diff --git a/Blog/EditorViewController.m b/Blog/EditorViewController.m
index 1a8ab76..3e50362 100644
--- a/Blog/EditorViewController.m
+++ b/Blog/EditorViewController.m
@@ -212,15 +212,23 @@
 
 #pragma mark - State restoration
 
+static NSString *const StateRestorationPostKey = @"post";
+static NSString *const StateRestorationModifiedPostKey = @"modifiedPost";
+static NSString *const StateRestorationTextViewContentOffsetKey = @"textView.contentOffset";
+
 - (void)encodeRestorableStateWithCoder:(NSCoder *)coder {
-    [coder encodeObject:self.post forKey:@"post"];
-    [coder encodeObject:self.modifiedPost forKey:@"modifiedPost"];
+    NSLog(@"%@ encode restorable state with coder %@", self, coder);
+    [coder encodeObject:self.post forKey:StateRestorationPostKey];
+    [coder encodeObject:self.modifiedPost forKey:StateRestorationModifiedPostKey];
+    [coder encodeCGPoint:self.textView.contentOffset forKey:StateRestorationTextViewContentOffsetKey];
     [super encodeRestorableStateWithCoder:coder];
 }
 
 - (void)decodeRestorableStateWithCoder:(NSCoder *)coder {
-    self.post = [coder decodeObjectForKey:@"post"];
-    self.modifiedPost = [coder decodeObjectForKey:@"modifiedPost"];
+    NSLog(@"%@ decode restorable state with coder %@", self, coder);
+    self.post = [coder decodeObjectForKey:StateRestorationPostKey];
+    self.modifiedPost = [coder decodeObjectForKey:StateRestorationModifiedPostKey];
+    self.textView.contentOffset = [coder decodeCGPointForKey:StateRestorationTextViewContentOffsetKey];
     [super decodeRestorableStateWithCoder:coder];
 }
 
diff --git a/Blog/PostCollection.m b/Blog/PostCollection.m
index c5c64d7..6694b3d 100644
--- a/Blog/PostCollection.m
+++ b/Blog/PostCollection.m
@@ -19,18 +19,21 @@
     return self;
 }
 
+static NSString *const PostsKey = @"posts";
+static NSString *const TitleKey = @"title";
+
 - (id)initWithCoder:(NSCoder *)coder {
     self = [super init];
     if (self) {
-        _title = [coder decodeObjectForKey:@"title"];
-        _posts = [coder decodeObjectForKey:@"posts"];
+        _title = [coder decodeObjectForKey:TitleKey];
+        _posts = [coder decodeObjectForKey:PostsKey];
     }
     return self;
 }
 
 - (void)encodeWithCoder:(NSCoder *)coder {
-    [coder encodeObject:self.title forKey:@"title"];
-    [coder encodeObject:self.posts forKey:@"posts"];
+    [coder encodeObject:self.title forKey:TitleKey];
+    [coder encodeObject:self.posts forKey:PostsKey];
 }
 
 @end
diff --git a/Blog/PostsViewController.m b/Blog/PostsViewController.m
index 0f27545..4c08f87 100644
--- a/Blog/PostsViewController.m
+++ b/Blog/PostsViewController.m
@@ -246,21 +246,26 @@ static const NSUInteger SectionPublished = 1;
 
 #pragma mark - State restoration
 
+static NSString *const StateRestorationPostCollectionsKey = @"postCollections";
+static NSString *const StateRestorationBlogStatusDateKey = @"blogStatusDate";
+static NSString *const StateRestorationBlogStatusTextKey = @"blogStatusText";
+static NSString *const StateRestorationTabelViewContentOffsetKey = @"tableView.contentOffset";
+
 - (void)encodeRestorableStateWithCoder:(NSCoder *)coder  {
     NSLog(@"%@ encode restorable state with coder %@", self, coder);
-    [coder encodeObject:self.postCollections forKey:@"postCollections"];
-    [coder encodeObject:self.blogStatusDate forKey:@"blogStatusDate"];
-    [coder encodeObject:self.blogStatusText forKey:@"blogStatusText"];
-    [coder encodeCGPoint:self.tableView.contentOffset forKey:@"tableView.contentOffset"];
+    [coder encodeObject:self.postCollections forKey:StateRestorationPostCollectionsKey];
+    [coder encodeObject:self.blogStatusDate forKey:StateRestorationBlogStatusDateKey];
+    [coder encodeObject:self.blogStatusText forKey:StateRestorationBlogStatusTextKey];
+    [coder encodeCGPoint:self.tableView.contentOffset forKey:StateRestorationTabelViewContentOffsetKey];
     [super encodeRestorableStateWithCoder:coder];
 }
 
 - (void)decodeRestorableStateWithCoder:(NSCoder *)coder {
     NSLog(@"%@ decode restorable state with coder %@", self, coder);
-    self.postCollections = [coder decodeObjectForKey:@"postCollections"];
-    self.blogStatusDate = [coder decodeObjectForKey:@"blogStatusDate"];
-    self.blogStatusText = [coder decodeObjectForKey:@"blogStatusText"];
-    self.tableView.contentOffset = [coder decodeCGPointForKey:@"tableView.contentOffset"];
+    self.postCollections = [coder decodeObjectForKey:StateRestorationPostCollectionsKey];
+    self.blogStatusDate = [coder decodeObjectForKey:StateRestorationBlogStatusDateKey];
+    self.blogStatusText = [coder decodeObjectForKey:StateRestorationBlogStatusTextKey];
+    self.tableView.contentOffset = [coder decodeCGPointForKey:StateRestorationTabelViewContentOffsetKey];
     [super decodeRestorableStateWithCoder:coder];
 }
 
diff --git a/Blog/PreviewViewController.m b/Blog/PreviewViewController.m
index 5da7070..3a9bc96 100644
--- a/Blog/PreviewViewController.m
+++ b/Blog/PreviewViewController.m
@@ -41,19 +41,24 @@
     [self.webView loadHTMLString:@"<!doctype html><html><head><title></title></head><body></body></html>" baseURL:nil];
 }
 
+#pragma mark - State restoration
+
+static NSString *const StateRestorationInitialRequestKey = @"initialRequest";
+static NSString *const StateRestorationWebViewRequestURLKey = @"webView.request.URL";
+
 - (void)encodeRestorableStateWithCoder:(NSCoder *)coder {
-    [coder encodeObject:self.initialRequest forKey:@"initialRequest"];
-    [coder encodeObject:self.webView.request.URL forKey:@"webView.request.URL"];
+    [coder encodeObject:self.initialRequest forKey:StateRestorationInitialRequestKey];
+    [coder encodeObject:self.webView.request.URL forKey:StateRestorationWebViewRequestURLKey];
     [super encodeRestorableStateWithCoder:coder];
 }
 
 - (void)decodeRestorableStateWithCoder:(NSCoder *)coder {
-    NSURL *url = [coder decodeObjectForKey:@"webView.request.URL"];
+    NSURL *url = [coder decodeObjectForKey:StateRestorationWebViewRequestURLKey];
     if (url) {
         [self.webView loadRequest:[NSURLRequest requestWithURL:url]];
     }
     else {
-        self.initialRequest = [coder decodeObjectForKey:@"initialRequest"];
+        self.initialRequest = [coder decodeObjectForKey:StateRestorationInitialRequestKey];
     }
     [super decodeRestorableStateWithCoder:coder];
 }