Original subtitles

Alright, so we're all ready to start

writing apps for Android, but we should

probably start by answering the question

"What is Android?". Now Android is often

considered to be an operating system, but

it's also a software stack that consists

of an operating system, Linux, and a

framework for developing applications.

And it also includes a number of key

applications, such as contacts, that

reflect its purpose as a mobile platform.

Android was originally written by a

company called Android Incorporated, and

Google bought that company in 2005. Now

it's usual to think of Android as being

developed by Google, and I tend to talk

about Google a lot in this course, but

Android is in fact maintained by

the Open Handset Alliance. So rather than

releasing Android as a proprietary

system when they bought Android

Incorporated, Google got together with a

number of other companies to create the

Open Handset Alliance. The OHA. Now at

the time I'm recording this video, the

OHA has 84 members who are all committed

to keeping Android open source. So you

can actually download the complete

source code for Android, and modify it, if

you wish. There's actually a link to get

the source on the home page of the OHA.

I'm just going to bring that link up on

the screen there; again OHA, Open Handset

Alliance. You can see there's an option

there to get the source code. There's

also a link there to get the SDK as well.

Now the home page is a little bit

misleading, because the most recent entry

in the what's new section, over here,

actually has a date of July 18th 2011.

And that would give the impression that

not much is happening with the OHA, but

that couldn't be further from the truth.

You're taking this course, so you

probably know that version 8 of Android,

code named Oreo, was released in 2017. A new

version of Android is actually released

every year.

Android and the OHA are very much alive.

Now you can learn more about the OHA by

clicking on the Alliance menu item, at

the top of the page. Clicking on

Members, as I've done there, shows the

current members of the OHA; and if you

scroll down, if I scroll down, you can

probably recognize some of the names of

these companies. They're

actually part of the OHA. And there's

different categories here. What we

chose with the default is Mobile

Operators. Handset manufacturers - some

household names here for sure.

SUSE Tech is one, Dell is another,

Jitsu, so some quite well-known companies.

NEC, LG and so on. Now I'm not going to

spend time in this video going through it,

but the Android menu also is well worth

a read, to get an overview of the

thinking behind Android. Now I suggest

that it might be useful for you, if

you're on this page, to actually watch

this video. It's quite a useful video and

have a bit of a read there. All right,

so let's have a quick look at Android, to

see some of the things that we're going

to be looking at getting our apps to do.

Now for this demo we're going to be

using an Android emulator, or virtual

device, and we'll be looking at how to

create virtual devices a bit later in

the course. But think of them as so

basically a way to run our apps on a

wide variety of phones, without having to

buy loads of devices, because it's all

actually done in a virtual machine.

Which means it's running on your

computer. Now in fact, when Google

released Android studio 3, they also

updated the emulators. Now there's also a

couple of emulators that include the

Google Play Store.

and what that means is that you can

install just about any apps from the

Play Store onto your emulator, and we're

going to be discussing that in more

detail when we come to create our own

emulators. But it's something that

developers have been asking for for

quite a few years now. Alright, so I'm going

to switch over now to an emulator - you

can see that I've got it running, but we

can see that it looks like a real

Android phone. There at the bottom are

these three soft keys, and you

find those on just about all Android

devices these days. Though some

manufacturers do replace the middle

button with a physical key, rather than

having it on screen, but the function is

the same. Now the triangular button on

the left over here, that's the back

button, and some devices that appears as

a curved left pointing arrow, and

rather confusingly can appear on the

right-hand side of the screen instead.

The back button, though, is used to go

back to a previous app, dismiss

dialogues, cancel menus; basically it just

goes back to what you were doing before.

And just to see what I mean there,

I can come over here and click on it, to get into our list of

apps. I can choose Gmail, then I can

click on the back button to go back to

the list of apps. Now the middle button

down here, that's the home button, and as

I said some manufacturers use a physical

button for that instead. And this button

takes you back to the home screen. So if

I run Gmail again, and then press the

home button, we end up back on the home

screen, rather than the apps list that we

got when we clicked on back. Now it's got

another function - if you long tap, so

hold it down basically, it'll launch the

Google app: you can see that that's come

up there when I've done that. Now I don't

want to set up the Google assistant at

the moment, so I'm going to click on back

there to get out of that. And we're going

to need another app running for this

next bit, so I'm gonna launch Google Maps

as well. So I'm just going to go to the

home again, click on maps here, and open

up Google Maps as well. Then the square

button on the right, over here, has

various names. You'll find it referred

to as the recents button, or the

multitasking button, or even sometimes

the intents button. Now before I tap it,

one thing that may not be obvious is

that pressing back or home doesn't close

an Android app in the same sense as

closing a program on your PC. The app is

still running, and you can bring it back

to the same state it was when you

dismissed it.

Now the recent button shows all the apps

that are still running, and if I click on

that now, so you can see here that I've

got maps going, as well as Gmail. And you

can actually close it up completely by

clicking on the X up here, at the top

right. But Android will actually take

take care of closing the older apps for

you, if it needs to use the memory for

something else. So there's generally no

need to do that. What I'm doing instead

is tap Google Maps.

When I do that, it brings it to the

foreground. Then you can scroll through

the list of recent apps, so well to

demonstrate that I need a few more apps

running, so we've got a decent list to

scroll through. So I'm going to go back

to the home screen, using the middle

button, and go into apps, and we'll start

by launching calendar. Now back will take

me back to the list of apps, and this

time we're going to select photos.

That's a bit boring because I haven't

got any photos on this emulator. So I'm

gonna go back one more time now, this

time we're gonna start the YouTube app.

Okay, so we've now got a few apps running,

and I can view them all by tapping that

- recents button again. They're all the

apps I've just launched - stacked up with

the most recent on the top of the pile.

You can see on the bottom that's

YouTube. Now this is much easier to do on

a physical device. Using an emulator will

take a little bit of getting used to,

because the mouse pointer doesn't quite

behave the same as a finger on a

touchscreen. And hopefully I won't

accidentally touch an app while trying

to scroll through them. But the way to

scroll through them is to to hold the

mouse button down while moving the mouse,

to simulate a finger dragging. So if I do

that, you can see here that I can

actually move down and change the list

of apps, as I scroll down, or scroll up

for that matter. I'm getting the

different apps as I do that.

Basically it's simulating the finger

dragging of the phone's touchscreen. Now

you saw that when I was dragging, the

recent apps move off the bottom of

the screen, to reveal the older ones.

Like so. If I start down there, then as I

scroll up you can see Photos is coming

up, YouTube, and so on. Now the Linux

kernel allows multitasking, and Android's

built on top of the Linux kernel. So an

Android phone is a multitasking computer.

And you can have actually have several

apps running at the same time, which

we're doing here, and this can be very

useful if you need to do something like

checking your calendar while talking on

the phone, for example. And in fact we can

simulate that. I'll select Gmail from the

list of apps, so I'll scroll down, click

on Gmail. And next I'm going to phone my

emulator. Now at the bottom of the side

menu, over here, is this ellipsis - three

dots. If I click on that, that brings up

an extended controls; which I'll just

move over, so you can see the screen as

well. This the menu lets you play around

with things like location and text

messages. Now the phone option in the

left pane, over here, I click on that ... that

allows me to send SMS messages to the

phone and you can also simulate an

incoming

phone call, using the call phone button.

And you can even enter different phone

numbers, to build up a phone log, which

can be useful if you're testing an app

that works with the phone log. Now on

this Nexus emulator, that causes a

message to drop down so that I can

answer the call. Let's just do that.

call device, you can see that's popped up

there. I've come over here now onto the

device. I click on answer.

Now you can't really have a phone

conversation with the emulator, but the

emulator is now behaving like a real

phone that's in a phone call. So without

hanging up the phone, I could tap on the

recents button go back to my email, and

view that. Now there isn't much in this

email, because I'm using a test account

for this demo, but it can be useful to

check some details in an email during a

phone call. All right, so now that I've

checked my email, I can tap the recents

button again, and go back to the phone

call. And obviously if that was off the

list, we could scroll up and down to find

it. And just click it to actually bring

that back on screen again. So that's

pretty neat. The Android phone that fits

in your pocket is more powerful than most

desktop computers from just twenty years

ago. Now there is a slight oddity

sometimes with simulating phone calls on

the emulators. At the moment, when I tap

the red floating action button down here

during the call, the extended control

menu sometimes doesn't seem to update. It

thinks there's still a call in progress.

So tapping the button in there will end

the call, but in this case that has

actually worked okay, but if you get a

problem there, just tap on the button

over here, to end the call. It's not

really a big problem, just something to

be aware of when you're testing how your

apps behave when something like a phone

call happens. Now the phone app, by the

way, doesn't appear in the recents list

after you end a call. So when I tap the

recent button again, you can see that

it's actually disappeared. There's only

the apps I had running before the

phone call came in. To get back to it, we

need to tap the home button, click on

the blue phone icon here. Now I

haven't got any favourites saved, but the

middle tab, this one here with the clock

icon, shows the time and duration of the

you know quote-unquote call I just

received. And I can even simulate an

outgoing call by tapping the phone icon

on the right over here, and that

simulates, as I said, an outgoing phone

call. Of course we're not really going

to make a phone call, but it's a great

feature, again, when testing your apps.

Alright, so I'm going to hang up the phone,

let's hang up that call now.

Let's have a look at split screen mode. Now a

new feature that was introduced in

Android 7 Nougat is split screen mode.

As I said, don't worry if you haven't

got an Android 7 or later device. All the

apps we're developing this course will

run on all devices, on Android 4

- that's Android Jellybean - onwards. They

won't be able to use split screen mode

on earlier devices, but it's still useful

to see what it is. Now some

Samsung devices have had split screen

for a while, but it's now part of Android

itself, which means that all devices from

Nougat onwards will be able to use it.

Now you need one app already running, to

go into split screen mode, and I've

already got the phone dialer on the screen.

So we'll use that for this demo. Now with

that running, which it is, I'm gonna long

tap over here, on the recents button, and

again, on a phone, you'd be holding

your finger on it. In the emulator I

just held the mouse button down, until

that happened. Now on phones that've

got soft buttons, rather than physical

devices, the icon changes to show you

that you're in split screen. So instead

of just a square, it shows two boxes

inside the square, to represent the two

apps running. And that's what you can see

down here. Now I can scroll through the

list of apps down the bottom now, and tap

the one that I want to open in that

other half of the screen. Again I can just

come down and select them. like so. Now

some apps can't support running in split

screen, so you may see a message over

those apps informing you of that. But I

can scroll down and select, for example

the Gmail. Click on that, and I can have

that and the dialer running together on

the device, on screen at the same time. So

yeah that's pretty neat. And it's also

possible to copy and paste between the

two apps, but not all apps actually

support that. Now the bar in the middle

here looks like it lets you resize the

apps, but at the moment anyway it's just

used to close one or the other, by

dragging it over the app you want to

remove from the screen. So I'm going to

drag it to get rid of the dialer, so

we're left with just Gmail. So we're back

in single view mode. So we've now got the

one app running, and the recents button has

now changed back to the single square

again. Okay so let's have a look at some

of the things we're going to be learning

how to add to our apps. Now at the top

of the Gmail app is a toolbar, with a

settings menu on the left, and a search

button on the right. So there's the

settings and there's the search. The

settings menu, as I click it, produces

a navigation drawer. And in this course

we'll see how to create these, as well as

implementing search in our apps. Now to

dismiss the navigation drawer, swipe

to the left.

Now some older phones have a physical

Settings button, instead of the settings

3 bar icon appearing on the toolbar.

It works in the same way, just be aware

of that, if you create an app and the

settings icon doesn't appear on the

toolbar. Now it's also possible to have a

more traditional menu on the toolbar, and

we'll be learning how to create menus

before we get into navigation drawers.

Now the brief instructions at the top of

the list of emails looks like a snack

bar - this one here. These were introduced

with Lollipop and material design, but

are available now for all Android

versions - dating right back to version

2.1 And they're similar to the toast

messages that pop up briefly on the

screen, but you can also add actions to

them, which makes them more interactive

than the old toast messages. This one has

just a simple button to close the snack

bar, but you can also swipe them off the

screen, like so. Now, the emails appear in

a list, and we can create lists like this

using either the ListView widget or a

more recent replacement, called a RecyclerView.

Now, the RecyclerView is more

flexible, but you can't tell by looking

at the screen which one has been used

here. So we're gonna learn how to use

both in our apps anyway. And we'll also

see how to use this floating action

button, this is the circular button at

the bottom right of the screen. And that

should be reserved for the primary

function that users would perform from

for any from any particular screen. And

here it allows a new email to be entered.

Now I can scroll through the list of

emails. I'll just go back now, and as I do

that, the RecyclerView is taking care of

things for us - or the ListView, for

that matter, because again we're not sure

which one's being used here. Now I can

also tap on an email to read it, and

we're gonna learn how to respond to taps

and long taps, in our apps. We can also

add buttons to the list, like the star

next to each of these emails under here,

and that marks them as a favorite. Now by

the time you finish this course, you'll

have learnt how to create all these

effects, and a lot more, which is pretty

cool. Android devices can also

determine their location, and they do

this in two ways. The most accurate is by

using the built in GPS module. If the

device has one, then that allows a phone

to be used as a GPS device. An app such

as Copilot is as a good as dedicated GPS

devices, for giving directions or

driving. And Google Maps also has

the advantage of being free, and also

makes a pretty good pretty good GPS

navigator - though not all the emulators

have things like Google Maps installed.

And that's why I chose the API 26

emulator. At the time I'm recording this,

YouTube isn't installed on the API 25

emulators. Now the other way that Android

devices can check their location is

using the Wi-Fi or mobile phone location.

But this is far less accurate. Wi-Fi, in

particular, can be way out because it

only reliably knows the location of your

connection to the Internet.

The phone cabinet in the street, in

other words, which could be a mile or

more from your real location. Alright, so

go back to the home screen now, and

let's just launch Maps by clicking

it over here. Now the first time you

launch it, whether on an emulator or a

real device, you have to accept the terms

of conditions. But I've done that already,

and again that's pretty standard for a

lot of google apps. Alright the

emulators got a default location. We can

change that from the extended controls

menu that we just used to make a phone

call.

So come over here and click on location,

and I can tell the emulator that it's in

Adelaide.

Now the longitude let's type that in

first. That's choosing the longitude and

latitude for Adelaide. Longitude is going

to be one thirty eight thirty eight

point six oh one, and the latitude we

need to set that to minus thirty four

point nine two eight five. Tap on send,

that sends the new location to the

device. And it's important to make the

latitude negative. Adelaide's south of the

Equator, and if we leave it positive we'll

end up in the sea.

And as you can see when I did that, it

automatically went to Adelaide, when I

actually updated the latitude and

longitude. Now you can also simulate the

device moving, either by typing in and

sending new coordinates, or by loading a

set of coordinates stored in a GPX

file. So I'm going to load a file using

the load a GPX XML button, down here. I'm

going to select the file I've already

got here, adelaide.gpx, and open.

So once I've done that, I can come over here

and click on the play button, and when I

do that, the coordinates are sent to

the device just as if we were coming

from a real GPS module. You can see the

Google updates, er, Google Maps is updating

as we do that.

And as you can see, it also tracks time

as well as location, so the speed varies;

just like it would if you got out of a

car and started walking. All right, so

that's the GPS demonstration. And

basically that's a quick demonstration

of how Android apps work, and interact

with the Android operating system.

Now in the next sections, let's start

off with a simple app to get the hang of

using Android Studio to develop apps. And

then we're going to build up to create more

complex apps, involving databases, Google

Maps, REST services and more. And there's

also a tutorial section coming up, and if

you already know Java or Kotlin

(depending on which course you're

watching this video in) then feel free to

skip those videos. But if you're new to

the language, the tutorials will actually

give you the basics. And you'll find the

tutorials in section 4. Alright, so in the

next video we're going to download and

install Android Studio, which is the tool

you'll need to start creating your

Android apps. So we'll see you in that

next video.