how to call a ui component of a fragment from another fragment Android

Question

how can I call a ui component defined in a fragment A from a fragment B. I have declared a texview in fragment A and I want to set a calculated value in fragment B in said textview.I use java to develop the app. Greetings

Answer 1

You don't, directly. There's a couple of ways you can do this, but Fragment A and Fragment B shouldn't know about each other. They're independent. Instead, Fragment A should define an interface it calls when an event (such as changing the value of its textview) occurs. This can be a callback function in an interface, a message bus, an Observable, a view model, or a variety of other mechanisms. In Fragment B, you have an API that sets the value. This can be a function call, passing in an observable you subscribe to which sets the value, passing in a message bus that will tell it when the value changes, using a ViewModel and subscribing to updates to that, etc.

Then the Activity is in charge of wiring up the interface on A to effect the interface on B. Which way you choose depends on what technologies the rest of your app uses.

Answer 2

Why you have to call ui component you can pass your calculated value in fragment B or you can use eventbus library for that. implementation("org.greenrobot:eventbus:3.3.1")