Fix MaterialAlertDialogBuilder crash with unthemed application context

ultrasonic/src/main/kotlin/org/moire/ultrasonic/util/Dialogs.kt

@@ -9,11 +9,22 @@ package org.moire.ultrasonic.util
 
 import android.app.Activity
 import android.content.Context
+import android.view.ContextThemeWrapper
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import java.lang.ref.WeakReference
 import org.moire.ultrasonic.R
 import timber.log.Timber
 
+/**
+ * MaterialAlertDialogBuilder requires a context whose theme inherits from Theme.AppCompat
+ * (it resolves the colorPrimary attribute in ThemeEnforcement). An application or service
+ * context carries no app theme, so it must be wrapped in a ContextThemeWrapper.
+ */
+private fun themedContext(context: Context): Context {
+    if (context is Activity || context is ContextThemeWrapper) return context
+    return ContextThemeWrapper(context, UiUtil.getStyleFromSettings(context))
+}
+
 /*
  * InfoDialog can be used to show some information to the user. Typically it cannot be cancelled,
  * only dismissed via OK.
@@ -25,7 +36,8 @@ open class InfoDialog(
     private val finishActivityOnClose: Boolean = false
 ) {
     private val activityRef: WeakReference<Activity?> = WeakReference(activity)
-    open var builder: MaterialAlertDialogBuilder = Builder(activityRef.get() ?: context, message)
+    open var builder: MaterialAlertDialogBuilder =
+        Builder(themedContext(activityRef.get() ?: context), message)
 
     fun show() {
         builder.setOnCancelListener {
@@ -74,7 +86,8 @@ class ErrorDialog(
     finishActivityOnClose: Boolean = false
 ) : InfoDialog(context, message, activity, finishActivityOnClose) {
 
-    override var builder: MaterialAlertDialogBuilder = Builder(activity ?: context, message)
+    override var builder: MaterialAlertDialogBuilder =
+        Builder(themedContext(activity ?: context), message)
 
     class Builder(context: Context) : MaterialAlertDialogBuilder(context) {
         constructor(context: Context, message: CharSequence?) : this(context) {
@@ -101,7 +114,8 @@ class ConfirmationDialog(
     activity: Activity? = null,
     finishActivityOnClose: Boolean = false
 ) : InfoDialog(context, message, activity, finishActivityOnClose) {
-    override var builder: MaterialAlertDialogBuilder = Builder(activity ?: context, message)
+    override var builder: MaterialAlertDialogBuilder =
+        Builder(themedContext(activity ?: context), message)
 
     class Builder(context: Context) : MaterialAlertDialogBuilder(context) {
         constructor(context: Context, message: CharSequence?) : this(context) {

ultrasonic/src/main/kotlin/org/moire/ultrasonic/util/UiUtil.kt

@@ -43,7 +43,8 @@ object UiUtil {
         context.setTheme(R.style.UltrasonicTheme_Base)
     }
 
-    private fun getStyleFromSettings(context: Context): Int = when (Settings.theme.lowercase()) {
+    @JvmStatic
+    fun getStyleFromSettings(context: Context): Int = when (Settings.theme.lowercase()) {
         context.getString(R.string.setting_key_theme_dark) -> {
             R.style.UltrasonicTheme_Dark
         }