Like Windows that is message-based Operating system and notify user input to program with send message to them,android using intent to do that!
Commented Dec 11, 2014 at 15:28An Intent is an "intention" to perform an action; in other words,
a messaging object you can use to request an action from another app component
An Intent is basically a message to say you did or want something to happen. Depending on the intent, apps or the OS might be listening for it and will react accordingly. Think of it as a blast email to a bunch of friends, in which you tell your friend John to do something, or to friends who can do X ("intent filters"), to do X. The other folks will ignore the email, but John (or friends who can do X) will react to it.
To listen for an broadcast intent (like the phone ringing, or an SMS is received), you implement a broadcast receiver, which will be passed the intent. To declare that you can handle another's app intent like "take picture", you declare an intent filter in your app's manifest file.
If you want to fire off an intent to do something, like pop up the dialer, you fire off an intent saying you will.
151k 60 60 gold badges 329 329 silver badges 416 416 bronze badges answered Jul 5, 2011 at 4:54 56.9k 29 29 gold badges 154 154 silver badges 199 199 bronze badges @Chirag Raval What is the difference between an intent and action listener? Commented Jan 13, 2014 at 9:04 May please explain again the last sentence ? If you want to fire off .. Commented Aug 4, 2015 at 12:44 Similar to C# delegates? Commented Mar 31, 2016 at 7:06Actually an action means you can start one component from another component using an Intent. That is what it is primarily used for.
Commented Sep 13, 2017 at 13:11 Also to add to this. Intent is asynchronous. Commented Sep 13, 2017 at 13:12An 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:
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:
Here are additional technical details about Intents from the Android documentation.
I appreciate the use of computer science concepts in this explanation. This makes the discussion more concrete, and especially helpful to readers with a solid degree in computer science.
Commented Jun 29, 2015 at 9:25Intents are a way of telling Android what you want to do. In other words, you describe your intention. Intents can be used to signal to the Android system that a certain event has occurred. Other components in Android can register to this event via an intent filter.
Following are 2 types of intents
used to call a specific component. When you know which component you want to launch and you do not want to give the user free control over which component to use. For example, you have an application that has 2 activities. Activity A and activity B. You want to launch activity B from activity A. In this case you define an explicit intent targeting activityB and then use it to directly call it.
used when you have an idea of what you want to do, but you do not know which component should be launched. Or if you want to give the user an option to choose between a list of components to use. If these Intents are send to the Android system it searches for all components which are registered for the specific action and the data type. If only one component is found, Android starts the component directly. For example, you have an application that uses the camera to take photos. One of the features of your application is that you give the user the possibility to send the photos he has taken. You do not know what kind of application the user has that can send photos, and you also want to give the user an option to choose which external application to use if he has more than one. In this case you would not use an explicit intent. Instead you should use an implicit intent that has its action set to ACTION_SEND and its data extra set to the URI of the photo.
An explicit intent is always delivered to its target, no matter what it contains; the filter is not consulted. But an implicit intent is delivered to a component only if it can pass through one of the component's filters
If an Intents is send to the Android system, it will determine suitable applications for this Intents. If several components have been registered for this type of Intents, Android offers the user the choice to open one of them.
This determination is based on IntentFilters. An IntentFilters specifies the types of Intent that an activity, service, orBroadcast Receiver can respond to. An Intent Filter declares the capabilities of a component. It specifies what anactivity or service can do and what types of broadcasts a Receiver can handle. It allows the corresponding component to receive Intents of the declared type. IntentFilters are typically defined via the AndroidManifest.xml file. For BroadcastReceiver it is also possible to define them in coding. An IntentFilters is defined by its category, action and data filters. It can also contain additional metadata.
If a component does not define an Intent filter, it can only be called by explicit Intents.
Following are 2 ways to define a filter
If you define the intent filter in the manifest, your application does not have to be running to react to the intents defined in it’s filter. Android registers the filter when your application gets installed.
If you want your broadcast receiver to receive the intent only when your application is running. Then you should define your intent filter during run time (programatically). Keep in mind that this works for broadcast receivers only.