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in the past programmers have often

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wondered which architectural pattern to

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use when designing their apps should

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they be using NBC MVP MVM or one of the

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other patterns available and in the past

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Google refused to make any specific

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recommendations the android framework

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provided tools that could be used with

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any architecture with varying degrees of

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difficulty and Google left that up to

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developers to use the most suitable

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architecture for their apps but with the

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recent introduction of architecture

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components Google are now suggesting in

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architecture and that's mvvm now mvvm

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stands for model view viewmodel

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and the android framework now includes a

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view model class that we can use in our

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apps there isn't time to discuss the

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various architectural patterns in this

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course this is a practical programming

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course not a theoretical computer

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science course now if you do want to

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know more about the various patterns

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then the Google search engine as always

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is your friend I've got a Wikipedia

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article which I'm just going to briefly

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bring up on the screen this is a good

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starting point for mvvm and the actual

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article contains the link to MVC and MVP

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if you want to learn more about those

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patterns as well so in this section of

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the course we're going to introduce the

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frameworks view model class and see how

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it can make our apps more responsive and

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easier to maintain and starting up in

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the next video we'll have a look at

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androids view model class to get a feel

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for what it can do for us

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will then convert a couple of our apps

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to use a view model we'll start with the

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calculator app from a few sections ago

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that's a really simple example and makes

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it really easy to see where the view

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model fits into the overall design

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after that we'll then convert the top

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ten downloader app to use a view model

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to see a more real-world use of view

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model in an app and our data base app in

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the later section still we'll be using a

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view model as well so let's get started

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and see what these view models are all

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about see you in the next video