PV239 #android2
cv1
Marek Sedlak
@msed__
ANDROID IS THE BEST
OPERATING SYSTEM IN
THE WORLD
FAKE NEWS
@me
● I like android, but I like iOS too (psssh)
● I am multiplatform because I my first real job was this:
○ Implement iOS + Android + Win + Linux + OSX + Product delivery or gtfo
○ About the product and people, not platforms => meet the demand
● Currently mostly STRV
○ Android dev, Java/Node.js Backend dev
○ Multiple product lead
● Quantity vs quality? Long term => good balance
● Quality first
Organisation of PV239 android2
● Thursdays at 8:00am @A218
● 5 weeks in a row, then once per 2 weeks
● We will tykať si
● Need something? Slack me
● Slack rules
○ Full name on profile
○ Be in #android2
○ Make use of it, it’s a great tool
Organisation of PV239 android2
● Projects
○ Groups of 2-3 ppl
■ Already have a group? OK
■ Nope? Find someone :) you can use slack.
○ Anyone already has a project? -> Tell me
● By the end of 3rd exercise lesson -> groups decided
● Once you have a group && a project, you can actually start
● No need to wait If you like
● Use git (get a repo asap, e.g. github/bitbucket/gitlab ..)
○ https://github.com/github/gitignore/blob/master/Android.gitignore
LET’S DO SOME ANDROID
ANDROID STUDIO
What do you need?
ANDROID STUDIO
It is really simple to get started.
● Android Studio 2.2.3
○ Includes Android SDK
● 8GB RAM (my recomm.)
● Testing device (can be an emulator)
New project:
File > New Project… Next, Next, Next, Finish
https://developer.android.com/
PROJECT STRUCTURE
What’s inside? Slides with many
lines - sorry.
ANDROID STUDIO PROJECT STRUCTURE
● .idea - IDE specific (-> .gitignore)
○ This is the folder of IntelliJ IDEA IDE
● .gradle (-> gitignore)
○ Gradle data, state, cache (internal stuff)
○ Gradle - build tool, like Maven, ANT
● app - no .gitignore this time
○ The Actual App
● gradle - gradle wrapper
○ Java lib of a specific version of gradle
THE APP FOLDER - FINALLY THE ANDROID PROJECT
● It does not have to be named app
○ actually, it is a module within the android studio project
● build.gradle - important file, gradle settings
● build - output, once you build
● libs - place for libraries used within the project
● src
○ main
■ java - java classes
■ res - assets, images, strings, layouts,...
● drawable, mipmap - graphics
● layout - xml layouts
● values - place for strings, colors, styles
■ AndroidManifest.xml - important, manifest file
UI COMPONENTS
Remember. UI Sells.
EACH JAVA OBJECT EXTENDS OBJECT CLASS
Typical ViewGroups:
● LinearLayout
● RelativeLayout
● FrameLayout
● TableLayout
● etc..
Typical Views:
● TextView
● Button
● EditText
● etc..
You typically use these elements in the:
● Activity
● Fragment
● etc..
LITTLE LESS ABSTRACT :)
http://www.itcsolutions.eu/2011/08/27/android-tutorial-4-procedural-vs-declarative-design-of-user-interfaces/
ACTIVITY
Activity has a lifecycle
● Activity Created
○ onCreate()
○ onStart()
○ onResume()
● Activity Running
○ onPause()
○ onStop()
○ onDestroy()
● Activity shut down
Navigation among activities
● android.content.Intent
INTERACTION WITH THE LAYOUT IN JAVA CODE
● XML
android:id="@+id/loginButton"
● JAVA
Button loginButton = (Button) findViewById( R.id.loginButton)
loginButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// process with login (API call, etc..)
}
});
● much better: ButterKnife (try at home)
EXERCISES
Let’s give it a try.
(The same as Android#1)
EXERCISE1
Use the activity to capture the input from the user
● Use vertical LinearLayout
● Put a text on the screen saying “Message”
○ Use TextView
● Place an input UI element with the button on the screen
○ They should be next to each other - horizontally (horizontal LinearLayout)
○ It’s EditText and Button
○ Name the button “Send”
EXERCISE2
a) Use the “Send” button to show Toast
b) Use the “Send” button to pass the input to another activity and show it on
the screen there.
● Use Intent
// 1st activity
Intent intent = new Intent(getBaseContext(), MessageActivity.class);
intent.putExtra("EXTRA_MESSAGE", message);
startActivity(intent);
// 2nd activity
String message = getIntent().getStringExtra("EXTRA_MESSAGE");
THANK YOU
See you on Slack.