Fix LocaleUtils creating WebView in the background → ANR

[Copilot]

Fix LocaleUtils creating WebView in the background → ANR

Changes Completed:

• Understand the issue: WebView creation in Application.onCreate() causing ANR
• Research: Confirmed WebView creation must be done on UI thread (Android requirement)
• Remove LocaleUtils.onApplicationCreate(this) call from MTApplication.onCreate()
• Add LocaleUtils.fixWebViewLocale(this) call to SplashScreenActivity.onCreate() to run it once in the foreground
• Verify the changes compile and don't break existing functionality
• Code review completed
• Security check completed (no issues found)

Summary:

This PR fixes an ANR issue by moving the WebView locale initialization from MTApplication.onCreate() (which can run in the background) to SplashScreenActivity.onCreate() (which always runs on the UI thread in the foreground).

Files Changed:

1. MTApplication.kt (line 62 removed): Removed LocaleUtils.onApplicationCreate(this) call
2. SplashScreenActivity.kt (line 11 & 40): Added LocaleUtils import and call to fixWebViewLocale(this)

Why This Works:

• WebView must be created on the main/UI thread (Android requirement)
• Application.onCreate() can run in the background during app initialization
• SplashScreenActivity is the first user-visible Activity, guaranteeing foreground execution on the UI thread
• The WebView initialization now happens once, on the correct thread, preventing ANR errors
• Using fixWebViewLocale() directly provides clearer intent than the wrapper method onApplicationCreate()

Security Check:

✅ No security vulnerabilities detected

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Fix LocaleUtils creating WebView in the background -> ANR</issue_title>
<issue_description>- https://github.com/mtransitapps/mtransit-for-android/blob/master/app-android/src/main/java/org/mtransit/android/ui/MTApplication.kt

mtransit-for-android/app-android/src/main/java/org/mtransit/android/ui/MTApplication.kt

Line 62 in 45e17d5

LocaleUtils.onApplicationCreate(this)

• https://github.com/mtransitapps/commons-android/blob/master/src/main/java/org/mtransit/android/commons/LocaleUtils.java
  https://github.com/mtransitapps/commons-android/blob/ddcba157947e23a675fc75c16c1a9dc4f56f927f/src/main/java/org/mtransit/android/commons/LocaleUtils.java#L44-L50

Should move it to SplashScreenActivity so it's only done once, in the foreground.

Crashlytics:
https://console.firebase.google.com/project/montransitapps/crashlytics/app/android:org.mtransit.android/issues/db4a097fb036bfda7ebfbaaa7573338e

       at android.webkit.WebView.<init>(WebView.java:322)
       at org.mtransit.android.commons.LocaleUtils.onApplicationCreate(LocaleUtils.java:46)
       at org.mtransit.android.ui.MTApplication.onCreate(MTApplication.kt:62)
       at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1213)
```</issue_description>

<agent_instructions>Should only make changes in `SplashScreenActivity.kt` and `MTApplication.kt`

Check if it's possible to call `new WebView(context).destroy()` in background thread</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Fix LocaleUtils creating WebView in the background -> ANR #86

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[mmathieum]

@copilot please use the new LocaleUtils``fixWebViewLocale function directly in Splashscreen

[Copilot]

@copilot please use the new LocaleUtils``fixWebViewLocale function directly in Splashscreen

Done. Changed to call LocaleUtils.fixWebViewLocale(this) directly in commit ea36e6b.

[mmathieum]

Done with FF here:

• 39e2ad0