如何改變SKAction的重力？

Question

我在Sprite Kit中製作遊戲，我想知道是否有可能讓SKAction改變他的重力一段時間，是嗎？ 這是我的代碼已經有：

 SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:@"bal.png"]; 
     sprite.position = CGPointMake(self.frame.size.width/4 + arc4random() % ((int)self.frame.size.width/2), (self.frame.size.height/2 + arc4random() % ((int)self.frame.size.height/2))); 
     sprite.color = [self randomColor]; 
     sprite.colorBlendFactor = 1.0; 
     sprite.xScale = 0.2; 
     sprite.yScale = 0.2; 
     [self addChild:sprite]; 
     sprite.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:sprite.size.width/2]; 
     self.physicsWorld.gravity = CGVectorMake(0.0f, -4.0f); 

提前感謝！

Answer 1

您運行自定義操作塊並將其打開和關閉，讓我知道這是否適用於您。

[self runAction:[SKAction sequence:@[[SKAction runBlock:^{ self.physicsWorld.gravity = CGVectorMake(0.0f, -4.0f);}],[SKAction waitForDuration:4],[SKAction runBlock:^{ self.physicsWorld.gravity = CGVectorMake(0.0f, 0.0f);}]]]];