Build a Fragment (Pick Players)

Kotlin and Android Development featuring Jetpack — by Michael Fazio (18 / 125)

👈 Chapter 2 Build Views with Fragments | TOC | Add Data Binding to the App 👉

Throughout this book, we’re going to be using <ConstraintLayout> view groups as the main containers for most of our screens. We could handle things a few ways, but <ConstrainLayout> is a great way to get things right where you want them on each screen while still allowing for the flexibilty needed for multiple device types. In fragment_pick_players.xml, we can replace the entire existing <FrameLayout> tag with this new <ConstraintLayout>. The XML will then look like this:

​ ​<?xml version="1.0" encoding="utf-8"?>​
​ <androidx.constraintlayout.widget.ConstraintLayout
​     xmlns:android=​"http://schemas.android.com/apk/res/android"​
​     xmlns:app=​"http://schemas.android.com/apk/res-auto"​
​     xmlns:tools=​"http://schemas.android.com/tools"​
​     android:layout_width=​"match_parent"​
​     android:layout_height=​"match_parent"​
​     android:layout_margin=​"16dp"​
​     tools:context=​".fragments.PickPlayersFragment"​>
​ 
​     ​<!-- Content will eventually go in here. -->​
​ 
​ </androidx.constraintlayout.widget.ConstraintLayout>

If Android Studio is complaining that the xmlns:app attribute isn’t being used, that’s OK. It won’t be used until we start adding constraints to the views inside this <ConstraintLayout>.