Upstream Chrome on iOS source code [7/11].

ios/chrome/browser/ui/settings/handoff_collection_view_controller.mm

+// Copyright 2016 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.
+
+#import "ios/chrome/browser/ui/settings/handoff_collection_view_controller.h"
+
+#import "base/mac/foundation_util.h"
+#include "components/handoff/pref_names_ios.h"
+#include "components/prefs/pref_member.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#import "ios/chrome/browser/ui/collection_view/cells/MDCCollectionViewCell+Chrome.h"
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_footer_item.h"
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_switch_item.h"
+#import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
+#include "ios/chrome/grit/ios_strings.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace {
+
+typedef NS_ENUM(NSInteger, SectionIdentifier) {
+  SectionIdentifierSwitch = kSectionIdentifierEnumZero,
+  SectionIdentifierFooter,
+};
+
+typedef NS_ENUM(NSInteger, ItemType) {
+  ItemTypeSwitch = kItemTypeEnumZero,
+  ItemTypeFooter,
+};
+
+}  // namespace
+
+@interface HandoffCollectionViewController () {
+  // Pref for whether Handoff is enabled.
+  BooleanPrefMember _handoffEnabled;
+}
+
+- (void)switchChanged:(UISwitch*)switchView;
+
+@end
+
+@implementation HandoffCollectionViewController
+
+#pragma mark - Initialization
+
+- (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState {
+  DCHECK(browserState);
+  self = [super initWithStyle:CollectionViewControllerStyleAppBar];
+  if (self) {
+    self.title = l10n_util::GetNSString(IDS_IOS_OPTIONS_CONTINUITY_LABEL);
+    _handoffEnabled.Init(prefs::kIosHandoffToOtherDevices,
+                         browserState->GetPrefs());
+    [self loadModel];
+  }
+  return self;
+}
+
+#pragma mark - CollectionViewController
+
+- (void)loadModel {
+  [super loadModel];
+  CollectionViewModel* model = self.collectionViewModel;
+
+  [model addSectionWithIdentifier:SectionIdentifierSwitch];
+  CollectionViewSwitchItem* switchItem = [[[CollectionViewSwitchItem alloc]
+      initWithType:ItemTypeSwitch] autorelease];
+  switchItem.text =
+      l10n_util::GetNSString(IDS_IOS_OPTIONS_ENABLE_HANDOFF_TO_OTHER_DEVICES);
+  switchItem.on = _handoffEnabled.GetValue();
+  [model addItem:switchItem toSectionWithIdentifier:SectionIdentifierSwitch];
+
+  // The footer item must currently go into a separate section, to work around a
+  // drawing bug in MDC.
+  // TODO(crbug.com/650424) Use setFooter:forSectionWithIdentifier:.
+  [model addSectionWithIdentifier:SectionIdentifierFooter];
+  CollectionViewFooterItem* footer = [[[CollectionViewFooterItem alloc]
+      initWithType:ItemTypeFooter] autorelease];
+  footer.text = l10n_util::GetNSString(
+      IDS_IOS_OPTIONS_ENABLE_HANDOFF_TO_OTHER_DEVICES_DETAILS);
+  [model addItem:footer toSectionWithIdentifier:SectionIdentifierFooter];
+}
+
+#pragma mark - UICollectionViewDataSource
+
+- (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView
+                 cellForItemAtIndexPath:(NSIndexPath*)indexPath {
+  UICollectionViewCell* cell =
+      [super collectionView:collectionView cellForItemAtIndexPath:indexPath];
+
+  ItemType itemType = static_cast<ItemType>(
+      [self.collectionViewModel itemTypeForIndexPath:indexPath]);
+
+  if (itemType == ItemTypeSwitch) {
+    CollectionViewSwitchCell* switchCell =
+        base::mac::ObjCCastStrict<CollectionViewSwitchCell>(cell);
+    [switchCell.switchView addTarget:self
+                              action:@selector(switchChanged:)
+                    forControlEvents:UIControlEventValueChanged];
+  }
+  return cell;
+}
+
+#pragma mark - MDCCollectionViewStylingDelegate
+
+- (CGFloat)collectionView:(UICollectionView*)collectionView
+    cellHeightAtIndexPath:(NSIndexPath*)indexPath {
+  CollectionViewItem* item =
+      [self.collectionViewModel itemAtIndexPath:indexPath];
+  if (item.type == ItemTypeFooter)
+    return [MDCCollectionViewCell
+        cr_preferredHeightForWidth:CGRectGetWidth(collectionView.bounds)
+                           forItem:item];
+  return MDCCellDefaultOneLineHeight;
+}
+
+- (MDCCollectionViewCellStyle)collectionView:(UICollectionView*)collectionView
+                         cellStyleForSection:(NSInteger)section {
+  NSInteger sectionIdentifier =
+      [self.collectionViewModel sectionIdentifierForSection:section];
+  switch (sectionIdentifier) {
+    case SectionIdentifierFooter:
+      // Display the Learn More footer in the default style with no "card" UI
+      // and no section padding.
+      return MDCCollectionViewCellStyleDefault;
+    default:
+      return self.styler.cellStyle;
+  }
+}
+
+- (BOOL)collectionView:(UICollectionView*)collectionView
+    shouldHideItemBackgroundAtIndexPath:(NSIndexPath*)indexPath {
+  NSInteger sectionIdentifier =
+      [self.collectionViewModel sectionIdentifierForSection:indexPath.section];
+  switch (sectionIdentifier) {
+    case SectionIdentifierFooter:
+      // Display the Learn More footer without any background image or
+      // shadowing.
+      return YES;
+    default:
+      return NO;
+  }
+}
+
+- (BOOL)collectionView:(UICollectionView*)collectionView
+    hidesInkViewAtIndexPath:(NSIndexPath*)indexPath {
+  NSInteger type = [self.collectionViewModel itemTypeForIndexPath:indexPath];
+  switch (type) {
+    case ItemTypeSwitch:
+      return YES;
+    default:
+      return NO;
+  }
+}
+
+#pragma mark - Private
+
+- (void)switchChanged:(UISwitch*)switchView {
+  _handoffEnabled.SetValue(switchView.isOn);
+}
+
+@end