example(micropython): updated MicroPython examples according to LVGL changes (#4031)

examples/widgets/arc/lv_example_arc_1.py

@@ -1,8 +1,23 @@
+def value_changed_event_cb(e,label):
+    arc = e.get_target_obj()
+
+    txt = "{:d}%".format(arc.get_value())
+    label.set_text(txt)
+
+    # Rotate the label to the current position of the arc
+    arc.rotate_obj_to_angle(label, 25)
+
+label = lv.label(lv.scr_act())
+
 # Create an Arc
 arc = lv.arc(lv.scr_act())
-arc.set_end_angle(200)
 arc.set_size(150, 150)
+arc.set_rotation(135)
+arc.set_bg_angles(0, 270)
+arc.set_value(10)
 arc.center()
+arc.add_event(lambda e: value_changed_event_cb(e,label),lv.EVENT.VALUE_CHANGED, None)
 
-
+# Manually update the label for the first time
+arc.send_event(lv.EVENT.VALUE_CHANGED, None)
 

examples/widgets/arc/lv_example_arc_2.py

@@ -1,37 +1,24 @@
-#
-# An `lv_timer` to call periodically to set the angles of the arc
-#
-class ArcLoader():
-    def __init__(self):
-        self.a = 270
-
-    def arc_loader_cb(self,tim,arc):
-        # print(tim,arc)
-        self.a += 5
-
-        arc.set_end_angle(self.a)
-
-        if self.a >= 270 + 360:
-            tim._del()
-
+def set_angle(obj, v):
+    obj.set_value(v)
 
 #
 # Create an arc which acts as a loader.
 #
-
 # Create an Arc
 arc = lv.arc(lv.scr_act())
+arc.set_rotation(270)
 arc.set_bg_angles(0, 360)
-arc.set_angles(270, 270)
+arc.remove_style(None, lv.PART.KNOB)   # Be sure the knob is not displayed
+arc.clear_flag(lv.obj.FLAG.CLICKABLE)  #To not allow adjusting by click
 arc.center()
 
-# create the loader
-arc_loader = ArcLoader()
-
-# Create an `lv_timer` to update the arc.
-
-timer = lv.timer_create_basic()
-timer.set_period(20)
-timer.set_cb(lambda src: arc_loader.arc_loader_cb(timer,arc))
-
+a = lv.anim_t()
+a.init()
+a.set_var(arc)
+a.set_time(1000)
+a.set_repeat_count(lv.ANIM_REPEAT_INFINITE)    #Just for the demo
+a.set_repeat_delay(500)
+a.set_values(0, 100)
+a.set_custom_exec_cb(lambda a,val: set_angle(arc,val))
+lv.anim_t.start(a)