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Everybody this is Caleb with Deb's slopes and in this video we're going to use our managed object context

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to create fair request that's going to pull data that we've saved in our persistent store.

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Really really cool stuff.

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Then we're going to fill our array or we're going to create an array fill it with those goals and then

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later on we're going to use that to actually pull in that data to our table view.

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So go ahead and pull open your X code project load up goals VC and now we're going to go ahead and create

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functions that are going to fetch all of our gold data.

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Super super cool.

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Let's go ahead and do that now.

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So we're going to actually create an extension of goals Visi like so by typing extension go VC or goals

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VC.

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And inside here we're going to write three functions.

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Now we've got to make sure that we have core data important.

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We do.

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So that's a good thing.

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Let's go ahead and let's write this function.

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It's going to fetch all of our gold data and then save it into an array which we're going to create

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and maybe two minutes.

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So go ahead and type phunk fetch and we're going to go ahead and create a completion handler just like

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we did with save so that we know when we're done.

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So go ahead and type completion and the completion is going to happen inside of here.

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OK.

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And what we're going to do is we're first going to set a constant here called complete and it's going

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to be of type Boolean and this closure which is a function is going to basically return to us an empty

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function so that we can just pass in a value to here.

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And then when we call fetch we get a value return to here and then we can do something inside of the

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closure completion.

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So really cool.

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Here's what we got to do in order to get that data from our managed object context.

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We're going to basically first create a constant to hold the managed object context.

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We're going to create a fecche request which is a part of grabbing data from the persistent storage

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coordinator.

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Then we're going to basically use our managed object context to fetch all that data through the fetch

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request and then set our array full of goals.

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OK.

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So let's do that.

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Let's go ahead and type guard let managed context equals app delegate dot persistent container view

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context.

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If we don't have that else we'll just return.

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OK so assuming that we have our managed object context which more than likely we will we're going to

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move on and create what's called a fetch request.

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So let's go ahead and name that.

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Let fecche request equals and s fecche request.

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And what we're going to do is we're going to set a type of fecche request meaning what should we be

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fetching.

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Now this is going to be of type and as fecche request and if we put a parentheses we can see that we

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can call an entity name.

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Now the interesting thing is if we go to our X-C data model our entity is named goal.

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So if we go in here we can pass a string of goal.

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So now it knows that we are trying to fetch items that are of this particular entity very very cool.

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Now what we need to do is we need to call managed context fetch and pass it the fetch request but do

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you notice that it throws.

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That's our clue that we need to use.

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Do try and catch.

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So we'll just enter this and we'll pass it the fetch request but we need to call a do try catch block.

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So go ahead and type do.

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And then down below we might as well just type catch because that's where we'll handle errors.

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And now we're going to go ahead and paste this in here.

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Managed context not fetch.

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But like I said we need to go ahead and call try.

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Now do try and catch our what we use in order to do things that can throw errors and if they do we're

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going to use Debug print debug print apparently I can't type Debug.

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Print.

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There we go.

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And we're going to go ahead and print could not fetch and we'll pass the exact error from our.

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Do try and we'll give it the localized description there so that we know exactly what it's talking about.

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Very cool.

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And so this is great but I want you to notice for this function fetch if you let's call it again fetch

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you'll notice that it returns to us an array of N.S. fetch request result.

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So if we pass in our fetch requests like that it's going to return to us an array of whatever request

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we asked for which in this case is goal.

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So if this function returns to us an array of all of the results that it gets from its request we should

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create an array of goals and then set this to fetch and pass those into our array.

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So let's go up to the top.

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Beneath our table view let's go ahead and create an array.

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So type var goals which is an array of type goal OK that's easy enough and we're going to just instantiate

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it from the get go to be empty.

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OK that's easy enough.

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But down at the bottom when we get all of our managed context fetcher Quest results we're going to go

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ahead and set goals to be equal to this because the try here.

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Goals try.

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Here is going to basically call fetch return an array of the results which we know are going to be of

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type goal.

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So we can append them directly to our goals array.

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Super duper cool.

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And now that that's done once we successfully do that we can actually call our completion handler so

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we can say hey we're done.

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And you know while we're here we may as well print successfully fetched data.

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OK.

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If there is an error we're going to say could not fetch and will call completion false.

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OK so we're using our completion handler there that's great.

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And now here's what we're going to do.

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We need to think about when should we be fetching data when should that happen.

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Now if you did load is great but it's only called once when the view originally loads and if we have

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presented our create goal VC are finished.

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VC if we've presented those on the top and we dismiss them feuded load is not called because we're just

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presenting a view on top of it and dismissing it.

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What we can do is we can put this in view will appear because when the view appears that is because

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whether the app loads initially whether on a screen is presented and then dismissed view will appear

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is going to be called every single time the view appears not just when it loads.

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So we're going to call view will appear because that is actually the perfect place to put this call

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super view will appear and pass animated.

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So now we're going to go ahead and call self not fetch and we're going to pass it a completion handler

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here.

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And let's just say complete and if it's complete We're going to go ahead and do a check to see whether

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or not we should show or hide our table view because if we fetch all of our data but we get zero results

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we still should not show our table view remember that it's hidden from default.

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So we're going to go ahead and see if goals count is greater than or equal to one meaning if there's

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at least one we're going to go ahead and say table view is hidden equals false meaning table view is

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showing if there's more than one result that's brought back our table is going to be showing.

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But if that's not true else we're going to go ahead and say table view is hidden equals true cause if

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nothing is returned our table you should definitely not be showing.

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Kate that's pretty easy.

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So when the view appears it'll fetch the data it'll load the table view and it'll show it or hide it

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if it needs to really easy.

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So that's awesome.

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But now we need to go ahead and think about our table view.

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It's not going to be able to load the appropriate information into the table view because we have it

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set here to only load a static three cells.

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So in order to get the proper count for goals we're going to actually pass it goals count.

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If we had four items we would have four rows Okay.

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Very cool.

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The same thing goes for the cells we're not properly setting up the cells here because we're not properly

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accessing the goals.

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So we need to go ahead and do that by creating an instance of goal lead goal and we're going to go ahead

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and pull out each goal at the index path for each cell.

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So we're going to go into the goals array and we're going to pull out the item at the index path daro.

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And if you've ever worked with a table view and models you understand how this works.

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If the index path is one it's going to pull out the item at index Cathro one that's super easy.

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And as you can tell goal is going to be of type goal because it's coming from Arkell's Right.

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Now what we're going to do is we're going to pass in all the information we need for each cell we passed

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in a static title here.

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But what we're going to do now is actually type goal dot goal description.

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Okay.

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And that's where we're going to actually get the data from that specific goal the type we're going to

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get from gold gold type.

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All right.

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The progress amount we're going to take from.

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Goal.

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Goal progress or let's say goal progress amount because that doesn't initially have a value let's think.

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Well no you know what it needs to show the goal progress because the goal completion value is actually

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saved.

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When we create the goal the progress values always 0 from the beginning.

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So it should start at zero because as we add one little increment the number that makes way more sense.

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So very cool.

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That looks awesome.

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And we have now officially configured the cell phone our goals array I think we should build and run

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it to see if it works.

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OK let's build and run.

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Let's see if our fetch function is going to successfully work.

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And it looks like we're getting some errors here.

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Interesting.

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So let's go ahead and find out what the deal is.

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We get one error here.

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Oh of course it is not unwrapped.

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We have an optional type of string from goal description so unwrap that.

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Now it's saying that generic parameter result type could not be inferred.

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OK so we just need to set an explicit type for this as fecche request.

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We're telling it to fetch goals but we need to actually tell it that we explicitly need the type goal

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like.

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So by putting it in the carrot's there that tells it that we're asking for the type goal specifically.

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So that's great.

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All right so it's giving us an air here cannot convert value of type string to expected argument type

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gold type construct gold type.

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We don't want to do that.

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We don't want to make it into a gold type when you want to pass in the string value.

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You know what.

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I almost wonder if it would be easier if we went into gold sell and instead of passing in these values

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like this what if we just passed in a goal of type goal and instead of passing in a specific description

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value we could just say goal Daco description we could say goal dot type K because it comes in as a

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string.

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That's better.

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And then for this one we could go ahead and type goal dot goal progress.

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Now I think we're still going to have to put that into a string like so remember it's string describing.

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OK so that should still work OK.

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Nothing's wrong here but we are definitely going to have an error here.

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Now it's going to be easier on this end because configure cell now just asks for a goal and so we'll

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pass it that goal.

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And now we shouldn't get any errors.

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We should be able to properly fix that.

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Let's go look at gold type just to make sure.

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Or go sell I mean yeah because gold type comes in from our bowl is a string because when we save it

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we save it as a string.

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Awesome.

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So very very cool.

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Let's build and run this let's see if it works.

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And let's check it out.

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OK.

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Hey look at that.

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This is actually these are the ones that we've already saved.

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Let's try saving another one.

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Dance twice today just in case you feel like getting funky.

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All right.

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Press Next how many points until complete let's say three.

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And if we did this properly when Goles VC appears meaning when this dismisses it should fetch all of

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our data and it should set our table view to be showing or hiding so it's saying that it successfully

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fetch the data.

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But I'm not seeing it updating here.

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That's interesting.

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I wonder if we were to build and run it again if it would show up because I think that we're not yet

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reloading our table view like we need to.

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OK.

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Yes we'll look at that.

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So it's there but we just need to reload our table view.

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And you know what I think let's think so.

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If goals don't count as greater than 1.

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We want the table view to be showing.

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And you know what that would also be a great place to reload the table view.

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OK.

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Well no you know what.

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Because what if there's less than one.

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We also need to reload the data because if one were to be deleted.

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So you know instead of putting it here how about every time the view appears we're going to reload the

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table view then we fetch the data or no you know what.

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Even better let's fetch the data and then at the very end we will reload the table view no matter what.

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So that whether it's hidden or showing if there's more than 1 or 0 it'll reload every time.

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So let's try this out.

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Let's create a goal go to the park twice a week and let's do that for three weeks.

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Create goal.

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There we go.

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OK.

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So it shows up.

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Awesome.

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I am noticing a problem we are having some issues here with the text labels being out of place.

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So let's go fix that really quick.

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In main story board that does not look pretty.

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Ok so yeah it's probably an issue with our stack view here.

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And you know what.

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Let's see so goal is set this is set.

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And how are we filling this filling proportionally in case that's going to be a problem if we have smaller

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text.

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So let's go ahead and let's fix this so that it's not going to move anywhere.

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What we're going to do is we're going to change this to fill and fill and then what we're going to do

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is we're going to set a goal to have an explicit with so that this always is going to be the same distance

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from goal.

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So with the goal label selected click the pin menu select with and we're going to make this 50 y.

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Let's see if that works ok.

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Awesome.

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So let's go ahead let's build and run this let's see if that fixed our problem and we should be good

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to go.

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Guys we are loading data from core data we're pulling it from the ones that we've saved.

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Oh yeah look at that.

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That looks way better.

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We did mess up this one at the bottom but we can fix that by also giving type an explicit with let's

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just make it 40 and then let's build and run again.

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Let's see if that fixed our problem.

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It should unless we're not actually using the right stack.

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Ok no look at that.

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That looks perfect.

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So we're pulling the data we've saved long term short term titles.

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The the completion everything is showing exactly as we want.

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This is amazing guys awesome awesome work.

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We filled an array.

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We filled our table view with data from that array and then the next video we're going to write a function

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that's going to allow us to remove objects from core data and allow us to swipe and delete them.

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Then we're going to go ahead and add a really nice animation.

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So when you press delete it animates up no matter which row you choose to delete it's going to be super

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cool.

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And let's go build it now guys we're so close this is amazing.

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Let's move on to the next video.

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Amazing work with this one.

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I'll see you there.