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14.1.3 Example Widget

This example source is a copy of the Google Pie Chart example widget which is shipped with Visual LANSA.

function( PROTOTYPE, WIDGET )

{

  //--------------------------------------------------------------------------

  // LOAD GOOGLE PIECHART ONLY WHEN THAT IS COMPLETED CAN WE FINALIZE THE WIDGET

  //--------------------------------------------------------------------------

  google.load( 'visualization', '1', { packages:["corechart"], callback: WIDGET.Finalize } );

 

  //--------------------------------------------------------

  // WIDGET-INTERFACE FUNCTIONS (CALLED FROM THE VL-RUNTIME)

  //--------------------------------------------------------

 

  //

  // 'onCreateInstance' - gets called when LANSA creates an instance of this class.

  //

  PROTOTYPE.onCreateInstance = function()

  {

    // Create the datatable

    this.m_DataTable = new google.visualization.DataTable();

 

    this.m_DataTable.addColumn( 'string', 'Caption' );

    this.m_DataTable.addColumn( 'number', 'Value' );

  }

  

  //

  // 'onRealizeControl' - gets called when LANSA creates a visual representation of an instance of this class.

  //

  // Parameters:

  //

  // - parentDiv : the div that's been created as a container for this control. Its size and style are controlled by

  //               RDMLX, its content by the JavaScript below.

  //

  PROTOTYPE.onRealizeControl = function( parentDiv )

  {

    // Create the piechart

    this.m_Chart = new google.visualization.PieChart( parentDiv );

 

    // Hook up event handlers

    this.AttachEvents();

 

    // We're ready to draw it

    this.DrawChart();

  }

 

  //

  // 'onSizeChanged - gets called when the widget changes size.

  //

  PROTOTYPE.onSizeChanged = function()

  {

    this.DrawChart();

  }

 

  ////////////////

  // Properties //

  ////////////////

 

  //

  // getTitle

  //

  PROTOTYPE.getTitle = function()

  {

    return this.m_Title;

  }

 

  //

  // setTitle

  //

  PROTOTYPE.setTitle = function( strTitle )

  {

    this.m_Title = strTitle;

 

    this.DrawChart();

  }

 

  /////////////

  // Methods //

  /////////////

 

  //

  // Insert - Insert data into the piechart

  //

  // Parameters:

  // - Value: Integer

  // - Caption: String

  //

  // Return Type: Integer

  //

  PROTOTYPE.Insert = function( iValue, strCaption )

  {   

    var index = this.m_DataTable.addRow( [ strCaption, iValue ] );

 

    this.DrawChart();

 

    return index;

  }

 

  //

  // Clear - Clears all data

  //

  PROTOTYPE.Clear = function()

  {

    // Initialize member data

    this.m_DataTable.removeRows( 0, this.m_DataTable.getNumberOfRows() );

 

    this.DrawChart();

  }

 

  //

  // Remove - Removes the given index from the piechart

  //

  // Parameters:

  // - Index: Integer

  //

  PROTOTYPE.Remove = function( index )

  {

    index -= 1;

 

    if ( ( index >= 0 ) && ( index < this.m_DataTable.getNumberOfRows() ) )

    {

      this.m_DataTable.removeRow( index );

 

      this.DrawChart();

    }

  }

 

  //////////////////////

  // Helper functions //

  //////////////////////

 

  //

  // DrawChart

  //

  PROTOTYPE.DrawChart = function()

  {

    if ( this.m_Chart )

    {

      // Draw it using our data.

      this.m_Chart.draw( this.m_DataTable,

      {

        title          : this.m_Title,

        legend         : 'none',

        pieSliceText   : 'label',

        backgroundColor: 'transparent'

      });

    }

  }

 

  //

  // AttachEvents

  //

  PROTOTYPE.AttachEvents = function()

  {

    var pThis = this;

 

    // EVENT: select

    google.visualization.events.addListener( this.m_Chart, 'select', function()

    {

      var

        selectedItem = pThis.m_Chart.getSelection()[0];

 

      if ( selectedItem )

      {

        pThis.fireItemSelected( ( selectedItem.row + 1 ), pThis.m_DataTable.getValue( selectedItem.row, 1 ), pThis.m_DataTable.getValue( selectedItem.row, 0 ) );

      }

    }); 

  }

 

  // We're still loading (waiting for a callback)

  return WIDGET.Loading;

}