Explain why permissions are needed

app/src/main/java/eu/faircode/email/FragmentSetup.java

@@ -464,8 +464,17 @@ public class FragmentSetup extends FragmentBase {
         if (granted)
             selectAccount();
         else
+            new AlertDialog.Builder(getContext())
+                    .setMessage(R.string.title_setup_gmail_rationale)
+                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
                             requestPermissions(permissions.toArray(new String[0]), ActivitySetup.REQUEST_CHOOSE_ACCOUNT);
                         }
+                    })
+                    .setNegativeButton(android.R.string.cancel, null)
+                    .show();
+    }
 
     private void selectAccount() {
         Log.i("Select account");

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

@@ -137,7 +137,7 @@
     <string name="title_setup_wizard">Wizard</string>
     <string name="title_setup_gmail" translatable="false">Gmail</string>
     <string name="title_setup_other">Other provider</string>
-    <string name="title_authorizing">Authorizing &#8230;</string>
+    <string name="title_setup_gmail_rationale">Please grant permissions to select an account and read your name</string>
     <string name="title_setup_instructions">Setup instructions</string>
     <string name="title_setup_no_settings">No settings found for domain \'%1$s\'</string>
     <string name="title_setup_quick_success">An account and an identity have successfully been added</string>
@@ -419,6 +419,7 @@
     <string name="title_activesync_support">ActiveSync is not supported</string>
     <string name="title_oauth_support">OAuth is not supported</string>
     <string name="title_authorize">Authorize</string>
+    <string name="title_authorizing">Authorizing &#8230;</string>
 
     <string name="title_synchronize_now">Synchronize now</string>
     <string name="title_synchronize_all">Synchronize all messages</string>