[splash-screen] Fix reading splash image from the android.splash config

[bbarthec]

Why

Partially resolves #10382 - only ExpoClient flow.
This PR resolves reading android.splash.*dpi images as splash image.

How

After integrating expo-splash-screen *dpi keys form the config were no longer read by the Android.
It restores previous behaviour.
Splash image is now searched for under following keys (and the first hit is used):

• android.splash.*dpi (from xxxhdpi down to mdpi)
• android.splash.image (this one is not working yet, needs schema update to transform image into imageUrl, to be delivered soon)
• splash.image

Test Plan

• create an app with the config:

{
  "splash": {} // intentionally empty,
  "android": {
    "splash": {
      "xxxhdpi": "<relativePathToTheSplashImage>"
    }
  }
}

• start the app and see the splash image is presented

[sjchmiela]

So… would this return the first non-empty value for any of the keys defined in *arrayOf("xxxhdpi"…)? Wouldn't we want to use a lower-resolution image on a lower-resolution device?

[bbarthec]

We've been always doing this that way (code from the sdk-38 branch):

expo/android/expoview/src/main/java/host/exp/exponent/LoadingView.java

Lines 271 to 295 in 9db4ea6

	private String backgroundImageURL(final JSONObject manifest) {
	if (isUsingNewSplashScreenStyle(manifest)) {
	JSONObject splash;
	if (manifest.has("android")) {
	final JSONObject android = manifest.optJSONObject("android");
	if (android.has(ExponentManifest.MANIFEST_SPLASH_INFO_KEY)) {
	splash = android.optJSONObject(ExponentManifest.MANIFEST_SPLASH_INFO_KEY);
	// Use the largest available image in the `android.splash` object, or `splash.imageUrl` if none is available .
	final String[] keys = {"xxxhdpiUrl", "xxhdpiUrl", "xhdpiUrl", "hdpiUrl", "mdpiUrl", "ldpiUrl"};
	for (String key : keys) {
	if (splash.has(key) && splash.optString(key) != null) {
	return splash.optString(key);
	}
	}
	}
	}
	if (manifest.has(ExponentManifest.MANIFEST_SPLASH_INFO_KEY)) {
	splash = manifest.optJSONObject(ExponentManifest.MANIFEST_SPLASH_INFO_KEY);
	if (splash.has(ExponentManifest.MANIFEST_SPLASH_IMAGE_URL)) {
	return splash.optString(ExponentManifest.MANIFEST_SPLASH_IMAGE_URL);
	}
	}

The image is fetched into ImageView, so we rather prefer to always have the best resolution here.
These *dpi are only usable in standalone's builds.

[sjchmiela]

Ah so this won't be used in standalone apps, sorry. 👍

[brentvatne]

if it's the way we've always done it then let's stick with that. we can follow up with improvements over status quo if needed in another pr

[brentvatne]

what was the motivation for moving this?

[bbarthec]

This config variable is only used in the if block, os it was just natural for me to scope it into if block as well 🤷

[brentvatne]

ah, ok. i just wasn't sure if it was somehow intended to be related to the fix