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Hey buddy what's going on says Caleb with Debs Lopes dot com.

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And in this video we're going to actually write the code that we need to do to get accelerometer updates

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using see a motion manager so go ahead and pull open your project here and what we're going to do is

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we're first woman clothes the assistant editor and then just simply go into our view controller here.

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Now what we need to do before we begin anything is import a library called core motion.

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OK.

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Because that's the one we just talked about in the previous video.

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So go ahead and type import core motion.

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OK.

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And this is going to give us access to all that cool stuff accelerometer gyroscope magnetometer all

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that stuff.

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That's all included in core motion.

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Now if you've ever used the map kit framework or Core Location you know that there is something called

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a location manager and actually now that I think of it that's part of C-L location manager.

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Now the location manager is in charge of managing the location.

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Same with core motion there's going to be something called a CM motion manager that's in charge of managing

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the motion.

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OK.

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So we're going to actually create and so we're actually going to create a variable called Motian manager

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var motion manager and it's going to be of type CM motion manager.

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Now go ahead and put an exclamation mark there because it's not yet used but we are going to instantiate

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it later in view to load when we do need it.

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So when the view loads in view load We're going to go ahead and instantiate it like slow motion manager

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equals CM motion manager okay and instantiate it there with some parentheses.

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Now all we need to do to start keeping track of accelerometer updates is literally just to go like this

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motion manager dot start accelerometer updates that easy I promise.

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So I want you to notice though that if I type start you can see start Jairo updates start device Motian

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updates Macken magnetometer updates and accelerometer updates so we can get all that good stuff.

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But we want to control what happens whenever the accelerometer is updated right.

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We want to update our labels with the different access data.

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So go ahead and choose the function with the completion handler.

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Press enter and the operation queue here is just going to be main.

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All right.

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So we're just doing this on the main queue.

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And for the handler I want to I want you to check out what's inside of it so click on the placeholder

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there and press enter.

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And as you can see it returns an instance of S.M. accelerometer data that's optional as well as an optional

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error.

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And before we actually dive into this we're going to create a function that has both of these parameters

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and we're going to actually call that where the completion handler is.

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And it's just kind of an easier way to compartmentalize it so we don't have to put everything up here

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in view to load.

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So go ahead and type a function here func and we'll call the update labels because that's what the function

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will do.

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And just like our completion handler up here we're going to go ahead and write a property here for data

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of type S.M. accelerometer data.

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It's going to be optional like so then we're going to have an error of type error and it's also going

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to be optional.

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OK so now that we have the two required properties for the completion handler watch what we can do.

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You can actually go ahead and call this again.

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We're going to put on the main queue and I can just call update labels okay and I can actually even

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get rid of these as well.

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So we just have update labels because this function here does or at least has the parameters that get

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passed when this accelerometer update is completed.

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We passed it into data.

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And if there's an error we pass it into the error OK.

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So I want to go ahead and create a constant that's going to hold the value for the data that comes in.

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And we're just going to print it out to see what raw data we get.

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So I'm going to create a constant using guard let Because this comes in as optional.

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So guard let Excel or turr data data is going to be equal to data.

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Else we're just going to return.

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OK.

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So if there's an error we're going to go ahead and return or if there is no data if it's nil.

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We're also going to return.

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So now that we have our accelerometer data let's just go ahead and print it.

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So as soon as it updates we're going to just print accelerometer data.

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Ok so I don't know about you but I want you to try this out.

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I'm pretty excited to see how this works.

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We created a motion manager using cmd motion manager we instantiated it in view to load and we started

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accelerometer updates on the main queue and we were returning all the values from our accelerometer

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through this function called update labels and they were simply printing out the data there.

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Now I want you to look at the description here.

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It says it starts accelerometer updates on an operation queue and with a specified handler.

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Now if you want it to stop you need to call stop accelerometer updates in our app.

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We don't necessarily want it to stop.

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But in an app where maybe you only need it for a certain period of time.

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That would be a good thing to call.

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And basically the handler is what is going to pass back that data that's going to print out.

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So let's go ahead and I'm going to build and run it on my phone and we'll see what we get.

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So build and run and as soon as it's ready we're going to go ahead and pull it up here on the screen

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and I'll show you using my device and building it to my actual iPhone because the simulator device doesn't

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actually have an accelerometer even a virtual one so you have to build it to an actual device and check

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out what's happening right here on the screen do you see this.

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We're getting a lot of printouts and as you can see this is a very exact amount of data that goes to

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like six or seven decimal points.

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So what I can do is as I move it you'll see the values start to change.

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So I'm actually moving my device here and the numbers are changing.

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Now we're going to set it up later so that we only get a certain number of decimal points at the end

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and therefore it will appear to be updating a little less frequently because this is actually creating

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a lot of updates and we don't necessarily want to be printing that much that much data even though the

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data will be coming in and iOS can handle it.

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We're going to actually go ahead and set it so that when we move our device we're just going to reduce

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the amount of decimal points so that it changes less sporadically it's kind of hard to look at to be

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honest.

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So go ahead and kill it and we're going to go ahead and reduce that down to the bottom.

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But guys we are getting accelerometer data printing out now literally all we have to do is pull out

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the individual data for each individual access X Y and Z and display it when ever the accelerometer

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is updated.

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So that will happen in the next video.

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We're going to handle our results.

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We're going to pull it out.

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We're going to do some string formatting all kinds of fun stuff so let's head over to the next video

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and let's get our accelerometer data showing up in our labels.

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I'll see you there.