How do i make a function that loops, and changes sprite's position?

so i need a function or something that can make my 2 sprites move up and down, all the time! from the app starts with out anything have been touched on the screen..

heres what i have tryed to do, but since it in my init, it only runs once.. how can i make this loop its self so its looks dynamic ?

if (bgSkyer == false) {
            [bg3 runAction:[CCMoveTo actionWithDuration:0.5 position:ccp(240,100)]];
            [bg2 runAction:[CCMoveTo actionWithDuration:1.5 position:ccp(240,95)]];
            bgSkyer = true;
        }else {
            [bg3 runAction:[CCMoveTo actionWithDuration:0.5 position:ccp(240,112)]];
            [bg2 runAction:[CCMoveTo actionWithDuration:1.5 posi开发者_C百科tion:ccp(240,80)]];
            bgSkyer = false;
        }

As shown in Jebego's answer, you need to use CCRepeatForever. However, assuming you are using bgSkyer as a flag to toggle between the two positions, we can use skip that flag altogether if you are using CCRepeatForever together with CCSequence, as shown below (explicit variables are used for clarity but you can always merge them into one-liners if you want):

CCMoveTo *moveTo_240_95 = [CCMoveTo actionWithDuration:1.5 position:ccp(240,95)];
CCMoveTo *moveTo_240_80 = [CCMoveTo actionWithDuration:1.5 position:ccp(240,80)];
CCSequence *actionsForBg2 = [CCSequence actions:moveTo_240_95, moveTo_240_80, nil];
CCAction *repeatForBg2 = [CCRepeatForever actionWithAction:actionsForBg2];
[bg2 runAction:repeatForBg2]

CCMoveTo *moveTo_240_100 = [CCMoveTo actionWithDuration:0.5 position:ccp(240,100)];
CCMoveTo *moveTo_240_112 = [CCMoveTo actionWithDuration:0.5 position:ccp(240,112)];
CCSequence *actionsForBg3 = [CCSequence actions:moveTo_240_100, moveTo_240_112, nil];
CCAction *repeatForBg3 = [CCRepeatForever actionWithAction:actionsForBg3];
[bg3 runAction:repeatForBg3]

CCSequence performs the actions you pass to it one after another in a sequence, CCRepeatForever will repeat the sequence forever, until you call [node stopAllActions] on the node or until the node is dealloc'ed.

I think something like this may be what you're looking for:

if (bgSkyer == false) {
    CCMoveTo *moveOne = [CCMoveTo actionWithDuration:0.5 position:ccp(240,100)];
    CCRepeatForever *repeatOne = [CCRepeatForever actionWithAction:moveOne];
    [bg3 runAction:repeatOne];

    CCMoveTo *moveTwo = [CCMoveTo actionWithDuration:1.5 position:ccp(240,95)];
    CCRepeatForever *repeatTwo = [CCRepeatForever actionWithAction:moveTwo];
    [bg3 runAction:repeatTwo];
}else{
    //just repeat code, etc...
}

Hope it works!