Broadcast & Broadcast Receiver↗

Broadcast Overview

Android apps can send or receive broadcast messages from the Android system and other Android apps

These broadcasts are sent when an event of interest occurs. For example, the Android system sends broadcasts when various system events occur, such as when the system boots up or the device starts charging. Apps can also send custom broadcasts, for example, to notify other apps of something that they might be interested in (for example, some new data has been downloaded).

Apps can register to receive specific broadcasts. When a broadcast is sent, the system automatically routes broadcasts to apps that have subscribed to receive that particular type of broadcast.

Generally speaking, broadcasts can be used as a messaging system across apps and outside of the normal user flow.

Basics

Either android system or an application can broadcast and an android application can receive it silently or to open an UI. To handle this broadcast a broadcast receiver comes into the action.

Apps can receive broadcasts in two ways: through manifest-declared receivers and context-registered receivers.

Dynamic broadcast receiver 

context-registered receivers. Context-registered receivers receive broadcasts as long as their registering context is valid. For an example, if you register within an Activity context, you receive broadcasts as long as the activity is not destroyed. If you register with the Application context, you receive broadcasts as long as the app is running.

1. Create the broadcast receiver sub class and register that registerReciever() method with intent filters

2. If the broadcasted messages matches the intent filters then the broadcast will route to out subclass

3. Subclass receive the broadcasted intent and use the information

Static broadcast receivers

manifest-declared receivers: Register and unregister receiver is not needed in this case.It will receive the notification even if the app is not active

Send a broadcast to other app

If you want to send a specific app then use a package name otherwise you can  send to all apps also