Skip to main content

Intents in Android

 An intent is a type of message.You can think of Intent as "intent to do something".It's type of message that allows you to bind separate objects(such as activities) together at runtime.


If one activity wants to start a second activit, it does it by sending an intent to android. Then android does its job by starting the second activity and pass it the intent.




Syntax for create the intent:

Intent intent=new Intent(this,Target.class);

The first parameter specifies from which activity intent is coming.Keyword 'this' can be used as replacement here as it specifies the same thing.
The second parameter specifies the activity you want to start. It’s like putting an address on an envelope.
Once the intent is created next step is to send it to Android like this
startActivity(intent);
This informs the android to start the activity specified by the intent.
After receiving the intent the Android checks everything is OK and then tells the activity to start.
If it can’t find the activity, it throws'ActivityNotFoundException'.

Sending data along with intent:

putExtra() puts extra data in an intent that can be easily picked by the receiving activity.

intent.putExtra(key,value);
where key is the key which uniquely attached to the value.
The putExtra() method is overloaded so value has many possible types.
You can use putExtra() repeatedly to add numerous extra data to the intent. If you do this, make sure you give each one a unique key.


Retrieving the data from intent:
getIntent():returns the intent that started the activity, and you can use this to retrieve any extra information that was sent along with it. How you do this depends on the type of information that was sent. As an example, if you know the intent includes a String value with a name of “message”, you would use the following:

Intent intent = getIntent();
String string = intent.getStringExtra("message");

You’re not just limited to retrieving String values. As an example, you can use
to retrieve an int with a name of name. default_value specifies what int value you should use as a default.
int intNum = intent.getIntExtra("name", default_value);

There are other datatypes data such as boolean,long etc. that can be received by intent.

Comments

Post a Comment

Popular posts from this blog

Firebase FireStore

  Firestore is a subset of Firebase-Real-Time Database Firestore is a NOSQL Cloud Database which is extremely,customizable,efficient and scalable. Unlike SQL,we don't need to specify the column name and entity before putting the data in the table rather in NOSQL we don't need to predefined the structure of the database. In case of NOSQL, Database is called collection and Tables are called Documents. Documents allow us to add key-value pair which is basically the json format because json is easy to manipulate,query and very flexible. We can add documents inside the collection by specifing its name otherwise firebase we create an id for it. SetUp: 1) Inside Android Studio,go to tools select Firebase. 2) CLick on Log an Analytics event below the Analytics. 3) You will be redirected to login with your google account. 4) Log In into your account. 5) Go back to Studio you will that the Connected will be written with checked sign. 6) Now click on Add Analytics to your app.Now android ...
2 comments
Read more

Android Basics

  The Android Runtime(Art): Java apps take too much memory and time to run inside the JVM especially running on low powered processors or low memory device.So in order to decrease these two factors Android have their own virtual machine to run the apps called the Android Runtime(Art). First .java code is converted to .class code. Then .class code is converted to .dex file. Finally the .dex file is converted .apk file. All .class, .dex, .apk are machine readable language. Android SDK: The Android Software Development Kit contains the libraries and tools you need to develop android apps. Some main things inside SDK: 1)SDK Platform: There's one for each version of Android. 2) SDK Tools: Tools for useful utilities like debugging and testing. 3) Sample Apps: To get information about how to use some APIs sample apps provide great help. 4)Documentation: Offline documentation. 5) Android Support: Extra APIs that aren't available in the standard platform. 6) Google Play Billing: It help...
Post a Comment
Read more

Creating Chooser for Intents

  There's a way around you can create your own chooser that asks you to pick an activity without asking if you always want to use it. This task can be acheived using 'Intent.createChooser()'. Intent.createChooser() allows you to specify a title for the chooser dialog, and doesn’t give the user the option of selecting an activity to use by default. It also lets the user know if there are no matching activities by displaying a message. Syntax: Intent chosenIntent = Intent.createChooser(intent, "Send message..."); intent is the original Intent that we have made which describe the types of activity you want the chooser to display. "Send message..." here specifies the title of the activity chooser. The createChooser() method returns a brand-new Intent. What happens in the background: 1) The createChooser() method gets called. The method includes an intent that specifies the action and MIME type that’s required. 2)Android create a chooser for activities that ...
Post a Comment
Read more