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Everyone in this theater early on we're going to go ahead and create and apply this.



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OK.



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And in this application we're going to actually use the expandable list view in our application.



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So let me show you how this works.



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As you can see here we have an application that actually uses an expandable list view.



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And if we actually tickle the kindest support here as you can see here now about this group view this



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sport is actually has a child.



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OK.



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And we can see that these are values that are inside of this support group view is actually are actually



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the children of this sport.



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OK.



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And if I click on this computer as you can see we have this computer and we have these children of this



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computer.



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And as you can see this is the same story for the food here.



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So this is called the group view.



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OK.



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And these are the children of this group view as you can see here.



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And if you have car OK and we have these children and this child of this car and we have these TV and



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we have these children of these TV.



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OK.



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So in this obligation between we can actually create an app like this we need to actually click on this



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start in your Android studio project and then for the application name just type in here app 55 and



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then click on next and he has two API 16 Android 4.1 Jelly Bean next launch activity next and then click



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and finish.



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And now let's actually select this hello or take you here and then press on delete key on your keyboard



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and then double click on this address folder here lay out and then activity underline made that example.



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So now it's actually the selectees of floating action button here.



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And then press on delete key on your keyboard.



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OK.



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So let's actually to go back inside this content underline made that example and here of any to actually



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design the user interface of our application.



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Now let's actually try and expandable this view into this lay out here.



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OK but first of all it's actually a linear layout vertical into this relatively out and put it at the



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center of these relatively here and now let's actually go inside these containers for that as you can



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see here.



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As you can see we have these expandable at least.



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OK.



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Just select it and put it at the center of these linearly outwards the call.



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OK.



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And as you can see we have these expendible is you hear double click on it as you can see we have this



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idea here.



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OK.



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So this is the idea of this expendible this view and just leave it as default expendible this view OK.



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So let's actually go back inside the Smain activity that you will find here and now this actually did



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it.



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These lines of code that are related to the to the Options menu.



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OK.



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And here I select this block of code and then delete this.



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OK as you can see this block of code is actually related to the fluting action button.



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OK.



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So we don't need it.



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And now inside this class there's actually create an object of type expandable list view expand double



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list view as you can see here you have this up close here expandable list view and actually give a name



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to this object expand the broadest view and put a semicolon here.



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So as you can see here we are just declaring this object here inside of this class and inside of these



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uncreate.



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I want to initialize this object.



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So here I could just refer to the name of this object expandable list view assignment operator.



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And here I need to cast this object on to an expandable view object.



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So as you can see here find view by id r that Id dot expendible list view.



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OK.



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And then put a semicolon at the end of your statement.



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So now let's actually create a Java class.



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OK.



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So that we can actually bind are expendable.



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Few coats of it these are expendable Eastview OK.



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So if you actually create another separate class our job would be more our work would be more cleaner.



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OK.



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And it is more professional to actually create a classes for every specific job that you want to actually



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perform in your program.



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So I just need to click on file.



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Neal.



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Okay.



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And then dhaba class and here for the name of my class I can just type in expandable list view adapter.



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OK.



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So as you can see here are the job of the adapter is to actually buying the data of the view that we



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have in our layouts.



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OK.



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So that's why we need to actually create an adapter.



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OK.



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And then click on OK.



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So as you can see here we have these expandable this new adapter here.



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OK.



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So now we need to actually extend from the base are expandable list adapter class.



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So as you can see here we have these basic expandable adapter and this glass expandable this adapter



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is actually inheriting all of the features and behaviors that are inside of this base expandable adapter



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class.



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OK.



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So let's actually open our web browser and see what is this based expandable adapter.



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So as you can see here this is the android documentation and you can actually enter this.



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You are ill in your web browser in order to be guided to this page.



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And we have these are based expandable adapter.



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And as you can see here this is actually an abstract class.



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OK.



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So objects can be created from this class.



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OK.



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And here you can see it says that base class for a expandable list adapter used to provide data and



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views from some data to an expandable view.



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OK.



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So if you have an expandable is you here as you can see this is our least view and this class expandable



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this adapter used to provide data.



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Okay.



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And views from some data are to an expandable list view.



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OK.



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Adapter's inheriting this class should verify that the base implementations of get combined child ID



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and get combined group ID are correct in generating unique IDs from the group or student IDs.



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OK.



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And we can see some efforts that are inside of the space expandable it after class.



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OK.



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And we need to actually implement some of those methods.



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OK.



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And you can see we have these if it's here gets combined globality and we have this good group type



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and other methods.



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So now let's actually go to our Android studio and let's to go inside this expandability adapter class



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here.



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And as you can see it's now showing us an error.



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So let's actually hover our mouse pointer here and it says class expendible this adapter must either



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be declared abstract or implement abstract methods that are inside of these base expandable adapter.



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So how can we know actually what are the methods what are the abstract benefits that we need to actually



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implement inside of this class.



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So here I can just right click inside of this class expendible this adapter and then click on generate



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as you can see here and then click on implement Misfit's.



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So as you can see here we need to actually implement all of these methods that are here.



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OK.



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As you can see if you have lots of efforts here and we need to actually implement all of these benefits



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or in other words we need to actually overwrite these methods.



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OK so here if I click on OK as you can see now the error is gone.



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OK now I am actually overwriting them if the methods that I am actually inheriting from these abstract



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class.



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OK.



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So this is really important but first of all it's actually putting some more lines of code here inside



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of this class and then we're going to go ahead and implement these methods.



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OK so now I'm pasting some lines of code here and then I'm going to explain to you what's going on here.



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OK.



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So as you can see here these are the lines of code that I actually paste that here first of all I actually



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created an array of string values as you can see here.



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This is actually a one dimensional array.



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And the name of this area is group names.



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So as you can see here in our emulator this is our application and these are the names of the group



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will take groupings.



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So as you can see here sport computer food court TV and here as you can see inside of this Arai I actually



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assign these values sports computer food court TV and we have a two dimensional array for child names



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as you can see here.



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This is actually a two dimensional array.



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And the name of these are Ariz child names.



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And as you know our two dimensional art is actually an hour raise is actually a raise or an alley of



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race.



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OK.



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Our two dimensional alley is actually an army of Ivory's.



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OK.



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So if you have an A here and we have some trees inside of these arii OK for example for the first grade



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that is actually inside of this army we have boxing kickboxing judo football basketball.



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And here we can see that if I click on this sport here you can see these values inside of this sport



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here.



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OK.



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And as you can see if you have for the second grade that is actually inside of these child names two



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dimensional array.



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We have this computer laptop computer smartphone computer.



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And if you click on this computer you can see these values.



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And here you can see that we have another ice cream banana.



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And as you can see this is for food and you have Mercedes-Benz and we have this card here and we have



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these same same TV and LG TV.



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And this is for these TV here.



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Well Kate.