components/AppBar/examples/AppBarDelegateForwardingExample.m

/*
 Copyright 2016-present the Material Components for iOS authors. All Rights Reserved.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

#import <UIKit/UIKit.h>

#import "MaterialAppBar.h"

// This example builds upon AppBarTypicalUseExample.

@interface AppBarDelegateForwardingExample : UITableViewController
@property(nonatomic, strong) MDCAppBar *appBar;
@end

@implementation AppBarDelegateForwardingExample

- (void)viewDidLoad {
  [super viewDidLoad];

  // UITableViewController's tableView.delegate is self by default. We're setting it here for
  // emphasis.
  self.tableView.delegate = self;

  self.appBar.headerViewController.headerView.trackingScrollView = self.tableView;
  [self.appBar addSubviewsToParent];

  self.tableView.layoutMargins = UIEdgeInsetsZero;
  self.tableView.separatorInset = UIEdgeInsetsZero;
}

#pragma mark - UIScrollViewDelegate

// The following four methods must be forwarded to the tracking scroll view in order to implement
// the Flexible Header's behavior.

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  if (scrollView == self.appBar.headerViewController.headerView.trackingScrollView) {
    [self.appBar.headerViewController.headerView trackingScrollViewDidScroll];
  }
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
  if (scrollView == self.appBar.headerViewController.headerView.trackingScrollView) {
    [self.appBar.headerViewController.headerView trackingScrollViewDidEndDecelerating];
  }
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
  MDCFlexibleHeaderView *headerView = self.appBar.headerViewController.headerView;
  if (scrollView == headerView.trackingScrollView) {
    [headerView trackingScrollViewDidEndDraggingWillDecelerate:decelerate];
  }
}

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView
                     withVelocity:(CGPoint)velocity
              targetContentOffset:(inout CGPoint *)targetContentOffset {
  MDCFlexibleHeaderView *headerView = self.appBar.headerViewController.headerView;
  if (scrollView == headerView.trackingScrollView) {
    [headerView trackingScrollViewWillEndDraggingWithVelocity:velocity
                                          targetContentOffset:targetContentOffset];
  }
}

@end

@implementation AppBarDelegateForwardingExample (CatalogByConvention)

+ (NSArray *)catalogBreadcrumbs {
  return @[ @"App Bar", @"Delegate Forwarding" ];
}

+ (BOOL)catalogIsPrimaryDemo {
  return NO;
}

- (BOOL)catalogShouldHideNavigation {
  return YES;
}

@end

@implementation AppBarDelegateForwardingExample (TypicalUse)

- (id)init {
  self = [super init];
  if (self) {
    _appBar = [[MDCAppBar alloc] init];
    [self addChildViewController:_appBar.headerViewController];

    self.title = @"Delegate Forwarding";

    UIColor *color = [UIColor colorWithWhite:0.2 alpha:1];
    _appBar.headerViewController.headerView.backgroundColor = color;
    MDCAppBarTextColorAccessibilityMutator *mutator =
        [[MDCAppBarTextColorAccessibilityMutator alloc] init];
    [mutator mutate:_appBar];
  }
  return self;
}

- (UIViewController *)childViewControllerForStatusBarHidden {
  return self.appBar.headerViewController;
}

- (UIViewController *)childViewControllerForStatusBarStyle {
  return self.appBar.headerViewController;
}

- (void)viewWillAppear:(BOOL)animated {
  [super viewWillAppear:animated];

  [self.navigationController setNavigationBarHidden:YES animated:animated];
}

@end

#pragma mark - Typical application code (not Material-specific)

@implementation AppBarDelegateForwardingExample (UITableViewDataSource)

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
  return 50;
}

- (UITableViewCell *)tableView:(UITableView *)tableView
         cellForRowAtIndexPath:(NSIndexPath *)indexPath {
  UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"cell"];
  if (!cell) {
    cell =
        [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];
  }
  cell.layoutMargins = UIEdgeInsetsZero;
  return cell;
}

@end