问题描述
当互联网关闭时，我收到以下消息。
import pygame
pygame.init()
WIDTH,HEIGHT = 750,500
WINDOW = pygame.display.set_mode((WIDTH,HEIGHT))
pygame.display.set_caption("PONG")
WINNER_FONT = pygame.font.SysFont('comicsans',100)
BLUE = (0,255)
RED = (255,0)
YELLOW = (255,255,0)
WHITE = (255,255)
BLACK = (0,0)
class Paddle(pygame.sprite.Sprite):
def __init__(self):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.Surface([10,75])
self.image.fill(WHITE)
self.rect = self.image.get_rect()
self.paddle_speed = 4
self.points = 0
class Ball(pygame.sprite.Sprite):
def __init__(self):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.Surface([10,10])
self.image.fill(YELLOW)
self.rect = self.image.get_rect()
self.speed = 2
self.dx = 1
self.dy = 1
def init():
global paddle1,paddle2,ball,all_sprites
paddle1 = Paddle()
paddle1.image.fill(BLUE)
paddle1.rect.x = 25
paddle1.rect.y = 225
paddle2 = Paddle()
paddle2.image.fill(RED)
paddle2.rect.x = 715
paddle2.rect.y = 225
ball = Ball()
ball.rect.x = 375
ball.rect.y = 250
all_sprites = pygame.sprite.Group()
all_sprites.add(paddle1,ball)
def redraw():
WINDOW.fill(BLACK)
font = pygame.font.SysFont("Consolas",35)
text = font.render("---[PONG]---",1,YELLOW)
textRect = text.get_rect()
textRect.center = (WIDTH//2,25)
WINDOW.blit(text,textRect)
#Player 1 score
p1_score = font.render(str([paddle1.points]),WHITE)
p1Rect = p1_score.get_rect()
p1Rect.center = (50,50)
WINDOW.blit(p1_score,p1Rect)
#Player 2 score
p2_score = font.render(str([paddle2.points]),WHITE)
p2Rect = p2_score.get_rect()
p2Rect.center = (700,50)
WINDOW.blit(p2_score,p2Rect)
all_sprites.draw(WINDOW)
pygame.display.update()
def draw_winner(text):
draw_text = WINNER_FONT.render(text,WHITE)
WINDOW.blit(draw_text,(WIDTH//2 - draw_text.get_width()/2,HEIGHT//2 - draw_text.get_height()/2))
pygame.display.update()
def main():
init()
winner_text = ""
restart_time = 0
game_over = False
clock = pygame.time.Clock()
run = True
while run:
clock.tick(100)
current_time = pygame.time.get_ticks()
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
pygame.quit()
if not game_over:
if paddle1.points >= 10:
winner_text = "Blue Wins!"
restart_time = current_time + 5000
game_over = True
if paddle2.points >= 10:
winner_text = "Red Wins!"
restart_time = current_time + 5000
game_over = True
if game_over:
draw_winner(winner_text)
if current_time > restart_time:
init()
game_over = False
else:
continue
# Paddle movement
key = pygame.key.get_pressed()
if key[pygame.K_w]:
paddle1.rect.y -= paddle1.paddle_speed
if key[pygame.K_s]:
paddle1.rect.y += paddle1.paddle_speed
if key[pygame.K_UP]:
paddle2.rect.y -= paddle2.paddle_speed
if key[pygame.K_DOWN]:
paddle2.rect.y += paddle2.paddle_speed
# Ensures paddles never move off the screen
if paddle1.rect.y < 0:
paddle1.rect.y = 0
if paddle1.rect.y > 425:
paddle1.rect.y = 425
if paddle2.rect.y < 0:
paddle2.rect.y = 0
if paddle2.rect.y > 425:
paddle2.rect.y = 425
# Ball movement
ball.rect.x += ball.speed * ball.dx
ball.rect.y += ball.speed * ball.dy
# Setting up collision detection with the walls by changing ball's direction
if ball.rect.y > 490:
ball.dy = -1
if ball.rect.x > 740:
ball.rect.x,ball.rect.y = 375,250
paddle1.points += 1
if ball.rect.y < 10:
ball.dy = 1
if ball.rect.x < 10:
ball.rect.x,250
paddle2.points += 1
# Setting up collision detection with the paddles
if paddle1.rect.colliderect(ball.rect):
ball.dx = 1
if paddle2.rect.colliderect(ball.rect):
ball.dx = -1
redraw()
if __name__ == "__main__":
main()
E/Flutter (26162): [ERROR:Flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: This widget has been unmounted,so the State no longer has a context (and should be considered defunct).
E/Flutter (26162): Consider canceling any active work during "dispose" or using the "mounted" getter to determine if the State is still active.
我没有为此使用任何处置方法。如果有人知道，请告诉我如何解决这个问题。如何处置。我的应用程序关闭后收到崩溃报告，如下所示
@override
void initState() {
super.initState();
try {
InternetAddress.lookup('google.com').then((result) {
if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
// internet conn available
Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (context) =>
(Constants.prefsMobile.getString("mobile") == null
? Login()
// : SignupPayoutPassword(signupdata: [])),: Home(signindata: signinData)),));
} else {
// no conn
_showdialog();
}
}).catchError((error) {
// no conn
_showdialog();
});
} on SocketException catch (_) {
// no internet
_showdialog();
}
Connectivity()
.onConnectivityChanged
.listen((ConnectivityResult connresult) {
if (connresult == ConnectivityResult.none) {
} else if (prevIoUs == ConnectivityResult.none) {
// internet conn
Navigator.of(context).pop();
Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (context) =>
(Constants.prefsMobile.getString("mobile") == null
? Login()
: Home(signindata: signinData)),));
}
prevIoUs = connresult;
});
}
这是针对上述问题的崩溃消息吗？请帮忙。
解决方法
请使用。
@override
void dispose() {
Connectivity().onConnectivityChanged.cancel();
super.dispose();
}
最好在 initState 之外定义您的流：
Stream _connectivityStream = Connectivity().onConnectivityChanged;
并在处置中使用 _connectivityStream.cancel();。
该错误意味着您实例化了一个流，该流在事件更改时触发构建更改。此流在 initState 期间设置，这意味着首次创建小部件时。 Connectivity().onConnectivityChanged.listen(....etc)。
但是当小部件被释放时，你永远不会告诉 flutter 取消监听这个流。
这就是dispose方法的作用。类似于您希望在构建小部件时如何执行逻辑，您使用 initState，您也应该在您不再对这些逻辑更改感兴趣时告诉它。
如果不这样做，除了内存泄漏之外，还会导致您遇到的错误。
这是您发布的错误 This widget has been unmounted,so the State no longer has a context (and should be considered defunct). 的翻译。 “哎，这个widget已经不在树中了，它的状态没有mounted，我无法重建它，你需要注意它。
请考虑对这些 Flutter 元素使用 dispose 方法，不要提及所有元素，而是从我的脑海中：
- 动画控制器。
- 计时器。
- 流监听器。