Learn how to create a fully functional Android app in Java by taking a project-based approach.

Android Development with Java

In this module, we’ll take a hands-on, project-based approach to developing Android applications. We’ll work with the most common tools that Android developers use every day including Java, Groovy, and XML. As we learn, we’ll build a fully functional Travel Blog application that will be a great addition to our portfolio.
By the end of this module, we’ll have built a fully functional Android application and be ready to build even more complex projects.

Modern Android App Development with Java

### Flow overview

When a user clicks the *_login_* button, we will perform a data validation flow, and if the data is valid, proceed to:

1. Simulate long-running operation for 2 seconds
2. Open *_MainActivity_* 
3. Finish *_LoginActivity_*

### Simulate a long-running operation

In this lesson, we are not going to do a real login HTTP call, so let’s just simulate it via delay of 2 seconds before opening *_MainActivity_*. To do this, we can use the `Handler` object.

In Android, `Handler` is an object which is tied to the looper of the thread in which it’s been created. It typically has two use-cases:

1. If we want to execute code on the *_main_* thread
2. If we want to execute code with a delay or at the specific time

Let’s modify our `performLogin` method and create a `Handler` object at the very end.  Now we can use this object's `postDelayed` method to execute code with a delay. This method has two parameters:

- `Runnable` that will be executed *_(presented as lambda in the code below)_*
- delay (in milliseconds) until the `Runnable` will be executed

# Flow overview

When a user clicks the *_login_* button, we will perform a data validation flow, and if the data is valid, proceed to:

1. Simulate long-running operation for 2 seconds
2. Open *_MainActivity_* 
3. Finish *_LoginActivity_*

# Simulate a long-running operation

In this lesson, we are not going to do a real login HTTP call, so let’s just simulate it via delay of 2 seconds before opening *_MainActivity_*. To do this, we can use the `Handler` object.

In Android, `Handler` is an object which is tied to the looper of the thread in which it’s been created. It typically has two use-cases:

1. If we want to execute code on the *_main_* thread
2. If we want to execute code with a delay or at the specific time

Let’s modify our `performLogin` method and create a `Handler` object at the very end.  Now we can use this object's `postDelayed` method to execute code with a delay. This method has two parameters:

- `Runnable` that will be executed *_(presented as lambda in the code below)_*
- delay (in milliseconds) until the `Runnable` will be executed

This lesson will cover how to simulate a long-running operation and open a new screen.

Android Ecosystem

Hello World

Travel Blog - Login Scree

Travel Blog - Details Screen

Travel Blog - List Screen

Travel Blog - Search & Sort

Travel Blog - Offline

Conclusion

Launch Second Screen

Flow overview #

Simulate a long-running operation #