Setting Fonts

How to set fonts for form controls at runtime.

About this technique	Details
Category	Core Programming Techniques> Java
Description	You'll learn about: Setting a default font name, size, and style in list boxes Handling a user selection from the font name list box Handling a user selection from the font size list box Handling a user selection from the font style list box Making the font change
	You can run this technique code from: Database: Examples3_Java Form: frmFonts NOTE   First make sure that database is running on your localhost SilverStream Server
Related reading	See the chapter on coding Java for SilverStream applications in the Programmer's Guide

This example sets a font programmatically. You select a font name, size, and style from three list boxes. A text field then displays some sample text in the chosen font.

Setting a default font name, size, and style in list boxes   

The following code illustrates how to set up default choices in the list boxes.

  protected void formLoaded() 
  { 
     // Select the Dialog font 
     lbFont.setSelectedValue("Dialog", true); 
         
    // Select the font size 16 
    lbSize.setSelectedValue(new Integer(16), true); 
       
    // Select the font style Italic 
    lbStyle.setSelectedValue(new Integer(ITALIC), true); 
  } 

Notes about the code

• When the form is loaded, the code automatically selects a default font name, size, and style in the list boxes by calling setSelectedValue() on each list box.

Handling a user selection from the font name list box   

The following code illustrates how a custom method is called when you make a selection from the list box. The custom method will translate the choice into a new font name.

  private void handle_lbFont_valueChanged(AgoPropertyChangeEvent 
     evt) 
    { 
      // Get the source of the value change 
      int source = evt.getChangeSource(); 
     // Only change the font for user and program value changes 
      if (source == AgoValueChangedInfo.SOURCE_USER ||  
           source == AgoValueChangedInfo.SOURCE_PROG) 
        { 
          changeFont(); 
        } 
    } 

Notes about the code

• Whenever the selection in the font name list box is changed by you or is changed programmatically, the code calls the changeFont() method, which is described below.

Handling a user selection from the font size list box   

The following code illustrates how a custom method is called when you make a selection from the list box. The custom method will translate the choice into a new font size.

  private void handle_lbSize_valueChanged(AgoPropertyChangeEvent evt) 
    { 
      // Get the source of the value change 
      int source = evt.getChangeSource(); 
     // Only change the font size for user and program value changes 
      if (source == AgoValueChangedInfo.SOURCE_USER ||  
         source == AgoValueChangedInfo.SOURCE_PROG) 
       { 
         changeFont(); 
       } 
    } 

Notes about the code

• Whenever the selection in the font size list box is changed by you or is changed programmatically, the code calls the changeFont() method, which is described below.

Handling a user selection from the font style list box   

The following code illustrates how a custom method is called when you make a selection from the list box. The custom method will translate the choice into a new font style.

  private void handle_lbStyle_valueChanged(AgoPropertyChangeEvent 
    evt) 
    { 
      // Get the source of the value change 
      int source = evt.getChangeSource(); 
     // Only change the font style for user and program  
      // value changes 
      if (source == AgoValueChangedInfo.SOURCE_USER ||  
         source == AgoValueChangedInfo.SOURCE_PROG) 
       { 
         changeFont(); 
       } 
    } 

Notes about the code

• Whenever the selection in the font style list box is changed by you or is changed programmatically, the code calls the changeFont() method, which is described below.

Making the font change   

The following code illustrates how to change the font of a sample text field to reflect the font name, size, and style currently selected in the list boxes. This is a custom (user-defined) method that you can view in the General section of the Programming Editor.

  public void changeFont() 
    { 
      // Get the index of the selected font 
      int iSelectedRow = lbFont.getSelectedIndex(); 
      if (iSelectedRow < 0) 
        return;        // No font selected, so return 
     
      // Get the index of the selected font size 
      iSelectedRow = lbSize.getSelectedIndex(); 
      if (iSelectedRow < 0) 
        return;        // No font size selected, so return 
     
      // Get the index of the selected font style 
      iSelectedRow = lbStyle.getSelectedIndex(); 
      if (iSelectedRow < 0) 
        return;        // No font style selected, so return 
     
      // Get the selected font size 
      int iSize = Integer.parseInt((String)lbSize.getValue()); 
     
      // Get the selected font style 
      int iStyle = Integer.parseInt((String)lbStyle.getValue()); 
   
      // Get the font name 
      String sName = lbFont.getItemValue( 
         lbFont.getSelectedIndex()).toString();     
      Font newFont = new Font(sName, iStyle, iSize); 
      
     // Change the label's font attributes to those of the new  
     // font identifier 
      lblExample.setFont(newFont); 
    } 

Notes about the code

• The code checks to make sure something is selected in the list boxes by calling getSelectedIndex() for each list box.

• Next, the code uses getValue() with Integer.parseInt() to get the associated size and style values as defined in the Property Inspector for those list boxes. These values will be used later in the method.

• The new font name is obtained by calling getIemValue() on getSelectedIndex() of the font name list box. (The index must be converted to a String)

• The code then creates a new Font instance using the Font Class constructor.

• Finally, the code changes the font of the sample text field to the new Font instance by calling setFont().