lvppDropdown Class Reference

Support for drop-down lists and choosing from a dropdown. Utilizes multiple inheritance of lvppBase and lvppOptions. More...

#include <lvpp.h>

Inheritance diagram for lvppDropdown:

Collaboration diagram for lvppDropdown:

Public Member Functions
	lvppDropdown (const char *fName, const char *pOptions=nullptr, lv_obj_t *parent=nullptr)
	Construct a new lvpp Dropdown object and optionially give its starting options list.
void	setOptions (const char *pOptions)
	sets the complete list of options by way of a char pointer with options separated by \n
void	setOptions (std::vector< std::string > &options)
	sets the complete list of options by way of a reference to a vector of std::string values
void	clearOptions (void)
	Removes all options from the dropdown.
void	setDropdownDirection (lv_dir_t dropDirection)
	Set the Dropdown Direction. Depending on the screen location of the drop-down, it may be desirable to have the dropdown "open" above rather than below the widget location.
uint16_t	getSelectedIndex ()
	Get the Index of the selected option.
void	setSelectedIndex (uint16_t curInd)
	Set the selected option manually/programmatically.
void	getSelectedText (char *selStr, uint8_t selStrLen)
	Get the Text value of the currently selected option.
Public Member Functions inherited from lvppBase
	lvppBase (const char *fName, const char *oType)
	Construct a new lvpp Base object.
	~lvppBase ()
void	createObj (lv_obj_t *o)
	Create the handlers and store the newly created object.
lv_obj_t *	getObj (void)
	Get the Obj object.
lv_obj_t *	getLabelObj (void)
	Get the label object.
virtual void	setSize (lv_coord_t width, lv_coord_t height)
	Set the Size object. Most of the time, LVGL does a great job of setting a sane size, but manipulation of things like the text or the font size can cause this to no longer be a good size. It is a common use pattern to instantiate a widget and then use setSize() and align() to place them in your user interface as needed.
void	align (lv_align_t align, lv_coord_t x_ofs, lv_coord_t y_ofs)
	Change the x/y location of the object.
void	setFontSize (uint8_t points)
	Set the Font Size for the object in simple 'points'.
void	setFont (const lv_font_t *pF)
	Set the Font to be used. This is a more complete/complex version of setFontSize(). The fact that the font pointer is required at least means the user knows the font exists.
void	setBGColor (lv_color_t color)
	Set the background color of the object.
void	setColorGradient (lv_color_t col1, lv_color_t col2, lv_grad_dir_t direction)
	Sets a Color Gradient from col1 to col2 in a vertical or horizontal direction. The gradient is place on the indicator for lvppBar, lvppSlider, and lvppArc. The graident is placed on the 'main' area of all other objects.
virtual void	setText (const char *pText)
	Set the Text for the primary text label. For a button, for instance, this is the text on top of the button.
std::string	getText ()
	Get the Text from the object/label and put it in a std::string.
void	setTextAlign (lv_align_t align, lv_coord_t xoff, lv_coord_t yoff)
	Set the Text Alignment. This allows the object's primary label to be moved from its 'center' position.
void	setTextColor (lv_color_t newColor)
	Set the Text Color of the primary label object.
void	setLabelJustificationAlignment (lv_text_align_t _align)
	Set the Label's text alignment (left/right/center)
void	setLabelColorizationEnabled (bool bEnable=true)
	Turn on or off inline text colorization. To use colors inline, simply use #RRGGBB in the text where the R, G, and B are hex values. Be sure to have a space before and after.
virtual void	setAdjText (const char *pText, lv_coord_t x_ofs=-10000, lv_coord_t y_ofs=-10000)
	Set the text for the adjacent text label. This label is not enabled by default. Setting this text will create and enable the adjacent label object. The label's position can be set, optionally, as well.
void	setAdjTextColor (lv_color_t newColor)
	Set the Adjacent text color.
void	setAdjBGColor (lv_color_t color)
	set the background color for the adjacent text
void	setAdjColorGradient (lv_color_t col1, lv_color_t col2, lv_grad_dir_t direction)
	Sets a Color Gradient from col1 to col2 in a vertical or horizontal direction.
void	setAdjFont (const lv_font_t *pF)
	Set the Font to be used for the adjacent text.
void	setAdjJustificationAlignment (lv_text_align_t _align)
	Set the adjacent Label's text alignment (left/right/center)
virtual void	onClicked ()
	Callback that derived objects can use to get notification when the object is clicked.
virtual void	internalOnClicked ()
	Internal version of the onClicked() callback which is used for other derived internal objects in the library.
virtual void	onValueChanged ()
	Callback that derived objects can use to get notification when the value changes of an object.
virtual void	internalOnValueChanged ()
	Internal version of the onValueChanged() callback which is used for other derived internal objects in the library.
void	setFriendlyName (const char *pName)
	Set the Friendly Name of the object. This is the name given in the constructor's fName parameter and is unlikely to be changed. However, it can be via this method.
std::string	getFriendlyName ()
	Get the Friendly Name of the object.
std::string	getObjType ()
	Get the Obj Type.
const char *	whoAmI (void)
	Utility useful for dumping the friendly name and object type if needed.
void	setCallbackOnClicked (std::function< void()> cbF)
	Uses a lambda callback for when an object is clicked.
void	setCallbackOnValueChanged (std::function< void()> cbF)
	Uses a lambda callback for when an object value changes.
virtual void	setNewParent (lv_obj_t *pNewParent)
	Changes the parent object on the fly. Used primarily for lvppScreen::addObject(). Sets parents of adjacent label, value label, and label appropriately.
Public Member Functions inherited from lvppOptions
virtual void	setOptions (const char *pOpts)
	Set the Options all in one shot from a const char*.
virtual void	setOptions (std::vector< std::string > &_opts)
	Set the Options using a vector of strings.
virtual void	setOptionsWithIDs (std::vector< std::pair< std::string, uint64_t > > &valIDs)
	Set the Options along with a related ID. This is intended to give the user a more meaningful item to 'get' than text or index of what has been selected. Used in conjunction with getCurrentID()
virtual void	addOption (const char *pOpt)
	Add a single option to the options list.
virtual void	addOptionWithID (const char *pOpt, uint64_t id)
	Add a single option to the options list and pair it with a meaningful ID. To be used in conjunction with getSelectedID().
virtual void	addOption (std::string &_opt)
	Add a single option to the options list.
virtual void	addOptionWithID (std::string &_opt, uint64_t id)
	Add a single option to the options list and pair it with a meaningful ID. To be used in conjunction with getSelectedID().
virtual void	clearOptions ()
	Removes all entries from the options list. NOTE: Method does not clear the LVGL widget. User should declare their own clearOptions() method and make a call to the base object for clearing the options list prior to the user clearing the widget's actual list visually.
virtual uint64_t	getSelectedID ()
	Get the ID associated with the currently selected item. Using this method only makes sense if the list of options was built using setOptionsWithIDs() and/or addOptionWithID().

Protected Member Functions
void	lvOptionSetter (const char *pOpts)
	This is the implementation of the pure virtual in lvppOptions. It is responsible for doing the actual class-specific 'set' - in this case lv_dropdown_set_options().
virtual uint16_t	lvOptionGetIndex ()
	This is the implementation of the pure virtual in lvppOptions. It is responsible for doing the actual class-specific 'get' - in this case lv_dropdown_get_selected().
Protected Member Functions inherited from lvppBase
void	setObjType (const char *pType)
void	baseEventHandler (lv_event_t *event)
	Main event handler loop for all events. This handler makes calls for onClicked() and onValueChanged()
virtual void	eventHandler (lv_event_t *event)
	Any events not handled by baseEventHandler come here. Can be overridden by a derived class.
Protected Member Functions inherited from lvppOptions
virtual void	lvOptionSetter (const char *pOpts)=0
	This is the pure virtual which must be implemented by any class that utilizes lvppOptions. It is called by the 'set' functions to do the actual setting. Since lvppOptions is just a utility class, it must rely on the the child to do the actual appropriate set function.
virtual uint16_t	lvOptionGetIndex ()=0
	This is the pure virtual method which must be implemented by any class that utilizes lvppOptions. The implementation should return the index of the currently selected value in the list. The specific function will vary based on what the child's widget type is.
const char *	getNewlineSepOptions ()
	Packs all the option strings into a single newline separated pointer.

Additional Inherited Members
Static Public Member Functions inherited from lvppBase
static const char *	getEventName (lv_event_code_t code)
	Get the Event Name from a given event code. Translate it to text, essentially.
static bool	isUnknownCode (lv_event_code_t code)
	Check to see if an event code is valid or not. Utility function.
Static Protected Member Functions inherited from lvppBase
static void	lvCallback (lv_event_t *event)
	Static member to handle all inbound callback events. Used to "route" event handling to the appropriate C++ object.
static void	initEventNames (void)
	One-time initialization of the event names array.
Protected Attributes inherited from lvppBase
lv_obj_t *	label
	Primary label.
lv_obj_t *	adjLabel
	For items that have a label 'nearby' (adjacent label)
std::function< void()>	cbOnClicked =nullptr
	Start without a lambda callback.
std::function< void()>	cbOnValueChanged =nullptr
	Start without a lambda callback.
lv_obj_t *	obj
	The LVGL object that was created for this widget.
lv_obj_t *	objParent
	Any parent object (following same principle as LVGL here)
std::string	objType
std::string	friendlyName
lv_style_t	style_obj
	Main style object - unsure if I'm handling all of the style bit correctly.
Protected Attributes inherited from lvppOptions
std::string	oneString
	Temp area for getNewlineSepOptions()
std::vector< std::string >	options
	The vector of options kept locally.
std::vector< uint64_t >	idList
	The vector of associated ID values (if used)
Static Protected Attributes inherited from lvppBase
static bool	bEventNamesInitComplete = false
	Status of the event names table to avoid re-processing.

Detailed Description

Support for drop-down lists and choosing from a dropdown. Utilizes multiple inheritance of lvppBase and lvppOptions.

Constructor & Destructor Documentation

lvppDropdown()

lvppDropdown::lvppDropdown	(	const char *	fName,
		const char *	pOptions = nullptr,
		lv_obj_t *	parent = nullptr
	)

Construct a new lvpp Dropdown object and optionially give its starting options list.

Parameters

fName	Internal object name. This is generally used in findObj() or lvppScreen
pOptions	Optional char pointer with a list of options which are separated by \n
parent	If provided, the parent of the object. This is a real LVGL lv_obj_t pointer

Member Function Documentation

clearOptions()

void lvppDropdown::clearOptions ( void  )

virtual

Removes all options from the dropdown.

Reimplemented from lvppOptions.

getSelectedIndex()

uint16_t lvppDropdown::getSelectedIndex ( )

inline

Get the Index of the selected option.

Returns

uint16_t Value from 0-(n-1) of the selected option.

getSelectedText()

void lvppDropdown::getSelectedText ( char *  selStr, uint8_t  selStrLen  )

inline

Get the Text value of the currently selected option.

Parameters

selStr	A pointer to a string where the current option string will be copied.
selStrLen	The size of the selStr location to ensure a long option value won't overrun selStr memory. Be sure to use the size of selStr MINUS one here to ensure you can fit a null terminator.

lvOptionGetIndex()

uint16_t lvppDropdown::lvOptionGetIndex ( )

protectedvirtual

This is the implementation of the pure virtual in lvppOptions. It is responsible for doing the actual class-specific 'get' - in this case lv_dropdown_get_selected().

Implements lvppOptions.

lvOptionSetter()

void lvppDropdown::lvOptionSetter ( const char *  pOpts )

protectedvirtual

This is the implementation of the pure virtual in lvppOptions. It is responsible for doing the actual class-specific 'set' - in this case lv_dropdown_set_options().

Parameters

pOpts

newline-separated list of options.

Implements lvppOptions.

setDropdownDirection()

void lvppDropdown::setDropdownDirection

(

lv_dir_t

dropDirection

)

Set the Dropdown Direction. Depending on the screen location of the drop-down, it may be desirable to have the dropdown "open" above rather than below the widget location.

Parameters

dropDirection

An lv_dir_t value such as LV_DIR_BOTTOM, LV_DIR_TOP.

setOptions() [1/2]

void lvppDropdown::setOptions ( const char *  pOptions )

virtual

sets the complete list of options by way of a char pointer with options separated by \n

Parameters

pOptions

pointer to a string of options separated by \n

Reimplemented from lvppOptions.

setOptions() [2/2]

void lvppDropdown::setOptions ( std::vector< std::string > &  options )

virtual

sets the complete list of options by way of a reference to a vector of std::string values

Parameters

options

A reference to a std::vector of std::string values.

Reimplemented from lvppOptions.

setSelectedIndex()

void lvppDropdown::setSelectedIndex

(

uint16_t

curInd

)

Set the selected option manually/programmatically.

Parameters

curInd

Value from 0-(n-1) of the desired option.

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The documentation for this class was generated from the following files:

• src/lvpp.h
• src/lvppDropdown.cpp