Difference between revisions of "Documentation/BASIC Guide/Working With Dialogs"

Latest revision as of 14:09, 30 January 2021

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Apache OpenOffice Basic dialogs consist of a dialog window that can contain text fields, list boxes, radio buttons, and other control elements.

Creating Dialogs

You can create and structure dialogs using the Apache OpenOffice dialog editor:

Create and structure dialogs in the dialog editor

You can drag the control elements from the design pallet (right) into the dialog area, and define their position and size.

The example shows a dialog that contains a label and a list box.

A dialog containing a label and a list box

You can open a dialog with the following code:

Dim Dlg As Object
 
DialogLibraries.LoadLibrary("Standard")
Dlg = CreateUnoDialog(DialogLibraries.Standard.DlgDef)
Dlg.Execute()
Dlg.dispose()

CreateUnoDialog creates an object called Dlg that references the associated dialog. Before you can create the dialog, you must ensure that the library it uses (in this example, the Standard library) is loaded. The LoadLibrary method performs this task.

Once the Dlg dialog object has been initialized, you can use the Execute method to display the dialog. Dialogs such as this one are described as modal because they do not permit any other program action until they are closed. While this dialog is open, the program remains in the Execute call.

The dispose method at the end of the code releases the resources used by the dialog once the program ends.

Closing Dialogs

Closing With OK or Cancel

If a dialog contains an OK or a Cancel button, the dialog is automatically closed when you click one of these buttons. More information about working with these buttons is discussed in Dialog Control Elements in Detail.

If you close a dialog by clicking the OK button, the Execute method returns a return value of 1, otherwise a value of 0 is returned.

Dim Dlg As Object
 
DialogLibraries.LoadLibrary("Standard")
Dlg = CreateUnoDialog(DialogLibraries.Standard.MyDialog)
Select Case Dlg.Execute() 
Case 1
  MsgBox "Ok pressed"
Case 0 
  MsgBox "Cancel pressed"
End Select

Closing With the Close Button in the Title Bar

You can close a dialog by clicking the close button on the title bar of the dialog window. The Execute method of the dialog returns the value 0, which is the same as when you click Cancel.

Closing With an Explicit Program Call

From a routine called by an event of a control, e.g. push of a normal button, you can also close an open dialog window with the endExecute method:

Dlg.endExecute()

The dialog object must be accessible from the event routine. A simple way is to declare it as a Private or Public variable common to the main dialog routine and the event routine.

The execute method of the dialog returns the value 0, which is the same as when you click Cancel.

The endDialog method of the dialog is an improvement of endExecute. Its argument specifies the value that will be returned by execute method.

Dlg.endDialog(2)  ' Dlg.execute will return 2

Access to Individual Control Elements

A dialog can contain any number of control elements. You can access these elements through the getControl method that returns the control element by name.

Dim Ctl As Object
 
Ctl = Dlg.getControl("MyButton")
Ctl.Label = "New Label"

This code determines the object for the MyButton control element and then initializes the Ctl object variable with a reference to the element. Finally, the code sets the Label property of the control element to the New Label value.

Unlike Apache OpenOffice Basic identifiers, the names of control elements are case-sensitive.

Working With the Model of Dialogs and Control Elements

The division between visible program elements (View) and the data or documents behind them (Model) occurs at many places in Apache OpenOffice API. In addition to the methods and properties of control elements, both dialog and control element objects have a subordinate Model object. This object allows you to directly access the content of a dialog or control element.

In dialogs, the distinction between data and depiction is not always as clear as in other API areas of Apache OpenOffice. Elements of the API are available through both the View and the Model.

The Model property provides program-controlled access to the model of dialog and control element objects.

Dim cmdNext As Object
 
cmdNext = Dlg.getControl("cmdNext")
cmdNext.Model.Enabled = False

This example deactivates the cmdNext button in the Dlg dialog with the aid of the model object from cmdNext.