I have a rather general question. Assuming I have a RecyclerView in some kind of a MainActivity. The content of this RecyclerView is being updated in multiple places in other activities.
For example there could be the possibility to make new entries by starting a new Activity and saving it there.In that case I would intuitively start that activity with startActivityForResult() and receive the changes in the onActivityResult() method in the MainActivity.
But lets say deeper inside the application, there is the possibility to delete all entries. Now how do we notify the MainActivity about this change in the dataset? I thought about setting a flag of some kind and clearing it after the content has been updated in the MainActivity. But somehow using global variables does not really follow the principle of proper encapsulation, does it?
Sorry for this vague question, but I find it quite hard to properly handle information flow in Android in a elegant manner, so here we are.
How about a local broadcast? You can find the idea of broadcast in this document. You need local broadcast and it is preferred if you want to pass data within your app only.
Android apps can send or receive broadcast messages from the Android system and other Android apps, similar to the publish-subscribe design pattern. 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).