example(get_started): add simple hello world example

examples/get_started/lv_example_get_started_2.py

@@ -1,62 +1,29 @@
-#
-# Create styles from scratch for buttons.
-#
-style_btn =  lv.style_t()
-style_btn_red = lv.style_t()
-style_btn_pressed = lv.style_t()
+class CounterBtn():
+    def __init__(self):
+        self.cnt = 0
+        #
+        # Create a button with a label and react on click event.
+        #
 
-# Create a simple button style
-style_btn.init()
-style_btn.set_radius(10)
-style_btn.set_bg_opa(lv.OPA.COVER)
-style_btn.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 3))
-style_btn.set_bg_grad_color(lv.palette_main(lv.PALETTE.GREY))
-style_btn.set_bg_grad_dir(lv.GRAD_DIR.VER)
+        btn = lv.btn(lv.scr_act())                               # Add a button the current screen
+        btn.set_pos(10, 10)                                      # Set its position
+        btn.set_size(120, 50)                                    # Set its size
+        btn.align(lv.ALIGN.CENTER,0,0)
+        btn.add_event_cb(self.btn_event_cb, lv.EVENT.ALL, None)  # Assign a callback to the button
+        label = lv.label(btn)                                    # Add a label to the button
+        label.set_text("Button")                                 # Set the labels text
+        label.center()
 
-# Add a border
-style_btn.set_border_color(lv.color_white())
-style_btn.set_border_opa(lv.OPA._70)
-style_btn.set_border_width(2)
+    def btn_event_cb(self,evt):
+        code = evt.get_code()
+        btn = evt.get_target()
+        if code == lv.EVENT.CLICKED:
+            self.cnt += 1
 
-# Set the text style
-style_btn.set_text_color(lv.color_white())
+        # Get the first child of the button which is the label and change its text
+        label = btn.get_child(0)
+        label.set_text("Button: " + str(self.cnt))
 
-# Create a red style. Change only some colors.
-style_btn_red.init()
-style_btn_red.set_bg_color(lv.palette_main(lv.PALETTE.RED))
-style_btn_red.set_bg_grad_color(lv.palette_lighten(lv.PALETTE.RED, 2))
 
-# Create a style for the pressed state.
-style_btn_pressed.init()
-style_btn_pressed.set_bg_color(lv.palette_main(lv.PALETTE.BLUE))
-style_btn_pressed.set_bg_grad_color(lv.palette_darken(lv.PALETTE.RED, 3))
-
-# Create a button and use the new styles
-btn = lv.btn(lv.scr_act())                  # Add a button the current screen
-# Remove the styles coming from the theme
-# Note that size and position are also stored as style properties
-# so lv_obj_remove_style_all will remove the set size and position too
-btn.remove_style_all()                      # Remove the styles coming from the theme
-btn.set_pos(10, 10)                         # Set its position
-btn.set_size(120, 50)                       # Set its size
-btn.add_style(style_btn, 0)
-btn.add_style(style_btn_pressed, lv.STATE.PRESSED)
-
-label = lv.label(btn)                       # Add a label to the button
-label.set_text("Button")                    # Set the labels text
-label.center()
-
-# Create another button and use the red style too
-btn2 = lv.btn(lv.scr_act())
-btn2.remove_style_all()                     # Remove the styles coming from the theme
-btn2.set_pos(10, 80)                        # Set its position
-btn2.set_size(120, 50)                      # Set its size
-btn2.add_style(style_btn, 0)
-btn2.add_style(style_btn_red, 0)
-btn2.add_style(style_btn_pressed, lv.STATE.PRESSED)
-btn2.set_style_radius(lv.RADIUS_CIRCLE, 0)  # Add a local style
-
-label = lv.label(btn2)                      # Add a label to the button
-label.set_text("Button 2")                  # Set the labels text
-label.center()
+counterBtn = CounterBtn()