为什么我的游戏从后台返回后无法正常运行？

Question

我正在开发一款即将完成的游戏，但我运行遇到了一个我自己无法解决的问题（老实说，有多个问题，但让我们把它留到其他问题).

我的游戏是这样组织的：MainMenu --> GameScene --> Pause/GameOver Pause 和 GameOver 菜单基本上只是由 Sprite 和 Label 节点组成的叠加层。

在游戏中，有一个玩家需要避免接触每隔 x 时间生成一次的敌人。我通过重复运行永远是一个代码块的 SKAction 来实现这一点。

当游戏暂停时（按下暂停按钮时），它会将布尔值 (isPaused) 更改为 YES，这会导致所有方法停止。它还删除了生成敌人的动作。

游戏重新启动时，它会删除当前存在的所有内容并重新创建整个场景。

问题是：每当我点击暂停按钮时，菜单就会出现，然后然后退出应用程序（只是背景实际上并没有退出）然后回来并按重新启动，敌人不会产生因此动作不会运行（我检查过节点数也没有增加）。

这是一些代码：

我不会把所有东西都放进去，所以如果你发现某些东西引用了不存在的东西，那东西可能在原始代码中就存在。

在GameScene.m中：

-(void)didMoveToView:(SKView *)view {
if (!self.contentCreated) {
    [self createSceneContents];
    self.contentCreated = YES;
    }
   }

-(void)createSceneContents {
self.isTouchingGround = NO;
self.isPaused = NO;
self.world = [SKNode node];
NSLog(@"likewhatever");
self.playerCategory = 1;
self.enemyCategory = 2;
self.edgeCategory = 4;
self.bottomCategory = 8;
self.playerScore = 0;

[GameDataHelper sharedGameData].score = 0;

self.physicsWorld.contactDelegate = self;

SKSpriteNode *bottom = [SKSpriteNode spriteNodeWithColor:[SKColor blackColor] size:CGSizeMake(self.frame.size.width, 10)];
bottom.position = CGPointMake(self.frame.size.width/2, 0);
bottom.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:bottom.size];
bottom.physicsBody.dynamic = NO;
bottom.physicsBody.restitution = 0;
bottom.physicsBody.categoryBitMask = self.bottomCategory;
bottom.physicsBody.contactTestBitMask = self.playerCategory | self.enemyCategory;

SKSpriteNode *left = [[SKSpriteNode alloc]init];
left.size = CGSizeMake(1, self.frame.size.height);
left.position = CGPointMake(0, self.frame.size.height/2);
left.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:left.size];
left.physicsBody.dynamic = NO;
left.physicsBody.restitution = 0;

SKSpriteNode *right  = [[SKSpriteNode alloc]init];
right.size = CGSizeMake(1, self.frame.size.height);
right.position = CGPointMake(self.frame.size.width - 1, self.frame.size.height/2);
right.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:right.size];
right.physicsBody.dynamic = NO;
right.physicsBody.restitution = 0;


self.backgroundColor = [SKColor blackColor];
self.playerData = [[Player alloc]init];
self.customUnit = self.frame.size.width/7;
self.player = [self.playerData newPlayer:self.customUnit];
self.player.physicsBody.categoryBitMask = self.playerCategory;
self.player.physicsBody.contactTestBitMask = self.enemyCategory | self.edgeCategory | self.bottomCategory;
self.player.position = CGPointMake(CGRectGetMidX(self.frame), self.customUnit*5);
[self.playerData movementSetup];

[self createUI];

NSString *path = [NSString stringWithFormat:@"%@/gamemusic2.mp3", [[NSBundle mainBundle]resourcePath]];
NSURL *mainMusicURL = [NSURL fileURLWithPath:path];
self.mainMusicPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:mainMusicURL error:nil];
self.mainMusicPlayer.volume = 0.1;
self.mainMusicPlayer.numberOfLoops = -1;
[self.mainMusicPlayer play];

[self spawnObject];
[self addChild:self.world];
[self.world addChild:bottom];
[self.world addChild:self.player];
[self addChild:left];
[self addChild:right];
[self addChild:self.pause];
[self addChild:self.scoreLabelInGame];
[self addChild:self.actualScore];



}

-(void)createUI {

self.pause = [SKSpriteNode spriteNodeWithImageNamed:@"pausebutton.png"];
self.pause.size = CGSizeMake(self.customUnit,self.customUnit);
self.pause.name = @"pauseButton";
self.pause.position = CGPointMake(30, self.frame.size.height - 30);

self.pausedImage = [SKSpriteNode spriteNodeWithImageNamed:@"paused.png"];
self.pausedImage.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame)*1.5);

self.restart = [SKLabelNode labelNodeWithFontNamed:@"Futura"];
self.restart.text = @"RESTART";
self.restart.fontSize = 25;
self.restart.position = CGPointMake(CGRectGetMidX(self.frame), self.pausedImage.position.y - self.pausedImage.position.y/5);

self.resume = [SKLabelNode labelNodeWithFontNamed:@"Futura"];
self.resume.text = @"RESUME";
self.resume.fontSize = 25;
self.resume.position = CGPointMake(self.restart.position.x, self.restart.position.y - self.customUnit);

self.scoreLabelInGame = [SKLabelNode labelNodeWithFontNamed:@"Futura"];
self.scoreLabelInGame.text = @"";
self.scoreLabelInGame.fontSize = 25;
self.scoreLabelInGame.position = CGPointMake(self.frame.size.width - 100, self.frame.size.height - 40);

self.actualScore = [SKLabelNode labelNodeWithFontNamed:@"Futura"];
self.actualScore.text = @"SCORE: 0";
self.actualScore.fontSize = 25;
self.actualScore.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeRight;
self.actualScore.position = CGPointMake(self.frame.size.width - 20, self.frame.size.height - 40);


self.deathImage = [SKSpriteNode spriteNodeWithImageNamed:@"youdied.png"];
self.deathImage.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame)*1.5);
}

-(void)spawnObject {
NSLog(@"called");
if (self.isPaused == NO){
    NSLog(@"notpaused");
    self.spawningSpeed = 1.5;
    self.enemyData = [[Enemy alloc]init];
    SKAction *wait = [SKAction waitForDuration:self.spawningSpeed];
    SKAction *run = [SKAction runBlock:^{
        NSLog(@"spawned");
        SKSpriteNode *aNewEnemy = [self.enemyData createEnemyWithSize:self.customUnit andWidth:self.frame.size.width andHeight:self.frame.size.height + self.player.position.y];
        aNewEnemy.physicsBody.allowsRotation = NO;
        aNewEnemy.physicsBody.categoryBitMask = self.enemyCategory;
        aNewEnemy.physicsBody.collisionBitMask = self.enemyCategory | self.playerCategory | self.edgeCategory | self.bottomCategory;
        aNewEnemy.physicsBody.contactTestBitMask = self.enemyCategory | self.playerCategory | self.edgeCategory | self.bottomCategory;
        [self.world addChild:aNewEnemy];



    }];
    SKAction *action = [SKAction repeatActionForever:[SKAction sequence:@[wait,run]]];
    [self runAction:action withKey:@"spawn"];




}
}

-(void)didBeginContact:(SKPhysicsContact *)contact {

if (self.isPaused == NO) {

    SKPhysicsBody *firstBody, *secondBody;

    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
        firstBody = contact.bodyA;
        secondBody = contact.bodyB;
    }else {
        firstBody = contact.bodyB;
        secondBody = contact.bodyA;
    }
    if (firstBody.categoryBitMask == self.playerCategory && secondBody.categoryBitMask == self.bottomCategory) {
        self.isTouchingGround = YES;
    }
    if (firstBody.categoryBitMask == self.playerCategory && secondBody.categoryBitMask == self.enemyCategory) {
        self.isTouchingGround = YES;
        if ([secondBody.node.name isEqualToString:@"fallingEnemy"] && self.player.position.y < secondBody.node.position.y) {
           [self gameOver];
        }
    }

    if (firstBody.categoryBitMask == self.enemyCategory && secondBody.categoryBitMask == self.enemyCategory) {

        [self.enemyData changeBlock:firstBody.node];
        [self.enemyData changeBlock:secondBody.node];
        [self impactSound];

        [self updateScore];

        NSLog(@"Change1");
    }
    if (firstBody.categoryBitMask == self.enemyCategory && secondBody.categoryBitMask == self.bottomCategory) {
        NSLog(@"Change2");
        [self.enemyData changeBlock:firstBody.node];
        [self impactSound];

        [self updateScore];

    }





}
}

-(void)pauseGame {
NSLog(@"Pausing...");
[self removeActionForKey:@"spawn"];
[self addChild:self.pausedImage];
[self addChild:self.restart];
[self addChild:self.resume];

NSString *path = [NSString stringWithFormat:@"%@/menu_music.mp3", [[NSBundle mainBundle]resourcePath]];
NSURL *pauseMusicURL = [NSURL fileURLWithPath:path];
self.pauseMusicPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:pauseMusicURL error:nil];
self.pauseMusicPlayer.numberOfLoops = -1;
[self.pauseMusicPlayer play];

[self.pause removeFromParent];
self.scoreLabelInGame.position = CGPointMake(self.restart.position.x, self.resume.position.y - self.customUnit);
self.actualScore.position = CGPointMake(self.restart.position.x, self.scoreLabelInGame.position.y - self.customUnit);
self.isPaused = YES;
[self.mainMusicPlayer pause];
}

-(void)restartGame {
[self removeAllChildren];
[self removeAllActions];
self.isPaused = NO;
[self.pauseMusicPlayer stop];
[self createSceneContents];
}

-(void)resumeGame {
self.isPaused = NO;
[self.pauseMusicPlayer stop];
[self spawnObject];
self.scoreLabelInGame.position = CGPointMake(self.frame.size.width - 100, self.frame.size.height - 40);
self.actualScore.position = CGPointMake(self.frame.size.width - 20, self.frame.size.height - 40);
[self.mainMusicPlayer play];
[self.restart removeFromParent];
[self.resume removeFromParent];
[self.pausedImage removeFromParent];
[self addChild:self.pause];

}

-(void)gameOver {
NSLog(@"Game Over");
GameDataHelper *gameData = [[GameDataHelper alloc]init];

[self removeActionForKey:@"spawn"];
[self addChild:self.restart];
[self addChild:self.deathImage];
SKAction *gameOverSound = [SKAction playSoundFileNamed:@"gameover_tune.mp3" waitForCompletion:NO];
[self runAction:gameOverSound];

NSString *path = [NSString stringWithFormat:@"%@/menu_music.mp3", [[NSBundle mainBundle]resourcePath]];
NSURL *pauseMusicURL = [NSURL fileURLWithPath:path];
self.pauseMusicPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:pauseMusicURL error:nil];
self.pauseMusicPlayer.numberOfLoops = -1;
[self.pauseMusicPlayer play];
[self.pause removeFromParent];

SKLabelNode *highScore = [SKLabelNode labelNodeWithFontNamed:@"Futura"];
NSString *highScoreText = [NSString stringWithFormat:@"HIGHSCORE: %ld",[GameDataHelper sharedGameData].highScore];
highScore.text = highScoreText;
highScore.fontSize = 25;
highScore.position = CGPointMake(self.frame.size.width/2, self.restart.position.y - (2*self.customUnit));
[self addChild:highScore];

self.scoreLabelInGame.position = CGPointMake(self.restart.position.x, self.resume.position.y - self.customUnit);
self.actualScore.position = CGPointMake(self.restart.position.x, self.scoreLabelInGame.position.y - self.customUnit);
self.isPaused = YES;
[self.mainMusicPlayer pause];
   [gameData save];
}

在Enemy.m中：

-(SKSpriteNode *)createEnemyWithSize:(float)size andWidth:(float)width andHeight:(float)height {
self.enemy = [SKSpriteNode spriteNodeWithImageNamed:@"block.png"];
self.enemy.size = CGSizeMake(size - 5, size - 5);
self.enemy.name = @"fallingEnemy";
self.enemy.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(size - 3, size - 3)];
self.enemy.physicsBody.restitution = 0;
self.enemy.physicsBody.allowsRotation = NO;
int randomSection = arc4random_uniform(7);
switch (randomSection) {
    case 0:

        self.enemy.position = CGPointMake(2.5 + self.enemy.size.width/2, height-5);

        break;
    case 1:


        self.enemy.position = CGPointMake(width/7 + self.enemy.size.width/2, height-5);

        break;
    case 2:

        self.enemy.position = CGPointMake((width/7*2)  + self.enemy.size.width/2, height-5);

        break;
    case 3:

        self.enemy.position = CGPointMake((width/7*3)  + self.enemy.size.width/2, height-5);

        break;
    case 4:

        self.enemy.position = CGPointMake((width/7*4)  + self.enemy.size.width/2, height-5);

        break;
    case 5:

        self.enemy.position = CGPointMake((width/7*5)  + self.enemy.size.width/2, height-5);

        break;
    case 6:

        self.enemy.position = CGPointMake((width/7*6)  + self.enemy.size.width/2, height-5);


        break;
    default:

        break;
}


return self.enemy;
}

-(void)changeBlock:(SKNode *)block{
    block.physicsBody.dynamic = NO;
    block.name = @"staticEnemy";



}

Answer 1

我遇到了与您非常相似的问题（并注意到您的其他问题性质相似）。我很幸运能够解决这个问题，希望我能为您提供一些见解。

我的情况： 我正在创建一个基于物理的游戏，它使用粒子发射器和 SKActions 来处理游戏的某些方面。但是，我注意到这些 "broke" 从非活动状态返回时；那就是粒子发射器没有显示任何东西，尽管所有属性在进入背景之前和之后都是相同的，并且 SKActions 不工作，即使它们在从非活动状态返回后被初始化。和你一样，我使用自定义“isPaused”变量来维护游戏状态。

我的解决方案： 将“isPaused”标志的名称更改为类似“gameIsPaused”的名称。

为什么？ 我的研究使我相信它与场景如何保持其子级以及 SpriteKit 进入背景时的行为的某种组合有关。虽然 Apple 没有公布引擎盖下发生的事情，但各种论坛似乎表明 SpriteKit 会在应用程序不活动时自动暂停场景。

但是，通过拥有自己的 "isPaused" 变量，我认为您正在踩踏一些导致错误的幕后流程。

其他利用 NSNotification 中心 (What is causing my SKAction timer to behave strangely?) 的解决方案通过重命名“isPaused”标志按预期工作。

为什么我的游戏从后台返回后无法正常运行？

Why does my game not function properly after returning from the background?

objective-c

ios

sprite-kit