Android is a multitasking operating system, it was built from the ground up with the ethos of not having to kill tasks ground into its methodology. The designers intentionally left out a task killer and ways to close apps. Just think about this for a second. You gmail app is an app designed by google, but you don?t see a close button anywhere do you? In fact I bet a lot of people don?t know its even running (we will define ?running? later). Google did not want to burden the mobile user with having to close applications when they are ?done? with them. They decided to do this on the basis that a mobile user will repeatedly and briefly interact with a wide variety of applications throughout the day.
Think about your own usage for a minute, I know that this stands true for me, as it will 99.9% of you out there. We use our mobiles on and off, jumping from app to app. For instance, send sms, call friend, check facebook, play a game, make a note, check the weather, etc, etc. Sound familiar? It ought to, as mentioned this is how we use mobiles, and the list can literally go on an on and on.
Ok so we now understand why google decided not to include exit options, or task killer applications. But it?s going to take more than that to convince you right? Lets drop down a level and discuss what exactly happens when you leave (press home or back) an application. Within android applications, there are two fundamental things you should be aware of, an application, and a process. These two concepts are together what make up an application, and are key to understanding why a task killer is not required.
What Is a Process?
A process is an activity that can be performed by 1 or more applications. When you think of an application actually doing something, for example playing music, posting a message to facebook or syncing your rss feed, these are processes. However, it is important to note that just because a process exists, does not mean it may be actually; doing anything. If you like, it may be easier to say that processes may be in an idle or active state.
What Is an Application?
An application is something that makes use of many different processes to provide you with some wanted functionality. For example, the official facebook or twitter apps. An application may also be idle or active, depending if it has any active processes currently associated with it.
When you leave an application, that application is allowed to keep its process running in the background (true multitasking) allowing it to carry on doing whatever work it needs to do. For example continue to download the rest of a webpage or playing music. However, just because an application leaves processes ?running? in the background, does not mean they are actually doing anything at all. They are being kept in memory just in case you are going to use them again soon. Many people cite this as a battery drain, nothing could be further from the truth however. Storing a footprint of an application in memory uses exactly the same amount of battery as it would if that section of memory is free. If you continue to open applications, then more of your memory will be used.