Mobile ComputingLECTURE # 3

The CourseCourse Code: IT-4545

Course Title: Mobile Computing

Instructor: JAWAD AHMAD◦ Email Address: jawadahmad@uoslahore.edu.pk

Web Address: http://csandituoslahore.weebly.com/mc.html

Term (Semester): Spring 2018

Duration: 15/16 Weeks

Activity and its life cycle

What is an Activity?

• Activity is a window that contains GUI.

• An Application can have 1or more Activities.

• Android Applications normally have several

Activities.

• Several Activities together make an

Application.

• User interacts with Activity.

• Activities are built independent of each other.

Activity Life Cycle

How Activity Life Cycle Works?

OnCreate() Event

• Called when Activity is created

• Normally all the initialization are done in this method

OnStart() Event

• Called when Activity is becoming visible to the User

OnRestart() Event

• Called when Activity is stopped and restarting

OnResume() Event

• Called when Activity is available for interacting

• Called when Activity is in the foreground

OnPause() Event

• Called when System is about to resume some other activity

• Called when System is about to start another activity

OnStop() Event

• Called when Activity is no longer visible to User

OnDestroy() Event

• Final call before the Activity is destroyed

• Activity can be destroyed manually by user or Automatically by System

Android Activities work in Stack

Switching Between Activities

Switching Between Activities