Prepare secure connections only

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

@@ -38,6 +38,7 @@ public class ActivityError extends ActivityBase {
 
     private TextView tvTitle;
     private TextView tvMessage;
+    private TextView tvCertificate;
     private Button btnPassword;
     private ImageButton ibSetting;
     private ImageButton ibInfo;
@@ -52,6 +53,7 @@ public class ActivityError extends ActivityBase {
 
         tvTitle = findViewById(R.id.tvTitle);
         tvMessage = findViewById(R.id.tvMessage);
+        tvCertificate = findViewById(R.id.tvCertificate);
         btnPassword = findViewById(R.id.btnPassword);
         ibSetting = findViewById(R.id.ibSetting);
         ibInfo = findViewById(R.id.ibInfo);
@@ -86,18 +88,16 @@ public class ActivityError extends ActivityBase {
         long identity = intent.getLongExtra("identity", -1L);
         int protocol = intent.getIntExtra("protocol", -1);
         int auth_type = intent.getIntExtra("auth_type", -1);
-
-        if (message != null &&
-                (message.contains("CertPathValidatorException") ||
-                        message.contains("CertificateExpiredException")))
-            intent.putExtra("faq", 4);
-
         int faq = intent.getIntExtra("faq", -1);
 
+        boolean isCertificateException = (message != null && message.contains("CertificateException"));
+
         tvTitle.setText(title);
         tvMessage.setMovementMethod(LinkMovementMethodCompat.getInstance());
         tvMessage.setText(message);
 
+        tvCertificate.setVisibility(isCertificateException ? View.VISIBLE : View.GONE);
+
         boolean password = (auth_type == ServiceAuthenticator.AUTH_TYPE_PASSWORD);
 
         btnPassword.setText(password ? R.string.title_password : R.string.title_setup_oauth_authorize);
@@ -169,7 +169,7 @@ public class ActivityError extends ActivityBase {
         ibInfo.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
-                Helper.viewFAQ(view.getContext(), faq);
+                Helper.viewFAQ(view.getContext(), isCertificateException ? 4 : faq);
             }
         });
 

app/src/main/res/layout/activity_error.xml

@@ -67,6 +67,19 @@
                         app:layout_constraintStart_toStartOf="parent"
                         app:layout_constraintTop_toBottomOf="@id/tvTitle" />
 
+                    <TextView
+                        android:id="@+id/tvCertificate"
+                        android:layout_width="0dp"
+                        android:layout_height="wrap_content"
+                        android:layout_marginTop="24dp"
+                        android:text="@string/title_certificate_error"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
+                        android:textColor="?attr/colorError"
+                        android:textStyle="bold|italic"
+                        app:layout_constraintEnd_toEndOf="parent"
+                        app:layout_constraintStart_toStartOf="parent"
+                        app:layout_constraintTop_toBottomOf="@id/tvMessage" />
+
                     <Button
                         android:id="@+id/btnPassword"
                         android:layout_width="wrap_content"
@@ -75,7 +88,7 @@
                         android:drawablePadding="6dp"
                         android:text="@string/title_password"
                         app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toBottomOf="@id/tvMessage" />
+                        app:layout_constraintTop_toBottomOf="@id/tvCertificate" />
 
                     <ImageButton
                         android:id="@+id/ibSetting"

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

@@ -1271,6 +1271,10 @@
     <string name="title_service_port">Please double check the port number</string>
     <string name="title_service_protocol">Please double check the protocol (SSL/TLS or STARTTLS)</string>
     <string name="title_service_error10">This account needs to be authenticated again, which can be done via the quick setup wizard</string>
+    <string name="title_certificate_error">
+        Due to Google\'s Play Store policies, it is no longer possible for the version of FairEmail distributed in the Play Store to support insecure connections to email servers with certificate issues.
+        Therefore, this issue can only be resolved by your email provider - the above error information may help them resolve this issue.
+    </string>
 
     <string name="title_advanced_browse">Browse messages on the server</string>
     <string name="title_advanced_expand_read">Mark messages read on expanding</string>