.. _lv_buttonmatrix: =============================== Button Matrix (lv_buttonmatrix) =============================== Overview ******** The Button Matrix Widget is a lightweight way to display multiple Buttons in rows and columns --- lightweight because the buttons are not actually created but just virtually drawn on the fly. With Button Matrix, each button uses only eight extra bytes of memory instead of the ~100-150 bytes a normal :ref:`Button ` Widget plus the 100 or so bytes for the :ref:`Label ` Widget. New Button Matrix Widgets are added to the default group (if one is set). Additionally, Button Matrix is an editable Widget: it allows selecting and clicking the buttons with encoder and keyboard navigation as well. .. _lv_buttonmatrix_parts_and_styles: Parts and Styles **************** - :cpp:enumerator:`LV_PART_MAIN` The background of the Button Matrix, uses the typical background style properties. ``pad_row`` and ``pad_column`` sets the space between the buttons. - :cpp:enumerator:`LV_PART_ITEMS` The buttons all use the text and typical background style properties except translations and transformations. .. _lv_buttonmatrix_usage: Usage ***** .. _button map: Button map ----------- The number of buttons, their positions and text are controlled by a descriptor string array, called a *map*, passed to :cpp:expr:`lv_buttonmatrix_set_map(btn_matrix, my_map)`. The declaration of a map should look like ``const char * map[] = {"button1", "button2", "button3", NULL}``. Note that the last element must be either ``NULL`` or an empty string (``""``)! Use ``"\n"`` in the map to insert a **line break**. E.g. ``{"button1", "button2", "\n", "button3", ""}``. Each line's buttons have their width calculated automatically. So in the example the first row will have 2 buttons each with 50% width and a second row with 1 button having 100% width. .. note:: The number of buttons neither includes the newline elements nor the terminating element of the array. Button widths ------------- The buttons' width can be set in proportion to the width of other buttons in the same row with :cpp:expr:`lv_buttonmatrix_set_button_width(btn_matrix, button_id, width)` E.g. in a line with two buttons: *buttonA, width = 1* and *buttonB, width = 2*, *buttonA* will have 33 % width and *buttonB* will have 66 % width. This is similar to how the `"flex-grow" `__ property works in CSS. The width must be in the range [1..15] with the default being 1. Button behavior --------------- Each button's behavior can be customized with the following control flags: - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_HIDDEN`: Hides button; it continues to hold its space in layout. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_NO_REPEAT`: Do not emit :cpp:enumerator:`LV_EVENT_LONG_PRESSED_REPEAT` events while button is long-pressed. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_DISABLED`: Disables button like :cpp:enumerator:`LV_STATE_DISABLED` on normal Widgets. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_CHECKABLE`: Enable toggling of :cpp:enumerator:`LV_STATE_CHECKED` when clicked. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_CHECKED`: Make the button checked. It will use the :cpp:enumerator:`LV_STATE_CHECHKED` styles. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_CLICK_TRIG`: 1: Enables sending :cpp:enumerator:`LV_EVENT_VALUE_CHANGE` on ``CLICK``, 0: sends :cpp:enumerator:`LV_EVENT_VALUE_CHANGE` on ``PRESS``. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_POPOVER`: Show button text in a pop-over while being pressed. - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_RECOLOR`: Enable text recoloring with ``#color`` - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_CUSTOM_1`: Custom free-to-use flag - :cpp:enumerator:`LV_BUTTONMATRIX_CTRL_CUSTOM_2`: Custom free-to-use flag By default, these flags are disabled. To set and clear a button's control flags, use - :cpp:expr:`lv_buttonmatrix_set_button_ctrl(btn_matrix, button_id, LV_BUTTONMATRIX_CTRL_...)` and - :cpp:expr:`lv_buttonmatrix_clear_button_ctrl(btn_matrix, button_id, LV_BUTTONMATRIX_CTRL_...)` respectively. ``button_id`` is a zero-based button index (0 = first button). ``LV_BUTTONMATRIX_CTRL_...`` values can be bit-wise OR-ed together when passed to these functions. To set and clear the same control attribute for all buttons in a Button Matrix, use - :cpp:expr:`lv_buttonmatrix_set_button_ctrl_all(btn_matrix, LV_BUTTONMATRIX_CTRL_...)` and - :cpp:expr:`lv_buttonmatrix_clear_button_ctrl_all(btn_matrix, LV_BUTTONMATRIX_CTRL_...)` respectively. To set a control map for a Button Matrix (similar to `Button map`_), use - :cpp:expr:`lv_buttonmatrix_set_ctrl_map(btn_matrix, ctrl_map)`. An element of ``ctrl_map`` should look like :cpp:expr:`ctrl_map[0] = width | LV_BUTTONMATRIX_CTRL_NO_REPEAT | LV_BUTTONMATRIX_CTRL_CHECHKABLE`. The number of elements must be equal to the number of buttons. One checked ----------- The "One-checked" feature can be enabled with :cpp:expr:`lv_buttonmatrix_set_one_checked(btn_matrix, true)` to allow only one button to be checked at a time. .. _lv_buttonmatrix_events: Events ****** - :cpp:enumerator:`LV_EVENT_VALUE_CHANGED`: Sent when a button is pressed/released or repeated after long press. The event parameter is set to the ID of the pressed/released button. :cpp:expr:`lv_buttonmatrix_get_selected_button(btn_matrix)` returns the index of the button most recently released (the button with focus) or :cpp:enumerator:`LV_BUTTONMATRIX_BUTTON_NONE` if no such button was found. :cpp:expr:`lv_buttonmatrix_get_button_text(btn_matrix, button_id)` returns a pointer to the text of the button specified by zero-based index ``button_id``. .. admonition:: Further Reading Learn more about :ref:`lv_obj_events` emitted by all Widgets. Learn more about :ref:`events`. .. _lv_buttonmatrix_keys: Keys **** - ``LV_KEY_RIGHT/UP/LEFT/RIGHT`` To navigate among the buttons to select one - :cpp:enumerator:`LV_KEY_ENTER` To press/release the selected button Note that long pressing the Button Matrix with an encoder can mean to enter/leave edit mode and simply long pressing a button to make it repeat as well. To avoid this contradiction, add :cpp:expr:`lv_buttonmatrix_set_button_ctrl_all(btn_matrix, LV_BUTTONMATRIX_CTRL_CLICK_TRIG | LV_BUTTONMATRIX_CTRL_NO_REPEAT)` to the Button Matrix if used with an encoder. This disables the repeat feature so the button will not be activated upon leaving edit mode. .. admonition:: Further Reading Learn more about :ref:`indev_keys`. .. _lv_buttonmatrix_example: Example ******* .. include:: ../../examples/widgets/buttonmatrix/index.rst .. _lv_buttonmatrix_api: API ***