Navigation: ABC Library Reference > EntryLocatorClass >====== EntryLocatorClass Overview ====== | |
The EntryLocatorClass is a LocatorClass with an input control (ENTRY, COMBO, or SPIN). An Entry Locator is a multi-character locator that activates when the locator control is accepted (not upon each keystroke).
Use an Entry Locator when you want a multi-character search on numeric or alphanumeric keys and you want to delay the search until the user accepts the locator control. This delayed search reduces network traffic and provides a smoother search in a client-server environment.
EntryLocatorClass Concepts
The EntryLocatorClass lets you specify a locator control and a sort field on which to search (the free key element) for a BrowseClass object. The BrowseClass object uses the EntryLocatorClass to locate and scroll to the nearest matching item.
When the end user places one or more characters in the locator control, then accepts the control by pressing TAB, pressing a locator button, or selecting another control on the screen, the EntryLocatorClass object advances the BrowseClass object's LIST to the nearest matching record.
EntryLocatorClass Relationship to Other Application Builder Classes
The BrowseClass uses the EntryLocatorClass to locate and scroll to the nearest matching item. Therefore, if your program's BrowseClass objects use an Entry Locator, your program must instantiate the EntryLocatorClass for each use. Once you register the EntryLocatorClass object with the BrowseClass object (see BrowseClass.AddLocator), the BrowseClass object uses the EntryLocatorClass object as needed, with no other code required. See the Conceptual Example.
EntryLocatorClass ABC Template Implementation
The ABC BrowseBox template generates code to instantiate the EntryLocatorClass for your BrowseBoxes. The EntryLocatorClass objects are called BRWn::Sort#:Locator, where n is the template instance number and # is the sort sequence (id) number. As this implies, you can have a different locator for each BrowseClass object sort order.
You can use the BrowseBox's Locator Behavior dialog (the Locator Class button) to derive from the EntryLocatorClass. The templates provide the derived class so you can modify the locator's behavior on an instance-by-instance basis.
EntryLocatorClass Source Files
The EntryLocatorClass source code is installed by default to the Clarion \LIBSRC folder. The specific EntryLocatorClass source code and their respective components are contained in:
ABBROWSE.INC | EntryLocatorClass declarations | |
ABBROWSE.CLW | EntryLocatorClass method definitions |
EntryLocatorClass Conceptual Example
The following example shows a typical sequence of statements to declare, instantiate, initialize, use, and terminate a BrowseClass object and related objects, including an EntryLocatorClass object. The example initializes and page-loads a LIST, then handles a number of associated events, including scrolling, updating, and locating records.
Note that the WindowManager and BrowseClass objects internally handle the normal events surrounding the locator.
PROGRAM
INCLUDE('ABWINDOW.INC') !declare WindowManager class
INCLUDE('ABBROWSE.INC') !declare BrowseClass and Locator
MAP
END
State FILE,DRIVER('TOPSPEED'),PRE(ST),THREAD
StateCodeKey KEY(ST:STATECODE),NOCASE,OPT
Record RECORD,PRE()
STATECODE STRING(2)
STATENAME STRING(20)
END
END
StView VIEW(State) !declare VIEW to process
END
StateQ QUEUE !declare Q for LIST
ST:STATECODE LIKE(ST:STATECODE)
ST:STATENAME LIKE(ST:STATENAME)
ViewPosition STRING(512)
END
Access:State CLASS(FileManager) !declare Access:State object
Init PROCEDURE
END
Relate:State CLASS(RelationManager) !declare Relate:State object
Init PROCEDURE
END
VCRRequest LONG(0),THREAD
StWindow WINDOW('Browse States'),AT(,,123,152),IMM,SYSTEM,GRAY
PROMPT('Find:'),AT(9,6)
ENTRY(@s2),AT(29,4),USE(ST:STATECODE)
LIST,AT(8,5,108,124),USE(?StList),IMM,HVSCROLL,FROM(StateQ),|
FORMAT('27L(2)|M~CODE~@s2@80L(2)|M~STATENAME~@s20@')
END
ThisWindow CLASS(WindowManager) !declare ThisWindow object
Init PROCEDURE(),BYTE,PROC,VIRTUAL
Kill PROCEDURE(),BYTE,PROC,VIRTUAL
END
BrowseSt CLASS(BrowseClass) !declare BrowseSt object
Q &StateQ
END
StLocator EntryLocatorClass !declare StLocator object
StStep StepStringClass !declare StStep object
CODE
ThisWindow.Run() !run the window procedure
ThisWindow.Init PROCEDURE() !initialize things
ReturnValue BYTE,AUTO
CODE
ReturnValue = PARENT.Init() !call base class init
IF ReturnValue THEN RETURN ReturnValue.
Relate:State.Init !initialize Relate:State object
SELF.FirstField = ?ST:STATECODE !set FirstField for ThisWindow
SELF.VCRRequest &= VCRRequest !VCRRequest not used
Relate:State.Open !open State and related files
!Init BrowseSt object by naming its LIST,VIEW,Q,RelationManager & WindowManager
BrowseSt.Init(?StList,StateQ.ViewPosition,StView,StateQ,Relate:State,SELF)
OPEN(StWindow)
SELF.Opened=True
BrowseSt.Q &= StateQ !reference the browse QUEUE
!initialize the StStep object
StStep.Init(+ScrollSort:AllowAlpha,ScrollBy:Runtime)
BrowseSt.AddSortOrder(StStep,ST:StateCodeKey) !set the browse sort order
BrowseSt.AddLocator(StLocator) !plug in the browse locator
!initialize the locator object
StLocator.Init(?ST:STATECODE,ST:STATECODE,1,BrowseSt)
!set a column to browse
BrowseSt.AddField(ST:STATECODE,BrowseSt.Q.ST:STATECODE)
!set a column to browse
BrowseSt.AddField(ST:STATENAME,BrowseSt.Q.ST:STATENAME)
SELF.SetAlerts() !alert any keys for ThisWindow
RETURN ReturnValue
ThisWindow.Kill PROCEDURE() !shut down things
ReturnValue BYTE,AUTO
CODE
ReturnValue = PARENT.Kill() !call base class shut down
IF ReturnValue THEN RETURN ReturnValue.
Relate:State.Close !close State and related files
Relate:State.Kill !shut down Relate:State object
GlobalErrors.Kill !shut down GlobalErrors object
RETURN ReturnValue