Expand "lv_btnmatrix_set_one_check" to allow radio-button functionality

Feature request
1

Right now there is no radio button in lvgl.

It seems like there almost exists this functionality in the btnmatrix widget, when combined with the lv_btnmatrix_set_one_check function.

The only thing missing is that lv_btnmatrix_set_one_check makes it so only one thing can be checked, but it doesn’t make is to that one thing must be checked. With a radio button, one of the options must be selected.

2

It sounds quite reasonable. I can’t imagine a use case where either 0 or 1 option can to be selected. It should be always 1. So I’d agree to update lv_btnmatrix_set_one_check to ensure there is at least one checked button.

3

@kisvegabor,
Now that lv_btnmatrix_set_one_check works correctly, there needs to be a way to programmatically set which button is checked. Currently this is not possible, that I can see.

4

It should be possible using lv_btnmatrix_set_btn_ctrl(btnm, btn_id, LV_BTNMATRIX_CTRL_CHECK_STATE).

5

This makes it look checked, yes, but doesn’t handle anything else.
That is: it is the only one checked, it is the currently active button, etc.
It should be possible to programmatically check the button and have the same effects that pressing it does.

6

What about this?

void lv_btnmatrix_set_btn_ctrl(lv_obj_t * btnm, uint16_t btn_id, lv_btnmatrix_ctrl_t ctrl)
{
    LV_ASSERT_OBJ(btnm, LV_OBJX_NAME);

    lv_btnmatrix_ext_t * ext = lv_obj_get_ext_attr(btnm);

    if(btn_id >= ext->btn_cnt) return;

    /*Uncheck all buttons if required*/
    if(ext->one_check && (ctrl & LV_BTNMATRIX_CTRL_CHECKED)) {
        lv_btnmatrix_clear_btn_ctrl_all(btnm, LV_BTNMATRIX_CTRL_CHECKED);
    }

    ext->ctrl_bits[btn_id] |= ctrl;
    invalidate_button_area(btnm, btn_id);
}
7

That seems sound, but ext->btn_id_act must still be set.

8

True!
I’ve added it to master.