PspdfkitWidget AppCompatActivity issue

The PspdfkitWidget for Flutter requires the MainActivity in the Flutter Android project to extend AppCompatActivity, but currently, none of the available Flutter Activity implementations extend AppCompatActivity. This leads to a crash when you use it in your application:

java.lang.ClassCastException: com.example.app.MainActivity cannot be cast to androidx.appcompat.app.AppCompatActivity

You can fix this by extending our custom implementation of FlutterAppCompatActivity instead. You might see compile errors if androidx.appcompat:appcompat isn’t included in your dependencies, so make sure the android/app/build.gradle file has the line below under dependencies, and replace $appcompat_version with an actual version:

implementation "androidx.appcompat:appcompat:$appcompat_version"

Using FlutterAppCompatActivity also introduces another issue if your application’s theme isn’t AppCompat based:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.activitylifecycletest/com.example.activitylifecycletest.DialogActivity}:
java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

Fix this by changing your Android project’s main theme parent to an AppCompat-based theme. We recommend using PSPDFKit.Theme.Default. Go to /android/app/src/main/res/values/styles.xml and make the following changes:

<style name="NormalTheme" parent="@style/PSPDFKit.Theme.Default">
       ......
 </style>

For dark mode support, set the parent theme in the values-night/styles.xml file. We recommend using the PSPDFKit.Theme.Dark theme. Go to /android/app/src/main/res/values-night/styles.xml and make the following changes:

<style name="NormalTheme" parent="@style/PSPDFKit.Theme.Dark">
       ......
 </style>