add content description for toggle service button

app/src/main/java/org/schabi/newpipe/MainActivity.java

@@ -73,6 +73,7 @@ public class MainActivity extends AppCompatActivity {
     private DrawerLayout drawer = null;
     private NavigationView drawerItems = null;
     private TextView headerServiceView = null;
+    private Button toggleServiceButton = null;
 
     private boolean servicesShown = false;
     private ImageView serviceArrow;
@@ -266,8 +267,8 @@ public class MainActivity extends AppCompatActivity {
 
         serviceArrow = hView.findViewById(R.id.drawer_arrow);
         headerServiceView = hView.findViewById(R.id.drawer_header_service_view);
-        Button action = hView.findViewById(R.id.drawer_header_action_button);
-        action.setOnClickListener(view -> {
+        toggleServiceButton = hView.findViewById(R.id.drawer_header_action_button);
+        toggleServiceButton.setOnClickListener(view -> {
             toggleServices();
         });
     }
@@ -279,6 +280,7 @@ public class MainActivity extends AppCompatActivity {
         drawerItems.getMenu().removeGroup(R.id.menu_tabs_group);
         drawerItems.getMenu().removeGroup(R.id.menu_options_about_group);
 
+
         if(servicesShown) {
             showServices();
         } else {
@@ -364,6 +366,8 @@ public class MainActivity extends AppCompatActivity {
             String selectedServiceName = NewPipe.getService(
                     ServiceHelper.getSelectedServiceId(this)).getServiceInfo().getName();
             headerServiceView.setText(selectedServiceName);
+            toggleServiceButton.setContentDescription(
+                    getString(R.string.drawer_header_description) + selectedServiceName);
         } catch (Exception e) {
             ErrorActivity.reportUiError(this, e);
         }
@@ -557,6 +561,14 @@ public class MainActivity extends AppCompatActivity {
         }
     }
 
+    private void updateDrawerHeaderString(String content) {
+        NavigationView navigationView = findViewById(R.id.navigation);
+        View hView =  navigationView.getHeaderView(0);
+        Button action = hView.findViewById(R.id.drawer_header_action_button);
+
+        action.setContentDescription(content);
+    }
+
     private void handleIntent(Intent intent) {
         try {
             if (DEBUG) Log.d(TAG, "handleIntent() called with: intent = [" + intent + "]");

app/src/main/res/layout-v21/drawer_header.xml

@@ -9,6 +9,7 @@
         android:id="@+id/drawer_header_action_button"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
+        android:contentDescription="@string/drawer_header_description"
         android:background="?android:attr/selectableItemBackground" />
 
     <ImageView

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

@@ -250,6 +250,7 @@
     <string name="short_thousand">K</string>
     <string name="short_million">M</string>
     <string name="short_billion">B</string>
+    <string name="drawer_header_description">Toggle service, currently selected:</string>
     <!--Zero don't get selected (in some languages) as it is not a "special case" for android-->
     <string name="no_subscribers">No subscribers</string>
     <plurals name="subscribers">