Made sure to request the permission to change ringer mode to silent

app/src/main/AndroidManifest.xml

@@ -10,6 +10,7 @@
     <uses-permission android:name="android.permission.READ_CALL_LOG" />
     <uses-permission android:name="android.permission.READ_PHONE_STATE" />
     <uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS" />
+    <uses-permission android:name="android.permission.ACCESS_NOTIFICATION_POLICY" />
     <uses-permission android:name="android.permission.CALL_PHONE" />
     <uses-permission android:name="android.permission.ANSWER_PHONE_CALLS" />
     <uses-permission android:name="android.permission.RECEIVE_SMS" />

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/ControlCenterv2.java

@@ -19,6 +19,7 @@ package nodomain.freeyourgadget.gadgetbridge.activities;
 
 import android.Manifest;
 import android.annotation.TargetApi;
+import android.app.NotificationManager;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -81,7 +82,7 @@ public class ControlCenterv2 extends AppCompatActivity
 
     private boolean isLanguageInvalid = false;
 
-    public static final int MENU_REFRESH_CODE=1;
+    public static final int MENU_REFRESH_CODE = 1;
 
     private static PhoneStateListener fakeStateListener;
 
@@ -205,7 +206,7 @@ public class ControlCenterv2 extends AppCompatActivity
         if (cl.isFirstRun()) {
             try {
                 cl.getLogDialog().show();
-            } catch (Exception ignored){
+            } catch (Exception ignored) {
                 GB.toast(getBaseContext(), "Error showing Changelog", Toast.LENGTH_LONG, GB.ERROR);
 
             }
@@ -338,6 +339,7 @@ public class ControlCenterv2 extends AppCompatActivity
     @TargetApi(Build.VERSION_CODES.M)
     private void checkAndRequestPermissions() {
         List<String> wantedPermissions = new ArrayList<>();
+        GB.toast(this, getString(R.string.permission_granting_mandatory), Toast.LENGTH_LONG, GB.ERROR);
 
         if (ContextCompat.checkSelfPermission(this, Manifest.permission.BLUETOOTH) == PackageManager.PERMISSION_DENIED)
             wantedPermissions.add(Manifest.permission.BLUETOOTH);
@@ -368,12 +370,21 @@ public class ControlCenterv2 extends AppCompatActivity
         try {
             if (ContextCompat.checkSelfPermission(this, Manifest.permission.MEDIA_CONTENT_CONTROL) == PackageManager.PERMISSION_DENIED)
                 wantedPermissions.add(Manifest.permission.MEDIA_CONTENT_CONTROL);
-        } catch (Exception ignored){
+        } catch (Exception ignored) {
         }
 
         if (!wantedPermissions.isEmpty())
             ActivityCompat.requestPermissions(this, wantedPermissions.toArray(new String[0]), 0);
 
+        /* In order to be able to set ringer mode to silent in PhoneCallReceiver
+           the permission to access notifications is needed above Android M
+           ACCESS_NOTIFICATION_POLICY is also needed in the manifest */
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            if (!((NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE)).isNotificationPolicyAccessGranted()) {
+                startActivity(new Intent(android.provider.Settings.ACTION_NOTIFICATION_POLICY_ACCESS_SETTINGS));
+            }
+        }
+
         // HACK: On Lineage we have to do this so that the permission dialog pops up
         if (fakeStateListener == null) {
             fakeStateListener = new PhoneStateListener();

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/externalevents/PhoneCallReceiver.java

@@ -26,12 +26,16 @@ import android.content.Intent;
 import android.media.AudioManager;
 import android.telephony.TelephonyManager;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 import nodomain.freeyourgadget.gadgetbridge.model.CallSpec;
 import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 
 
 public class PhoneCallReceiver extends BroadcastReceiver {
+    private static final Logger LOG = LoggerFactory.getLogger(PhoneCallReceiver.class);
 
     private static int mLastState = TelephonyManager.CALL_STATE_IDLE;
     private static String mSavedNumber;
@@ -45,12 +49,16 @@ public class PhoneCallReceiver extends BroadcastReceiver {
             mSavedNumber = intent.getExtras().getString("android.intent.extra.PHONE_NUMBER");
         } else if(intent.getAction().equals("nodomain.freeyourgadget.gadgetbridge.MUTE_CALL")) {
             // Handle the mute request only if the phone is currently ringing
-            if(mLastState != TelephonyManager.CALL_STATE_RINGING)
+            if (mLastState != TelephonyManager.CALL_STATE_RINGING)
                 return;
 
             AudioManager audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
             mLastRingerMode = audioManager.getRingerMode();
-            audioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
+            try {
+                audioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
+            } catch (SecurityException e) {
+                LOG.error("SecurityException when trying to set ringer (no permission granted :/ ?), not setting it then.");
+            }
             mRestoreMutedCall = true;
         } else {
             if (intent.hasExtra(TelephonyManager.EXTRA_INCOMING_NUMBER)) {

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

@@ -878,6 +878,7 @@
     <string name="about_additional_device_support">Additional device support</string>
     <string name="about_additional_contributors" translatable="false">João Paulo Barraca (HPlus)\nVitaly Svyastyn (NO.1 F1)\nSami Alaoui (Teclast H30)\n“ladbsoft” (XWatch)\nSebastian Kranz (ZeTime)\nVadim Kaushan (ID115)\n“maxirnilian” (Lenovo Watch 9)\n“ksiwczynski”, “mkusnierz”, “mamutcho” (Lenovo Watch X Plus)\nAndreas Böhler (Casio GB-6900B)\nJean-François Greffier (Mi Scale 2)\nJohannes Schmitt (BFH-16)\nLukas Schwichtenberg (Makibes HR3)\nDaniel Dakhno (Fossil Q Hybrid, Fossil Hybrid HR)\nGordon Williams (Bangle.js)\nPavel Elagin (JYou Y5)\nTaavi Eomäe (iTag)</string>
     <string name="about_additional_contributions">Many thanks to all unlisted contributors for contributing code, support, ideas, motivation, bug reports, money… ✊</string>
+    <string name="permission_granting_mandatory">All these permissions are required and instability might occur if not granted</string>
     <plurals name="widget_alarm_target_hours">
         <item quantity="one">%d hour</item>
         <item quantity="two">%d hours</item>