CODEWITHSUNDEEP
androidandroid-intent
Perley
Perley

Reputation: 302

What does an Android Intent do with its URIs?

Reading through the document and a couple others, none really specified what an Intent does with the URI that it is passed. I'm simply curious as to what happens when it gets a URI. I know it depends on the scheme, so if the scheme was http, does it then attempt to open that web URI?

I ask since I'm trying to consume RESTful API that sends data back in JSON format. Having it open the URI for me when trying to pass the data from one Activity to another rather than making the HTTP call myself via HttpClient would be nice. Not a big deal but I was just curious if that is how works.

Upvotes: 1

Views: 665

Answers (3)

hasanghaforian
hasanghaforian

Reputation: 14022

An intent is an abstract description of an operation to be performed.uri specific data that intent has to do operation on it:

Intent Structure

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.
    Some examples of action/data pairs are:

    ACTION_VIEW content://contacts/people/1 -- Display information about the person whose identifier is "1".

    ACTION_VIEW tel:123 -- Display the phone dialer with the given number filled in. Note how the VIEW action does what what is considered the most reasonable thing for a particular URI.

    ACTION_VIEW content://contacts/people/ -- Display a list of people, which the user can browse through. This example is a typical top-level entry into the Contacts application, showing you the list of people. Selecting a particular person to view would result in a new intent { ACTION_VIEW content://contacts/N } being used to start an activity to display that person.

So you can see that same Action with different data/uri perform different Action on data operate on.

Upvotes: 0

Kristopher Micinski
Kristopher Micinski

Reputation: 7672

It's not entirely clear what you mean, however the behavior of Intents is basically dictated by the Android package manager. You can think of an Intent as being a procedure call: you specify someone to handle the Intent, along with some additional data (parameters), possibly some category, etc...

The Android package manager looks at your intent and basically asks the question "what app on the system is prepared to consume and handle this intent?" The system then opens up that app (if it is not already resident in memory), and then throws the intent at the app. Note that there are cases where there exist some possibility of ambiguity among intent handlers: multiple apps could be prepared to handle the intent. You can sometimes see this in the form of the user being asked to select what app should handle the intent (and the user can select a default one).

The dynamic semantics of how intents are handled depends, of course, on the set of apps installed on the system, and may change depending on the type of app installed. It sounds like, in your case, you are mostly concerned with intents that have an ACTION_VIEW action associated with them. In the general case, things that look like URLs will be "caught" by the browser (though there is no guarantee that this be the case!), and the package manager will look at the structure of the URI and say "hey, this looks like it should be handled by app X," I'm going to send this URL to it. (And, of course, new apps can change this behavior by registering other intent filters..)

Upvotes: 1

CSmith
CSmith

Reputation: 13458

An Intent is just an object ... it does nothing with the URI. An Intent is used in function calls like startActivity(), sendBroadcast(), etc.

For example, when you pass an Intent to startActivity(), that Intent object is made available to the Activity. The Activity can interpret the URI as it pleases.

Android also uses Intent Filters to help route intents to various installed activities, these intent filters may inspect the URI.

Review http://developer.android.com/guide/components/intents-filters.html for all the info.

Upvotes: 2

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