Kivy : How to select item in RecycleView using `up` and `down` key?

Question

How to select item using up and down keyboard key in RecycleView?

test.py

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.recycleview import RecycleView
from kivy.core.window import Window

Builder.load_string('''
<RV>:
    viewclass: 'Label'
    RecycleBoxLayout:
        default_size: None, dp(56)
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        orientation: 'vertical'
''')

class RV(RecycleView):
    def __init__(self, **kwargs):
        super(RV, self).__init__(**kwargs)
        self._keyboard = Window.request_keyboard(self._keyboard_closed, self)
        self._keyboard.bind(on_key_down=self._on_keyboard_down)
        self.data = [{'text': str(x)} for x in range(10)]

    def _keyboard_closed(self):
        pass

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        if keycode[1] == 'down':
            print('down')
        elif keycode[1] == 'up':
            print("up")


class TestApp(App):
    def build(self):
        return RV()

if __name__ == '__main__':
    TestApp().run()

Answer 1

Based on tomasantunes' solution, but contains auto-scrolling and the bug is fixed (when Kivy crashes when an item out of the box is selected)

from kivy.app import App
from kivy.core.window import Window
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.button import Button
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.recycleview import RecycleView
from kivy.uix.image import Image
from kivy.graphics import Color, Rectangle
from kivy.animation import Animation
from kivy.clock import Clock
from kivy.properties import BooleanProperty
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior

import subprocess
import time


Builder.load_string(
    """
<SelectableLabel>:
    # Draw a background to indicate selection
    color: (0.0, 0.0, 0.0, 0.9) if self.selected else (1.0, 1.0, 1.0, 1.0)
    canvas.before:
        Color:
            rgba: (0.9, 0.6, 0.0, 1.0) if self.selected else (0.0, 0.0, 0.0, 1.0)
        Rectangle:
            pos: self.pos
            size: self.size

<RV>:
    viewclass: 'SelectableLabel'
    scroll_y: 0
    effect_cls: "ScrollEffect" 
    SelectableRecycleBoxLayout:
        id: box
        default_size: 360, dp(56)
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        orientation: 'vertical'
        multiselect: False
        touch_multiselect: False
"""
)


class SelectableRecycleBoxLayout(
    FocusBehavior, LayoutSelectionBehavior, RecycleBoxLayout
):
    """ Adds selection and focus behaviour to the view. """


class SelectableLabel(RecycleDataViewBehavior, Label):
    """ Add selection support to the Label """

    index = None
    selected = BooleanProperty(False)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self, rv, index, data):
        """ Catch and handle the view changes """
        self.index = index
        return super(SelectableLabel, self).refresh_view_attrs(rv, index, data)

    def apply_selection(self, rv, index, is_selected):
        """ Respond to the selection of items in the view. """
        self.selected = is_selected
        if is_selected:
            print("selection changed to {0}".format(rv.data[index]))
        else:
            print("selection removed for {0}".format(rv.data[index]))


class RV(RecycleView):
    def __init__(self, **kwargs):
        super(RV, self).__init__(**kwargs)
        cells = list(Cell.all('wlan0'))

        self.data = [
            {
                "text": "Item " + str(x),
                "markup": "True",
                "font_size": "30px",
            }
            for x in range(100)
        ]
        self.selectedItem = -1
        self.scroll_y = 1

    def nextItem(self):
        if self.selectedItem < len(self.data) - 1:
            self.selectedItem += 1
        else:
            return
  
        self.scroll_to_index(self.selectedItem)
        self.ids.box.select_node(self.selectedItem)
        print(self.selectedItem)

    def prevItem(self):
        if self.selectedItem > 0:
            self.selectedItem -= 1
        else:
            return
        
        self.scroll_to_index(self.selectedItem)
        self.ids.box.select_node(self.selectedItem)
        print(self.selectedItem)

    def selectItem(self, index):
        self.selectedItem = index
        self.scroll_to_index(self.selectedItem)
        self.ids.box.select_node(index)

    def scroll_to_index(self, index):
        box = self.children[0]
        pos_index = (box.default_size[1] + box.spacing) * index
        scroll = self.convert_distance_to_scroll(
            0, pos_index - (self.height * 0.5))[1]
        if scroll > 1.0:
            scroll = 1.0
        elif scroll < 0.0:
            scroll = 0.0
        self.scroll_y = 1.0 - scroll

class ConnectScreen(Screen):
    def __init__(self, **kwargs):
        super(ConnectScreen, self).__init__(**kwargs)
        layout = FloatLayout()
        
        self.wifiList = RV()

        layout.add_widget(self.wifiList)
        self.add_widget(layout)
        return None

    def nextItem(self):
        self.wifiList.nextItem()

    def prevItem(self):
        self.wifiList.prevItem()

    def selectItem(self, index):
        self.wifiList.selectItem(index)


connectScreen = ConnectScreen(name="connect")

sm = ScreenManager()
sm.add_widget(connectScreen)

class PasswordApp(App):
    # Build
    def build(self):
        self._keyboard = Window.request_keyboard(
            self._keyboard_closed, self.root, "text"
        )
        self._keyboard.bind(on_key_down=self._on_keyboard_down)

        # Window.show_cursor = False

        return sm

    # Keyboard Down Event
    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        if keycode[1] == "f10":
            App.get_running_app().stop()
        elif keycode[1] == "down":
            connectScreen.nextItem()
        elif keycode[1] == "up":
            connectScreen.prevItem()

    # Keyboard Closed Event
    def _keyboard_closed(self):
        elf._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

PasswordApp().run()

Answer 2

I have implemented a few methods in the class SelectableRecycleGridLayout to make use of methods in the class LayoutSelectionBehavior. Please refer to the test plans, concerns, example, and output for details.

Test Plans

1. Clicked Test, RecycleView displayed and first row highlighted.
2. Press down arrow key, next row highlighted.
3. At last row, press down arrow key, the first row highligthed.
4. Press up arrow key, previous row hightlighted.
5. At first row, press up arrow key, last row highlighted.
6. Press Ctrl + e, Popup window display informations of highlighted row.
7. Mouse click on any row that is not highlighted, the mouse clicked row is selected, and Popup window open.
8. After Popup dismiss, keyboard events still works!

Example

main.py

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import BooleanProperty, ListProperty, ObjectProperty, NumericProperty, DictProperty
from kivy.lang import Builder

from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.button import Button
from kivy.uix.recyclegridlayout import RecycleGridLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior
from kivy.uix.popup import Popup
from kivy.core.window import Window
from kivy.clock import Clock

Window.size = (600, 325)


class EditStatePopup(Popup):
    col_data = ListProperty(["?", "?"])

    def __init__(self, obj, **kwargs):
        super(EditStatePopup, self).__init__(**kwargs)
        self.col_data[0] = obj["Id"]
        self.col_data[1] = obj["Name"]


class SelectableRecycleGridLayout(FocusBehavior, LayoutSelectionBehavior,
                                  RecycleGridLayout):
    ''' Adds selection and focus behaviour to the view. '''

    selected_row = NumericProperty(0)

    def get_nodes(self):
        nodes = self.get_selectable_nodes()
        if self.nodes_order_reversed:
            nodes = nodes[::-1]
        if not nodes:
            return None, None

        selected = self.selected_nodes
        if not selected:    # nothing selected, select the first
            self.select_node(nodes[0])
            self.selected_row = 0
            return None, None

        if len(nodes) == 1:     # the only selectable node is selected already
            return None, None

        last = nodes.index(selected[-1])
        self.clear_selection()
        return last, nodes

    def select_next(self):
        ''' Select next row '''
        last, nodes = self.get_nodes()
        if not nodes:
            return

        if last == len(nodes) - 1:
            self.select_node(nodes[0])
            self.selected_row = nodes[0]
        else:
            self.select_node(nodes[last + 1])
            self.selected_row = nodes[last + 1]

    def select_previous(self):
        ''' Select previous row '''
        last, nodes = self.get_nodes()
        if not nodes:
            return

        if not last:
            self.select_node(nodes[-1])
            self.selected_row = nodes[-1]
        else:
            self.select_node(nodes[last - 1])
            self.selected_row = nodes[last - 1]

    def select_current(self):
        ''' Select current row '''
        last, nodes = self.get_nodes()
        if not nodes:
            return

        self.select_node(nodes[self.selected_row])


class SelectableButton(RecycleDataViewBehavior, Button):
    ''' Add selection support to the Button '''
    index = None
    selected = BooleanProperty(False)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self, rv, index, data):
        ''' Catch and handle the view changes '''

        self.index = index
        return super(SelectableButton, self).refresh_view_attrs(rv, index, data)

    def on_touch_down(self, touch):
        ''' Add selection on touch down '''
        if super(SelectableButton, self).on_touch_down(touch):
            return True
        if self.collide_point(*touch.pos) and self.selectable:
            print("on_touch_down: self=", self)
            return self.parent.select_with_touch(self.index, touch)

    def apply_selection(self, rv, index, is_selected):
        ''' Respond to the selection of items in the view. '''
        self.selected = is_selected


class RV(BoxLayout):
    data_items = ListProperty([])
    row_data = DictProperty({})
    col1_data = ListProperty([])
    col2_data = ListProperty([])
    col1_row_controller = ObjectProperty(None)
    col2_row_controller = ObjectProperty(None)

    def __init__(self, **kwargs):
        super(RV, self).__init__(**kwargs)
        self.get_states()
        Clock.schedule_once(self.set_default_first_row, .0005)
        self._request_keyboard()

    def _request_keyboard(self):
        self._keyboard = Window.request_keyboard(
            self._keyboard_closed, self, 'text'
        )
        if self._keyboard.widget:
            # If it exists, this widget is a VKeyboard object which you can use
            # to change the keyboard layout.
            pass
        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def _keyboard_closed(self):
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        if keycode[1] == 'down':    # keycode[274, 'down'] pressed
            # Respond to keyboard down arrow pressed
            self.display_keystrokes(keyboard, keycode, text, modifiers)
            self.col1_row_controller.select_next()
            self.col2_row_controller.select_next()

        elif keycode[1] == 'up':    # keycode[273, 'up] pressed
            # Respond to keyboard up arrow pressed
            self.display_keystrokes(keyboard, keycode, text, modifiers)
            self.col1_row_controller.select_previous()
            self.col2_row_controller.select_previous()

        elif len(modifiers) > 0 and modifiers[0] == 'ctrl' and text == 'e':     # ctrl + e pressed
            # Respond to keyboard ctrl + e pressed, and call Popup
            self.display_keystrokes(keyboard, keycode, text, modifiers)
            keyboard.release()
            self.on_keyboard_select()

        # Keycode is composed of an integer + a string
        # If we hit escape, release the keyboard
        if keycode[1] == 'escape':
            keyboard.release()

        # Return True to accept the key. Otherwise, it will be used by
        # the system.
        return True

    def display_keystrokes(self, keyboard, keycode, text, modifiers):
        print("\nThe key", keycode, "have been pressed")
        print(" - text is %r" % text)
        print(" - modifiers are %r" % modifiers)

    def on_keyboard_select(self):
        ''' Respond to keyboard event to call Popup '''

        # setup row data for Popup
        self.row_data = self.col1_data[self.col1_row_controller.selected_row]

        # call Popup
        self.popup_callback()

    def on_mouse_select(self, instance):
        ''' Respond to mouse event to call Popup '''

        if (self.col1_row_controller.selected_row != instance.index
                or self.col2_row_controller.selected_row != instance.index):
            # Mouse clicked on row is not equal to current selected row
            self.col1_row_controller.selected_row = instance.index
            self.col2_row_controller.selected_row = instance.index

            # Hightlight mouse clicked/selected row
            self.col1_row_controller.select_current()
            self.col2_row_controller.select_current()

        # setup row data for Popup
        # we can use either col1_data or col2_data because they are duplicate and each stores the same info
        self.row_data = self.col1_data[instance.index]

        # call Popup
        self.popup_callback()

    def popup_callback(self):
        ''' Instantiate and Open Popup '''
        popup = EditStatePopup(self.row_data)
        popup.open()

        # enable keyboard request
        self._request_keyboard()

    def set_default_first_row(self, dt):
        ''' Set default first row as selected '''
        self.col1_row_controller.select_next()
        self.col2_row_controller.select_next()

    def update(self):
        self.col1_data = [{'text': str(x[0]), 'Id': str(x[0]), 'Name': x[1], 'key': 'Id', 'selectable': True}
                          for x in self.data_items]

        self.col2_data = [{'text': x[1], 'Id': str(x[0]), 'Name': x[1], 'key': 'Name', 'selectable': True}
                          for x in self.data_items]

    def get_states(self):
        rows = [(1, 'Test1'), (2, 'Test2'), (3, 'Test3')]

        i = 0
        for row in rows:
            self.data_items.append([row[0], row[1], i])
            i += 1
        print(self.data_items)
        self.update()


class MainMenu(BoxLayout):
    states_cities_or_areas = ObjectProperty(None)
    rv = ObjectProperty(None)

    def display_states(self):
        self.remove_widgets()
        self.rv = RV()
        self.states_cities_or_areas.add_widget(self.rv)

    def remove_widgets(self):
        self.states_cities_or_areas.clear_widgets()


class FactApp(App):
    title = "test"

    def build(self):
        self.root = Builder.load_file('test.kv')
        return MainMenu()


if __name__ == '__main__':
    FactApp().run()

test.kv

#:kivy 1.10.0

<EditStatePopup>:
    size_hint: None, None
    title_size: 20
    title_font: "Verdana"
    size: 400, 275
    auto_dismiss: False

    BoxLayout:
        orientation: "vertical"
        GridLayout:
            cols: 2
            #background_color: 0, 0.517, 0.705, 1
            spacing: 10, 10
            padding: 20, 20
            Label:
                text: "Id"
                text_size: self.size
            Label:
                text: root.col_data[0]
                text_size: self.size
            Label:
                text: "Name"
                text_size: self.size
                valign: 'middle'
            TextInput:
                text: root.col_data[1]
                text_size: self.size
                focus: True
        BoxLayout:
            Button:
                size_hint: 1, 0.4
                text: "Save Changes"
                on_release:
                    root.dismiss()
            Button:
                size_hint: 1, 0.4
                text: "Cancel Changes"
                on_release: root.dismiss()


<SelectableButton>:
    canvas.before:
        Color:
            rgba: (0, 0.517, 0.705, 1) if self.selected else (0, 0.517, 0.705, 1)
        Rectangle:
            pos: self.pos
            size: self.size
    background_color: [1, 0, 0, 1]  if self.selected else [1, 1, 1, 1]  # dark red else dark grey
    on_press: app.root.rv.on_mouse_select(self)


<RV>:
    col1_row_controller: col1_row_controller
    col2_row_controller: col2_row_controller

    orientation: "vertical"

    GridLayout:
        size_hint: 1, None
        size_hint_y: None
        height: 25
        cols: 3

        Label:
            size_hint_x: .1
            text: "Id"
        Label:
            size_hint_x: .5
            text: "Name"

    BoxLayout:
        RecycleView:
            size_hint_x: .1
            data: root.col1_data
            viewclass: 'SelectableButton'
            SelectableRecycleGridLayout:
                id: col1_row_controller
                key_selection: 'selectable'
                cols: 1
                default_size: None, dp(26)
                default_size_hint: 1, None
                size_hint_y: None
                height: self.minimum_height
                orientation: 'vertical'
                multiselect: True
                touch_multiselect: True

        RecycleView:
            size_hint_x: .5
            data: root.col2_data
            viewclass: 'SelectableButton'
            SelectableRecycleGridLayout:
                id: col2_row_controller
                key_selection: 'selectable'
                cols: 1
                default_size: None, dp(26)
                default_size_hint: 1, None
                size_hint_y: None
                height: self.minimum_height
                orientation: 'vertical'
                multiselect: True
                touch_multiselect: True


<MenuButton@Button>:
    text_size: self.size
    valign: "middle"
    padding_x: 5
    size : (80,30)
    size_hint : (None, None)
    background_color: 90 , 90, 90, 90
    background_normal: ''
    color: 0, 0.517, 0.705, 1
    border: (0, 10, 0, 0)


<MainMenu>:
    states_cities_or_areas: states_cities_or_areas

    BoxLayout:
        orientation: 'vertical'
        #spacing : 10

        BoxLayout:
            canvas.before:
                Rectangle:
                    pos: self.pos
                    size: self.size

            size_hint_y: 1

            MenuButton:
                id: btn
                text: 'Test'
                size : (60,30)
                on_release: root.display_states()


        BoxLayout:
            canvas.before:
                Rectangle:
                    pos: self.pos
                    size: self.size

                Color:
                    rgb: (1,1,1)

            Label:
                size_hint_x: 45

        BoxLayout:
            id: states_cities_or_areas
            size_hint_y: 10

        Label:
            size_hint_y: 1

Output

Answer 3

You need to create the SelectableLabel class and update the current label

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.recycleview import RecycleView
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.label import Label
from kivy.properties import BooleanProperty
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior
from kivy.core.window import Window

Builder.load_string('''
<RV>:
    viewclass: 'SelectableLabel'
    RecycleBoxLayout:
        default_size: None, dp(56)
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        orientation: 'vertical'
        multiselect: False

<SelectableLabel>:
    # Draw a background to indicate selection
    canvas.before:
        Color:
            rgba: (.0, 0.9, .1, .3) if self.selected else (0, 0, 0, 1)
        Rectangle:
            pos: self.pos
            size: self.size
''')

class SelectableLabel(RecycleDataViewBehavior, Label):
    ''' Add selection support to the Label '''
    index = None
    selected = BooleanProperty(False)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self, rv, index, data):
        ''' Catch and handle the view changes '''
        self.index = index
        return super(SelectableLabel, self).refresh_view_attrs(
            rv, index, data)


    def apply_selection(self, rv, index, is_selected):
        ''' Respond to the selection of items in the view. '''
        self.selected = is_selected
        if is_selected:
            print("selection changed to {0}".format(rv.data[index]))
        else:
            print("selection removed for {0}".format(rv.data[index]))

class RV(RecycleView):
    def __init__(self, **kwargs):
        super(RV, self).__init__(**kwargs)
        self._keyboard = Window.request_keyboard(self._keyboard_closed, self)
        self._keyboard.bind(on_key_down=self._on_keyboard_down)
        self.data = [{'text': str(x)} for x in range(10)]
        self.selectedItem = -1

    def _keyboard_closed(self):
        pass

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        print()
        if keycode[1] == 'down':
            self.clearAll()
            self.nextItem()
            print('down')
        elif keycode[1] == 'up':
            self.clearAll()
            self.prevItem()
            print("up")

    def clearAll(self):
        if (self.selectedItem > -1):
            for i in range(len(self.view_adapter.views) - 1):
                self.view_adapter.views[self.selectedItem].selected = 0


    def nextItem(self):
        if self.selectedItem < len(self.data) - 1:
            self.selectedItem += 1
        else:
            self.selectedItem = 0
        self.view_adapter.views[self.selectedItem].selected = 1
        print(self.selectedItem)


    def prevItem(self):     
        if self.selectedItem > 0:
            self.selectedItem -= 1
        else:
            self.selectedItem = len(self.data) - 1
        self.view_adapter.views[self.selectedItem].selected = 1
        print(self.selectedItem)


class TestApp(App):
    def build(self):
        return RV()

if __name__ == '__main__':
    TestApp().run()