What is an Intent in Android?

Question

• What is an Intent in Android?
• Can someone elaborate with an example?
• What are the types of Intents, and why we are using them?
• Why are Intents so important in Android?

Answer 1

what is Intent ?

It is a kind of message or information that is passed to the components. It is used to launch an activity, display a web page, send sms, send email etc.

There are two types of intents in android:

Implicit Intent
Explicit Intent

Implicit intent is used to invoke the system components

Example

Intent i = newIntent(android.content.Intent.ACTION_VIEW,Uri.parse(“http://www.amazon.com”));

startActivity(i);

Explicit intent is used to invoke the activity class.

Example

Intent intent = newIntent (this, SecondActivity.class);

startActivity(intent);

you can read more

http://www.vogella.com/tutorials/AndroidIntent/article.html#intents_overview http://developer.android.com/reference/android/content/Intent.html

Answer 2

An intent is an abstract description of an operation to be performed. It can be used with startActivity to launch an Activity, broadcastIntent to send it to any interested BroadcastReceiver components, and startService(Intent) or bindService(Intent, ServiceConnection, int) to communicate with a background Service.

For more details see these links :

1). http://developer.android.com/reference/android/content/Intent.html

2) http://developer.android.com/guide/topics/intents/intents-filters.html

3). http://www.vogella.de/articles/AndroidIntent/article.html

there are many more articles are available.

Answer 3

From the paper Deep Dive into Android IPC/Binder Framework atAndroid Builders Summit 2013 link

The intent is understood in some small but effective lines

1. Android supports a simple form of IPC(inter process communication) via intents
2. Intent messaging is a framework for asynchronous communication among Android components (activity, service, content providers, broadcast receiver )
3. Those components may run in the same or across different apps (i.e. processes)
4. Enables both point-to-point as well as publish subscribe messaging domains
5. The intent itself represents a message containing the description of the operation to be performed as well as data to be passed to the recipient(s).

From this thread a simple answer of android architect Dianne Hackborn states it as a data container which it actually is.

From android architecture point of view :

Intent is a data container that is used for inter process communication. It is built on top of the Binder from android architecture point of view.

Answer 4

What is an Intent ?

An Intent is basically a message that is passed between components (such as Activities, Services, Broadcast Receivers, and Content Providers). So, it is almost equivalent to parameters passed to API calls. The fundamental differences between API calls and invoking components via intents are:

• API calls are synchronous while intent-based invocations are asynchronous.
• API calls are compile-time binding while intent-based calls are run-time binding.

Of course, Intents can be made to work exactly like API calls by using what are called explicit intents, which will be explained later. But more often than not, implicit intents are the way to go and that is what is explained here.

One component that wants to invoke another has to only express its intent to do a job. And any other component that exists and has claimed that it can do such a job through intent-filters, is invoked by the Android platform to accomplish the job. This means, neither components are aware of each other's existence but can still work together to give the desired result for the end-user.

This invisible connection between components is achieved through the combination of intents, intent-filters and the Android platform.

This leads to huge possibilities like:

• Mix and match or rather plug and play of components at runtime.
• Replacing the inbuilt Android applications with custom developed applications.
• Component level reuse within and across applications.
• Service orientation to the most granular level, if I may say.

Here are additional technical details about Intents from the Android documentation.

An intent is an abstract description of an operation to be performed. It can be used with startActivity to launch an Activity, broadcastIntent to send it to any interested BroadcastReceiver components, and startService(Intent) or bindService(Intent, ServiceConnection, int) to communicate with a Background Service.

An Intent provides a facility for performing late runtime binding between the code in different applications. Its most significant use is in the launching of activities, where it can be thought of as the glue between activities. It is basically a passive data structure holding an abstract description of an action to be performed. The primary pieces of information in an intent are:

• action The general action to be performed, such as ACTION_VIEW, ACTION_EDIT, ACTION_MAIN, etc.
• data The data to operate on, such as a person record in the contacts database, expressed as a Uri.

Learn more

• Lars Vogel's tutorial
• ProgrammerGuru article
• Common intents

Answer 5

To understand intents basically I would suggest you to go through the site: http://developer.android.com/guide/topics/intents/intents-filters.html

Also, I've discussed about intents with examples in my personal blog: http://androiddesk.wordpress.com/2011/12/24/explicit-intent/

http://androiddesk.wordpress.com/2012/01/13/implicit-intent/

Just have a look if you think would be useful..

Thank you

Answer 6

After writing a single activity, there comes a need to transition to another activity to perform another task either with or without information from the first activity.

Android platform allows transition by means of Intent Interface.

Words are taken from here: Using Intent Demo and i suggest you to go through this example because they also have provided a code file as well. so you can use it and easily understand the same.