Show swipe action icons

Fixes #59

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

@@ -22,6 +22,8 @@ package eu.faircode.email;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
 import android.text.TextUtils;
@@ -159,10 +161,47 @@ public class FragmentMessages extends FragmentEx {
                 return false;
             }
 
+            @Override
+            public void onChildDraw(Canvas canvas, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
+                int pos = viewHolder.getAdapterPosition();
+                if (pos == RecyclerView.NO_POSITION)
+                    return;
+
+                TupleMessageEx message = ((AdapterMessage) rvMessage.getAdapter()).getCurrentList().get(pos);
+                boolean inbox = (EntityFolder.ARCHIVE.equals(message.folderType) || EntityFolder.TRASH.equals(message.folderType));
+
+                View itemView = viewHolder.itemView;
+                int margin = Math.round(12 * (getResources().getDisplayMetrics().density));
+
+                if (dX > margin) {
+                    // Right swipe
+                    Drawable d = getResources().getDrawable(inbox ? R.drawable.baseline_inbox_24 : R.drawable.baseline_archive_24, getContext().getTheme());
+                    d.setBounds(
+                            itemView.getLeft() + margin,
+                            itemView.getTop() + d.getIntrinsicHeight() / 2,
+                            itemView.getLeft() + margin + d.getIntrinsicWidth(),
+                            itemView.getTop() + (itemView.getHeight() - d.getIntrinsicHeight() / 2));
+                    d.draw(canvas);
+                } else if (dX < -margin) {
+                    // Left swipe
+                    Drawable d = getResources().getDrawable(inbox ? R.drawable.baseline_inbox_24 : R.drawable.baseline_delete_24, getContext().getTheme());
+                    d.setBounds(
+                            itemView.getLeft() + itemView.getWidth() - d.getIntrinsicWidth() - margin,
+                            itemView.getTop() + d.getIntrinsicHeight() / 2,
+                            itemView.getLeft() + itemView.getWidth() - margin,
+                            itemView.getTop() + (itemView.getHeight() - d.getIntrinsicHeight() / 2));
+                    d.draw(canvas);
+                }
+
+                super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
+            }
+
             @Override
             public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
                 int pos = viewHolder.getAdapterPosition();
-                if (pos != RecyclerView.NO_POSITION) {
+                if (pos == RecyclerView.NO_POSITION)
+                    return;
+
                 TupleMessageEx message = ((AdapterMessage) rvMessage.getAdapter()).getCurrentList().get(pos);
                 Log.i(Helper.TAG, "Swiped dir=" + direction + " message=" + message.id);
 
@@ -218,7 +257,6 @@ public class FragmentMessages extends FragmentEx {
                     }
                 }.load(FragmentMessages.this, args);
             }
-            }
         }).attachToRecyclerView(rvMessage);
 
         fab.setOnClickListener(new View.OnClickListener() {

app/src/main/res/drawable/baseline_inbox_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0"
+        android:tint="?attr/colorControlNormal">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19,3L4.99,3c-1.11,0 -1.98,0.89 -1.98,2L3,19c0,1.1 0.88,2 1.99,2L19,21c1.1,0 2,-0.9 2,-2L21,5c0,-1.11 -0.9,-2 -2,-2zM19,15h-4c0,1.66 -1.35,3 -3,3s-3,-1.34 -3,-3L4.99,15L4.99,5L19,5v10z"/>
+</vector>

app/src/main/res/drawable/baseline_move_to_inbox_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0"
+        android:tint="?attr/colorControlNormal">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19,3L4.99,3c-1.11,0 -1.98,0.9 -1.98,2L3,19c0,1.1 0.88,2 1.99,2L19,21c1.1,0 2,-0.9 2,-2L21,5c0,-1.1 -0.9,-2 -2,-2zM19,15h-4c0,1.66 -1.35,3 -3,3s-3,-1.34 -3,-3L4.99,15L4.99,5L19,5v10zM16,10h-2L14,7h-4v3L8,10l4,4 4,-4z"/>
+</vector>