Python kivy 足球杂耍比赛

Question

I'm making a game in kivy. It's a soccer juggling game where whenever the soccer ball is clicked on the ball moves up and then comes down automatically in a straight line. What I'm trying to do is whenever I click on the left side of the soccer ball I want the ball to move up and move to the right and whenever I click on the right side of the ball I want the ball to move up and move to the left side. How can I do that? any help is very much appreciated! Below is my code!

Also, here's a link to a game similar to the one I'm trying to make https://s3-eu-west-1.amazonaws.com/apps.playcanvas.com/ajGKB8bb/index.html

main.py

from kivy.app import App
from kivy.uix.screenmanager import Screen
from kivy.uix.image import Image
from kivy.core.audio import SoundLoader
from kivy.clock import Clock
from kivy.properties import NumericProperty
from kivy.vector import Vector


class HomeScreen(Screen):
    pass

    def play_sound(self):
        sound = SoundLoader.load('button press sound.wav.')
        if sound:
            sound.play()


sound = SoundLoader.load('Crowd sound effect.wav')
sound.loop = True
sound.play()


class GameScreen(Screen):
    pass

    def play_sound(self):
        sound = SoundLoader.load('button press sound.wav.')
        if sound:
            sound.play()


class Ball(Image):
    velocity = NumericProperty(0)


    def on_touch_down(self, touch):
        if Vector(self.center).distance(touch.pos) <= 33:
            label = App.get_running_app().root.get_screen('game_screen').ids.score
            label.text = str(int(label.text) + 1)
            sound = SoundLoader.load('Soccer ball sound.wav')
            sound.play()
            self.source = "icons/ball.png"
            self.velocity = 275
        return super().on_touch_down(touch)


    def on_touch_up(self, touch):
        if Vector(self.center).distance(touch.pos) <= 33:
            self.source = "icons/ball.png"
        return super().on_touch_up(touch)


class MainApp(App):
    GRAVITY = 300


    def move_ball(self, time_passed):
        ball = self.root.ids.game_screen.ids.ball
        ball.y = ball.y + ball.velocity * time_passed
        ball.velocity = ball.velocity - self.GRAVITY * time_passed
        self.check_collision()

    def check_collision(self):
        ball = self.root.ids.game_screen.ids.ball
        if ball.top < 96:
            self.root.ids.game_screen.ids.score.text = "0"
            self.game_over()


    def game_over(self):
        self.root.ids.game_screen.ids.ball.pos = (0, (0.5) )
        print("game over")
        self.frames.cancel()
        self.root.ids.game_screen.ids.start_button.disabled = False
        self.root.ids.game_screen.ids.start_button.opacity = 1
        self.root.ids.game_screen.ids.over.opacity = 1

    def next_frame(self, time_passed):
        self.move_ball(time_passed)


    def start_game(self):
        #Clock.schedule_interval(self.move_ball, 1/60.)
        self.root.ids.game_screen.ids.ball.velocity = 275
        self.frames = Clock.schedule_interval(self.next_frame, 1/60.)
        self.root.ids.game_screen.ids.score.text = "0"
        self.root.ids.game_screen.ids.over.opacity = 0

    def change_screen(self, screen_name):
        self.root.current = screen_name



MainApp().run()

homescreen.kv

#:import utils kivy.utils
#:import FadeTransition kivy.uix.screenmanager.FadeTransition


<HomeScreen>:
    FloatLayout:
        canvas:
            Color:
                rgb: utils.get_color_from_hex("#39B3F2")
            Rectangle:
                size: self.size
                pos: self.pos
        GridLayout:
            rows: 1
            pos_hint: {"top": 1, "left": 1}
            size_hint: 1, .9
            Image:
                source: "icons/keepyup.png"
        FloatLayout:
            Button:
                font_size: dp(20)
                font_name: 'SackersGothicStd-Medium.otf'
                text: "PLAY"
                color: "gold"
                pos_hint: { "center_x": .5, "center_y": .3}
                size: 80, 55
                size_hint: None, None
                background_normal: ''
                background_color: (57/255.0, 179/255.0, 242/255.0, .10)


                on_press:

                on_release:
                    root.play_sound()
                    root.manager.transition = FadeTransition()
                    app.change_screen("game_screen")

gamescreen.kv

#:import utils kivy.utils


<GameScreen>:
    FloatLayout:
        canvas:
            Color:
                rgb: utils.get_color_from_hex("#39B3F2")
            Rectangle:
                size: self.size
                pos: self.pos
        GridLayout:
            rows: 1
            pos_hint: {"top": 1, "left": 1}
            size_hint: 1, .1
            Image:
                source: "icons/sun.png"
        GridLayout:
            rows: 1
            pos_hint: {"top": 1, "left": 1}
            size_hint: 1, .2
            Image:
                source: "icons/clouds.png"
        GridLayout:
            rows: 1
            pos_hint: {"bottom": 1, "left": 1}
            size_hint: 1, .5
            Image:
                source: "icons/Field4.png"
                allow_stretch: True
                keep_ratio: False
                pos: self.pos

        Label:
            id: score
            size_hint: None, None
            font_size: dp(25)
            font_name: 'SackersGothicStd-Medium.otf'
            text: "0"
            color: "gold"
            pos_hint: { "center_x": 0.1, "center_y": 0.9}



        Label:
            id: over
            size_hint: None, None
            font_size: dp(25)
            font_name: 'SackersGothicStd-Medium.otf'
            text: "GAME OVER!"
            color: "white"
            outline_color: "black"
            outline_width: 1.5
            pos_hint: { "center_x": 0.5, "center_y": 0.6}
            opacity: 0


        Button:
            size_hint: None, None
            font_size: dp(20)
            font_name: 'SackersGothicStd-Medium.otf'
            text: "Start Game"
            color: "gold"
            pos_hint: { "center_x": 0.5, "center_y": 0.3}
            size: 150, 55
            size_hint: None, None
            background_normal: ''
            background_color: (57/255.0, 179/255.0, 242/255.0, .10)
            id: start_button
            on_release:
                self.disabled = True
                self.opacity = 0
                root.play_sound()
                app.start_game()


        Ball:
            source: "icons/ball.png"
            size_hint: None, None
            size: 500, 500
            pos_hint: {"center_x": 0.5}
            id: ball

main.kv

#:include kv/homescreen.kv
#:include kv/gamescreen.kv


ScreenManager:
    id: screen_manager
    HomeScreen:
        name: "home_screen"
        id: home_screen
    GameScreen:
        name: "game_screen"
        id: game_screen

Answer 1

I can't test it but you should check something like self.center.x < touch.pos.x to detect click on right side and set velocity_x

velocity_x = NumericProperty(0)

def on_touch_down(self, touch):
    if Vector(self.center).distance(touch.pos) <= 33:

        if   self.center.x < touch.pos.x:  # click on right side
           self.velocity_x = -0

        elif self.center.x > touch.pos.x:  # click on left side
           self.velocity_x = +10

        else:   # click center
           self.velocity_x = 0

and later use velocity_x to move it

    def move_ball(self, time_passed):
        ball = self.root.ids.game_screen.ids.ball
        ball.y = ball.y + ball.velocity * time_passed

        ball.x = ball.x + ball.velocity_x * time_passed

---

To make simpler to click center you can use some range on both sides - ie. 5 pixels

        if   self.center.x + 5 < touch.pos.x:    # click on right side
           self.velocity_x = -10

        elif self.center.x - 5 > touch.pos.x:  # click on left side
           self.velocity_x = +10

        else:   # click center
           self.velocity_x = 0