components/FlexibleHeader/examples/FlexibleHeaderUINavigationBarExample.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 "FlexibleHeaderUINavigationBarSupplemental.h"

#import "MaterialButtons.h"
#import "MaterialFlexibleHeader.h"

static const CGFloat kFlexibleHeaderMinHeight = 200.f;

@interface FlexibleHeaderUINavigationBarExample () <UIScrollViewDelegate>

@property(nonatomic) MDCFlexibleHeaderViewController *fhvc;
@property(nonatomic) UIButton *button;

@end

@implementation FlexibleHeaderUINavigationBarExample

- (instancetype)init {
  self = [super init];
  if (self) {
    [self commonMDCFlexibleHeaderViewControllerInit];
  }
  return self;
}

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if (self) {
    [self commonMDCFlexibleHeaderViewControllerInit];
  }
  return self;
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
  self = [super initWithCoder:aDecoder];
  if (self) {
    [self commonMDCFlexibleHeaderViewControllerInit];
  }
  return self;
}

- (void)commonMDCFlexibleHeaderViewControllerInit {
  _fhvc = [[MDCFlexibleHeaderViewController alloc] initWithNibName:nil bundle:nil];
  _fhvc.headerView.minimumHeight = kFlexibleHeaderMinHeight;
  [self addChildViewController:_fhvc];

  // Use a standard UINavigationBar in the flexible header.
  CGRect navBarFrame = CGRectMake(0, 0, _fhvc.headerView.frame.size.width, 60);
  UINavigationBar *navBar = [[UINavigationBar alloc] initWithFrame:navBarFrame];
  [navBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
  navBar.shadowImage = [UIImage new];
  navBar.translucent = YES;
  navBar.autoresizingMask = UIViewAutoresizingFlexibleWidth;
  navBar.tintColor = [UIColor whiteColor];

  [self.fhvc.headerView addSubview:navBar];

  UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"Back"
                                                               style:UIBarButtonItemStylePlain
                                                              target:self
                                                              action:@selector(doneAction:)];
  UIBarButtonItem *doneItem = [[UIBarButtonItem alloc] initWithTitle:@"Done"
                                                               style:UIBarButtonItemStylePlain
                                                              target:self
                                                              action:@selector(doneAction:)];

  UINavigationItem *navItem = [[UINavigationItem alloc] initWithTitle:@"UINavigationBar"];
  [navItem setLeftBarButtonItem:backItem animated:YES];
  [navItem setRightBarButtonItem:doneItem animated:YES];
  [navBar setItems:[NSArray arrayWithObject:navItem] animated:YES];

  self.button = [[UIButton alloc] init];
  [self.button setTitle:@"UIButton" forState:UIControlStateNormal];
  [self.button sizeToFit];
  [self.button addTarget:self
                  action:@selector(didTapButton:)
        forControlEvents:UIControlEventTouchUpInside];
  self.button.tintColor = [UIColor redColor];
  self.button.autoresizingMask = UIViewAutoresizingFlexibleWidth;
  [self.fhvc.headerView addSubview:self.button];
}

- (void)didTapButton:(id)sender {
  NSLog(@"Button Tapped");
}

- (void)doneAction:(id)sender {
  [super.navigationController popViewControllerAnimated:YES];
}

- (void)viewDidLoad {
  [super viewDidLoad];

  self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
  self.scrollView.backgroundColor = [UIColor whiteColor];
  self.scrollView.autoresizingMask =
      UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
  [self.view addSubview:self.scrollView];

  self.scrollView.delegate = self;
  self.fhvc.headerView.trackingScrollView = self.scrollView;

  self.fhvc.view.frame = self.view.bounds;
  [self.view addSubview:self.fhvc.view];
  [self.fhvc didMoveToParentViewController:self];

  self.fhvc.headerView.backgroundColor = [UIColor colorWithWhite:0.1 alpha:1.0];
}

- (void)viewWillAppear:(BOOL)animated {
  [super viewWillAppear:animated];
  
  [self.navigationController setNavigationBarHidden:YES animated:animated];
  self.button.center = CGPointMake(CGRectGetMidX(self.fhvc.headerView.frame),
                                   CGRectGetMidY(self.fhvc.headerView.frame) + 50.f);
}

// This method must be implemented for MDCFlexibleHeaderViewController's
// MDCFlexibleHeaderView to properly support MDCFlexibleHeaderShiftBehavior should you choose
// to customize it.
- (UIViewController *)childViewControllerForStatusBarHidden {
  return self.fhvc;
}

#pragma mark - <UIScrollViewDelegate>

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  [self.fhvc scrollViewDidScroll:scrollView];
}

@end