Force close app if Webview isn't available

app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt

@@ -32,6 +32,8 @@ import eu.kanade.tachiyomi.ui.source.SourceController
 import eu.kanade.tachiyomi.ui.source.global_search.GlobalSearchController
 import eu.kanade.tachiyomi.util.lang.launchInUI
 import eu.kanade.tachiyomi.util.lang.launchUI
+import eu.kanade.tachiyomi.util.system.WebviewUtil
+import eu.kanade.tachiyomi.util.system.toast
 import java.util.Date
 import java.util.concurrent.TimeUnit
 import kotlinx.coroutines.Dispatchers
@@ -64,6 +66,12 @@ class MainActivity : BaseActivity<MainActivityBinding>() {
 
         binding = MainActivityBinding.inflate(layoutInflater)
 
+        // Enforce Webview availability
+        if (!WebviewUtil.supportsWebview(this)) {
+            toast(R.string.information_webview_required, Toast.LENGTH_LONG)
+            finishAndRemoveTask()
+        }
+
         // Do not let the launcher create a new activity http://stackoverflow.com/questions/16283079
         if (!isTaskRoot) {
             finish()

app/src/main/java/eu/kanade/tachiyomi/util/system/WebviewUtil.kt

@@ -1,15 +1,23 @@
 package eu.kanade.tachiyomi.util.system
 
+import android.content.Context
+import android.content.pm.PackageManager
 import android.webkit.WebView
 
-private val WEBVIEW_UA_VERSION_REGEX by lazy {
-    Regex(""".*Chrome/(\d+)\..*""")
-}
+object WebviewUtil {
+    val WEBVIEW_UA_VERSION_REGEX by lazy {
+        Regex(""".*Chrome/(\d+)\..*""")
+    }
+
+    const val MINIMUM_WEBVIEW_VERSION = 79
 
-private const val MINIMUM_WEBVIEW_VERSION = 79
+    fun supportsWebview(context: Context): Boolean {
+        return context.packageManager.hasSystemFeature(PackageManager.FEATURE_WEBVIEW)
+    }
+}
 
 fun WebView.isOutdated(): Boolean {
-    return getWebviewMajorVersion(this) < MINIMUM_WEBVIEW_VERSION
+    return getWebviewMajorVersion(this) < WebviewUtil.MINIMUM_WEBVIEW_VERSION
 }
 
 // Based on https://stackoverflow.com/a/29218966
@@ -19,7 +27,7 @@ private fun getWebviewMajorVersion(webview: WebView): Int {
     // Next call to getUserAgentString() will get us the default
     webview.settings.userAgentString = null
 
-    val uaRegexMatch = WEBVIEW_UA_VERSION_REGEX.matchEntire(webview.settings.userAgentString)
+    val uaRegexMatch = WebviewUtil.WEBVIEW_UA_VERSION_REGEX.matchEntire(webview.settings.userAgentString)
     val webViewVersion: Int = if (uaRegexMatch != null && uaRegexMatch.groupValues.size > 1) {
         uaRegexMatch.groupValues[1].toInt()
     } else {

app/src/main/res/values/strings.xml

@@ -593,6 +593,7 @@
     <string name="information_empty_library">Your library is empty, add series to your library from the sources.</string>
     <string name="information_empty_category">You have no categories. Hit the plus button to create one for organizing your library.</string>
     <string name="information_cloudflare_bypass_failure">Failed to bypass Cloudflare</string>
+    <string name="information_webview_required">Webview is required for Tachiyomi</string>
     <string name="information_webview_outdated">Please update the WebView app for better compatibility</string>
 
     <!-- Download Notification -->