Made encryption a pro feature

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

@@ -23,11 +23,13 @@ import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
 import android.text.TextUtils;
+import android.view.MenuItem;
 
 import java.util.ArrayList;
 
 import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentTransaction;
+import androidx.lifecycle.Lifecycle;
 
 public class ActivityCompose extends ActivityBilling implements FragmentManager.OnBackStackChangedListener {
     static final int REQUEST_CONTACT_TO = 1;
@@ -125,4 +127,16 @@ public class ActivityCompose extends ActivityBilling implements FragmentManager.
         if (getSupportFragmentManager().getBackStackEntryCount() == 0)
             finish();
     }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case android.R.id.home:
+                if (getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.RESUMED))
+                    getSupportFragmentManager().popBackStack();
+                return true;
+            default:
+                return false;
+        }
+    }
 }

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

@@ -898,12 +898,15 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
     }
 
     private void onDecrypt(Intent intent) {
+        if (Helper.isPro(this)) {
             Intent data = new Intent();
             data.setAction(OpenPgpApi.ACTION_DECRYPT_VERIFY);
             data.putExtra(OpenPgpApi.EXTRA_USER_IDS, new String[]{intent.getStringExtra("to")});
             data.putExtra(OpenPgpApi.EXTRA_REQUEST_ASCII_ARMOR, true);
 
             decrypt(data, intent.getLongExtra("id", -1));
+        } else
+            onShowPro(intent);
     }
 
     private void onShowPro(Intent intent) {

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

@@ -488,6 +488,7 @@ public class FragmentCompose extends FragmentEx {
     }
 
     private void onEncrypt() {
+        if (Helper.isPro(getContext()))
             try {
                 String to = etTo.getText().toString();
                 InternetAddress ato[] = (TextUtils.isEmpty(to) ? new InternetAddress[0] : InternetAddress.parse(to));
@@ -510,6 +511,11 @@ public class FragmentCompose extends FragmentEx {
                 else
                     Helper.unexpectedError(getContext(), ex);
             }
+        else {
+            FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
+            fragmentTransaction.replace(R.id.content_frame, new FragmentPro()).addToBackStack("pro");
+            fragmentTransaction.commit();
+        }
     }
 
     private void encrypt(Intent data) {