// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#import "ios/chrome/browser/shared/ui/table_view/table_view_illustrated_empty_view.h"
#import "ios/chrome/browser/shared/ui/table_view/table_view_constants.h"
#import "ios/chrome/common/ui/colors/semantic_color_names.h"
namespace {
// The StackView vertical spacing between the image, the title and the subtitle.
const CGFloat kStackViewVerticalSpacingPt = 12.0;
// The StackView width.
const CGFloat kStackViewWidthPt = 310.0;
// The UIImageView height.
const CGFloat kImageHeightPt = 150.0;
NSAttributedString* GetAttributedMessage(NSString* message) {
return [[NSAttributedString alloc]
initWithString:message
attributes:[TableViewIllustratedEmptyView
defaultTextAttributesForSubtitle]];
}
} // namespace
@interface TableViewIllustratedEmptyView () <UITextViewDelegate>
// The image that will be displayed.
@property(nonatomic, strong) UIImage* image;
// The title that will be displayed under the image.
@property(nonatomic, copy) NSString* title;
// The subtitle that will be displayed under the title.
@property(nonatomic, copy) NSAttributedString* subtitle;
// The inner ScrollView so the whole content can be seen even if it is taller
// than the TableView.
@property(nonatomic, strong) UIScrollView* scrollView;
// The height constraint of the ScrollView.
@property(nonatomic, strong) NSLayoutConstraint* scrollViewHeight;
@end
@implementation TableViewIllustratedEmptyView
// Synthesized from the ChromeEmptyTableViewBackground protocol
@synthesize scrollViewContentInsets = _scrollViewContentInsets;
- (instancetype)initWithFrame:(CGRect)frame
image:(UIImage*)image
title:(NSString*)title
subtitle:(NSString*)subtitle {
self = [self initWithFrame:frame
image:image
title:title
attributedSubtitle:GetAttributedMessage(subtitle)];
return self;
}
- (instancetype)initWithFrame:(CGRect)frame
image:(UIImage*)image
title:(NSString*)title
attributedSubtitle:(NSAttributedString*)attributedSubtitle {
if ((self = [super initWithFrame:frame])) {
_title = title;
_subtitle = attributedSubtitle;
_image = image;
self.accessibilityIdentifier = [[self class] accessibilityIdentifier];
}
return self;
}
#pragma mark - Public
+ (NSString*)accessibilityIdentifier {
return kTableViewIllustratedEmptyViewID;
}
+ (NSDictionary*)defaultTextAttributesForSubtitle {
NSMutableParagraphStyle* paragraph_style =
[[NSMutableParagraphStyle alloc] init];
paragraph_style.lineBreakMode = NSLineBreakByWordWrapping;
paragraph_style.alignment = NSTextAlignmentCenter;
return @{
NSFontAttributeName :
[UIFont preferredFontForTextStyle:UIFontTextStyleSubheadline],
NSForegroundColorAttributeName : [UIColor colorNamed:kTextSecondaryColor],
NSParagraphStyleAttributeName : paragraph_style
};
}
#pragma mark - ChromeEmptyTableViewBackground
- (void)setScrollViewContentInsets:(UIEdgeInsets)scrollViewContentInsets {
_scrollViewContentInsets = scrollViewContentInsets;
self.scrollView.contentInset = scrollViewContentInsets;
self.scrollViewHeight.constant =
scrollViewContentInsets.top + scrollViewContentInsets.bottom;
}
- (NSString*)viewAccessibilityLabel {
return self.accessibilityLabel;
}
- (void)setViewAccessibilityLabel:(NSString*)label {
if ([self.viewAccessibilityLabel isEqualToString:label]) {
return;
}
self.accessibilityLabel = label;
}
#pragma mark - UIView
- (void)willMoveToSuperview:(UIView*)newSuperview {
[super willMoveToSuperview:newSuperview];
[self createSubviews];
}
#pragma mark - UITextViewDelegate
- (BOOL)textView:(UITextView*)textView
shouldInteractWithURL:(NSURL*)URL
inRange:(NSRange)characterRange
interaction:(UITextItemInteraction)interaction {
[self.delegate tableViewIllustratedEmptyView:self didTapSubtitleLink:URL];
return NO;
}
- (void)textViewDidChangeSelection:(UITextView*)textView {
// Make the textView not selectable while allowing interactions with links in
// it.
textView.selectedTextRange = nil;
}
#pragma mark - Private
// Create elements to display the image, title and subtitle. Add them to a
// StackView to arrange them. Then, add the StackView to a ScrollView to make
// the empty view scrollable if the content is taller than the frame.
- (void)createSubviews {
// Return if the subviews have already been created and added.
if (!(self.subviews.count == 0)) {
return;
}
// Scroll view used to scroll the content if it is too big.
UIScrollView* scrollView = [[UIScrollView alloc] init];
scrollView.translatesAutoresizingMaskIntoConstraints = NO;
scrollView.contentInset = self.scrollViewContentInsets;
self.scrollView = scrollView;
UIImageView* imageView = [[UIImageView alloc] initWithImage:self.image];
imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.clipsToBounds = YES;
NSMutableArray* subviewsArray = [NSMutableArray arrayWithObject:imageView];
if ([self.title length]) {
UILabel* titleLabel = [[UILabel alloc] init];
titleLabel.isAccessibilityElement = NO;
titleLabel.numberOfLines = 0;
titleLabel.text = self.title;
titleLabel.font = [UIFont preferredFontForTextStyle:UIFontTextStyleTitle2];
titleLabel.adjustsFontForContentSizeCategory = YES;
titleLabel.textColor = [UIColor colorNamed:kTextPrimaryColor];
titleLabel.textAlignment = NSTextAlignmentCenter;
[subviewsArray addObject:titleLabel];
}
if ([self.subtitle length]) {
UITextView* subtitleTextView = [[UITextView alloc] init];
subtitleTextView.isAccessibilityElement = NO;
subtitleTextView.attributedText = self.subtitle;
subtitleTextView.delegate = self;
subtitleTextView.scrollEnabled = NO;
subtitleTextView.backgroundColor = UIColor.clearColor;
subtitleTextView.adjustsFontForContentSizeCategory = YES;
[subviewsArray addObject:subtitleTextView];
}
self.isAccessibilityElement = YES;
self.accessibilityLabel =
[NSString stringWithFormat:@"%@ - %@", self.title ?: @"",
self.subtitle.string ?: @""];
// Vertical stack view that holds the image, title and subtitle.
UIStackView* verticalStack =
[[UIStackView alloc] initWithArrangedSubviews:subviewsArray];
verticalStack.axis = UILayoutConstraintAxisVertical;
verticalStack.spacing = kStackViewVerticalSpacingPt;
verticalStack.distribution = UIStackViewDistributionFill;
verticalStack.layoutMarginsRelativeArrangement = YES;
verticalStack.layoutMargins = UIEdgeInsetsMake(
kStackViewVerticalSpacingPt, 0, kStackViewVerticalSpacingPt, 0);
verticalStack.translatesAutoresizingMaskIntoConstraints = NO;
[scrollView addSubview:verticalStack];
[self addSubview:scrollView];
// The scroll view should contains the stack view without scrolling enabled if
// it is small enough.
NSLayoutConstraint* scrollViewHeightConstraint = [scrollView.heightAnchor
constraintEqualToAnchor:verticalStack.heightAnchor
constant:(self.scrollViewContentInsets.top +
self.scrollViewContentInsets.bottom)];
scrollViewHeightConstraint.priority = UILayoutPriorityDefaultLow;
scrollViewHeightConstraint.active = YES;
self.scrollViewHeight = scrollViewHeightConstraint;
[NSLayoutConstraint activateConstraints:@[
// The vertical stack is horizontal centered.
[verticalStack.topAnchor constraintEqualToAnchor:scrollView.topAnchor],
[verticalStack.bottomAnchor
constraintEqualToAnchor:scrollView.bottomAnchor],
[verticalStack.centerXAnchor constraintEqualToAnchor:self.centerXAnchor],
[verticalStack.widthAnchor constraintEqualToConstant:kStackViewWidthPt],
[imageView.heightAnchor constraintEqualToConstant:kImageHeightPt],
// Have the scroll view taking the full width of self and be vertically
// centered, which is useful when the label isn't taking the full height.
[scrollView.centerYAnchor constraintEqualToAnchor:self.centerYAnchor],
[scrollView.topAnchor constraintGreaterThanOrEqualToAnchor:self.topAnchor],
[scrollView.bottomAnchor
constraintLessThanOrEqualToAnchor:self.bottomAnchor],
[scrollView.leadingAnchor constraintEqualToAnchor:self.leadingAnchor],
[scrollView.trailingAnchor constraintEqualToAnchor:self.trailingAnchor],
]];
}
@end
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