Overzicht van enkele centrale interfaces
- Universal Network Objects (UNO)
- Eigenschappen en methoden
- Modules, services en interfaces
- Gereedschap voor werken met UNO
- Overzicht van centrale interfaces
Sommige interfaces van Apache OpenOffice kunnen worden gevonden in vele delen van de Apache OpenOffice API. Zij definiëren reeksen van methoden voor abstracte taken welke kunnen worden toegepast voor verschillende problemen. Hier vindt u een overzicht van de meest voorkomende van deze interfaces.
De herkomst van de objecten wordt op een later punt in deze gids verklaard. Op dit punt worden slechts enkele van de abstracte aspecten van objecten, waarvoor de Apache OpenOffice API sommige centrale interfaces verschaft, besproken.
Context-afhankelijke objecten maken
De Apache OpenOffice API verschaft twee opties voor het creëren van objecten. Eén kan worden gevonden in de functie createUnoService, vermeld aan het begin van dit hoofdstuk. createUnoService maakt een object dat universeel kan worden gebruikt. Zulke objecten en services zijn ook bekend als context-onafhankelijke services.
In aanvulling op de context-onafhankelijke services, zijn er ook context-afhankelijke services waarvan de objecten alleen handig zijn in samenhang met een ander object. Een tekenobject voor een werkbladdocument kan daarom bijvoorbeeld alleen bestaan in samenhang met dat ene document.
Interface com.sun.star.lang.XMultiServiceFactory
Context-afhankelijke objecten worden normaal gesproken gemaakt door middel van een objectmethode, waar het object van afhankelijk is. De methode createInstance, welke wordt gedefinieerd in de interface XMultiServiceFactory, wordt speciaal gebruikt in de objecten document.
Het tekenobject kan bijvoorbeeld als volgt worden gemaakt door gebruik van een object werkbladdocument:
Dim RechthoekVorm As Object RechthoekVorm = _ Spreadsheet.createInstance("com.sun.star.drawing.RectangleShape")
Een sjabloon voor een alinea in een tekstdocument wordt op dezelfde manier gemaakt:
Dim Opmaakprofiel as Object Opmaakprofiel = Textdocument.createInstance("com.sun.star.style.ParagraphStyle")
Named Access to Subordinate Objects
The XNameAccess and XNameContainer interfaces are used in objects that contain subordinate objects, which can be addressed using a natural language name.
While XNameAccess permits access to the individual objects, XNameContainer takes on the insertion, modification and deletion of elements.
com.sun.star.container.XNameAccess Interface
An example of the use of XNameAccess is provided by the sheets object of a spreadsheet. It combines all the pages within the spreadsheet. The individual pages are accessed from the sheets object, by using the getByName method from XNameAccess:
Dim Sheets As Object Dim Sheet As Object Sheets = Spreadsheet.Sheets Sheet = Sheets.getByName("Sheet1")
The getElementNames method provides an overview of the names of all elements. As a result, it returns a data field containing the names. The following example shows how all element names of a spreadsheet can thereby be determined and displayed in a loop:
Dim Sheets As Object Dim SheetNames Dim I As Integer Sheets = Spreadsheet.Sheets SheetNames = Sheets.getElementNames For I=LBound(SheetNames) To UBound(SheetNames) MsgBox SheetNames(I) Next I
The hasByName method of the XNameAccess interface reveals whether a subordinate object with a particular name exists within the basic object. The following example therefore displays a message that informs the user whether the Spreadsheet object contains a page of the name Sheet1.
Dim Sheets As Object Sheets = Spreadsheet.Sheets If Sheets.HasByName("Sheet1") Then MsgBox " Sheet1 available" Else MsgBox "Sheet1 not available" End If
com.sun.star.container.XNameContainer Interface
The XNameContainer interface takes on the insertion, deletion and modification of subordinate elements in a basic object. The functions responsible are insertByName, removeByName and replaceByName.
The following is a practical example of this. It calls a text document, which contains a StyleFamilies object and uses this to in turn make the paragraph templates (ParagraphStyles) of the document available.
Dim StyleFamilies As Object Dim ParagraphStyles As Object Dim NewStyle As Object StyleFamilies = Textdoc.StyleFamilies ParagraphStyles = StyleFamilies.getByName("ParagraphStyles") ParagraphStyles.insertByName("NewStyle", NewStyle) ParagraphStyles.replaceByName("ChangingStyle", NewStyle) ParagraphStyles.removeByName("OldStyle")
The insertByName line inserts the NewStyle style under the name of the same name in the ParagraphStyles object. The replaceByName line changes the object behind ChangingStyle into NewStyle. Finally, the removeByName call removes the object behind OldStyle from ParagraphStyles.
Index-Based Access to Subordinate Objects
The XIndexAccess and XIndexContainer interfaces are used in objects which contain subordinate objects and which can be addressed using an index.
XIndexAccess provides the methods for accessing individual objects. XIndexContainer provides methods for inserting and removing elements.
com.sun.star.container.XIndexAccess Interface
XIndexAccess provides the getByIndex and getCount methods for calling the subordinate objects. getByIndex provides an object with a particular index. getCount returns how many objects are available.
Dim Sheets As Object Dim Sheet As Object Dim I As Integer Sheets = Spreadsheet.Sheets For I = 0 to Sheets.getCount() - 1 Sheet = Sheets.getByIndex(I) ' Editing sheet Next I
The example shows a loop that runs through all sheet elements one after another and saves a reference to each in the Sheet object variable. When working with the indexes, note that getCount returns the number of elements. The elements in getByIndex however are numbered beginning with 0. The counting variable of the loop therefore runs from 0 to getCount()-1.
com.sun.star.container.XIndexContainer Interface
The XIndexContainer interface provides the insertByIndex and removeByIndex functions. The parameters are structured in the same way as the corresponding functions in XNameContainer.
Iterative Access to Subordinate Objects
In some instances, an object may contain a list of subordinate objects that cannot be addressed by either a name or an index. In these situations, the XEnumeration and XenumerationAccess interfaces are appropriate. They provide a mechanism through which all subordinate elements of an objects can be passed, step by step, without having to use direct addressing.
com.sun.star.container.XEnumeration and XenumerationAccess Interfaces
The basic object must provide the XEnumerationAccess interface, which contains only a createEnumeration method. This returns an auxiliary object, which in turn provides the XEnumeration interface with the hasMoreElements and nextElement methods. Through these, you then have access to the subordinate objects.
The following example steps through all the paragraphs of a text:
Dim ParagraphEnumeration As Object Dim Paragraph As Object ParagraphEnumeration = Textdoc.Text.createEnumeration While ParagraphEnumeration.hasMoreElements() Paragraph = ParagraphEnumeration.nextElement() Wend
The example first creates a ParagraphEnumeration auxiliary object. This gradually returns the individual paragraphs of the text in a loop. The loop is terminated as soon as the hasMoreElements method returns the False value, signaling that the end of the text has been reached.
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