生成签名APK时提示未知类错误，该如何解决？

Hey there! Let's work through those unknown class errors you're hitting while trying to generate a signed APK. These issues almost always come down to missing dependencies, misconfigured build settings, or accidental references to non-public APIs. Here's how to fix each one:

1. com.google.android.gms.common.internal.safeparcel.SafeParcelable #

This class is part of Google Play Services, so you're probably missing the required dependency for it.

• Add the Play Services Base dependency to your module-level build.gradle file:

  implementation 'com.google.android.gms:play-services-base:17.6.0' // Use the latest stable version available
  

• Double-check that your project-level build.gradle includes the Google Maven repository (where Play Services artifacts are hosted):

  repositories {
      google()
      // Other repos like mavenCentral() go here
  }
  

2. android.app.OnActivityPausedListener #

Heads up—this is a hidden system API that's not intended for public use. You shouldn't be referencing it directly in your code or relying on libraries that do.

• First, scan your own code for any mentions of this interface. If you find it, replace it with standard Android lifecycle callbacks (like overriding onPause() in your Activity/Fragment instead).
• If the reference comes from a third-party library, try updating that library to the latest version—most developers fix hidden API references in newer releases. If updating isn't an option, consider swapping it for a more maintained alternative.

3. com.mopub.nativeads.CustomEventNative #

This is a MoPub-specific class for native ad custom events. The error means your project references MoPub's native ad functionality but doesn't have the SDK dependency added.

• Add the MoPub Native SDK to your module-level build.gradle:

  implementation 'com.mopub:mopub-sdk-native:5.17.0' // Use the latest stable version
  

• If you're using ProGuard/R8 for code shrinking, add rules to keep MoPub's classes from being obfuscated:

  -keep class com.mopub.** { *; }
  -dontwarn com.mopub.**
  

• Also, note the hint in your error log: if you meant to use AdMob's mediation custom events instead, make sure you reference com.google.android.gms.ads.mediation.customevent.CustomEventNative (not the MoPub one). Double-check your code's import statements to confirm you're using the right class.

After making these changes, clean your project (Build > Clean Project), rebuild it, and try generating the signed APK again. That should clear up those unknown class references!

内容的提问来源于stack exchange，提问作者Bala