How can I pass multiple objects to a delayed metho

问题:

How can I pass

-(void)explosionFromPoint:(CGPoint)explosionPoint withSprite:(CCSprite*)sprite;

in a

[self performSelector:@selector(//Right here) withObject:nil afterDelay:3];?

You cant put the whole selector inside the @selector(), and withObjectfirst of all only allows one object to be passed over, and neither do I understand how to use it.

How can I pass a method with objects after a delay? I also tried a workaround where I call

[self performSelector:@selector(waitExplosion) withObject:nil afterDelay:3]; which then runs the action itself, [self explosionFromPoint:c0TileCoord withSprite:bomb]; , but this is a really bad way to do it as I have to re-declare the variables and it's just bad.

How can I pass a method with objects after a delay?

回答1:

You could use dispatch_after.

double delayInSeconds = 2.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
    [self explosionFromPoint:aPoint withSprite:sprite]; 
});

Where aPoint and sprite are defined outside of your block.

回答2:

If you want to pass multiple arguments to a method using performSelector: , keep all the arguments in a NSArray or NSDictionary and then pass that array/dictionary like

  [self performSelector:@selector(testWith:) withObject:array afterDelay:3];  

Edit

  NSArray *array =[NSArray arrayWithObjects:@"arg1",@"arg2"];
 [self performSelector:@selector(testWith:) withObject:array afterDelay:3];


 -(void)testWith:(NSArray *)array
 {

   NSString * arg1 =[array objectAtIndex:0];// first argument
   NSString *arg2 = [array objectAtIndex:1];// second argument
   // do other stuff
 }

回答3:

Another aproach you can use is to pass an NSArray or an NSMutableArray as parameter to your method. An Example:

NSString *firstItem = @"first Item";
NSNumber *secondItem = [[NSNumber numberWithBool:YES];
YourCustomObject *thirdItem= [[YourCustomObject alloc] init];

//your array to pass
NSArray *arrayToPass = [[NSArray arrayWithObjects:firstItem, secondItem, thirdItem, nil];

//call you method after delay and pass all the objects:
[self oerformSelector:@selector(doStuffWithMultipleParams:) withObject:arrayToPass afterDelay:3.0f];

The method could be used like this:

 - (void)doStuffWithMultipleParams:(NSArray *)passedArray{
    String *s; 
    BOOL b;
    YourCustomObject *obj;
    if ([[passedArray objectAtIndex:0] isKindOfClass:[NSString class]]){
        s = [passedArray objectAtIndex:0];
    }
    if ([[passedArray objectAtIndex:1] isKindOfClass:[NSNumber class]]){
        b = [[passedArray objectAtIndex:1] boolValue];
    }
    if ([[passedArray objectAtIndex:1] isKindOfClass:[YourCustomObject class]]){
        obj = [passedArray objectAtIndex:2];
    }
    if (s || b || obj){
        //now do stuff with these objects
    }


}

回答4:

As per the documentation. For your case you can make use of another method of NSObject. ie

- (id)performSelector:(SEL)aSelector withObject:(id)object1 withObject:(id)object2;

But unfortunately in this method you can not give the delay.