Show headers in EML viewer

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

@@ -47,6 +47,7 @@ import android.widget.Toast;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
+import androidx.cardview.widget.CardView;
 import androidx.constraintlayout.widget.Group;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
@@ -94,6 +95,8 @@ public class ActivityEML extends ActivityBase {
     private TextView tvBody;
     private TextView tvStructure;
     private ImageButton ibEml;
+    private CardView cardHeaders;
+    private TextView tvHeaders;
     private ContentLoadingProgressBar pbWait;
     private Group grpReady;
 
@@ -123,6 +126,8 @@ public class ActivityEML extends ActivityBase {
         tvBody = findViewById(R.id.tvBody);
         tvStructure = findViewById(R.id.tvStructure);
         ibEml = findViewById(R.id.ibEml);
+        cardHeaders = findViewById(R.id.cardHeaders);
+        tvHeaders = findViewById(R.id.tvHeaders);
         pbWait = findViewById(R.id.pbWait);
         grpReady = findViewById(R.id.grpReady);
 
@@ -205,6 +210,7 @@ public class ActivityEML extends ActivityBase {
         FragmentDialogTheme.setBackground(this, view, false);
         vSeparatorAttachments.setVisibility(View.GONE);
         grpReady.setVisibility(View.GONE);
+        cardHeaders.setVisibility(View.GONE);
 
         load();
     }
@@ -281,6 +287,8 @@ public class ActivityEML extends ActivityBase {
                     getStructure(imessage, ssb, 0, textColorLink);
                     result.structure = ssb;
 
+                    result.headers = HtmlHelper.highlightHeaders(context, helper.getHeaders(), false);
+
                     return result;
                 }
             }
@@ -358,7 +366,9 @@ public class ActivityEML extends ActivityBase {
 
                 tvBody.setText(result.body);
                 tvStructure.setText(result.structure);
+                tvHeaders.setText(result.headers);
                 grpReady.setVisibility(View.VISIBLE);
+                cardHeaders.setVisibility(!BuildConfig.PLAY_STORE_RELEASE ? View.VISIBLE : View.GONE);
             }
 
             @Override
@@ -672,5 +682,6 @@ public class ActivityEML extends ActivityBase {
         MessageHelper.MessageParts parts;
         Spanned body;
         Spanned structure;
+        Spanned headers;
     }
 }

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

@@ -306,6 +306,41 @@
                 </androidx.constraintlayout.widget.ConstraintLayout>
             </androidx.cardview.widget.CardView>
 
+            <androidx.cardview.widget.CardView
+                android:id="@+id/cardHeaders"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginHorizontal="3dp"
+                android:layout_marginTop="12dp"
+                app:cardBackgroundColor="?attr/colorCardBackground"
+                app:cardCornerRadius="6dp"
+                app:cardElevation="0dp"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/cardStructure">
+
+                <androidx.constraintlayout.widget.ConstraintLayout
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:paddingHorizontal="6dp"
+                    android:paddingVertical="12dp">
+
+                    <eu.faircode.email.FixedTextView
+                        android:id="@+id/tvHeaders"
+                        android:layout_width="0dp"
+                        android:layout_height="wrap_content"
+                        android:layout_marginTop="3dp"
+                        android:fontFamily="monospace"
+                        android:minHeight="30dp"
+                        android:text="Headers"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textIsSelectable="true"
+                        app:layout_constraintEnd_toEndOf="parent"
+                        app:layout_constraintStart_toStartOf="parent"
+                        app:layout_constraintTop_toTopOf="parent" />
+                </androidx.constraintlayout.widget.ConstraintLayout>
+            </androidx.cardview.widget.CardView>
+
             <androidx.constraintlayout.widget.Group
                 android:id="@+id/grpReady"
                 android:layout_width="0dp"