Respond to CR.

// FREEBIE

Signal/src/ViewControllers/SelectThreadViewController.m

@@ -90,6 +90,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)createViews
 {
+    OWSAssert(self.delegate);
+
     UIView *header = [self.delegate createHeader:self.view];
 
     // Table

Signal/src/ViewControllers/SendExternalFileViewController.m

@@ -6,6 +6,8 @@
 #import "Environment.h"
 #import "Signal-Swift.h"
 #import "ThreadUtil.h"
+#import "UIColor+OWS.h"
+#import "UIFont+OWS.h"
 #import <SignalServiceKit/OWSMessageSender.h>
 #import <SignalServiceKit/TSThread.h>
 
@@ -21,12 +23,18 @@ NS_ASSUME_NONNULL_BEGIN
 
 @implementation SendExternalFileViewController
 
+- (instancetype)init
+{
+    if (self = [super init]) {
+        self.delegate = self;
+    }
+    return self;
+}
+
 - (void)loadView
 {
     [super loadView];
 
-    self.delegate = self;
-
     _messageSender = [Environment getCurrent].messageSender;
 
     self.title = NSLocalizedString(@"SEND_EXTERNAL_FILE_VIEW_TITLE", @"Title for the 'send external file' view.");
@@ -51,7 +59,86 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (nullable UIView *)createHeader:(UIView *)superview
 {
-    return nil;
+    OWSAssert(superview)
+
+        const CGFloat imageSize
+        = ScaleFromIPhone5To7Plus(40, 40);
+    const CGFloat imageLabelSpacing = ScaleFromIPhone5To7Plus(5, 5);
+    const CGFloat titleVSpacing = ScaleFromIPhone5To7Plus(10, 10);
+    const CGFloat contentVMargin = ScaleFromIPhone5To7Plus(20, 20);
+
+    UIView *header = [UIView new];
+    [superview addSubview:header];
+    [header autoPinWidthToSuperview];
+    [header autoPinToTopLayoutGuideOfViewController:self withInset:0];
+
+    UIView *titleLabel = [self createTitleLabel];
+    [header addSubview:titleLabel];
+    [titleLabel autoHCenterInSuperview];
+    [titleLabel autoPinEdgeToSuperviewEdge:ALEdgeTop withInset:contentVMargin];
+
+    UIView *fileView = [UIView new];
+    [header addSubview:fileView];
+    [fileView autoHCenterInSuperview];
+    [fileView autoPinEdgeToSuperviewEdge:ALEdgeBottom withInset:contentVMargin];
+    [fileView autoPinEdge:ALEdgeTop toEdge:ALEdgeBottom ofView:titleLabel withOffset:titleVSpacing];
+
+    UIImage *image = [UIImage imageNamed:@"file-thin-black-large"];
+    OWSAssert(image);
+    UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
+    imageView.layer.minificationFilter = kCAFilterTrilinear;
+    imageView.layer.magnificationFilter = kCAFilterTrilinear;
+    [fileView addSubview:imageView];
+    [imageView autoSetDimension:ALDimensionWidth toSize:imageSize];
+    [imageView autoSetDimension:ALDimensionHeight toSize:imageSize];
+    [imageView autoPinEdgeToSuperviewEdge:ALEdgeLeft];
+    [imageView autoPinEdgeToSuperviewEdge:ALEdgeTop];
+    [imageView autoPinEdgeToSuperviewEdge:ALEdgeBottom];
+
+    UIView *fileNameLabel = [self createFileNameLabel];
+    [fileView addSubview:fileNameLabel];
+    [fileNameLabel autoAlignAxis:ALAxisHorizontal toSameAxisOfView:imageView];
+    [fileNameLabel autoPinEdge:ALEdgeLeft toEdge:ALEdgeRight ofView:imageView withOffset:imageLabelSpacing];
+    [fileNameLabel autoPinEdgeToSuperviewEdge:ALEdgeRight];
+
+    return header;
+}
+
+- (NSString *)formattedFileName
+{
+    OWSAssert(self.attachment) NSString *filename =
+        [self.attachment.filename stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+    OWSAssert(filename.length > 0);
+    const NSUInteger kMaxFilenameLength = 50;
+    if (filename.length > kMaxFilenameLength) {
+        // Truncate the filename if necessary.
+        //
+        // TODO: Use l10n-safe truncation.
+        filename = [[[filename substringToIndex:kMaxFilenameLength / 2] stringByAppendingString:@"…"]
+            stringByAppendingString:[filename substringFromIndex:filename.length - kMaxFilenameLength / 2]];
+    }
+    return filename;
+}
+
+- (UIView *)createFileNameLabel
+{
+    UILabel *label = [UILabel new];
+    label.text = [self formattedFileName];
+    label.textColor = [UIColor ows_materialBlueColor];
+    label.font = [UIFont ows_regularFontWithSize:16.f];
+    label.lineBreakMode = NSLineBreakByTruncatingMiddle;
+    return label;
+}
+
+
+- (UIView *)createTitleLabel
+{
+    UILabel *label = [UILabel new];
+    label.text
+        = NSLocalizedString(@"SEND_EXTERNAL_FILE_HEADER_TITLE", @"Header title for the 'send external file' view.");
+    label.textColor = [UIColor blackColor];
+    label.font = [UIFont ows_mediumFontWithSize:18.f];
+    return label;
 }
 
 @end

Signal/src/ViewControllers/SignalsViewController.m

@@ -10,6 +10,7 @@
 #import "OWSContactsManager.h"
 #import "PropertyListPreferences.h"
 #import "PushManager.h"
+#import "SendExternalFileViewController.h"
 #import "Signal-Swift.h"
 #import "TSAccountManager.h"
 #import "TSDatabaseView.h"
@@ -163,6 +164,19 @@ NSString *const SignalsViewControllerSegueShowIncomingCall = @"ShowIncomingCallS
                                                object:nil];
     
     [self updateBarButtonItems];
+
+    dispatch_async(dispatch_get_main_queue(), ^{
+        SignalAttachment *attachment =
+            [SignalAttachment attachmentWithData:[@"hi" dataUsingEncoding:NSUTF8StringEncoding]
+                                         dataUTI:(NSString *)kUTTypeText
+                                        filename:@"boink.txt"];
+
+        SendExternalFileViewController *viewController = [SendExternalFileViewController new];
+        viewController.attachment = attachment;
+        UINavigationController *navigationController =
+            [[UINavigationController alloc] initWithRootViewController:viewController];
+        [self presentTopLevelModalViewController:navigationController animateDismissal:NO animatePresentation:YES];
+    });
 }
 
 - (void)updateBarButtonItems {

Signal/translations/en.lproj/Localizable.strings

@@ -910,18 +910,15 @@
 /* No comment provided by engineer. */
 "SECURE_SESSION_RESET" = "Secure session was reset.";
 
-/* A label for the 'select contact' mode vs. 'select thread' mode. */
-"SELECT_CONTACT_MODE_LABEL" = "Contacts";
-
-/* A label for the 'select thread' mode vs. 'select contact' mode. */
-"SELECT_THREAD_MODE_LABEL" = "Conversations";
-
 /* No comment provided by engineer. */
 "SEND_AGAIN_BUTTON" = "Send Again";
 
 /* No comment provided by engineer. */
 "SEND_BUTTON_TITLE" = "Send";
 
+/* Header title for the 'send external file' view. */
+"SEND_EXTERNAL_FILE_HEADER_TITLE" = "Select a Recipient for:";
+
 /* Title for the 'send external file' view. */
 "SEND_EXTERNAL_FILE_VIEW_TITLE" = "Send File";