deep link into FSI setting if not granted

src/main/java/eu/siacs/conversations/ui/fragment/settings/NotificationsSettingsFragment.java

@@ -1,11 +1,15 @@
 package eu.siacs.conversations.ui.fragment.settings;
 
-import android.app.NotificationChannel;
+import android.app.NotificationManager;
+import android.content.ActivityNotFoundException;
+import android.content.Intent;
 import android.media.RingtoneManager;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
+import android.provider.Settings;
 import android.util.Log;
+import android.widget.Toast;
 
 import androidx.activity.result.ActivityResultLauncher;
 import androidx.annotation.NonNull;
@@ -56,12 +60,14 @@ public class NotificationsSettingsFragment extends XmppPreferenceFragment {
             @Nullable final Bundle savedInstanceState, final @Nullable String rootKey) {
         setPreferencesFromResource(R.xml.preferences_notifications, rootKey);
         final var messageNotificationSettings = findPreference("message_notification_settings");
+        final var fullscreenNotification = findPreference("fullscreen_notification");
         final var notificationRingtone = findPreference(AppSettings.NOTIFICATION_RINGTONE);
         final var notificationHeadsUp = findPreference(AppSettings.NOTIFICATION_HEADS_UP);
         final var notificationVibrate = findPreference(AppSettings.NOTIFICATION_VIBRATE);
         final var notificationLed = findPreference(AppSettings.NOTIFICATION_LED);
         final var foregroundService = findPreference(AppSettings.KEEP_FOREGROUND_SERVICE);
         if (messageNotificationSettings == null
+                || fullscreenNotification == null
                 || notificationRingtone == null
                 || notificationHeadsUp == null
                 || notificationVibrate == null
@@ -78,6 +84,44 @@ public class NotificationsSettingsFragment extends XmppPreferenceFragment {
         } else {
             messageNotificationSettings.setVisible(false);
         }
+        fullscreenNotification.setOnPreferenceClickListener(this::manageAppUseFullScreen);
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE
+                || requireContext()
+                        .getSystemService(NotificationManager.class)
+                        .canUseFullScreenIntent()) {
+            fullscreenNotification.setVisible(false);
+        }
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        final var fullscreenNotification = findPreference("fullscreen_notification");
+        if (fullscreenNotification == null) {
+            return;
+        }
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE
+                || requireContext()
+                        .getSystemService(NotificationManager.class)
+                        .canUseFullScreenIntent()) {
+            fullscreenNotification.setVisible(false);
+        }
+    }
+
+    private boolean manageAppUseFullScreen(final Preference preference) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+            return false;
+        }
+        final var intent = new Intent(Settings.ACTION_MANAGE_APP_USE_FULL_SCREEN_INTENT);
+        intent.setData(Uri.parse(String.format("package:%s", requireContext().getPackageName())));
+        try {
+            startActivity(intent);
+        } catch (final ActivityNotFoundException e) {
+            Toast.makeText(requireContext(), R.string.no_application_found, Toast.LENGTH_SHORT)
+                    .show();
+            return false;
+        }
+        return true;
     }
 
     @Override

src/main/res/drawable/ic_smartphone_24dp.xml

@@ -0,0 +1,12 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="?colorControlNormal"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M17,1.01L7,1c-1.1,0 -2,0.9 -2,2v18c0,1.1 0.9,2 2,2h10c1.1,0 2,-0.9 2,-2V3c0,-1.1 -0.9,-1.99 -2,-1.99zM17,19H7V5h10v14z" />
+
+</vector>

src/main/res/values/strings.xml

@@ -1062,5 +1062,7 @@
     <string name="pref_backup_summary">Create one-off, Schedule recurring</string>
     <string name="pref_create_backup_one_off_summary">Create one-off backup</string>
     <string name="pref_backup_recurring">Recurring backup</string>
+    <string name="pref_fullscreen_notification">Full screen notifications</string>
+    <string name="pref_fullscreen_notification_summary">Allow this app to show incoming call notifications that take up the full screen when the device is locked.</string>
 
 </resources>

src/main/res/xml/preferences_notifications.xml

@@ -46,6 +46,11 @@
         android:ringtoneType="ringtone"
         android:summary="@string/pref_call_ringtone_summary"
         android:title="@string/pref_ringtone" />
+    <Preference
+        android:icon="@drawable/ic_smartphone_24dp"
+        android:key="fullscreen_notification"
+        android:summary="@string/pref_fullscreen_notification_summary"
+        android:title="@string/pref_fullscreen_notification" />
     <ListPreference
         android:defaultValue="@integer/grace_period"
         android:entries="@array/grace_periods"