Select account is available in original versions only

FAQ.md

@@ -181,6 +181,7 @@ FairEmail follows all the best practices for an email client as decribed in [thi
 * [(106) Which launchers can show the number of new messages?](#user-content-faq106)
 * [(107) How do I used colored stars?](#user-content-faq107)
 * [(108) Can you add permanently delete messages from any folder?](#user-content-faq108)
+* [(109) Why is 'select account' available in official releases only?](#user-content-faq109)
 
 [I have another question.](#support)
 
@@ -1792,6 +1793,22 @@ Permanently delete messages from other folders would defeat the purpose of the t
 
 <br />
 
+<a name="faq109"></a>
+**(109) Why is 'select account' available in official releases only?**
+
+Using *select account* to select and authorize Google accounts require special permission from Google for security and privacy reasons.
+This special permission can only be acquired for apps a developer manages and is responsible for.
+Third party builds, like the F-Droid builds, are managed by third parties and are the responsibility of these third parties.
+So, only these third parties can acquire the required permission from Google.
+Since these third parties do not actually support FairEmail, they are most likely not going to request the required permission.
+
+You can solve this in two ways:
+
+* Switch to the official version of FairEmail, see [here](https://github.com/M66B/open-source-email/blob/master/README.md#downloads) for the options
+* Use app specific passwords, see [this FAQ](#user-content-faq6)
+
+<br />
+
 ## Support
 
 If you have another question, want to request a feature or report a bug, you can use [this forum](https://forum.xda-developers.com/android/apps-games/source-email-t3824168).

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

@@ -34,6 +34,7 @@ import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.graphics.Color;
 import android.graphics.drawable.GradientDrawable;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
@@ -361,6 +362,21 @@ public class FragmentAccount extends FragmentBase {
                 Log.i("Authorize " + provider);
 
                 if ("com.google".equals(provider.type)) {
+                    if (!Helper.hasValidFingerprint(getContext())) {
+                        Snackbar snackbar = Snackbar.make(view, R.string.title_no_xoauth2, Snackbar.LENGTH_LONG);
+                        final Intent intent = new Intent(Intent.ACTION_VIEW);
+                        intent.setData(Uri.parse(Helper.FAQ_URI + "#user-content-faq19"));
+                        if (intent.resolveActivity(getContext().getPackageManager()) != null)
+                            snackbar.setAction(R.string.title_info, new View.OnClickListener() {
+                                @Override
+                                public void onClick(View view) {
+                                    startActivity(intent);
+                                }
+                            });
+                        snackbar.show();
+                        return;
+                    }
+
                     String permission = Manifest.permission.GET_ACCOUNTS;
                     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O &&
                             !Helper.hasPermission(getContext(), permission)) {

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

@@ -30,6 +30,7 @@ import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
@@ -123,6 +124,21 @@ public class FragmentQuickSetup extends FragmentBase {
         btnAuthorize.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
+                if (!Helper.hasValidFingerprint(getContext())) {
+                    Snackbar snackbar = Snackbar.make(view, R.string.title_no_xoauth2, Snackbar.LENGTH_LONG);
+                    final Intent intent = new Intent(Intent.ACTION_VIEW);
+                    intent.setData(Uri.parse(Helper.FAQ_URI + "#user-content-faq19"));
+                    if (intent.resolveActivity(getContext().getPackageManager()) != null)
+                        snackbar.setAction(R.string.title_info, new View.OnClickListener() {
+                            @Override
+                            public void onClick(View view) {
+                                startActivity(intent);
+                            }
+                        });
+                    snackbar.show();
+                    return;
+                }
+
                 String permission = Manifest.permission.GET_ACCOUNTS;
                 if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O &&
                         !Helper.hasPermission(getContext(), permission)) {

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

@@ -317,6 +317,7 @@
     <string name="title_keep_alive_interval">Keep-alive/poll interval (minutes)</string>
     <string name="title_partial_fetch" translatable="false">Partial fetch</string>
     <string name="title_check">Check</string>
+    <string name="title_no_xoauth2">This feature is available in original versions only</string>
     <string name="title_no_name">Name missing</string>
     <string name="title_no_email">Email address missing</string>
     <string name="title_email_invalid">Email address invalid</string>