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Let's start by opening Android Studio and start a new project
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select all the default settings in plain app with an activity let's give it some time to start so
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once we generate a new project we will see some processes running in the background.
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These are related to Gradle. Gradle is the build system on the Android Studio. You have all the build
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properties in your gradle properties file, here you can include libraries from repositories and once
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you update the code the project will start building these gradle scripts and download whatever is
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included in them if it's the first time you're ever doing this it might take a while
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so let's just have a quick look at what is included in the application.
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So this is just an out of the box hello world application right we can see over here is the main activity
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which is created by default let's have a look inside.
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Next we have the layout of an application in our activity we point to a layout which is where we have
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the user interface another important file is the android manifest.
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Think of it as a file that explains the main features of an app to the Android operating system.
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Here we will define all app components and permissions that an app uses.
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Android wants to know in advance what the components in an application are so it goes to the Android
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manifest file and all the components will be defined within the manifest.
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There are different types of components.
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The idea of this section is to develop an app that makes use of all of these components another important
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thing defined in the manifest is the permissions. So for example say we want to make an application that
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can send S M S's. OK.
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You can write the code inside your activity.
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So say you go to your activity and write telephony manager dot send sms or something along those
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lines.
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This will not work unless we define the permission over here in the manifest.
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Saying this app can send sms. We'll show you how to do that later on in the course.
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OK.
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So we have the activity, the layout and the manifest.
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We also have the resources directory. Any resources that are to be included in the app be it xml files,
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strings or images, you should be placed in the resources directory.
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So for example under resources and values we have a file called strings.
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And this is where we would put all the strings that we refer to in the application.
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So for example say there's an app title that we want to refer to in different places in the application
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we'll define a string.
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Call it my title and then we can just refer to it across the application by using string slash my title.
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This is just used to keep everything consistent throughout the application similarly we have styles
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over here.
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So say for example in your app you don't want to show the taskbar or the action bar at the top then
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you can remove it from the style and every layout referring to this style will make use of it.
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So what else. OK.
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So the layout of the user interface that's associated with an activity.
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So here we see that by default it creates an activity called main activity.
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And the main activity sets the content to the activity underscore main layout and if we go on activity
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main layout we'll see that this is the user interface that's created by default.
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We'll be looking at these user interfaces later on in the course. Drawables, here we can put any images.
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So for example by default you get the android logo as an image, so if for example you have your own logo
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you upload it over here and change the reference then all logos will be changed to yours. So that's our
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default application out of the box.