ios - 暂停返回后滚动 BG 丢失(iOS-SpriteKit-iphone)

Question

我在 Objective C Sprite Kit 框架中开发的游戏的滚动背景 (WAVE) 有问题。我正在使用“iOS 游戏教程”一书中的方法(强烈推荐 - 非常有用的书)作为指南，因为我是新手。

我一切正常，但在我关闭游戏后......我的 iPhone 已经坐了大约 20-30 分钟 - 我回到游戏时滚动 BG 空白了 5-15 秒然后它加载和滚动。奇怪的是，当我第一次测试游戏时 - 它立即加载没有问题。我也有节点/图形，它们每次都能快速加载，没有任何问题。

这是每帧更新的主要代码片段:

- (void)moveWave
{

    CGPoint waveVelocity = CGPointMake(-wave_speed, 0);
    CGPoint amtToMove = CGPointMultiplyScalar(waveVelocity, _dt);
    _waveLayer.position = CGPointAdd(_waveLayer.position, amtToMove);

    [_waveLayer enumerateChildNodesWithName:@"wave"
                               usingBlock:^(SKNode *node, BOOL *stop){
                                   SKSpriteNode * wave = (SKSpriteNode *) node;
                                   CGPoint waveScreenPos = [_waveLayer convertPoint:wave.position
                                                                         toNode:self];
                                   if (waveScreenPos.x <= -wave.size.width) {
                                       wave.position = CGPointMake(wave.position.x+wave.size.width*2,
                                                                 wave.position.y);
                                   }
                               }];

}

---

关于为什么回到 iPhone 闲置 20 分钟然后重新加载游戏的任何帮助或见解，只有滚动 BG 丢失但在 5-15 秒后，它开始并且看起来很好。同样，当我第一次加载它时......或退出 5 分钟然后返回游戏......一切正常并立即加载。

编辑 - 我知道这是滚动功能/方法，因为我尝试过不滚动就加载 BG 图像，即使在我退出游戏 20 多分钟后再回来时它也能正常加载。嗯嗯..即使没有加载滚动BG，我也可以玩游戏。滚动 BG 总是最终加载 - 通常是 5-10 秒后。

Answer 1

将以下代码添加到 1) 当用户按下主页按钮时暂停游戏和 2) 当用户点击应用程序图标时恢复游戏。

    // Register to be notified when the app is about to change to background state
    UIApplication *app = [UIApplication sharedApplication];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(applicationWillResignActive:)
                                                 name:UIApplicationWillResignActiveNotification
                                               object:app];

此方法在应用进入后台模式之前调用。

- (void) applicationWillResignActive:(NSNotification *)notification
{
    // Pause the game
    self.scene.view.paused = YES;

    UIApplication *app = [UIApplication sharedApplication];
    // Register to be notified when app is about to become the foreground app
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(applicationWillEnterForegroundOrDidBecomeActive:)
                                                 name:UIApplicationWillEnterForegroundNotification
                                               object:app];
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIApplicationWillResignActiveNotification
                                                  object:app];
}

此方法在应用进入前台模式之前调用。

- (void) applicationWillEnterForegroundOrDidBecomeActive:(NSNotification *)notification
{
    UIApplication *app = [UIApplication sharedApplication];
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIApplicationWillEnterForegroundNotification
                                                  object:app];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(applicationWillResignActive:)
                                                 name:UIApplicationWillResignActiveNotification
                                               object:app];
    // Add tap recognizer
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]
                                initWithTarget:self action:@selector(handleTapGesture:)];
    tapGesture.delegate = (id)self;
    [self.view addGestureRecognizer:tapGesture];
}

此方法会在用户点击屏幕时恢复游戏。

- (void) handleTapGesture:(UITapGestureRecognizer *)gesture
{
    // Remove the tap recognizer
    [self.view removeGestureRecognizer:gesture];
    // Resume the game
    self.scene.view.paused = NO;
}