[CRD iOS] Add a view for host fetch failure for non-user-triggered refresh

Previously if a host list fetch is not triggered by the user (refresh
control) and fails, then the app will simply pop up a toast complaining
about unavailable network and show nothing else. Pull-to-refresh
doesn't work.

This CL fixes this by providing a dialog-like view to allow user to
retry in that case.

Screenshot:
https://drive.google.com/file/d/0BytzIZKeM8nBMmN3b3A0bUhoMFU/view?usp=sharing

Bug: 771532
Change-Id: I64cb4015acc066322c3c6127b79b87d13cb06652
Reviewed-on: https://chromium-review.googlesource.com/700316Reviewed-by: Scott Nichols <nicholss@chromium.org>
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506537}

remoting/ios/app/BUILD.gn

@@ -36,6 +36,8 @@ source_set("common_source_set") {
     "host_collection_view_cell.mm",
     "host_collection_view_controller.h",
     "host_collection_view_controller.mm",
+    "host_fetching_error_view_controller.h",
+    "host_fetching_error_view_controller.mm",
     "host_fetching_view_controller.h",
     "host_fetching_view_controller.mm",
     "host_setup_footer_view.h",

remoting/ios/app/host_fetching_error_view_controller.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef REMOTING_IOS_APP_HOST_FETCHING_ERROR_VIEW_CONTROLLER_H_
+#define REMOTING_IOS_APP_HOST_FETCHING_ERROR_VIEW_CONTROLLER_H_
+
+#import <UIKit/UIKit.h>
+
+// This VC shows a dialog-like view to allow the user to retry host list
+// fetching. This is used when the host list has never been successfully,
+// fetched, i.e. pull-to-refresh is not available.
+@interface HostFetchingErrorViewController : UIViewController
+
+// Called when the retry button is tapped.
+@property(nonatomic) void (^onRetryCallback)();
+
+// Returns the label that shows the error message.
+@property(nonatomic, readonly) UILabel* label;
+
+@end
+
+#endif  // REMOTING_IOS_APP_HOST_FETCHING_ERROR_VIEW_CONTROLLER_H_

remoting/ios/app/host_fetching_error_view_controller.mm

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+#import "remoting/ios/app/host_fetching_error_view_controller.h"
+
+#import "ios/third_party/material_components_ios/src/components/Buttons/src/MaterialButtons.h"
+#import "ios/third_party/material_components_ios/src/components/Typography/src/MDCTypography.h"
+#import "remoting/ios/app/remoting_theme.h"
+
+#include "remoting/base/string_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+
+static const CGFloat kPadding = 20;
+static const CGFloat kLineSpace = 30;
+
+// The actual width will be min(kMaxWidth, screen width)
+static const CGFloat kMaxWidth = 500;
+
+// Adjust for the padding already existed inside the button.
+static const CGFloat kButtonRightPaddingAdjustment = -10;
+static const CGFloat kButtonBottomPaddingAdjustment = -5;
+
+@implementation HostFetchingErrorViewController {
+  UILabel* _label;
+}
+
+@synthesize onRetryCallback = _onRetryCallback;
+
+- (instancetype)init {
+  if (self = [super init]) {
+    // Label should be created right under init because it may be accessed
+    // before the view is loaded.
+    _label = [[UILabel alloc] initWithFrame:CGRectZero];
+  }
+  return self;
+}
+
+- (void)viewDidLoad {
+  UIView* contentView = [[UIView alloc] initWithFrame:CGRectZero];
+  contentView.backgroundColor = RemotingTheme.setupListBackgroundColor;
+  contentView.translatesAutoresizingMaskIntoConstraints = NO;
+  [self.view addSubview:contentView];
+
+  _label.font = MDCTypography.body1Font;
+  _label.numberOfLines = 0;
+  _label.lineBreakMode = NSLineBreakByWordWrapping;
+  _label.textColor = RemotingTheme.setupListTextColor;
+  _label.translatesAutoresizingMaskIntoConstraints = NO;
+  [contentView addSubview:_label];
+
+  MDCButton* button = [[MDCButton alloc] initWithFrame:CGRectZero];
+  [button setTitle:l10n_util::GetNSString(IDS_RETRY)
+          forState:UIControlStateNormal];
+  [button setBackgroundColor:UIColor.clearColor forState:UIControlStateNormal];
+  [button setTitleColor:RemotingTheme.flatButtonTextColor
+               forState:UIControlStateNormal];
+  [button sizeToFit];
+  [button addTarget:self
+                action:@selector(didTapRetry:)
+      forControlEvents:UIControlEventTouchUpInside];
+  button.translatesAutoresizingMaskIntoConstraints = NO;
+  [contentView addSubview:button];
+
+  NSLayoutConstraint* maxWidthConstraint =
+      [contentView.widthAnchor constraintEqualToConstant:kMaxWidth];
+  maxWidthConstraint.priority = UILayoutPriorityDefaultHigh;
+  [NSLayoutConstraint activateConstraints:@[
+    maxWidthConstraint,
+
+    // Trumps |maxWidthConstraint| when necessary.
+    [contentView.widthAnchor
+        constraintLessThanOrEqualToAnchor:self.view.widthAnchor],
+    [contentView.centerXAnchor constraintEqualToAnchor:self.view.centerXAnchor],
+    [contentView.centerYAnchor constraintEqualToAnchor:self.view.centerYAnchor],
+
+    [_label.leadingAnchor constraintEqualToAnchor:contentView.leadingAnchor
+                                         constant:kPadding],
+    [_label.trailingAnchor constraintEqualToAnchor:contentView.trailingAnchor
+                                          constant:-kPadding],
+    [_label.topAnchor constraintEqualToAnchor:contentView.topAnchor
+                                     constant:kPadding],
+
+    [button.trailingAnchor
+        constraintEqualToAnchor:contentView.trailingAnchor
+                       constant:-kPadding - kButtonRightPaddingAdjustment],
+    [button.topAnchor constraintEqualToAnchor:_label.bottomAnchor
+                                     constant:kLineSpace],
+    [button.bottomAnchor
+        constraintEqualToAnchor:contentView.bottomAnchor
+                       constant:-kPadding - kButtonBottomPaddingAdjustment],
+  ]];
+}
+
+- (UILabel*)label {
+  return _label;
+}
+
+#pragma mark - Private
+
+- (void)didTapRetry:(id)button {
+  if (_onRetryCallback) {
+    _onRetryCallback();
+  }
+}
+
+@end

remoting/ios/app/remoting_view_controller.mm

@@ -21,6 +21,7 @@
 #import "remoting/ios/app/app_delegate.h"
 #import "remoting/ios/app/client_connection_view_controller.h"
 #import "remoting/ios/app/host_collection_view_controller.h"
+#import "remoting/ios/app/host_fetching_error_view_controller.h"
 #import "remoting/ios/app/host_fetching_view_controller.h"
 #import "remoting/ios/app/host_setup_view_controller.h"
 #import "remoting/ios/app/host_view_controller.h"
@@ -88,6 +89,7 @@ ConnectionType GetConnectionType() {
   MDCAppBar* _appBar;
   HostCollectionViewController* _collectionViewController;
   HostFetchingViewController* _fetchingViewController;
+  HostFetchingErrorViewController* _fetchingErrorViewController;
   HostSetupViewController* _setupViewController;
   RemotingService* _remotingService;
 
@@ -108,6 +110,11 @@ ConnectionType GetConnectionType() {
   if (self) {
     _remotingService = RemotingService.instance;
 
+    __weak RemotingViewController* weakSelf = self;
+    RemotingRefreshAction refreshAction = ^{
+      [weakSelf didSelectRefresh];
+    };
+
     _collectionViewController = [[HostCollectionViewController alloc]
         initWithCollectionViewLayout:layout];
     _collectionViewController.delegate = self;
@@ -115,6 +122,10 @@ ConnectionType GetConnectionType() {
 
     _fetchingViewController = [[HostFetchingViewController alloc] init];
 
+    _fetchingErrorViewController =
+        [[HostFetchingErrorViewController alloc] init];
+    _fetchingErrorViewController.onRetryCallback = refreshAction;
+
     _setupViewController = [[HostSetupViewController alloc] init];
     _setupViewController.scrollViewDelegate = self.headerViewController;
 
@@ -151,10 +162,6 @@ ConnectionType GetConnectionType() {
           [(MDCShadowLayer*)layer setElevation:elevation];
         }];
 
-    __weak RemotingViewController* weakSelf = self;
-    RemotingRefreshAction refreshAction = ^{
-      [weakSelf didSelectRefresh];
-    };
     _refreshControls = @[
       [[RefreshControlProvider instance]
           createForScrollView:_collectionViewController.collectionView
@@ -199,7 +206,7 @@ ConnectionType GetConnectionType() {
 
   [NSNotificationCenter.defaultCenter
       addObserver:self
-         selector:@selector(hostListFetchDidFailedNotification:)
+         selector:@selector(hostListFetchDidFailNotification:)
              name:kHostListFetchDidFail
            object:nil];
 }
@@ -222,25 +229,10 @@ ConnectionType GetConnectionType() {
   [self refreshContent];
 }
 
-- (void)hostListFetchDidFailedNotification:(NSNotification*)notification {
+- (void)hostListFetchDidFailNotification:(NSNotification*)notification {
   HostListFetchFailureReason reason = (HostListFetchFailureReason)
       [notification.userInfo[kHostListFetchFailureReasonKey] integerValue];
-  int messageId;
-  switch (reason) {
-    case HostListFetchFailureReasonNetworkError:
-      messageId = IDS_ERROR_NETWORK_ERROR;
-      break;
-    case HostListFetchFailureReasonAuthError:
-      messageId = IDS_ERROR_OAUTH_TOKEN_INVALID;
-      break;
-    default:
-      NOTREACHED();
-      return;
-  }
-  [MDCSnackbarManager
-      showMessage:[MDCSnackbarMessage
-                      messageWithText:l10n_util::GetNSString(messageId)]];
-  [self stopAllRefreshControls];
+  [self handleHostListFetchFailure:reason];
 }
 
 #pragma mark - HostCollectionViewControllerDelegate
@@ -351,7 +343,14 @@ animationControllerForDismissedController:(UIViewController*)dismissed {
   }
 
   if (_remotingService.hostListState == HostListStateNotFetched) {
-    self.contentViewController = nil;
+    if (_remotingService.lastFetchFailureReason ==
+        HostListFetchFailureReasonNoFailure) {
+      self.contentViewController = nil;
+    } else {
+      // hostListFetchDidFailNotification might miss the first failure happened
+      // before the notification is registered. This logic covers that.
+      [self handleHostListFetchFailure:_remotingService.lastFetchFailureReason];
+    }
     return;
   }
 
@@ -381,6 +380,42 @@ animationControllerForDismissedController:(UIViewController*)dismissed {
   }
 }
 
+- (void)handleHostListFetchFailure:(HostListFetchFailureReason)reason {
+  int messageId;
+  switch (reason) {
+    case HostListFetchFailureReasonNetworkError:
+      messageId = IDS_ERROR_NETWORK_ERROR;
+      break;
+    case HostListFetchFailureReasonAuthError:
+      messageId = IDS_ERROR_OAUTH_TOKEN_INVALID;
+      break;
+    default:
+      NOTREACHED();
+      return;
+  }
+  NSString* errorText = l10n_util::GetNSString(messageId);
+  if ([self isAnyRefreshControlRefreshing]) {
+    // User could just try pull-to-refresh again to refresh. We just need to
+    // show the error as a toast.
+    [MDCSnackbarManager
+        showMessage:[MDCSnackbarMessage messageWithText:errorText]];
+    [self stopAllRefreshControls];
+    return;
+  }
+
+  // Pull-to-refresh is not available. We need to show a dedicated view to allow
+  // user to retry.
+
+  // Dismiss snackbars and hide the SSO menu so that the accessibility focus
+  // can shift into the label.
+  [MDCSnackbarManager dismissAndCallCompletionBlocksWithCategory:nil];
+  [AppDelegate.instance hideMenuAnimated:YES];
+
+  _fetchingErrorViewController.label.text = errorText;
+  remoting::SetAccessibilityFocusElement(_fetchingErrorViewController.label);
+  self.contentViewController = _fetchingErrorViewController;
+}
+
 - (BOOL)isAnyRefreshControlRefreshing {
   for (id<RemotingRefreshControl> control in _refreshControls) {
     if (control.isRefreshing) {

remoting/ios/facade/remoting_service.h

@@ -13,7 +13,7 @@
 @protocol RemotingAuthentication;
 
 typedef NS_ENUM(NSInteger, HostListState) {
-  // Nobody has requested a host list fetch.
+  // Nobody has requested a host list fetch since login or last failure.
   HostListStateNotFetched,
 
   // The host list is currently being fetched.
@@ -24,6 +24,7 @@ typedef NS_ENUM(NSInteger, HostListState) {
 };
 
 typedef NS_ENUM(NSInteger, HostListFetchFailureReason) {
+  HostListFetchFailureReasonNoFailure,
   HostListFetchFailureReasonNetworkError,
   HostListFetchFailureReasonAuthError,
   HostListFetchFailureReasonUnknown,
@@ -64,6 +65,12 @@ extern NSString* const kUserInfo;
 // resources used by the Chromoting clients
 @property(nonatomic, readonly) remoting::ChromotingClientRuntime* runtime;
 
+// Returns the last failure reason when fetching the host list. Returns
+// HostListFetchFailureReasonNoFailure when the host list has never been fetched
+// or the last fetch has succeeded.
+@property(nonatomic, readonly)
+    HostListFetchFailureReason lastFetchFailureReason;
+
 // This must be set immediately after the authentication object is created. It
 // can only be set once.
 @property(nonatomic) id<RemotingAuthentication> authentication;

remoting/ios/facade/remoting_service.mm

@@ -54,6 +54,7 @@ NSString* const kUserInfo = @"kUserInfo";
 
 @synthesize hosts = _hosts;
 @synthesize hostListState = _hostListState;
+@synthesize lastFetchFailureReason = _lastFetchFailureReason;
 
 // RemotingService is a singleton.
 + (RemotingService*)instance {
@@ -71,6 +72,7 @@ NSString* const kUserInfo = @"kUserInfo";
     _hosts = nil;
     // TODO(yuweih): Maybe better to just cancel the previous request.
     _hostListState = HostListStateNotFetched;
+    _lastFetchFailureReason = HostListFetchFailureReasonNoFailure;
     // TODO(nicholss): This might need a pointer back to the service.
     _clientRuntimeDelegate =
         new remoting::IosClientRuntimeDelegate();
@@ -152,6 +154,9 @@ NSString* const kUserInfo = @"kUserInfo";
   if (state == _hostListState) {
     return;
   }
+  if (state == HostListStateFetching || state == HostListStateFetched) {
+    _lastFetchFailureReason = HostListFetchFailureReasonNoFailure;
+  }
   _hostListState = state;
   [[NSNotificationCenter defaultCenter]
       postNotificationName:kHostListStateDidChange
@@ -208,22 +213,22 @@ NSString* const kUserInfo = @"kUserInfo";
           return;
         }
 
-        HostListFetchFailureReason reason;
         switch (status) {
           case RemotingAuthenticationStatusNetworkError:
-            reason = HostListFetchFailureReasonNetworkError;
+            _lastFetchFailureReason = HostListFetchFailureReasonNetworkError;
             break;
           case RemotingAuthenticationStatusAuthError:
-            reason = HostListFetchFailureReasonAuthError;
+            _lastFetchFailureReason = HostListFetchFailureReasonAuthError;
             break;
           default:
-            reason = HostListFetchFailureReasonUnknown;
+            _lastFetchFailureReason = HostListFetchFailureReasonUnknown;
         }
         [NSNotificationCenter.defaultCenter
             postNotificationName:kHostListFetchDidFail
                           object:self
                         userInfo:@{
-                          kHostListFetchFailureReasonKey : @(reason)
+                          kHostListFetchFailureReasonKey :
+                              @(_lastFetchFailureReason)
                         }];
       }];
 }