Capturing user input events

You can capture user input events in the application. For this purpose, you can implement a function block that is executed when user events occur.

Capturing the writing of variables

When the user completes the input of a value (in an input field), an edit control event is closed. You can capture this event in the application as follows.

Create a function block that implements the ‎VisuElems.IEditBoxInputHandler‎ interface from the ‎VisuElemBase‎ library.
Pass the instance to the global event manager ‎VisuElems.Visu_Globals.g_VisuEventManager‎ by calling the ‎SetEditBoxEventHandler‎ method.

Example

A visualization has two input fields for ‎iInput_A‎ and ‎rInput_B‎ and one text output element.

The input fields are rectangles that the user is prompted to click in order to input text.

The text output element is a rectangle where the contents of the text variable ‎PLC_PRG.stInfo‎ are printed. The text variable contains the last input by a user in one of the input fields and the additional information that was added.

Properties of the rectangle `‎iInput_A‎`
“Texts Text”	`‎iInput_A: %i‎`
“Text variables Text variable”	PLC_PRG.iInput_A
Properties of the rectangle `‎rInput_B‎`
“Texts Text”	`‎iInput_B: %i‎`
“Text variables Text variable”	PLC_PRG.rInput_B
Properties of the rectangle for the text output
“Texts Text”	`‎%s‎`
“Text variables Text variable”	PLC_PRG.stInfo

‎PLC_PRG‎ implementation

PROGRAM PLC_PRG
VAR_INPUT
	iInput_A:INT;  (* Used in the visualization as user input variable*)
	rInput_B:REAL; (* Used in the visualization as user input variable*)
	stInfo : STRING;  (* Informs about the user input via the edit control field; 
		String gets composed by method 'VariableWritten; 
		Result is displayed in the lower rectangle of the visualization *)
END_VAR
VAR
	inst : POU;
	bFirst : BOOL := TRUE;
END_VAR

IF bFirst THEN
	bFirst := FALSE;
	VisuElems.Visu_Globals.g_VisuEventManager.SetEditBoxEventHandler(inst); 
	(* Call of method VariableWritten *)
END_IF

‎POU‎ implementation

FUNCTION_BLOCK POU IMPLEMENTS VisuElems.IEditBoxInputHandler
(* no further declarations, no implementation code *)

Method ‎VariableWritten‎ assigned to ‎POU‎

METHOD VariableWritten : BOOL
(* provides some information always when an edit control field is closed in the visualization, that is a variable gets written by user input in one of the upper rectangles *)
VAR_INPUT
	pVar : POINTER TO BYTE;
	varType : VisuElems.Visu_Types;
	iMaxSize : INT;
	pClient : POINTER TO VisuElems.VisuStructClientData;
END_VAR

// String stInfo, which will be displayed in the lower rectangle, is composed here
PLC_PRG.stInfo := 'Variable written; type: ';
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, INT_TO_STRING(varType));
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, ', adr: ');
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, DWORD_TO_STRING(pVar));
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, ', by: ');
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, SEL(pClient^.globaldata.clienttype = VisuElems.Visu_ClientType.Targetvisualization,'other visu', 'targetvisu'));

Capturing keyboard events

When the user presses and releases the key, a keyboard event is triggered in the visualization. You can capture this event in the application as follows.

Create a function block that implements ‎VisuElems.IVisuUserEventManager‎ from the ‎VisuElemBase‎ library.
Pass the instance to the global event manager ‎VisuElems.Visu_Globals.g_VisuEventManager‎ by calling the ‎SetKeyEventHandler‎ method.

Example

A visualization has one text output element. The text output element is a rectangle where the contents of the text variable ‎PLC_PRG.stInfo‎ are printed. The text variable contains information about the last key pressed by the user.

Properties of the rectangle for the text output
“Texts Text”	`‎%s‎`
“Text variables Text variable”	PLC_PRG.stInfo

Implementation of the ‎PLC_PRG‎ program

PROGRAM PLC_PRG
VAR_INPUT
	stInfo : STRING;
END_VAR
VAR
	inst : POU;
	bFirst : BOOL := TRUE;
END_VAR

IF bFirst THEN
	bFirst := FALSE;
	VisuElems.Visu_Globals.g_VisuEventManager.SetKeyEventHandler(inst);
END_IF

Implementation of the ‎POU‎ function block

FUNCTION_BLOCK POU IMPLEMENTS VisuElems.IKeyEventHandler
(* no further declarations, no implementation code *)

Implementation of the ‎VariableWritten‎ method of the ‎POU‎ function block

/// This method will be called after a key event is released. 
/// RETURN:
/// TRUE - When the handler has handled this event and it should not be handled by someone else
/// FALSE - When the event is not handled by this handler
METHOD HandleKeyEvent : BOOL
VAR_INPUT
	/// Event type. The value is true if a key-up event was released.
	bKeyUpEvent : BOOL;
	/// Key code
	dwKey : DWORD;
	/// Modifier. Possible values:
	/// VISU_KEYMOD_SHIFT : DWORD := 1;
	/// VISU_KEYMOD_ALT : DWORD := 2;
	/// VISU_KEYMOD_CTRL : DWORD := 4;
	dwModifiers : DWORD;
	/// Pointer to the client structure were the event was released
	pClient : POINTER TO VisuStructClientData;
END_VAR
VAR
END_VAR

PLC_PRG.stInfo := 'KeyEvent up: ';
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, BOOL_TO_STRING(bKeyUpEvent));
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, ', key: ');
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, DWORD_TO_STRING(dwKey));
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, ', modifier: ');
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, DWORD_TO_STRING(dwModifiers));
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, ', by: ');
PLC_PRG.stInfo := CONCAT(PLC_PRG.stInfo, SEL(pClient^.globaldata.clienttype = 
                                             VisuElems.Visu_ClientType.Targetvisualization, 
																																													'other visu', 'targetvisu'));

Recording variable value changes triggered by input events

All visualization elements that change the value of a variable by user input call the ‎IValueChangedListener‎ interface. With this interface, the value changes can be recorded and then processed programmatically.

Implement a function block (example: ‎POU‎) that implements the ‎IValueChangedListener‎ interface.

‎FUNCTION_BLOCK POU IMPLEMENTS VisuElems.IValueChangedListener‎

In the device tree, the “ValueChanged” method is inserted below the function block.
In a program (example: “PLC_PRG”), implement the IEC code that registers the interface.

‎VisuElems.g_itfValueChangedListenerManager.AddValueChangedListener(itfValueChangedListener)‎

“PLC_PRG” receives all value changes by means of the “ValueChanged” method.

Now you can record and process the value changes.