material-components/material-components-android

[BottomNavigationView] BottomNavigationView can have only one setOnNavigationItemSelectedListener

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#735 opened on Nov 5, 2019

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Good First IssueWidget: BottomNavigationfeature request

Description

FEATURE REQUEST

As per title, BottomNavigationView can have only one setOnNavigationItemSelectedListener. This is annoying because if i use the bottomNavigationView.setupWithNavController(navController) this internally sets that listener, and i cannot use it anymore for anything else (like setting the text in a custom appBar, for example) A list of listeners would be the right thing in my opinion.

Ps. this probably applies to setOnNavigationItemReselectedListener(BottomNavigationView.OnNavigationItemReselectedListener listener) too.

For Pattern reference, see NavController addOnDestinationChangedListener and removeOnDestinationChangedListener

Contributor guide

Tech stack
javaandroid
Domain
mobiledesign
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Android developmentJavaMaterial Components for Android
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The issue requests allowing multiple listeners on BottomNavigationView instead of a single one. The recommended approach is to follow the pattern used by NavController's addOnDestinationChangedListener/removeOnDestinationChangedListener, which maintains a list of listeners. To implement, locate the BottomNavigationView class (likely in the library source code) and modify it to store a list of OnNavigationItemSelectedListener instances, then iterate over them when an item is selected. Ensure backward compatibility by keeping the single setter method but adapting it to the new list. No linked PRs or recent comments provide additional direction.