Android Oreo 8.0（三星S9）应用语言切换功能异常求助

Hey there, let's break down why your app's language switch isn't working fully on Android Oreo (8.0) when it worked perfectly on older devices like the S4.

First, let's recap your issue: you're switching app languages in-code, and on pre-Oreo devices, every Activity picks up the new language. But on the S9 running Oreo, only some content updates—most stays in the original language.

The Oreo Changes That Broke Your Old Logic #

Google made a few key changes to how app configuration and resource loading work in Android 8.0 that directly affect language switching:

• Immutable Configuration Objects: Before Oreo, you could modify the existing Configuration instance from getResources().getConfiguration() directly (like setting config.locale). But starting in Oreo, this object is immutable—any changes you make to it won't actually take effect because the system ignores modifications to the original config.

• Strict Context-Based Resource Loading: Oreo enforces that resources are loaded based on the context's configuration. If you don't create a new context with the updated language settings, some Activities or fragments might still pull resources from the old context's cache.

• Enhanced Resource Caching: Oreo optimized resource caching to improve performance, but this means old language resources might stick around longer. Even if you update the config, cached resources won't refresh unless you properly restart the app or use the new configuration context.

Fixing Your Language Switch Code #

Let's adjust your existing code snippet (I'll fill in the typical implementation you might have used) to work with Oreo:

Old (Pre-Oreo) Code (What You're Probably Using)

private View.OnClickListener btnLangue3Listener = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Locale locale = new Locale("es");
        Locale.setDefault(locale);
        Configuration config = getResources().getConfiguration();
        config.locale = locale;
        getResources().updateConfiguration(config, getResources().getDisplayMetrics());
        recreate();
    }
};

Updated Code for Oreo & Above

private View.OnClickListener btnLangue3Listener = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Locale locale = new Locale("es");
        Locale.setDefault(locale);
        
        // Create a new Configuration instance instead of modifying the existing one
        Configuration config = new Configuration(getResources().getConfiguration());
        
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            // Use setLocale() instead of direct field assignment (Oreo+)
            config.setLocale(locale);
            // Create a new context with the updated configuration
            Context updatedContext = createConfigurationContext(config);
            // Update the app's global resources to use the new config
            getApplicationContext().getResources().updateConfiguration(config, getResources().getDisplayMetrics());
        } else {
            // Fallback for older versions
            config.locale = locale;
            getResources().updateConfiguration(config, getResources().getDisplayMetrics());
        }
        
        // Restart the current activity to apply changes
        recreate();
        
        // For full global effect, consider restarting the entire app instead:
        // Intent restartIntent = new Intent(v.getContext(), MainActivity.class);
        // restartIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
        // startActivity(restartIntent);
        // finish();
    }
};

Key Takeaways to Ensure Full Language Switching #

• Never modify the original Configuration object: Always create a new instance and update that instead.
• Use setLocale() for Oreo+: Directly assigning config.locale is deprecated and ignored in Oreo.
• Update the application context: This ensures all future Activities use the new language config.
• Restart properly: Sometimes just recreating the current Activity isn't enough—restarting the entire app clears resource caches and guarantees all components pick up the new language.

内容的提问来源于stack exchange，提问作者Louis Bouchard