Tasmota LVGL: 'lv_event' object has no attribute 'code'

[jkwim]

I am trying to get the Berry script from https://templates.blakadder.com/sunton_ESP32-2432S028.html working on a ESP32-2424S012 device with GC9A01 Display & CST816S Touch Sensor.

Running a custom compiled Tasmota with CST816S Driver: Tasmota 14.3.0.7 (tasmota32c3-lvgl-cst816s)

I see the following error on the console:

00:00:01.730 BRY: Exception> 'attribute_error' - the 'lv_event' object has no attribute 'code'
00:00:01.732 stack traceback:
00:00:01.733 	<unknown source>: in function `dropdown_changed_cb`
00:00:01.735 	<unknown source>: in function `lvgl_event_dispatch`
00:00:01.737 	<unknown source>: in function `<lambda>`

My investigation points to following piece of code where the problem is:

def dropdown_changed_cb(obj, event)
    var option = "Unknown"

    var modes = ['Auto', 'Boost', 'On', 'Off', 'Adv', 'Day' ]

    var code = event.code <<<<<<<<<<<<<<<

    print ("Dropdown code:", code)
    if code == lv.EVENT_VALUE_CHANGED
       print("Dropdown code :", code )
       option = obj.get_selected()
   
       print("Dropdown set:", modes[option])
   
       #tasmota.publish("tele/ESP32-2432S028/SENSOR/Dropdown", modes[option] )
     end

end

Probably the var code = event.code statement is throwing out the error.

When I remark the line the error is not shown.

I need some help to correct the code.

[jkwim]

For reference here is the LVGL Documentation:
https://docs.lvgl.io/8.3/overview/event.html#event-codes

[s-hadinger]

There was a breaking change in LVGL 9.0. You should now use event.get_code() instead of event.code

[jkwim]

Oh! Thanks for the hint.

It was my mistake.

Having looked at https://tasmota.github.io/docs/LVGL_API_Reference/#class-lvevent I tried code = event.get_code without the braces and it was throwing out more errors, obviously.

Now it works.

[jkwim]

One more question:

Is there a way to change the alignment of the following widgets?

I want to get the clock display centered on the top line.

#- display wifi strength indicator icon (for professionals ;) -#
wifi_icon = lv_wifi_arcs_icon(stat_line)    # the widget takes care of positioning and driver stuff
clock_icon = lv_clock_icon(stat_line)

[s-hadinger]

Yes, one way to do it is using flex layout. Or simply set an absolute position since you have a fixed size screen

[jkwim]

Thanks. I was confused with the comment given for the wifi_icon above.

Managed to achieve what I wanted with absolute positioning.

#- display clock icon -#
clock_icon = lv_clock_icon(stat_line)
clock_icon.set_x(75)
clock_icon.set_y(10)

#- display wifi strength indicator icon (for professionals ;) -#
wifi_icon = lv_wifi_arcs_icon(stat_line)    # the widget takes care of positioning and driver stuff
wifi_icon.set_x(137)
wifi_icon.set_y(6)

[jkwim]

Need more help in following the example that I started with:

When I remove the remark from following line there is an error:

# label.set_text(str(value)) <<<<<<<<<<<<<<<<<<<

19:55:06.565 BRY: failed to load '/autoexec.be' (syntax_error - /autoexec.be:132: 'label' undeclared (first use in this function))

def slider_event_cb(obj, event)
    var slider = "Unknown"
    var value = "999"

    if   obj == slider  slider= "SLIDER"
    # elif obj == next_slider  slider= "Next"
    # elif obj == home_btn  slider= "Home"
    end

    value= obj.get_value()

    # Refresh the text
    # label.set_text(str(value))  <<<<<<<<<<<<<<<<<<<
   
    print("slider set:", str(value))
   
    tasmota.publish("tele/ESP32-2432S028/SENSOR/Slider", str(value))
end

# Create a slider in the center of the display
slider = lv.slider(scr)
slider.set_pos(20,vres-80) 
slider.set_width(200)                                              # Set the width
slider.center()                                                    # Align to the center of the parent (screen)
slider.add_event_cb(slider_event_cb, lv.EVENT_VALUE_CHANGED, None) # Assign an event function

# Create a label below the slider
label = lv.label(scr)
label.set_text("0")
label.align_to(slider, lv.ALIGN_OUT_TOP_MID, 0, -15)               # Align below the slider

If I move the line
label = lv.label(scr)

before the line
def slider_event_cb(obj, event)

then it works.

Is there some order of precedence that the object of the callback function can be defined after the callback function but all other objects need to be defined earlier in the order?

[sfromis]

Has nothing to do with precedence or callbacks, but the more basic Berry requirement of global variables needing to be defined before you try to use them, in source code order. What happens is that inside of a function, variables are by definition local unless already existing as globals, and local variables needs to be declared first.

One way (outside of moving lines around) would (inside of the function) be to have:
global.label.set_text(str(value))
This makes it explicit to the Berry compile that label is a global variable, and that it cannot check if it is declared already, but just allowing the code to be compiled.
It would also work (again without moving lines around) to add a var label before the def of the callback function, to have the variable declared at the global scope.

What I'd personally prefer would be to not use global variables, but refactor into a class with instance variables for shared context. That would be more of a change, but better programming practice than that example code. Of course, that preference comes from working with code on a larger scale than very simple scripting-style stuff.

[jkwim]

I see.

I just moved ahead with my testing with above change.

Now I am struggling to map the correct Berry instantiations following the C Code as a starting point.

I want to use the widget lv.arc.

Looked at the LVGL Docs for instantiating lv.arc

lv_obj_t * arc = lv_arc_create(lv_screen_active());

Tried in Berry:
arc = lv.arc_create(scr)
This is what I get:
22:32:01.274 BRY: failed to run compiled code (attribute_error - module 'lv' has no member 'arc_create')

I mean I could not find any examples of lv.arc in Berrry but Berry API reference lists lv.arc:

https://tasmota.github.io/docs/LVGL_API_Reference/#widget-lvarc

What am I doing wrong here?

[jkwim]

Update:

arc=lv.arc(src) works.

trying with rest of the code:

void lv_example_arc_1(void)
{
    lv_obj_t * label = lv_label_create(lv_screen_active());

    /*Create an Arc*/
    lv_obj_t * arc = lv_arc_create(lv_screen_active());
    lv_obj_set_size(arc, 150, 150);
    lv_arc_set_rotation(arc, 135);
    lv_arc_set_bg_angles(arc, 0, 270);
    lv_arc_set_value(arc, 10);
    lv_obj_center(arc);
    lv_obj_add_event_cb(arc, value_changed_event_cb, LV_EVENT_VALUE_CHANGED, label);

    /*Manually update the label for the first time*/
    lv_obj_send_event(arc, LV_EVENT_VALUE_CHANGED, NULL);
}

Stuck at
lv_obj_set_size(arc, 150, 150);
API Reference does not list set_size either

without the set_size anyway an arc get drawn but I cannot find a way to change its radius or position.

[jkwim]

[s-hadinger]

Have you tried HASPmota ? It should make things much simpler for you

https://tasmota.github.io/docs/HASPmota/

[jkwim]

This is a device without PSRAM.

Wouldn't it be more memory efficient to run raw LVGL instead of HASPmota?

Anyway I want to try HASPmota as well.

This is the first time I am trying out Berry (and LVGL also). So I am trying to get the hang of it first.

The learning curve is steep but I am making progress with help from all of you.

I managed to get an arc on the screen.

arc = lv.arc(scr)
arc.set_size(235,235)
arc.set_angles(20,160)
arc.set_bg_angles(20,160)
arc.center()

However once the arc is activated, the dropdown list and the slider does not work. Wonder whether it is a memory issue.

With Dropdown, Slider and Arc:

Without Arc

{UPDATE: Above memory discussion is not quite correct as I understood later. See my next reply]

I hope to have multiple screens ie. multiple .be files.

What is the best way to release the memory used by the first page before I draw the second page?

[sfromis]

No, using HASPmota on top of LVGL would not reduce memory needs, on your unsuitable device without PSRAM, which is severely limiting how much stuff you can do.

[jkwim]

Just a question based on my observation:

If I re-execute the same autoexec.be over and over again using the command Br load('autoexec.be') the free memory decreases which suggest that the previous lvgl instance doe not get destroyed.

So it appears that repeating the lines

#- start LVGL and init environment -#
lv.start()

again will instantiate another lvgl instance.

Suppose I want to jump to a second Berry file eg: page3.be but have a different set of objects in that page, how do I destroy the objects created in the first page?

There is a hint in the following post about a commandlv.obj_clean()but I do not understand how it works.

#18597

My interpretation is that if I have lv.start() once in the autoexec.be file and continue on to the second page page2.be and just keep adding objects then the memory usage increase will be incremental right? Can I use the lv.obj_clean() command in the page2.be to destroy the objects created in autoexec.be?

[sfromis]

Well, just don't run the same Berry code file again and again, unless your code takes step to avoid memory leaks. And if you want multiple LVGL pages, that should not be by expecting to remove all traces of one page, and start from cold with another. The idea is that the same setup can handle the pages in a combined manner. This is unrelated to what file various bits of the code happens to be stored in. Unless you create more and more additional objects, you should not expect memory usage to keep increasing, but get to a plateau with a stable set.

If you build Tasmota for development, you can get a big red "Restart Berry VM" button on the Berry REPL page, but that's obviously not for "normal operation", and not a "guarantee" for "totally zero".

Again, you do need a better device (with PSRAM) when you want more than basic things with a display.

[s-hadinger]

Keep in mind there is no connection between the Berry Garbage Collector and LVGL. It means that if you call repeatadly lv.start(), the previous LVGL objects are still using memory.

The best way to have multiple screens, just create separate screens and switch them at runtime

[jkwim]

The best way to have multiple screens, just create separate screens and switch them at runtime

Yes, that is what I am thinking of now having read more documentation which is somewhat scattered. I mean I ended up reading LVGL Docs and Berry Docs trying to match which is where.

I now have some better understanding about how the Berry widgets are built. So will spend some time playing with them to get the hang of it. Did not want to jump to HASPmota straight away. I am likely to settle down with HASPmota with another device that I bought.

[jkwim]

Found the two methods:

void lv_obj_delete([lv_obj_t])
	Delete an object and all of its children. Also remove the objects from their group and remove all animations (if any). Send LV_EVENT_DELETED to deleted objects. 
		Parameters:
			obj -- pointer to an object 
void lv_obj_clean([lv_obj_t])
	Delete all children of an object. Also remove the objects from their group and remove all animations (if any). Send LV_EVENT_DELETED to deleted objects. 
		Parameters:
			obj -- pointer to an object

[jkwim]

I have done some basic testing to achieve the page navigation as follows:

autoexec.be
     |
     |
     v
  page1.be --> page2.be--> page3.be --> page4.be
     ^                                     |
     |                                     |
     |                                     |
     ---------------------------------------

autoexec.be:
Contains the main top status bar and the navigation buttons

pageX.be contain the other widgets that I want to have.

I confirmed that the following two commands can be used for removing the widgets as one navigates between pages.

obj.clean Delete all children of an object
obj.delete Delete an object and all of its children

However I have an issue when deleting the dropdown widget.

I have the following on page1.be:

def dropdown_changed_cb(obj, event)
    var option = "Unknown"
    var modes = ['Auto', 'Boost', 'On', 'Off', 'Adv', 'Day' ]
    var code = event.get_code()
    if code == lv.EVENT_VALUE_CHANGED
       print("Dropdown code :", code )
       option = obj.get_selected()
 
       print("Dropdown set:", modes[option])
   
       #tasmota.publish("tele/ESP32-2432S028/SENSOR/Dropdown", modes[option] )
     end
end

var modes = ['Auto', 'Boost', 'On', 'Off', 'Adv', 'Day' ]
var modes_str = modes.concat('\n')
ddlist = lv.dropdown(scr)
ddlist.set_options(modes_str)
ddlist.set_pos(60,vres-200)
# ddlist.center()
ddlist.add_event_cb(dropdown_changed_cb, lv.EVENT_ALL, None)

And have the following in page2.be:

prev_page="page1.be"
next_page="page3.be"
label_status.set_text(next_page)
label.delete()
slider.delete()

#code.delete()
#option.delete()
print("Dropdown is being deleted")
ddlist.delete()

When the dropdown list get deleted I see the following error:

Dropdown is being deleted
BRY: Exception> 'key_error' - <ptr: 0x3fcb5204>
stack traceback:
	<native>: in native function
	<unknown source>: in function `lvgl_event_dispatch`
	<unknown source>: in function `<lambda>`
	<native>: in native function
	<unknown source>: in function `main`
	<unknown source>: in function `try_run_compiled`
	<unknown source>: in function `load`
	<unknown source>: in function `load`
	<unknown source>: in function `btn_clicked_cb`
	<unknown source>: in function `lvgl_event_dispatch`
	<unknown source>: in function `<lambda>`
BRY: failed to run compiled code (attribute_error - the 'lv_dropdown' object has no method '<')

From https://tasmota.github.io/docs/LVGL_API_Reference/#widget-lvobj

The base obj lv.obj has the delete method.

https://tasmota.github.io/docs/LVGL_API_Reference/#widget-lvdropdown

Is it a case where the the obj.dropdown has not inherited the methods from the base.obj?

[s-hadinger]

I will try to reproduce. It would be better to keep objects in memory (if you have enough memory) and just change the visible screen.