adding micropython examples (#2286)

* adding micropython examples

* adding micropython examples

examples/widgets/btn/lv_example_btn_1.py

@@ -1,21 +1,32 @@
-def event_handler(obj, event):
-    if event == lv.EVENT.CLICKED:
-        print("Clicked")
+def event_handler(evt):
+    code = evt.get_code()
 
+    if code == lv.EVENT.CLICKED:
+            print("Clicked event seen")
+    elif code == lv.EVENT.VALUE_CHANGED:
+        print("Value changed seen")
+        
+# create a simple button
 btn1 = lv.btn(lv.scr_act())
-btn1.set_event_cb(event_handler)
-btn1.align(None, lv.ALIGN.CENTER, 0, -40)
 
-label = lv.label(btn1)
+# attach the callback
+btn1.add_event_cb(event_handler,lv.EVENT.ALL, None)
+
+btn1.align(lv.ALIGN.CENTER,0,-40)
+label=lv.label(btn1)
 label.set_text("Button")
 
+# create a toggle button
 btn2 = lv.btn(lv.scr_act())
-# callback can be lambda:
-btn2.set_event_cb(lambda obj, event: print("Toggled") if event == lv.EVENT.VALUE_CHANGED else None)
-btn2.align(None, lv.ALIGN.CENTER, 0, 40)
-btn2.set_toggle(True)
-btn2.toggle()
-btn2.set_fit2(lv.FIT.NONE, lv.FIT.TIGHT)
 
-label = lv.label(btn2)
-label.set_text("Toggled")
+# attach the callback
+#btn2.add_event_cb(event_handler,lv.EVENT.VALUE_CHANGED,None)
+btn2.add_event_cb(event_handler,lv.EVENT.ALL, None)
+
+btn2.align(lv.ALIGN.CENTER,0,40)
+btn2.add_flag(lv.obj.FLAG.CHECKABLE)
+btn2.set_height(lv.SIZE.CONTENT)
+
+label=lv.label(btn2)
+label.set_text("Toggle")
+label.center()

examples/widgets/btn/lv_example_btn_2.py

@@ -0,0 +1,60 @@
+#
+# Style a button from scratch
+#
+
+# Init the style for the default state
+style = lv.style_t()
+style.init()
+
+style.set_radius(3)
+
+style.set_bg_opa(lv.OPA.COVER)
+style.set_bg_color(lv.palette_main(lv.PALETTE.BLUE))
+style.set_bg_grad_color(lv.palette_darken(lv.PALETTE.BLUE, 2))
+style.set_bg_grad_dir(lv.GRAD_DIR.VER)
+
+style.set_border_opa(lv.OPA._40)
+style.set_border_width(2)
+style.set_border_color(lv.palette_main(lv.PALETTE.GREY))
+
+style.set_shadow_width(8)
+style.set_shadow_color(lv.palette_main(lv.PALETTE.GREY))
+style.set_shadow_ofs_y(8)
+
+style.set_outline_opa(lv.OPA.COVER)
+style.set_outline_color(lv.palette_main(lv.PALETTE.BLUE))
+
+style.set_text_color(lv.color_white())
+style.set_pad_all(10)
+
+# Init the pressed style
+style_pr = lv.style_t()
+style_pr.init()
+
+# Add a large outline when pressed
+style_pr.set_outline_width(30)
+style_pr.set_outline_opa(lv.OPA.TRANSP)
+
+style_pr.set_translate_y(5)
+style_pr.set_shadow_ofs_y(3)
+style_pr.set_bg_color(lv.palette_darken(lv.PALETTE.BLUE, 2))
+style_pr.set_bg_grad_color(lv.palette_darken(lv.PALETTE.BLUE, 4))
+
+# Add a transition to the the outline
+trans = lv.style_transition_dsc_t()
+props = [lv.STYLE.OUTLINE_WIDTH, lv.STYLE.OUTLINE_OPA, 0]
+trans.init(props, lv.anim_t.path_linear, 300, 0, None)
+
+style_pr.set_transition(trans)
+
+btn1 = lv.btn(lv.scr_act())
+btn1.remove_style_all()                          # Remove the style coming from the theme
+btn1.add_style(style, 0)
+btn1.add_style(style_pr, lv.STATE.PRESSED)
+btn1.set_size(lv.SIZE.CONTENT, lv.SIZE.CONTENT)
+btn1.center()
+
+label = lv.label(btn1)
+label.set_text("Button")
+label.center()
+

examples/widgets/btn/lv_example_btn_3.py

@@ -0,0 +1,38 @@
+#
+# Create a style transition on a button to act like a gum when clicked
+#
+
+# Properties to transition
+props = [lv.STYLE.TRANSFORM_WIDTH, lv.STYLE.TRANSFORM_HEIGHT, lv.STYLE.TEXT_LETTER_SPACE, 0]
+
+# Transition descriptor when going back to the default state.
+# Add some delay to be sure the press transition is visible even if the press was very short*/
+transition_dsc_def = lv.style_transition_dsc_t()
+transition_dsc_def.init(props, lv.anim_t.path_overshoot, 250, 100, None)
+
+# Transition descriptor when going to pressed state.
+# No delay, go to pressed state immediately
+transition_dsc_pr = lv.style_transition_dsc_t()
+transition_dsc_pr.init(props, lv.anim_t.path_ease_in_out, 250, 0, None)
+
+# Add only the new transition to the default state
+style_def = lv.style_t()
+style_def.init()
+style_def.set_transition(transition_dsc_def)
+
+# Add the transition and some transformation to the presses state.
+style_pr = lv.style_t()
+style_pr.init()
+style_pr.set_transform_width(10)
+style_pr.set_transform_height(-10)
+style_pr.set_text_letter_space(10)
+style_pr.set_transition(transition_dsc_pr)
+
+btn1 = lv.btn(lv.scr_act())
+btn1.align(lv.ALIGN.CENTER, 0, -80)
+btn1.add_style(style_pr, lv.STATE.PRESSED)
+btn1.add_style(style_def, 0)
+
+label = lv.label(btn1)
+label.set_text("Gum");
+