Move several SKSpriteNode in array with delay? - ios

Question

I have a problem with moving several nodes in array. There is a code:
SKSpriteNode* paddle = (SKSpriteNode*)[self childNodeWithName: paddleXCategoryName];
SKAction *move = [SKAction moveTo:CGPointMake(paddle.position.x, CGRectGetMaxY(self.scene.frame)) duration:1.5];
NSMutableArray *shots = [[NSMutableArray alloc] init];
for (int i = 1; i<=10; i++) {
SKSpriteNode *shot = [[SKSpriteNode alloc] initWithImageNamed:#"shoot.png"];
shot.size = CGSizeMake(2, 5);
shot.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(2, 6)];
shot.physicsBody.categoryBitMask = shotCategory;
shot.physicsBody.contactTestBitMask = blockCategory;
shot.physicsBody.collisionBitMask = blockCategory;
[shots addObject:shot];
}
int i = 0;
for (SKSpriteNode *shot in shots) {
SKAction *wait = [SKAction waitForDuration:0.2+0.3*i];
shot.position = paddle.position;
[self addChild:shot];
[shot runAction:[SKAction sequence:#[wait, move]] completion:^{
[shot removeFromParent];
}];
}
I have only one node moving. What am I doing wrong?

Answer 1

Actually all of your nodes are moving together without delay to the same point. This is because you are not incrementing your i variable inside the loop. Try the code below. For the SKAction to work properly also set affectedByGravity to false.
int i = 0;
for (SKSpriteNode *shot in shots) {
SKAction *wait = [SKAction waitForDuration:0.2+0.3*i];
shot.position = paddle.position;
[self addChild:shot];
shot.physicsBody.affectedByGravity = false; // Added line.
[shot runAction:[SKAction sequence:#[wait, move]] completion:^{
[shot removeFromParent];
}];
i++; // Added line.
}

Answer 2

They all run the same move action. Each sprite needs to run its own copy of the action. Try changing the runAction statement by replacing move with [move copy]:
[shot runAction:[SKAction sequence:#[wait, [move copy]]] completion:^{
[shot removeFromParent];
}];