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Alright, so at the moment, we've got an

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interface that's not terribly pretty, and the

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options for formatting the information

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are fairly limited when you're using the

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basic ArrayAdapter class. But this

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example does demonstrate how easy it is

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to use the ListView and an Adapter

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together. Now if we wanted more control

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over exactly what happens in the

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ListView, we then have to create our own

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Adapter, and we'll actually do that in

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the next video.

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But what I want to do, though, is go

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through and we're going to comment out

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the toString method - the to

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String method in the FeedEntry class -

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just to show that the basic Array

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Adapter is using the object's toString

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method to display the class data. And

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it's also going to show you what the

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default toString method produces. So

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we're going back to our class,

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so we can go to ParseApplications.

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And if you remember, it was actually in

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MainActivity class FeedEntry, which we

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had in our MainActivity. So we're gonna

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comment out the function - the toString

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function. We're just gonna literally just

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select all of it, up to and including the

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closing right curly brace. Comment that out,

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and if we actually run the app again

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now,

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you can see that we're just getting

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the full class name and this strange

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hexadecimal number here, that's actually

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changing for each object.

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Well that number's the hash code of each

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instance of the FeedEntry class. So it's

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not very user friendly and we're not

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seeing any of the actual data in the

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objects. So that's why it was a good idea

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to override the toString

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function, so that we could see the actual

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data rather than this default

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representation of the objects. So I

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mentioned earlier that we have to cater

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for the Activity being destroyed while

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our AsyncTask's still running. Now that's

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quite easy. We can just cancel the task

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in the Activity's onDestroy method. Now

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we're going to have to move the declaration of

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downloadData to make it available in

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onDestroy, but let's go ahead and write

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the onDestroy method first. So I'm going

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to go back to our MainActivity, and we're

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going to put this just below the

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onCreate, before the companion object

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line. And we'll override - we're looking for

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onDestroy. So we're getting Android

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Studio to write the onDestroy stub

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for us - or create the stub for us. So

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in terms of the calls, we're going to

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leave the super.onDestroy in there,

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and we're gonna add this one extra line.

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So it's gonna be downloadData dot

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cancel parentheses true. Now at the

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moment, downloadData is local to the

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onCreate method, so to get this to

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work we need to declare it at the top of

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the class instead. So I'm going to come

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up to the top of the class and do just

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that, and we're going to put that just

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below the initial TAG here. So

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val downloadData is equal to

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DownloadData with capital Ds for both

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words, in parentheses this comma space

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xmlListView.

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Now I'm getting this warning here, or

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this error; public properly exposes its

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private type DownloadData. Now all

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properties in Kotlin are public by

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default, so downloadData's public. But

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as its type in our private class -

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come down here and have a look. We've got

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the type set for private here in on line 52 -

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that's what's causing a problem.

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So you can't expose an object whose type

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is private, so we have to make download

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Data private, which it really should be

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anyway, even if Kotlin doesn't enforce

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this or didn't enforce this. There's no

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reason why anything

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outside MainActivity should be using

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our DownloadData object anyway. So we're

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gonna go back up and change this - it

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should be private val. So we'll add the

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keyword private, to satisfy Kotlin there.

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Alright, so there's no error, but at the

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moment it won't work though. So why won't

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this work? Have a think about what's

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being passed to the DownloadData

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constructor here, and when we can

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reasonably expect things to exist. Pause

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the video now, and then I'll explain why

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the code won't work, when you come back.

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Alright, so did you figure out why? Well,

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what's wrong with that code? Well the

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problem's caused by passing the reference

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to our ListView, to the constructor. Now

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none of our widgets will exist until

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after the call to setContentView, in

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the onCreate method, and we saw this, if

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you recall, in the calculator app. The

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solution is to use by lazy, so that the

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initialisation isn't performed until the

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first time we need to use our download

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Data object. So let's go ahead and change

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that. So it should be private val

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downloaData by lazy, and we'll get rid

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of the equal sign, so by lazy. Then we

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put left and right curly braces,

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and we put 'this' in the left and right

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curly braces, like so. So by the time we

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use downloadData, the layout's been

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created and the widgets are available in

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our code. So if you're not clear about

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that, review the discussion that we had

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about this in the last section, about

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using by lazy. Alright, so that's it - the

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Activity's destroyed while our Async

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Task's running and the task will be

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cancelled. Now the other thing we need to

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do is, obviously, comment out our val

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downloadData, and what I didn't do was, I

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probably should have actually copied

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this line 41, and actually copied it over

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and sort of pasted it or moved it, I

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should say, back up to the reference here

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on line 34, because obviously we've got

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the definition of downloadData in two

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places now. So, obviously, that's another

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reason why we would have got an error

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when we're actually running this. But the

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point is, that should not be in there, so I'm

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going to actually remove that now - remove that

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entire definition on line 41. That's in

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the onCreate function, because obviously

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now, we've got the definitions showing up

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here on line 34 in our MainActivity

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class. And because, again, we're using by

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lazy, the values are only going to get

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updated when they're first accessed. Alright,

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so let's just run this again, to make

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sure it works. Alright, you can see that that's

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still working. What I'll do is, I'll also

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make a change and put back the to

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String again, just so we can see the

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normal values again. Then run it

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again. Okay, so that's working nicely. So

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now if the Activity is destroyed while

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our AsyncTask's running, the task will be

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cancelled. Now by the way, the boolean

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argument to the cancel function - I'm

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talking about this on line 40, code on line

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47 - that tells Android that it can

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interrupt the task, and that's why we're

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passing true there, to say if that is okay

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to do that. Now that may seem like a

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strange thing to have to specify when

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cancelling a task. However, you may want

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the task to complete anyway, depending on

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well it's doing. What you don't want, and

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what would cause a crash, is if you then

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try to pass its results back to the

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Activity that's being destroyed. So there

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are situations where you'd want to pass

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false to the cancel function. Alright,

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so I'm gonna stop the video here, and in

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the next one we're gonna start creating

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our own adapter. And this gives us far

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more control over what appears in the

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ListView, and it's also a good way to

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understand how adapters work. So I'll see

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you in the next video.