Force dark for WebView if possible

app/build.gradle

@@ -239,6 +239,7 @@ dependencies {
     def appcompat_version = "1.3.0-beta01"
     def activity_version = "1.2.0-rc01"
     def fragment_version = "1.3.0-rc01"
+    def webkit_version = "1.4.0"
     def recyclerview_version = "1.2.0-beta01"
     def coordinatorlayout_version = "1.1.0"
     def constraintlayout_version = "2.0.2"
@@ -288,6 +289,10 @@ dependencies {
     implementation "androidx.activity:activity:$activity_version"
     implementation "androidx.fragment:fragment:$fragment_version"
 
+    // https://developer.android.com/jetpack/androidx/releases/webkit
+    // https://mvnrepository.com/artifact/androidx.webkit/webkit
+    implementation "androidx.webkit:webkit:$webkit_version"
+
     // https://mvnrepository.com/artifact/androidx.viewpager2/viewpager2
     //implementation "androidx.viewpager2:viewpager2:1.1.0-alpha01"
 

app/src/main/java/eu/faircode/email/AdapterMessage.java

@@ -140,6 +140,7 @@ import androidx.recyclerview.widget.DiffUtil;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.StaggeredGridLayoutManager;
+import androidx.webkit.WebViewFeature;
 
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.google.android.material.snackbar.Snackbar;
@@ -3740,7 +3741,9 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
 
             if (full) {
                 TextView tvDark = dview.findViewById(R.id.tvDark);
-                tvDark.setVisibility(Helper.isDarkTheme(context) ? View.VISIBLE : View.GONE);
+                tvDark.setVisibility(Helper.isDarkTheme(context)
+                        && !WebViewFeature.isFeatureSupported(WebViewFeature.FORCE_DARK)
+                        ? View.VISIBLE : View.GONE);
             } else {
                 boolean disable_tracking = prefs.getBoolean("disable_tracking", true);
 

app/src/main/java/eu/faircode/email/WebViewEx.java

@@ -33,6 +33,11 @@ import android.webkit.WebView;
 import android.webkit.WebViewClient;
 
 import androidx.preference.PreferenceManager;
+import androidx.webkit.WebSettingsCompat;
+import androidx.webkit.WebViewFeature;
+
+import static androidx.webkit.WebSettingsCompat.FORCE_DARK_OFF;
+import static androidx.webkit.WebSettingsCompat.FORCE_DARK_ON;
 
 public class WebViewEx extends WebView implements DownloadListener, View.OnLongClickListener {
     private int height;
@@ -67,6 +72,10 @@ public class WebViewEx extends WebView implements DownloadListener, View.OnLongC
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
             settings.setSafeBrowsingEnabled(safe_browsing);
+
+        if (WebViewFeature.isFeatureSupported(WebViewFeature.FORCE_DARK))
+            WebSettingsCompat.setForceDark(settings,
+                    Helper.isDarkTheme(context) ? FORCE_DARK_ON : FORCE_DARK_OFF);
     }
 
     void init(int height, float size, Pair<Integer, Integer> position, IWebView intf) {