Emily Janzer cc3e27d484 Don't update dimensions for a new ReactRootView if they haven't changed ...

Summary:
ReactRootView currently caches the last seen DisplayMetrics so we can compare them against the current values in DisplayMetricsHolder to determine if the screen dimensions have changed. (If they have changed, we emit an event to notify JS of the new dimensions).

However, ReactRootView initializes these member variables with empty DisplayMetrics, which means that the first time we check against them in onGlobalLayout, we will *always* emit an event to JS.

This seems reasonable if you only have one ReactRootView, but if you create a new RRV for each RN screen in your app, then you're going to get updated dimensions on each navigation event, even though the screen dimensions have probably not changed.

In this diff, I'm no longer storing the DisplayMetrics in ReactRootView at all, but instead am using temporary variables to check the new DisplayMetrics values against the old.

Changelog: [Android][Fixed] Only update dimensions in ReactRootView if they've changed

Reviewed By: JoshuaGross, mdvacca

Differential Revision: D19395326

fbshipit-source-id: c01aee73064764503c9b49208032c790b83a1d29

2020-01-17 21:13:22 -08:00

..

androidTest

Convert easy files to flow strict-local

2019-12-05 16:06:46 -08:00

main

Don't update dimensions for a new ReactRootView if they haven't changed

2020-01-17 21:13:22 -08:00

test/java

Add an API for Detox to check if there are any timers expiring in a certain range (#27539)

2020-01-07 15:38:57 -08:00