问题
I'm trying have a grid layout, that I can have on item foucsed, and I can navigate using the arrow keys (up/down and left/right). the idea is for a leanback expireance application (i.e. android tv, or a home media center), with no touch or mouse.
I'm trying to reuse the FocusBehavior and CompoundSelectionBehavior for that I have something that is almost there, but I can't figure out how do I shift the selection to the next row, left/right keep on the first row that I've click with the mouse, and doesn't move.
from kivy.uix.behaviors.compoundselection import CompoundSelectionBehavior
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.app import App
class SelectableBoxLayout(FocusBehavior, CompoundSelectionBehavior, BoxLayout):
def keyboard_on_key_down(self, window, keycode, text, modifiers):
"""Based on FocusBehavior that provides automatic keyboard
access, key presses will be used to select children.
"""
print(keycode, text, modifiers)
print(self.orientation)
if super(SelectableBoxLayout, self).keyboard_on_key_down(
window, keycode, text, modifiers):
return True
if self.orientation == 'horizontal' and keycode[1] in ['up', 'down']:
self.clear_selection()
return self.parent.keyboard_on_key_down(window, keycode, text, modifiers)
if self.select_with_key_down(window, keycode, text, modifiers):
return True
return False
def keyboard_on_key_up(self, window, keycode):
"""Based on FocusBehavior that provides automatic keyboard
access, key release will be used to select children.
"""
if super(SelectableBoxLayout, self).keyboard_on_key_up(window, keycode):
return True
if self.orientation == 'horizontal' and keycode[1] in ['up', 'down']:
self.clear_selection()
return self.parent.keyboard_on_key_up(window, keycode)
if self.select_with_key_up(window, keycode):
return True
return False
def add_widget(self, widget):
""" Override the adding of widgets so we can bind and catch their
*on_touch_down* events. """
widget.bind(on_touch_down=self.button_touch_down,
on_touch_up=self.button_touch_up)
return super(SelectableBoxLayout, self).add_widget(widget)
def button_touch_down(self, button, touch):
""" Use collision detection to select buttons when the touch occurs
within their area. """
if button.collide_point(*touch.pos):
self.select_with_touch(button, touch)
def button_touch_up(self, button, touch):
""" Use collision detection to de-select buttons when the touch
occurs outside their area and *touch_multiselect* is not True. """
if not (button.collide_point(*touch.pos) or
self.touch_multiselect):
self.deselect_node(button)
def select_node(self, node):
node.background_color = (1, 0, 0, 1)
return super(SelectableBoxLayout, self).select_node(node)
def deselect_node(self, node):
node.background_color = (1, 1, 1, 1)
super(SelectableBoxLayout, self).deselect_node(node)
def on_selected_nodes(self, gird, nodes):
print("Selected nodes = {0}".format(nodes))
if self.orientation == 'vertical':
if nodes:
row = nodes[0]
row.clear_selection()
node_src, idx_src = row._resolve_last_node()
text = 'left'
node, idx = row.goto_node(text, node_src, idx_src)
row.select_node(node)
class TestApp(App):
def build(self):
grid = SelectableBoxLayout(orientation='vertical', touch_multiselect=False,
multiselect=False)
for i in range(0, 6):
row = SelectableBoxLayout(orientation='horizontal', touch_multiselect=False,
multiselect=False)
for j in range(0,5):
b = Button(text="Button {0}".format(j))
row.add_widget(b)
grid.add_widget(row)
row.get_focus_next().focus = True
return grid
TestApp().run()
回答1:
Took me a while debugging, but here's a working example:
from kivy.uix.behaviors.compoundselection import CompoundSelectionBehavior
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.app import App
class SelectableBoxLayout(FocusBehavior, CompoundSelectionBehavior, BoxLayout):
def keyboard_on_key_down(self, window, keycode, text, modifiers):
"""Based on FocusBehavior that provides automatic keyboard
access, key presses will be used to select children.
"""
print(keycode, text, modifiers)
print(self.orientation)
if super(SelectableBoxLayout, self).keyboard_on_key_down(
window, keycode, text, modifiers):
return True
if self.orientation == 'horizontal' and keycode[1] in ['up', 'down']:
self.clear_selection()
return self.parent.keyboard_on_key_down(window, keycode, text, modifiers)
if self.orientation == 'vertical' and keycode[1] in ['up', 'down']:
direction = 'focus_next' if keycode[1] == 'down' else 'focus_previous'
if self.selected_nodes:
next_row = self.selected_nodes[0]._get_focus_next(direction)
else:
next_row = self.children[-1]
self.clear_selection()
self.select_node(next_row)
if next_row:
next_row.focus = True
next = next_row.children[-1]
if next and not isinstance(next, SelectableBoxLayout):
print("moving to {0}".format(next))
next.focus = True
next_row.clear_selection()
next_row.select_node(next)
return True
if self.select_with_key_down(window, keycode, text, modifiers):
return True
return False
def keyboard_on_key_up(self, window, keycode):
"""Based on FocusBehavior that provides automatic keyboard
access, key release will be used to select children.
"""
if super(SelectableBoxLayout, self).keyboard_on_key_up(window, keycode):
return True
if self.orientation == 'horizontal' and keycode[1] in ['up', 'down']:
return self.parent.keyboard_on_key_up(window, keycode)
if self.select_with_key_up(window, keycode):
return True
return False
def add_widget(self, widget, index=0):
""" Override the adding of widgets so we can bind and catch their
*on_touch_down* events. """
widget.bind(on_touch_down=self.button_touch_down,
on_touch_up=self.button_touch_up)
return super(SelectableBoxLayout, self).add_widget(widget, index)
def button_touch_down(self, button, touch):
""" Use collision detection to select buttons when the touch occurs
within their area. """
if button.collide_point(*touch.pos):
self.select_with_touch(button, touch)
def button_touch_up(self, button, touch):
""" Use collision detection to de-select buttons when the touch
occurs outside their area and *touch_multiselect* is not True. """
if not (button.collide_point(*touch.pos) or
self.touch_multiselect):
self.deselect_node(button)
def select_node(self, node):
node.background_color = (1, 0, 0, 1)
print("select: {}".format(getattr(node, 'text', 'none')))
return super(SelectableBoxLayout, self).select_node(node)
def deselect_node(self, node):
node.background_color = (1, 1, 1, 1)
print("deselect: {}".format(getattr(node, 'text', 'none')))
super(SelectableBoxLayout, self).deselect_node(node)
def on_selected_nodes(self, grid, nodes):
pass
class TestingappApp(App):
"""Basic kivy app
Edit testingapp.kv to get started.
"""
def build(self):
grid = SelectableBoxLayout(orientation='vertical', touch_multiselect=False,
multiselect=False)
for i in range(0, 6):
row = SelectableBoxLayout(orientation='horizontal', touch_multiselect=False,
multiselect=False)
for j in range(0,5):
b = Button(text="Event A\n TT {}{}".format(i, j))
row.add_widget(b)
grid.add_widget(row)
row.get_focus_next().focus = True
return grid
来源：https://stackoverflow.com/questions/47212144/scrolling-and-focus-with-arrow-keys