update asserts

examples/widgets/arc/lv_example_arc_2.py

@@ -0,0 +1,43 @@
+# Create an arc which acts as a loader.
+class loader_arc(lv.arc):
+
+    def __init__(self, parent, color=lv.color_hex(0x000080), 
+                       width=8, style=lv.style_plain, rate=20):
+        super().__init__(parent)
+        
+        self.a = 0
+        self.rate = rate
+
+        # Create style for the Arcs
+        self.style = lv.style_t()
+        lv.style_copy(self.style, style)
+        self.style.line.color = color
+        self.style.line.width = width
+
+        # Create an Arc
+        self.set_angles(180, 180);
+        self.set_style(self.STYLE.MAIN, self.style);
+
+        # Spin the Arc
+        self.spin()
+
+    def spin(self):
+        # Create an `lv_task` to update the arc.
+        lv.task_create(self.task_cb, self.rate, lv.TASK_PRIO.LOWEST, {})
+
+    
+    # An `lv_task` to call periodically to set the angles of the arc
+    def task_cb(self, task):
+        self.a+=5;
+        if self.a >= 359: self.a = 359
+
+        if self.a < 180: self.set_angles(180-self.a, 180)
+        else: self.set_angles(540-self.a, 180)
+
+        if self.a == 359:
+            self.a = 0
+            lv.task_del(task)
+
+# Create a loader arc
+loader_arc = loader_arc(lv.scr_act())
+loader_arc.align(None, lv.ALIGN.CENTER, 0, 0)