element-ios/Riot/Categories/UIViewController+RiotSearch.m

/*
 Copyright 2015 OpenMarket Ltd
 Copyright 2017 Vector Creations Ltd

 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 "UIViewController+RiotSearch.h"

#import <objc/runtime.h>

#import "ThemeService.h"
#import "Riot-Swift.h"

/**
 `UIViewControllerRiotSearchInternals` is the internal single point storage for the search feature.
 
 It hosts all required data so that only one associated object can be used in the category.
 */
@interface UIViewControllerRiotSearchInternals : NSObject

// The search bar
@property (nonatomic) UISearchBar *searchBar;
@property (nonatomic) BOOL searchBarHidden;

// Backup of view when displaying search
@property (nonatomic) UIView *backupTitleView;
@property (nonatomic) UIBarButtonItem *backupLeftBarButtonItem;
@property (nonatomic) UIBarButtonItem *backupRightBarButtonItem;

// The Riot empty search background image (champagne bubbles)
@property (nonatomic) UIImageView *backgroundImageView;
@property (nonatomic) NSLayoutConstraint *backgroundImageViewBottomConstraint;

@end

@implementation UIViewControllerRiotSearchInternals
@end


#pragma mark - UIViewController+RiotSearch
#pragma mark -

@interface UIViewController ()

// The single associated object hosting all data.
@property(nonatomic) UIViewControllerRiotSearchInternals *searchInternals;

@end

@implementation UIViewController (RiotSearch)

- (UISearchBar *)searchBar
{
    return self.searchInternals.searchBar;
}

- (BOOL)searchBarHidden
{
    return self.searchInternals.searchBarHidden;
}

- (UIImageView*)backgroundImageView
{
    return self.searchInternals.backgroundImageView;
}

- (NSLayoutConstraint *)backgroundImageViewBottomConstraint
{
    return self.searchInternals.backgroundImageViewBottomConstraint;
}

- (void)showSearch:(BOOL)animated
{
    if (self.searchInternals.searchBarHidden)
    {
        // Backup screen header before displaying the search bar in it
        self.searchInternals.backupTitleView = self.navigationItem.titleView;
        self.searchInternals.backupLeftBarButtonItem = self.navigationItem.leftBarButtonItem;
        self.searchInternals.backupRightBarButtonItem = self.navigationItem.rightBarButtonItem;
        
        self.searchInternals.searchBarHidden = NO;
        
        // Reset searches
        self.searchBar.text = @"";
        
        // Customize search bar
        [ThemeService.shared.theme applyStyleOnSearchBar:self.searchBar];
        
        // Remove navigation buttons
        self.navigationItem.hidesBackButton = YES;
        self.navigationItem.rightBarButtonItem = nil;
        self.navigationItem.leftBarButtonItem = nil;
        
        // Add the search bar
        self.navigationItem.titleView = self.searchBar;
        
        // On iPad, there is no cancel button inside the UISearchBar
        // So, add a classic cancel right bar button
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
        {
            UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(onIPadCancelPressed:)];
            [self.navigationItem setRightBarButtonItem: cancelButton animated:YES];
        }
    }
    
    // And display the keyboard
    [self.searchBar becomeFirstResponder];
}

- (void)hideSearch:(BOOL)animated
{
    if (!self.searchInternals.searchBarHidden)
    {
        // Restore the screen header
        self.navigationItem.hidesBackButton = NO;
        self.navigationItem.titleView = self.searchInternals.backupTitleView;
        self.navigationItem.leftBarButtonItem = self.searchInternals.backupLeftBarButtonItem;
        self.navigationItem.rightBarButtonItem = self.searchInternals.backupRightBarButtonItem;
        
        self.searchInternals.searchBarHidden = YES;
    }
}

- (void)addBackgroundImageViewToView:(UIView*)view
{
    UIImage *searchBgImage = [MXKTools paintImage:[UIImage imageNamed:@"search_bg"] withColor:ThemeService.shared.theme.matrixSearchBackgroundImageTintColor];
    UIImageView *backgroundImageView = [[UIImageView alloc] initWithImage:searchBgImage];
    backgroundImageView.translatesAutoresizingMaskIntoConstraints = NO;

    [view addSubview:backgroundImageView];

    // Keep it at left
    NSLayoutConstraint *leftConstraint = [NSLayoutConstraint constraintWithItem:view
                                                                      attribute:NSLayoutAttributeLeading
                                                                      relatedBy:NSLayoutRelationEqual
                                                                         toItem:backgroundImageView
                                                                      attribute:NSLayoutAttributeLeading
                                                                     multiplier:1.0
                                                                     constant:0];
    // Same width as parent
    NSLayoutConstraint *widthConstraint = [NSLayoutConstraint constraintWithItem:view
                                                                       attribute:NSLayoutAttributeWidth
                                                                       relatedBy:NSLayoutRelationEqual
                                                                          toItem:backgroundImageView
                                                                       attribute:NSLayoutAttributeWidth
                                                                      multiplier:1.0f
                                                                        constant:0.0f];

    // Keep the image aspect ratio
    NSLayoutConstraint *aspectRatioConstraint = [NSLayoutConstraint
                                                  constraintWithItem:backgroundImageView
                                                  attribute:NSLayoutAttributeHeight
                                                  relatedBy:NSLayoutRelationEqual
                                                  toItem:backgroundImageView
                                                  attribute:NSLayoutAttributeWidth
                                                  multiplier:(backgroundImageView.frame.size.height / backgroundImageView.frame.size.width)
                                                  constant:0];

    // Set its position according to its bottom
    NSLayoutConstraint *bottomConstraint = [NSLayoutConstraint constraintWithItem:view
                                                                        attribute:NSLayoutAttributeBottom
                                                                        relatedBy:NSLayoutRelationEqual
                                                                           toItem:backgroundImageView
                                                                        attribute:NSLayoutAttributeBottom
                                                                       multiplier:1.0f
                                                                         constant:216];

    [NSLayoutConstraint activateConstraints:@[leftConstraint,
                                              widthConstraint,
                                              aspectRatioConstraint,
                                              bottomConstraint
                                              ]];

    self.searchInternals.backgroundImageView = backgroundImageView;
    self.searchInternals.backgroundImageViewBottomConstraint = bottomConstraint;

    // It will be showed once the keyboard appears
    backgroundImageView.hidden = YES;
}

- (void)setKeyboardHeightForBackgroundImage:(CGFloat)keyboardHeight
{
    // keyboardHeight = 0 means no keyboard
    if (keyboardHeight > 0)
    {
        self.searchInternals.backgroundImageView.hidden = NO;

        // 60 = 18 + 42 from the Riot design
        self.searchInternals.backgroundImageViewBottomConstraint.constant = keyboardHeight - 60;
    }
    else
    {
        // Hide the search
        self.searchInternals.backgroundImageView.hidden = YES;
    }
}

#pragma mark - UISearchBarDelegate

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar2
{
    // "Search" key has been pressed
    [self.searchBar resignFirstResponder];
}

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar2
{
    [self hideSearch:YES];
}

- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar2
{
    // Keep the search bar cancel button enabled even if the keyboard is not displayed
    dispatch_async(dispatch_get_main_queue(), ^{
        for (UIView *subView in self.searchBar.subviews)
        {
            for (UIView *view in subView.subviews)
            {
                if ([view isKindOfClass:[UIButton class]])
                {
                    [(UIButton *)view setEnabled:YES];
                }
            }
        }
    });
    return YES;
}

#pragma mark - Private methods

- (void)onIPadCancelPressed:(id)sender
{
    // Mimic the same behavior as  on iPhones and call the UISearchBar cancel delegate method
    if ([self.searchBar.delegate respondsToSelector:@selector(searchBarCancelButtonClicked:)])
    {
        [self.searchBar.delegate searchBarCancelButtonClicked:self.searchBar];
    }
}

#pragma mark - Internal associated object

- (void)setSearchInternals:(UIViewControllerRiotSearchInternals *)searchInternals
{
    objc_setAssociatedObject(self, @selector(searchInternals), searchInternals, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIViewControllerRiotSearchInternals *)searchInternals
{
    UIViewControllerRiotSearchInternals *searchInternals = objc_getAssociatedObject(self, @selector(searchInternals));
    if (!searchInternals)
    {
        // Initialise internal data at the first call
        searchInternals = [[UIViewControllerRiotSearchInternals alloc] init];

        UISearchBar *searchBar = [[UISearchBar alloc] init];
        searchBar.showsCancelButton = YES;
        searchBar.delegate = (id<UISearchBarDelegate>)self;
        searchInternals.searchBar = searchBar;

        self.searchInternals = searchInternals;
        self.searchInternals.searchBarHidden = YES;
    }
    return searchInternals;
}

@end