Info button for cert chain

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

@@ -5786,6 +5786,7 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                                 TextView tvEmail = dview.findViewById(R.id.tvEmail);
                                 TextView tvEmailInvalid = dview.findViewById(R.id.tvEmailInvalid);
                                 TextView tvSubject = dview.findViewById(R.id.tvSubject);
+                                ImageButton ibInfo = dview.findViewById(R.id.ibInfo);
                                 TextView tvAfter = dview.findViewById(R.id.tvAfter);
                                 TextView tvBefore = dview.findViewById(R.id.tvBefore);
                                 TextView tvExpired = dview.findViewById(R.id.tvExpired);
@@ -5803,22 +5804,22 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                                 tvBefore.setText(record.before == null ? null : TF.format(record.before));
                                 tvExpired.setVisibility(record.isExpired(time) ? View.VISIBLE : View.GONE);
 
-                                if (trace != null && trace.size() > 0)
-                                    tvSubject.setOnClickListener(new View.OnClickListener() {
-                                        @Override
-                                        public void onClick(View v) {
-                                            StringBuilder sb = new StringBuilder();
-                                            for (int i = 0; i < trace.size(); i++) {
-                                                if (i > 0)
-                                                    sb.append("\n\n");
-                                                sb.append(i + 1).append(") ").append(trace.get(i));
-                                            }
-
-                                            new AlertDialog.Builder(getContext())
-                                                    .setMessage(sb.toString())
-                                                    .show();
+                                ibInfo.setOnClickListener(new View.OnClickListener() {
+                                    @Override
+                                    public void onClick(View v) {
+                                        StringBuilder sb = new StringBuilder();
+                                        for (int i = 0; i < trace.size(); i++) {
+                                            if (i > 0)
+                                                sb.append("\n\n");
+                                            sb.append(i + 1).append(") ").append(trace.get(i));
                                         }
-                                    });
+
+                                        new AlertDialog.Builder(getContext())
+                                                .setMessage(sb.toString())
+                                                .show();
+                                    }
+                                });
+                                ibInfo.setVisibility(trace != null && trace.size() > 0 ? View.VISIBLE : View.GONE);
 
                                 AlertDialog.Builder builder = new AlertDialog.Builder(getContext())
                                         .setView(dview)

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

@@ -89,14 +89,27 @@
 
         <eu.faircode.email.FixedTextView
             android:id="@+id/tvSubjectTitle"
-            android:layout_width="wrap_content"
+            android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_marginTop="24dp"
+            android:layout_marginEnd="12dp"
             android:text="@string/title_signature_subject"
             android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            app:layout_constraintEnd_toStartOf="@+id/ibInfo"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvEmailInvalid" />
 
+        <ImageButton
+            android:id="@+id/ibInfo"
+            android:layout_width="24dp"
+            android:layout_height="24dp"
+            android:background="?android:attr/selectableItemBackgroundBorderless"
+            android:contentDescription="@string/title_info"
+            android:tooltipText="@string/title_info"
+            app:layout_constraintBottom_toBottomOf="@id/tvSubjectTitle"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:srcCompat="@drawable/baseline_info_24" />
+
         <eu.faircode.email.FixedTextView
             android:id="@+id/tvSubject"
             android:layout_width="wrap_content"