♪ (upbeat electronic music) ♪ Okay, now you have seen
what exactly is Android. So, now it's time to create
your very first app in Android. In this particular slide, we are going to cover
about Android Studio, create our very first
"Hello World" app, and we're going to understand the basic app development
workflow in Android Studio. And then, run our app
in a virtual device, and even in a physical device. The prerequisites for
Android application development will be Java
programming language, and you need to have a good idea about object-oriented
programming, and XML-- how exactly you put properties
and attributes in XMLs. And you need to have
a good idea of IDE, a prior IDE,
it doesn't really matter, an IDE which you
have used in the past. And we will see how exactly
we work around with our Android Studio. So your Android Studio
will look like this, and it will contain many tools, like de-buggers, logcat, monitors, emulators. So we're going to look
at each one of them in coming slides. First of all, we need to learn how exactly we can install
Android Studio in our machines. So, first we need
to download JDK. So, we'll go to our browser,
and type "download JDK." Download the latest one, JDK 8. This will take you
to the Oracle website. Accept the license agreement, and download it
for whatever the machine you are working with. For me, it's Mac,
so I will download that. Once your JDK is downloaded,
install your JDK. Install your JDK. And, <i>Continue, Install</i>
(typing) The steps in Windows
will be pretty much the same. (installer chimes) Once the JDK is installed, now, next you can go through
downloading your Android Studio. Just type
"download Android Studio". And, just click on the link. It will take you
to the developer website, and from here, you can
download Android Studio. It will identify automatically
in which machine you are working, and it will give you--
if you are working with Mac, it will give you Android Studio,
Mac version. If you are working with Windows, it will give you Android Studio
with Windows version. Or, the same goes with Linux. So, download the Android Studio,
accept the license and download. Once your Android Studio
is downloaded, you can start installing
your Android Studio. In Mac, you can just drag
and drop in Applications folder. In Windows, you will just
double-click your Android Studio and it will get you to Windows, and from there you just have
to follow the instructions, and that's next-- and install. And then, you can go here,
you'll see Android Studio here. Press on Android Studio-- click on Android Studio
and <i>Open</i>. Now, for the very first time, It will ask you for
installation of SDK. By default, it always installs
the latest SDK. Where exactly you want
to install your SDK, so this will be the path. You just click
on <i>Next</i>, and <i>Finish</i>. So, once the latest component
has been downloaded, press <i>Finish</i>,
and you will get to this screen. Now, from here on, before right away getting
into creating a new project, you'll click on <i>Configure</i>,
and click on <i>SDK Manager</i>. What exactly we are doing here is we are installing further SDK's,
which we will be needing while we are developing
our Android applications. Either you can install
SDK's from here, just click on Android 7.1,
or whichever version you want. Just click on that and press <i>OK</i>. Or, you can always go
on Launch Standalone SDK. Launch Standalone SDK
will give you more freedom to install your Android versions. For example, in your
Android 7.1.1, API 25, you don't really need
a system image of Android TV, because we are
not going to design-- or, this development is not
going to be for your Android TV. We might need Google API
Intel x86 Adam 64 System Image. If I am using 64,
so I don't need x86. So, you see, you can select
whatever you want to download, and whatever you
don't want to download. So, this is for your latest. If you want to work
with other versions also, you just have to go
inside those versions. You just have
to click those versions, and select whatever you want to download
inside those versions. Like in Android 6.0, you definitely want
SDK Platform. You don't want TV. You don't want Wear
system images installed. You don't want Android Wear
system images also. Then, you don't want ARM
system images also. Now, ARM is again
a system image, or it gives you an emulator
which can run your application, but ARM machines are slower. So, that's why
we need Intel machines, which are pretty faster
as compared to ARM. Now, in that context also, I could have chosen
Intel, normal machine. But, I will be choosing
Google API's Intel machine here, maybe 64-bit, or 32-bit, according to your
system configuration. Why Google API's Intel machine? Because it gives you
all the features which you have
in your normal Intel machine, plus it always provides you
with more freedom to use your Google API's also. So, if you are using a
Google API Intel machine, then you might have to download
Google API's also. And then, you definitely need the source code
for your Android SDK. Now, this is for one
of the stable versions in the higher one, but if you want
a minimum version also, like we'll be working with
one of the minimum versions, with API 15,
you are free to select whichever version you want
as your minimum version. You can go ahead and install stuff from that
particular version also. Like we need SDK platform, we are
not going to work with ARM. And here, also,
we'll be working with Google API Intel x86 machine,
and Google APIs, and source code for SDK. Like I said before, you can
download ARM and other machines, but it's of no use,
because we won't be using them. We want our application
to be running in a pretty faster manner,
so for that purpose we need Intel machines
with the Google API's in them. After that, just
go to the bottom, just come to the Extras section. In that Extras section, you will
require Google Play services if you want to use
any Google API's, like Maps, or the billing system
of Google API. And then, for Windows,
you might require Intel x86 Emulator Accelerator to run your Intel machine
in your Windows phone. And then, you can just click
on <i>Install Packages</i>, accept the license. Accept the license
for other options also, and click on <i>Install</i>. And this will start installing
your other Android SDK. So now, you have seen how
to install the Android Studio. So let's just learn
how to create your very first application,
"Hello, World" application. This will be the very first
screen you will be seeing, and you can create a new project by clicking on the
very first option, <i>Start A New Android Project</i>. Or, you can always
create a new project from inside the Android Studio. You will get transferred
to this screen, and this is where you put
the name of your application, what you want
to name your application, and the project location, where exactly you want
your application to be saved. After that, you
will get transferred to the different templates. >From all those different
templates, we will select <i>Empty Template</i>,
as we want to start from the very scratch. Next, we will give the name
to our activity. Like I said before,
activity is a screen, and we want to create
our very first screen for the application. And activity is
not just a Java code, it contains the UI part also. So it will have a Java file,
plus a XML file also, which will contain its UI part. So we will name Java file
as <i>MainActivity</i>, and XML file as<i>
activity_main</i>. This is how your
Android Studio will appear at the very starting. As you can see, on your left
is your Project Files. >From this pane, you can
navigate through your project, or you can click
on any one of these files, and you can open those files. In the middle, you have
Layout Editor or Code Area, where you can either create
your layout, UIs, drag and drop, or, you will be writing
your code in this middle area. At the bottom is
known as Console Area, where you will see
the status reports, or logcats, log messages
of your application, or the application
you are creating. When we talk about
project folders, there will be four folders. First will be manifest folder, which will contain
a manifest file, which will give you
the information about the application itself. Next will be java, which will
contain all your Java code. Next will be res, which will
contain all your resources. It can be a layout,
it can be a string, it can be images,
it can be audio files. So all those resources will be
kept inside your res folder. Last will be <i>build.gradle</i> files. So, <i>build.gradle</i> files will
give you the information about building your
project and app and module. We will see about this
in further slides. So, let me talk about Gradle. Gradle is a building tool
used by your Android Studio. And there are basically
three types of Gradle files: first, project-level
Gradle files, module-level Gradle files,
and settings Gradle files. What, exactly, a project-level
Gradle file contains? A project-level Gradle file will contain the information
about Gradle itself. What is the version
of Gradle you are using, and what kind of
repositories you are using inside your application. So, there will be one project
Gradle file per application. Next will be module Gradle file. Now, there can be one
module Gradle file, or more than one
module Gradle file. It depends upon the
number of modules you are making
for your application. Now, if you are creating an app,
let's say a weather application for mobile also, for Wear also,
and for TV also, now there will be three
module Gradle files, giving the information
about each module. Each module Gradle file
gives you the information about each module, like in which version you are
creating that particular module, what is the minimum version,
what is the maximum version, what is the application IDE, or what are all the
dependencies, so that will give you
the information about the module-level
Gradle file. Last is known
as settings Gradle file. Settings Gradle file
gives you the information about which module you want
to include for your compilation. So, if you just want to
compile your mobile module, then you will just include the mobile module
inside the Gradle file. If you want to compile
mobile plus TV, then you will include
mobile module plus TV module. For more information, you can follow the link
about the Gradle. Now, once you have
followed all these steps, there will be a default
app for you, "Hello World". So, how do you run
that application? There is a Run button
at the top, you click on that Run button, and it will ask you for
a virtual device. So, you can always
create a virtual device. There will be a button,<i>
Create New Virtual Device</i>, or you can go to your
Android AVD Manager, that is, Android
Virtual Device Manager. >From there, you can
choose the hardware-- which hardware you want to use, and for which resolution
you want to create an emulator, either Nexus 4 or Nexus 5. And then, click on one of the
hardware resolutions. Click on <i>Next</i>, and then
you can choose which version you want to install
in that particular hardware, Android 7.0 and Android 6.0. Now, please be apprised that whichever SDK you downloaded
at the time of installation, only those system images
will come here. So, whichever system images you downloaded
at the time of SDK installation, only those system images
will come inside this, and you can use one of those
system images here. And then, you can give the name
to your Android Virtual Device, and then click <i>Finish</i>. And it will give you your
Android emulator, and this is how your
Android emulator looks like. You can always make your real
device also as a testing device. For that to happen, you have
to make your real device a developer device,
or you have to turn on your device in developer mode. How do you do that? Go to <i>Settings</i>,
click on <i>About Phone</i>, and inside there will be
build number. Now, tap into the build number
seven times. Yeah, seven times. And then you will see that
the developer option, which was hidden before
into the settings, is available now. Now, go inside
the developer option, and turn on your
USB Debugging mode. And there you go-- your device
is now a developer device. Now, this is the first part. If you are using Mac,
this is all you have to do. Now you have to connect
your USB cable to your machine, and you will be able
to run your applications. But if you are not using Mac, if you are using Windows
or Linux machines, then you might have to download USB drivers for
that particular device also, and install that
in your machine. And after that, you connect
to the USB cables, and you will be able
to run your application in your real device also. As your app runs, and you
want to get the feedback, you want to see what exactly
is going on inside your app, so for that purpose
we have a logcat tool, which is inside
your Android Monitor. Whenever you will be
running your app, you will see this-- all the logs
inside your logcat popping up. So this will keep track of whatever is going on
inside your emulator, or your Android device. So, this is how you put a log. <i>Log.d</i> -- for debug mode --
give a tag and give the message. You will learn about logging
in detail in further slides. So, this is how your
logcat pane looks like. So you can see, you have
to enter a log statement inside your Java code,
and then at the bottom, you will see inside the Android
Monitor there is a logcat pane, and that's where you can see
whatever the log statement you have put inside
your Java code. To learn more,
you can follow these links about creating and managing
Android Virtual Studio and different platform versions. So next you can
follow the concept in <i>Kit Book</i> exercise 1.1, and then we are going
to go through with the practicals of creating your very first
Hello World app, and run it into the emulator. ♪ (upbeat electronic music) ♪
