Aligning the header text in a DataGrid column in Flex

The following example shows how you can set the text alignment on a Flex DataGrid control’s DataGridColumn by setting the headerStyleName and textAlign styles.

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/16/aligning-the-header-text-in-a-datagrid-column-in-flex/ -->
<mx:Application name="DataGrid_headerStyleName_textAlign_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.events.ListEvent;

            private function comboBox_change(evt:ListEvent):void {
                var value:String = comboBox.selectedItem.toString();
                var styleName:String = "." + dataGrid.getStyle("headerStyleName");
                var cssDecl:CSSStyleDeclaration = StyleManager.getStyleDeclaration(styleName);
                cssDecl.setStyle("textAlign", value);
            }
        ]]>
    </mx:Script>

    <mx:XML id="dp" source="data/products.xml" />

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="textAlign:">
                <mx:ComboBox id="comboBox"
                        dataProvider="[left,center,right,justify]"
                        change="comboBox_change(event);" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:DataGrid id="dataGrid"
            dataProvider="{dp.product}"
            rowCount="5"
            verticalScrollPolicy="on"
            width="300">
        <mx:columns>
            <mx:DataGridColumn id="dataGridColumn1"
                    dataField="@name"
                    headerText="This is a column with a long title:"
                    headerWordWrap="true"
                    minWidth="80" />
            <mx:DataGridColumn id="dataGridColumn2"
                    dataField="@price"
                    headerText="Price:"
                    headerWordWrap="false"
                    minWidth="20" />
        </mx:columns>
    </mx:DataGrid>

</mx:Application>

View source is enabled in the following example.

You can also set the text alignment in an external .CSS file or <mx:Style /> block, as seen in the following example:

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/16/aligning-the-header-text-in-a-datagrid-column-in-flex/ -->
<mx:Application name="DataGrid_headerStyleName_textAlign_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Style>
        DataGrid {
            headerStyleName: centerBold;
        }

        .centerBold {
            fontWeight: bold;
            textAlign: center;
        }
    </mx:Style>

    <mx:XML id="dp" source="data/products.xml" />

    <mx:DataGrid id="dataGrid"
            dataProvider="{dp.product}"
            rowCount="5"
            verticalScrollPolicy="on"
            width="300">
        <mx:columns>
            <mx:DataGridColumn id="dataGridColumn1"
                    dataField="@name"
                    headerText="This is a column with a long title:"
                    headerWordWrap="true"
                    minWidth="80" />
            <mx:DataGridColumn id="dataGridColumn2"
                    dataField="@price"
                    headerText="Price:"
                    headerWordWrap="false"
                    minWidth="20" />
        </mx:columns>
    </mx:DataGrid>

</mx:Application>

Due to popular demand, here is the “same” example in a more ActionScript friendly format:

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/16/aligning-the-header-text-in-a-datagrid-column-in-flex/ -->
<mx:Application name="DataGrid_headerStyleName_textAlign_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        initialize="init();">

    <mx:Script>
        <![CDATA[
            import flash.text.TextFormatAlign;

            import mx.containers.ApplicationControlBar;
            import mx.containers.Form;
            import mx.containers.FormItem;
            import mx.controls.ComboBox;
            import mx.controls.DataGrid;
            import mx.controls.dataGridClasses.DataGridColumn;
            import mx.core.ScrollPolicy;
            import mx.events.ListEvent;

            private const XML_URL:String = "data/products.xml";

            private var urlLoader:URLLoader;
            private var dp:XML;
            private var comboBox:ComboBox;
            private var dataGrid:DataGrid;
            private var dataGridColumn1:DataGridColumn;
            private var dataGridColumn2:DataGridColumn;

            private function init():void {
                urlLoader = new URLLoader();
                urlLoader.addEventListener(Event.COMPLETE,
                            urlLoader_complete);
                urlLoader.load(new URLRequest(XML_URL));

                var arr:Array = [];
                arr.push(TextFormatAlign.LEFT);
                arr.push(TextFormatAlign.CENTER);
                arr.push(TextFormatAlign.RIGHT);
                arr.push(TextFormatAlign.JUSTIFY);

                comboBox = new ComboBox();
                comboBox.dataProvider = arr;
                comboBox.addEventListener(ListEvent.CHANGE,
                            comboBox_change);

                var formItem:FormItem = new FormItem();
                formItem.label = "textAlign:";
                formItem.addChild(comboBox);

                var form:Form = new Form();
                form.styleName = "plain";
                form.addChild(formItem);

                var appControlBar:ApplicationControlBar;
                appControlBar = new ApplicationControlBar();
                appControlBar.dock = true;
                appControlBar.addChild(form);
                addChildAt(appControlBar, 0);

                dataGridColumn1 = new DataGridColumn("@name");
                dataGridColumn1.headerText = "This is a column with a long title:";
                dataGridColumn1.headerWordWrap = true;
                dataGridColumn1.minWidth = 80;

                dataGridColumn2 = new DataGridColumn("@price");
                dataGridColumn2.headerText = "Price:";
                dataGridColumn2.headerWordWrap = false;
                dataGridColumn2.minWidth = 20;

                dataGrid = new DataGrid();
                dataGrid.rowCount = 5;
                dataGrid.verticalScrollPolicy = ScrollPolicy.ON;
                dataGrid.width = 300;
                dataGrid.columns = [dataGridColumn1, dataGridColumn2];
                addChild(dataGrid);
            }

            private function urlLoader_complete(evt:Event):void {
                dataGrid.dataProvider = XML(evt.target.data).product;
            }

            private function comboBox_change(evt:ListEvent):void {
                var value:String = comboBox.selectedItem.toString();
                var styleName:String = "." + dataGrid.getStyle("headerStyleName");
                var cssDecl:CSSStyleDeclaration;
                cssDecl = StyleManager.getStyleDeclaration(styleName);
                cssDecl.setStyle("textAlign", value);
            }
        ]]>
    </mx:Script>

</mx:Application>

15 thoughts on “Aligning the header text in a DataGrid column in Flex

  1. It’s a great example, but is there any way to align also the header of the second column on vertical? So that “Price” label to be centered, not top.

  2. Wonder if there is a way of setting the style per column header? All left or all right etc. is no good. The header style depends on the column data. E.g. text columns left aligned, currency columns right aligned…data and header!

  3. Matthias,

    To align an individual DataGridColumn’s header (and data), you can set the textAlign style on that column:

    <mx:DataGrid id="dataGrid"
            dataProvider="{dp.product}"
            rowCount="5"
            verticalScrollPolicy="on"
            width="300">
        <mx:columns>
            <mx:DataGridColumn id="dataGridColumn1"
                    dataField="@name"
                    headerText="This is a column with a long title:"
                    headerWordWrap="true"
                    textAlign="left"
                    minWidth="80" />
            <mx:DataGridColumn id="dataGridColumn2"
                    dataField="@price"
                    headerText="Price:"
                    headerWordWrap="false"
                    textAlign="right"
                    minWidth="20" />
        </mx:columns>
    </mx:DataGrid>
    

    Peter

  4. Also, if you want to align/style the header separately from the column contents, you can set the headerStyleName style:

    <mx:Style>
        .centerAligned {
            textAlign: center;
            color: red;
        }
    </mx:Style>
    
    <mx:DataGrid id="dataGrid"
            dataProvider="{dp.product}"
            rowCount="5"
            verticalScrollPolicy="on"
            width="300">
        <mx:columns>
            <mx:DataGridColumn id="dataGridColumn1"
                    dataField="@name"
                    headerText="This is a column with a long title:"
                    headerWordWrap="true"
                    textAlign="left"
                    minWidth="80" />
            <mx:DataGridColumn id="dataGridColumn2"
                    dataField="@price"
                    headerText="Price:"
                    headerWordWrap="false"
                    headerStyleName="centerAligned"
                    textAlign="right"
                    minWidth="20" />
        </mx:columns>
    </mx:DataGrid>
    

    Peter

  5. Thanks Peter.

    the problem is twofold:

    I’m using the AdvancedDataGrid and AdvancedDateGridColumn classes

    I create the entire advanced datagrid in actionscript and the column number varies. So I can’t use any MXML. It also can be that the alignment of the header differs from the alignment of the column data.

    Whereas I’m able to set the styles attributes for the column data in action script, I have difficulties doing it for the headers.

    I followed your actionscript sample and I can’t even get this to work with the AdvancedDataGrid classes. Your actionscript sample above would only change the first column header and not both.

    With my code the whole thing doesn’t work. Of course my use of the AdvancedDataGrid is somewhat more complex. E.g. I use different custom renderers for each column.

    Could it be that there are some issues with the AdvancedDataGrid classes?

  6. Matthias,

    I haven’t used the AdvancedDataGrid classes yet, but if it isn’t working for you there may be a bug (or perhaps the syntax is just different for DataGrid and AdvancedDataGrid).
    I’d suggest posting on the FlexCoders mailing list and see if anybody there has tried creating an AdvancedDataGrid in ActionScript and setting column/header alignment.

    Sorry,
    Peter

  7. Peter,

    I would like to ask the same question as Sanda S. above: is there a way to center vertically the text of the headers.

    Thanks for a great blog!

    -Lev

  8. Peter I’d like to ask as Sanda did above. I cannot find a way to align my DataGrid header’s text vertically. Have you any hint please?

    thanks

  9. Maybe someone already has an idea how to align text vertically having wordwrap enabled?

Comments are closed.