May 2022
Intermediate to advanced
688 pages
20h 12m
English
book
Android Programming: The Big Nerd Ranch Guide, 5th Edition
by Bryan Sills, Brian Gardner, Kristin Marsicano, Chris Stewart
Content preview from Android Programming: The Big Nerd Ranch Guide, 5th Edition
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4 Persisting UI State
Destroying and re-creating activities on rotation can cause headaches, such as GeoQuiz’s bug of reverting to the first question when the device is rotated. To fix this bug, the post-rotation MainActivity instance needs to retain the old value of currentIndex. You need a way to save this data across a runtime configuration change, like rotation.
Luckily, there is a class that survives rotation that you can use to store your state. In this chapter, you will fix GeoQuiz’s UI state loss on rotation bug by storing its UI data in a ViewModel.
A ViewModel is the perfect complement to an Activity because of its simple lifecycle and ability to persist data across configuration changes. It is usually scoped to a ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.