGenerator#. [[components.grid.stylegeneration.row]] === Generating Row Styles You set a [interfacename]#RowStyleGenerator# to a grid with [methodname]#setRowStyleGenerator()#. The [methodname]#getStyle()# method gets a [classname]#RowReference#, which contains various information about the row and a reference to the grid, and should return a style name or [parameter]#null# if no style is generated. For example, to add a style names to rows having certain values in one column, you can style them as follows: [source, java] ---- grid.setRowStyleGenerator(rowRef -> {// Java 8 if (! ((Boolean) rowRef.getItem() .getItemProperty("alive") .getValue()).booleanValue()) return "grayed"; else return null; }); ---- You could then style the rows with CSS as follows: [source, css] ---- .v-grid-row.grayed { color: gray; } ---- [[components.grid.stylegeneration.cell]] === Generating Cell Styles You set a [interfacename]#CellStyleGenerator# to a grid with [methodname]#setCellStyleGenerator()#. The [methodname]#getStyle()# method gets a [classname]#CellReference#, which contains various information about the cell and a reference to the grid, and should return a style name or [parameter]#null# if no style is generated. For example, to add a style name to a specific column, you can match on the property ID of the column as follows: [source, java] ---- grid.setCellStyleGenerator(cellRef -> // Java 8 "born".equals(cellRef.getPropertyId())? "rightalign" : null); ---- You could then style the cells with a CSS rule as follows: [source, css] ---- .v-grid-cell.rightalign { text-align: right; } ---- [[components.grid.css]] == Styling with CSS [source, css] ---- .v-grid { .v-grid-scroller, .v-grid-scroller-horizontal { } .v-grid-tablewrapper { .v-grid-header { .v-grid-row { .v-grid-cell, .frozen, .v-grid-cell-focused { } } } .v-grid-body { .v-grid-row, .v-grid-row-stripe, .v-grid-row-has-data { .v-grid-cell, .frozen, .v-grid-cell-focused { } } } .v-grid-footer { .v-grid-row { .v-grid-cell, .frozen, .v-grid-cell-focused { } } } } .v-grid-header-deco { } .v-grid-footer-deco { } .v-grid-horizontal-scrollbar-deco { } .v-grid-editor { .v-grid-editor-cells { } .v-grid-editor-footer { .v-grid-editor-message { } .v-grid-editor-buttons { .v-grid-editor-save { } .v-grid-editor-cancel { } } } } } ---- A [classname]#Grid# has an overall [literal]#++v-grid++# style. The actual grid has three parts: a header, a body, and a footer. The scrollbar is a custom element with [literal]#++v-grid-scroller++# style. In addition, there are some decoration elements. Grid cells, whether thay are in the header, body, or footer, have a basic [literal]#++v-grid-cell++# style. Cells in a frozen column additionally have a [literal]#++frozen++# style. Rows have [literal]#++v-grid-row++# style, and every other row has additionally a [literal]#++v-grid-row-stripe++# style. The focused row has additionally [literal]#++v-grid-row-focused++# style and focused cell [literal]#++v-grid-cell-focused++#. By default, cell focus is visible, with the border stylable with [parameter]#$v-grid-cell-focused-border# parameter in Sass. Row focus has no visible styling, but can be made visible with the [parameter]#$v-grid-row-focused-background-color# parameter or with a custom style rule. In editing mode, a [literal]#++v-grid-editor++# overlay is placed on the row under editing. In addition to the editor field cells, it has an error message element, as well as the buttons. ((()))