Only one sprite on the scene at once Cocos2D 3.x - ios

Question

The sprite appears every time the screen is touched, then it shoots to the desired area. How would i make it that only one sprite will be on the scene at a time until it exits the scene or hits an object? (even though the screen is touched multiple times)
This is the projectile code
- (void)touchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
// 1
CGPoint touchLocation = [touch locationInNode:self];
// 2
CGPoint offset = ccpSub(touchLocation, _player.position);
float ratio = offset.y/offset.x;
int targetX = _player.contentSize.width/2 + self.contentSize.width;
int targetY = (targetX*ratio) + _player.position.y;
CGPoint targetPosition = ccp(targetX,targetY);
// 3
CCSprite *projectile = [CCSprite spriteWithImageNamed:#"projectile.png"];
projectile.position = _player.position;
projectile.physicsBody = [CCPhysicsBody bodyWithCircleOfRadius:projectile.contentSize.width/2.0f andCenter:projectile.anchorPointInPoints];
projectile.physicsBody.collisionGroup = #"playerGroup";
projectile.physicsBody.collisionType = #"projectileCollision";
[_physicsWorld addChild:projectile];
// 4
CCActionMoveTo *actionMove = [CCActionMoveTo actionWithDuration:1.5f position:targetPosition];
CCActionRemove *actionRemove = [CCActionRemove action];
[projectile runAction:[CCActionSequence actionWithArray:#[actionMove,actionRemove]]];
[[OALSimpleAudio sharedInstance] playEffect:#"pew-pew-lei.caf"];
}

Answer 1

If I understood your point correctly , you could simply add a flag , to be able to notice when there's already a sprite on the scene. Just declare on your class a
BOOL isSpritePresent;
Initialize it on your class custom id method.
-(id)init {
self=[super init];
isSpritePresent=NO;
return self; }
And then on the start of TouchBegan add something like
if(isSpritePresent){
return; //As there's already an sprite on the scene.
}
And at the end
isSpritePresent=YES;
And finally when the arrow or w/e it is reached its target , call a method to reset the Boolean.
Or... If you're looking forward to doing things simpler and you believe you have an specific time to let the user shoot again just add a delay after the other actions as ..
CCActionDelay *delay = [CCActionDelay actionWithDuration:1.2f];
[projectile runAction:[CCActionSequence actionWithArray:#[actionMove,actionRemove,delay]]];