How to make a pause and resume button for NSTimer in xcode 7!

Hello and welcome to this video.

And in this video, I'm going to attempt to

show you how to make a pause and resume

button for a game. So let's start a

new project in Xcode and choose a one-side

view, one, one-screen view, can't

remember. So anyway, just get your— what's

it called— and then get a You

need a ViewController, which is this

thing. Should be here already. And then we

need to do right-click on here and do New

File and do this

one, and then just name it like Game or

something. Doesn't really matter. And I

think we change this to UIViewController.

Was it actually? I can't remember.

UIViewController. Yeah, I think that was

it. Game or

something. Okay,

and then just save it, and then What

do we do now? Okay, so we have our files

up here. Okay, so first go to Storyboard,

and what we want to do is create an image

so it's like sliding across the screen,

and that's the image we're going to pause.

So type down the bottom ImageView and

drag it on. Now we need an image, and we

don't have anything in the supporting

files.

I guess we don't really need anything.

Okay, it doesn't have to be an image. We

can do a label or button. So let's do a

label instead. Yeah, my label.

Okay, so we have a label and we're going

to make it scroll across the screen. So

what we want in here is Game.h.

What do we need? We need curly brackets,

right? And then we want

IBOutlet and then UILabel, and then just

name your label something. And then we

need a void— hold on, let me check my,

my other game. Where is it?

Game.h should be— so

UIKit.

Now for the IBOutlet, we need in below

the UIViewController and then curly

brackets and then Close

curly brackets, and then we can do the

voids at the end.

So it should go underneath

UIViewController. So let's

go back. So we go underneath

there. Yeah,

and then we need an IBAction, so we can

make a button. To— we need a button to

pause and resume the game.

So first of all, we can have pause.

Oh, this is wrong. Hold on. We need

selector and name selector pause,

and then do it like this so you have ID

sender. And we also need an IBAction for

resume. So it should look like this.

And we also need IBOutlet for our

button, and we'll call it pause,

and another one for resume.

Let me turn my keyboard lights on because

it's getting dark.

Okay, let's see if we can get this to work

properly. Go to your storyboard.

Here it is. Get rid of this bit.

Okay, no, not this one. Where was the one

we had last time? The main storyboard.

Yeah, that's it. Okay, now we need 2

buttons. Drag it on

the screen and just call it pause, and

then copy and paste Copy,

paste, yeah. And we'll name it Resume.

Okay, so what's next? That's a good

question. Click on the top bit, on the top

border, then click on this one, the 6th

tab along. 1, 2, 3, 4, 5, 6.

And you'll find— okay, so that

didn't work.

There's something I'm missing. Oh yeah,

we have to do this. Change class to,

to game or something. Yeah, that's it.

Okay, it should work now. But then, yep,

we have label, drag it to label, and

pause, drag to pause. Resume can be

dragged to resume. And we want our— where

do I be? Actions. Oh, here. Received

actions. Pause and do touch up inside.

And resume, touch up inside.

Okay, so we have our buttons and our

labels declared. We need to write the code

to make the— well, we need to get rid of

this first. Implementation game or

something. Okay, make some room.

Okay, so we want the label to move across

the screen. Let's just move these down

here.

We want this to move across the screen,

so how do we do that? That's a good

question because I can't remember off the

top of my head.

Okay, where is— but we need a timer,

so let's make a timer. This can go— goes

here, I think. So NSTimer,

and we will call it— what

should we call it— labelTimer.

Right, and then we go to M, and then we

do— where's

viewDidLoad? So viewDidLoad is what

happens when the game starts. We need

the code. Let me get it from my other game

for the timer. It's quite long.

Where is it? No, game.m.

So copy this just like it,

like it, like it says on my screen. Go

back to your game. Now just paste it in

there. Now movement

timer should be changed to your timer

name. Ours was labelTimer. And this bit

will be in the void here. We need to make

a void right down here, so put void,

and then let's name it LabelMovement.

And then this should be changed to

LabelMovement. And then we'll make a void

in here called LabelMovement, and this

is where the code is going to go to make

our label move. So I

think I'm doing this right.

So the next thing we need to do is label,

choose this one, .center equals

CGPoint.make, and we shall do

label— whoops— label.center

Oh, we've done label wrong. It should be

capital L.

I spelled it wrong. No, it's not

capital L.

Yeah,

.center.x and then

label.center.y, close brackets

and then semicolon. Now we want it to move

to the right, so So we go on the

x-coordinate and we should do— is

it plus? So let's do +10,

and then let's see if it works.

There it goes, it's moving! Yeah, we did

it! Okay. So let's

close this simulator. Now I want simulator

on— that's fine. Close simulator.

Then go back to tutorial. Okay, so we want

the label to keep reappearing

on the screen after it's disappeared. So

how do we do that? Well, we do an if

statement. If label.center

equals— no, if label.x equal

is greater than— greater

than what? Greater than— off the edge of

the screen should be like 256

3. So look at the X here. So 320.

So if it's greater than 320, it should

reappear at -100.

320 and -100.

Okay, so go back to game or something. M.

If it's greater than 320 Then

we shall make it label.center equals

CGPoint make,

and then press Enter, and then do— do—

what was it?

Can't remember. -100, see,

and then I think this can be 0.

No, it should be 200.

Whoops. Okay, click on my label.

It was -100 and y-axis was 200.

Should be 200.

So if label.x is greater than 320,

labelAtCenter CGPoint.make, and this

should keep repeating over and over.

That's it. Yep, it keeps reappearing.

Okay, simulator, where are you?

Ah, doesn't matter. Anyway, it was a bit

too close on the left side of the screen,

so let's change this to 400.

So there it goes off the screen and

reappears.

Okay, let's just minimize this. And this—

oh, look at all this crap. Can we move

this? Move it here? Why can't I move it?

Okay, let's just close it, quit,

and run it again. No, why are

you on the left side? I don't want you on

this screen.

We could— hold

on. So where were we?

So the simulator is moving the label. So

we want a— we

need to make our buttons work for pause

and resume. Okay, so go into .m and

we do like this, baby action, and put

pause. Get rid of this

extra stuff and then open curly brackets.

And what we want here is when you press

pause, it does invalidate.

So we need labelTimer and then invalidate,

and that should be all. So when you press

pause, it should stop.

There, it stops. So how do we restart it?

That's easy. We do IBAction and

we type in resume.

And then we do just copy and paste your

timer code into here,

and then should work.

Pause, resume, pause,

resume. So what you could use this for is

imagine if you had a game and these were

like characters moving. On the timer.

And so if you press pause, it stops the

timer, and then if you press resume, it

runs the code for the timer again, so it

starts moving again. So it's quite easy,

quite simple to get your head around. All

you need to do is declare these buttons

and then make an NSTimer, and then do a

void for label movement, and then

IBActions for pause and resume.

Pretty simple. And then link them up.

Make sure they're all linked up like this.

So you can see linked up stuff. See, this

is linked up, received actions, and these

are outlets. So yeah, pretty simple.

Hope it helps you. If you have any

questions, just ask me and I'll try, but

I'm still new to coding. So I'm just

trying to teach you what I know already.

So don't think I'm like some kind of

expert because I'm not. I only started

about 2 weeks ago. So yeah, coding isn't

that difficult, I guess, like for the

basic stuff. Anyway, see you in the next

video.