LVGL does not display anything

Hello All,

When we write our LVGL display code, we put it into the initialize() function with a delay included. When we download to the cortex, nothing shows up. Below is a snippet of my code (keep in mind that I have already declared my button variable, I just did not include those for the sake of space).


lv_style_copy(&RedREL, &lv_style_plain);
RedREL.body.main_color = LV_COLOR_MAKE(150, 0, 0);
RedREL.body.grad_color = LV_COLOR_MAKE(150, 0, 0);
RedREL.body.radius = 0;
RedREL.text.color = LV_COLOR_MAKE(255, 255, 255);

lv_style_copy(&RedPR, &lv_style_plain);
RedPR.body.main_color = LV_COLOR_MAKE(255, 0, 0);
RedPR.body.grad_color = LV_COLOR_MAKE(255, 0, 0);
RedPR.body.radius = 0;
RedPR.text.color = LV_COLOR_MAKE(255, 255, 255);

lv_style_copy(&BlueREL, &lv_style_plain);
BlueREL.body.main_color = LV_COLOR_MAKE(0,0,150);
BlueREL.body.grad_color = LV_COLOR_MAKE(0,0,150);
BlueREL.body.radius = 0;
BlueREL.text.color = LV_COLOR_MAKE(255,255,255);

lv_style_copy(&BluePR, &lv_style_plain);
BluePR.body.main_color = LV_COLOR_MAKE(0,0,255);
BluePR.body.grad_color = LV_COLOR_MAKE(0,0,255);
BluePR.body.radius = 0;
BluePR.text.color = LV_COLOR_MAKE(255,255,255);

myButton = lv_btn_create(lv_scr_act(), NULL); //create button, lv_scr_act() is deafult screen object
lv_obj_set_free_num(myButton, 0); //set button is to 0
lv_btn_set_action(myButton, LV_BTN_ACTION_CLICK, btn_click_action); //set function to be called on button click
lv_btn_set_style(myButton, LV_BTN_STYLE_REL, &RedREL); //set the relesed style
lv_btn_set_style(myButton, LV_BTN_STYLE_PR, &RedPR); //set the pressed style
lv_obj_set_size(myButton, 200, 50); //set the button size
lv_obj_align(myButton, NULL, LV_ALIGN_IN_TOP_LEFT, 0, 0); //set the position to top mid	

myLabel = lv_label_create(lv_scr_act(), NULL); //create label and puts it on the screen
lv_label_set_text(myLabel, "Button has not been clicked yet"); //sets label text
lv_obj_align(myLabel, NULL, LV_ALIGN_IN_BOTTOM_MID, 0, 0); //set the position to center

First why do you need the 50millisecond delay, it shouldn’t cause any problems, but what purpose does it serve?

Did you declare all the style variables and the function btn_click_action? Also check that your code loop has delays, since lvgl runs in a separate thread. Other then that I can’t think of anything that would go wrong. Are there any errors?

Also seeing your entire code would help (upload as a zip file).

delay may be related to this issue.

try with the delay as 100mS.

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