android starting app development

AndroidStarting App Development

Contents

Android Architecture

Creating New Layouts

UI components

Running and Debugging apps

Activity Navigation

Android Architecture

Linux Kernel

Libraries

Android Runtime and Core libraries

Application Framework

Applications

Linux Kernel

Provides Basic System Functionality such as process management, memory

management and device management.

Provides all device drivers to communicate all different hardware in device like

Camera, Sensors, Bluetooth, WiFi, Audio and others.

Basic Libraries

Low level libraries which provide basic features like SQLite Database, web

browser, LibC, library for playing and recording Audio/Video etc.

Mainly written in C/C++.

Interact with device drivers to handle all the basic features of the OS.

Android Core Libraries

Java based libraries that are specific to Android.

Interact with Basic libraries to perform desired functionality such as handling

recording of Audio and Video.

User interface building, Graphics design(2D and 3D) and Database access.

Dalvik Virtual Machine

Each application run in its own instance of Dalvik Virtual machine.

Multiple instances of Dalvik VM’s can run efficiently.

Application Framework

Application Manager

Activity Manager

Notification Manager

Location Manager

..and others

Applications

All built in apps

And the third party apps

***

“Till 29th September, 2015 Android activations were 1.4

billion.”

Let’s Make Layouts - some basics

Height and Width - “match_parent” or “wrap_content” or digital value in “dp”

Unique id - “@+id/xxx”

Naming convention for Id’s - “@+id/tv_login_username”,

“@+id/button_login_submit”

Naming convention for layouts - activity_login.xml, activity_settings.xml

ImageView

<ImageView

android:id="@+id/iv_orders_list_footer"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

android:layout_margin="20dp"

android:src="@drawable/icon"

/>

Drawables

Located in res/drawable/filename.png

Support different size/resolution devices.

hdpi, mdpi, xhdpi, xxhdpi.

Referred in xml as “@drawable/abc” (for abc.png)

Usually prefer PNG images, can also use JPG images.

EditText

<EditText

android:id="@+id/et_login_password"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:hint="@string/passcode"

android:inputType="textPassword"

android:maxLength="30"

android:textSize="24dp"/>

Button

<Button

android:id="@+id/button_login_submit"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:backgroundTint="@color/primary_dark"

android:text="Login"

android:textColor="@color/primary_text"

android:textSize="24dp"/>

Button

OnClickListener

mButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

//Do the required task

}

});

Hands On

Login screen

***

“Android share in Chinese mobile market is 76.5%”

Running and Debugging

Android Studio features - Clean, Build, Run

Android Emulator(Android Virtual Device)

Third Party Simulator - Genymotion

Displaying Logs

***

“Average daily Android subscription is 1.5 million.”

Activities

Every Activity will inherit an “Activity”.

Inheritance

Inheritance

Inheritance

Extending a class.

Accessing inherited methods and member variables.

Overriding methods.

Start Another Activity - Intents

Intent - “A message either to start another Activity or to communicate to another

Activity.”

Intent Actions - What it should do?

Passing Arguments to next Activity

Sending Data To Activity

Intent Parameters

Arrangement of Activities - Backstack

Why Activities are Important

Application performance and behaviour.

Interview Questions!!

Activity Lifecycle

Activity Lifecycle - Callback methods

onCreate

onStart

onResume

onPause

onStop

onDestroy

Activity Lifecycle

onCreate

onStart

onResume

onPause

onStop

onDestroy

ListView

PlayStore

But Not To Worry...

800,0000 apps have < 100 downloads.

Another 700,000 have < 1000 downloads.

Another 400,000 have < 10,000 downloads.

Only 35,000 apps are downloaded more than 500,000.

###

Paramvir Singh, Android Developer and Trainer

Paramvir.singh88@gmail.com

https://in.linkedin.com/in/paramvir-singh-android-developer-b45b5321