_thread code crashes

[de-dh]

The code shown is working when all widgets are placed directly on the screen. Even the bars get updated with random values.
However, as soon as I try to center the label on the button (as a child) it results in a crash without further error information.

Is there any obvious mistake in this code?
Im running LVGL 9.3 / MPY 1.25.0 on the CYD.

from micropython import const
import lvgl as lv
import time
import task_handler
from machine import Timer
import lv_config # display setup

import _thread
import sys
import random
import gc

# ========== Start UI  ========== #
scrn = lv.obj()

bar1 = lv.bar(scrn)
bar1.set_pos(20, 20)

bar2 = lv.bar(scrn)
bar2.set_pos(20, 80)

btn = lv.button(scrn)
btn.set_size(100, 50)
btn.align(lv.ALIGN.CENTER, 0, 50)

# ========== Look here ========== #
# ========== Here is the problem  ========== #
btn_label = lv.label(scrn) # works
#btn_label = lv.label(btn) --> crash

btn_label.set_text("Click")
btn_label.set_align( lv.ALIGN.CENTER)

lv.screen_load(scrn)

def do():
    sleep_delay = 50
    start_time = time.ticks_ms()

    while True:
        s1_value = int(random.random() * 100.0)
        s2_value = int(random.random() * 100.0)
        
        bar1.set_value(s1_value, False)
        bar2.set_value(s2_value, False)

        end_time = time.ticks_ms()
        diff = time.ticks_diff(end_time, start_time)
        start_time = end_time

        if diff < sleep_delay:
            time.sleep_ms(sleep_delay - diff if diff < sleep_delay else 0)
        
        lv.tick_inc(diff)
        lv.task_handler()
        gc.collect()

_thread.start_new_thread(do, ())

[kdschlosser]

The only place I see you centering a label is outside of the thread loop. Which is fine but as a suggestion try using the center method for the button if you are not needing to pass any coordinates to offset it or anything like that.

give this a go and se what happens..

from micropython import const
import lvgl as lv
import time

#  you don' t need this imported.
# import task_handler  
# from machine import Timer

# make sure you are not running task_handler
# at all in your display setup code.
import lv_config # display setup

import _thread
import sys
import random
import gc

# ========== Start UI  ========== #

# this is a better thing to do because there is already a 
# screen that exists
scrn = lv.screen_active()
# scrn = lv.obj()

bar1 = lv.bar(scrn)
bar1.set_pos(20, 20)

bar2 = lv.bar(scrn)
bar2.set_pos(20, 80)

btn = lv.button(scrn)
# btn.set_size(100, 50)
# btn.align(lv.ALIGN.CENTER, 0, 50)

# ========== Look here ========== #
# ========== Here is the problem  ========== #
# btn_label = lv.label(scrn) # works
btn_label = lv.label(btn)

btn_label.set_text("Click")
btn_label..center()

btn.align(lv.ALIGN.CENTER, 0, 50)

# don't need this anymore
# lv.screen_load(scrn)

lv.tick_inc(1)
lv.refr_now(scrn.get_display())

def do():
    # you don't want to set this any larger than 33 milliseconds
    # otherwise it will make the input really sluggish.
    sleep_delay = 33
    start_time = time.ticks_ms()

    while True:

        s1_value = int(random.random() * 100.0)
        s2_value = int(random.random() * 100.0)
        
        bar1.set_value(s1_value, lv.ANIM.ON)
        bar2.set_value(s2_value, lv.ANIM.ON)

        end_time = time.ticks_ms()
        diff = time.ticks_diff(end_time, start_time)
        start_time = end_time

        lv.tick_inc(diff)
        lv.task_handler()
        gc.collect()
        
        if diff < sleep_delay:
            time.sleep_ms(sleep_delay - diff if diff < sleep_delay else 0)


_thread.start_new_thread(do, ())

[de-dh]

Thank you, that part works now. However, when I click the button (even without a defined event cb) the program crashes again.
Unfortunately, I don't understand what's causing all the problems.

The program looks like this now:

from micropython import const
import lvgl as lv
import time

#  you don' t need this imported.
# import task_handler  
# from machine import Timer

# make sure you are not running task_handler
# at all in your display setup code.
import lv_config # display setup

import _thread
import sys
import random
import gc

# ========== Start UI  ========== #

# this is a better thing to do because there is already a 
# screen that exists
scrn = lv.screen_active()
# scrn = lv.obj()

bar1 = lv.bar(scrn)
bar1.set_pos(20, 20)

bar2 = lv.bar(scrn)
bar2.set_pos(20, 80)

btn = lv.button(scrn)
btn_label = lv.label(btn)

btn_label.set_text("Click")
btn_label.center()

btn.align(lv.ALIGN.CENTER, 0, 50)

# ================= This is new ================= #
clicked = False
def btn_cb(e):
    global clicked
    clicked = True

btn.add_event_cb(btn_cb, lv.EVENT.CLICKED, None)

lv.tick_inc(1)
lv.refr_now(scrn.get_display())

def do():
    global clicked
    # you don't want to set this any larger than 33 milliseconds
    # otherwise it will make the input really sluggish.
    sleep_delay = 33
    start_time = time.ticks_ms()

    while True:

        s1_value = int(random.random() * 100.0)
        s2_value = int(random.random() * 100.0)
        
        bar1.set_value(s1_value, True)
        bar2.set_value(s2_value, True)
        
        # ================= This is new ================= #
        if clicked == True:
            clicked = False 
            print('Button was clicked.')

        end_time = time.ticks_ms()
        diff = time.ticks_diff(end_time, start_time)
        start_time = end_time

        lv.tick_inc(diff)
        lv.task_handler()
        gc.collect()
        
        if diff < sleep_delay:
            time.sleep_ms(sleep_delay - diff if diff < sleep_delay else 0)


_thread.start_new_thread(do, ())

Also, this is the lv_config.py, but I don't think it causes the error (it doesn't use the task_handler.

from micropython import const
import lvgl as lv
import machine
import lcd_bus
import ili9341
import xpt2046

# ============== Customize settings ============== #
_DISPLAY_WIDTH = const(320)
_DISPLAY_HEIGHT = const(240)
_DISPLAY_ROT = const(0xE0)
_DISPLAY_BGR = const(1)
_DISPLAY_RGB565_BYTE_SWAP = const(1)

# ============== Display / Indev initialization ============== #
# no need to change anything below here
_SPI_BUS_HOST = const(1)
_SPI_BUS_MOSI = const(13)
_SPI_BUS_MISO = const(12)
_SPI_BUS_SCK = const(14)
_INDEV_BUS_HOST = const(2)
_INDEV_BUS_MOSI = const(32)
_INDEV_BUS_MISO = const(39)
_INDEV_BUS_SCK = const(25)
_INDEV_DEVICE_FREQ = const(2000000)
_INDEV_DEVICE_CS = const(33)
_DISPLAY_BUS_FREQ = const(24000000)
_DISPLAY_BUS_DC = const(2)
_DISPLAY_BUS_CS = const(15)
_DISPLAY_BACKLIGHT_PIN = const(21)

spi_bus = machine.SPI.Bus(
    host=_SPI_BUS_HOST,
    mosi=_SPI_BUS_MOSI,
    miso=_SPI_BUS_MISO,
    sck=_SPI_BUS_SCK
)

indev_bus = machine.SPI.Bus(
    host=_INDEV_BUS_HOST,
    mosi=_INDEV_BUS_MOSI,
    miso=_INDEV_BUS_MISO,
    sck=_INDEV_BUS_SCK
)

indev_device = machine.SPI.Device(
    spi_bus=indev_bus,
    freq=_INDEV_DEVICE_FREQ,
    cs=_INDEV_DEVICE_CS
)

display_bus = lcd_bus.SPIBus(
    spi_bus=spi_bus,
    freq=_DISPLAY_BUS_FREQ,
    dc=_DISPLAY_BUS_DC,
    cs=_DISPLAY_BUS_CS
)

display = ili9341.ILI9341(
    data_bus=display_bus,
    display_width=_DISPLAY_WIDTH,
    display_height=_DISPLAY_HEIGHT,
    backlight_pin=_DISPLAY_BACKLIGHT_PIN,
    backlight_on_state=ili9341.STATE_PWM,
    color_space=lv.COLOR_FORMAT.RGB565,
    color_byte_order=ili9341.BYTE_ORDER_BGR if _DISPLAY_BGR else ili9341.BYTE_ORDER_RGB,
    rgb565_byte_swap=_DISPLAY_RGB565_BYTE_SWAP
)

# The rotation table MUST be defined
display._ORIENTATION_TABLE = (
    _DISPLAY_ROT, # this value sets the rotation
    0x0, # placeholder
    0x0, # placeholder
    0x0 # placeholder
)

# lv.DISPLAY_ROTATION._0 uses the first value from the
# display._ORIENTATION_TABLE to set display rotation
display.set_rotation(lv.DISPLAY_ROTATION._0)
display.set_power(True)
display.init(1)
display.set_backlight(100)


indev = xpt2046.XPT2046(device=indev_device)