如何以随机顺序以逐渐增加的速度添加和设置来自屏幕底部的无数个对象？
我有3个不同的精灵。 我想要不断地从屏幕底部进入这三个不同的精灵，随着进入的对象数量的增加而增加速度。 另外，三者应该随机排列。
所以，我尝试了下面的代码来获得三个精灵的任何随机顺序，但它没有按预期工作：
int randomNumber;
for (int i = 1; i<500; i++) { randomNumber = arc4random_uniform(3); NSLog(@"Value of random Number %d" ,randomNumber); if (randomNumber == 0) { [self addRedBall]; SKAction *moveBall = [SKAction moveToY:CGRectGetMaxY(self.frame) duration:5]; dispatch_queue_t actionDispatchRed; actionDispatchRed = dispatch_queue_create("com.redball.dispatch", NULL); dispatch_async(actionDispatchRed, ^ { [redBall runAction:moveBall]; }); [NSThread sleepForTimeInterval:2]; //Time interval to wait before the next ball comes in. } else if (randomNumber == 1) { [self addBlueBall]; dispatch_queue_t actionDispatchBlue; SKAction *moveBall = [SKAction moveToY:CGRectGetMaxY(self.frame) duration:5]; actionDispatchBlue = dispatch_queue_create("com.blueball.dispatch", NULL); dispatch_async(actionDispatchBlue, ^{ [blueBall runAction:moveBall]; }); [NSThread sleepForTimeInterval:2]; } else if (randomNumber == 2) { [self addGreenBall]; SKAction *moveBall = [SKAction moveToY:CGRectGetMaxY(self.frame) duration:5 ]; dispatch_queue_t actionDispatchGreen; actionDispatchGreen = dispatch_queue_create("com.greenball.dispatch", NULL); dispatch_async(actionDispatchGreen, ^ { [greenBall runAction:moveBall]; } ); [NSThread sleepForTimeInterval:2]; } } 当我使用[NSThread sleepForTimeInterval：2]; ，程序不会比起始画面更进一步。
当我尝试在没有sleepForTimeInterval的情况下运行程序时，大量的精灵进来并相互重叠，导致只有一个可见的精灵。
请帮忙。
我不会推荐使用[NSThread sleepForTimeInterval:2];
而是尝试使用[self performSelector:@selector(addBall) withObject:nil afterDelay:2];
-(void)addBall { self.addedBall++; if (self.addedBall > 500) { return; } randomNumber = arc4random_uniform(3); if (randomNumber == 0) { [self addRedBall]; SKAction *moveBall = [SKAction moveToY:CGRectGetMaxY(self.frame) duration:5]; dispatch_queue_t actionDispatchRed; actionDispatchRed = dispatch_queue_create("com.redball.dispatch", NULL); dispatch_async(actionDispatchRed, ^ { [redBall runAction:moveBall]; }); [self performSelector:@selector(addBall) withObject:nil afterDelay:2]; } //other else if stuff }
另外我不确定你为什么在dispatch_queue中运行你的SKA，可能不需要。
我希望有帮助。