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

ios/chrome/browser/ui/reading_list/number_badge_view.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/reading_list/number_badge_view.h"
+
+#import <Foundation/Foundation.h>
+
+#include "base/format_macros.h"
+#import "ios/chrome/common/material_timing.h"
+#import "ios/third_party/material_roboto_font_loader_ios/src/src/MaterialRobotoFontLoader.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+const CGFloat kAnimationDuration = ios::material::kDuration3;
+const CGFloat labelMargin = 2.5f;
+}  // namespace
+
+@interface NumberBadgeView ()
+@property(nonatomic, readonly, weak) UILabel* label;
+// This is a pill-shaped (rounded corners) view used in the background of the
+// badge.
+@property(nonatomic, readonly, weak) UIView* backgroundCircleView;
+@property(nonatomic, assign) NSInteger displayNumber;
+@end
+
+@implementation NumberBadgeView
+#pragma mark - properties
+@synthesize label = _label;
+@synthesize backgroundCircleView = _backgroundCircleView;
+@synthesize displayNumber = _displayNumber;
+
+#pragma mark - lifecycle
+- (instancetype)initWithFrame:(CGRect)frame {
+  self = [super initWithFrame:frame];
+  if (self) {
+    self.backgroundColor = [UIColor clearColor];
+
+    UIView* backgroundCircleView = [[UIView alloc] initWithFrame:CGRectZero];
+    _backgroundCircleView = backgroundCircleView;
+    [backgroundCircleView setTranslatesAutoresizingMaskIntoConstraints:NO];
+    [self addSubview:backgroundCircleView];
+
+    UILabel* label = [[UILabel alloc] initWithFrame:CGRectZero];
+    _label = label;
+    [label setFont:[[MDFRobotoFontLoader sharedInstance] boldFontOfSize:10]];
+    [label setTranslatesAutoresizingMaskIntoConstraints:NO];
+    [label setTextColor:[UIColor whiteColor]];
+    [self addSubview:label];
+
+    [NSLayoutConstraint activateConstraints:@[
+      // Position bubble.
+      [backgroundCircleView.trailingAnchor
+          constraintEqualToAnchor:self.trailingAnchor],
+      [backgroundCircleView.centerYAnchor
+          constraintEqualToAnchor:self.centerYAnchor],
+
+      // Position label on bubble.
+      [label.centerXAnchor
+          constraintEqualToAnchor:backgroundCircleView.centerXAnchor],
+      [label.centerYAnchor
+          constraintEqualToAnchor:backgroundCircleView.centerYAnchor],
+
+      // Make bubble fit label.
+      [backgroundCircleView.heightAnchor
+          constraintEqualToAnchor:label.heightAnchor
+                         constant:labelMargin * 2],
+      [backgroundCircleView.widthAnchor
+          constraintGreaterThanOrEqualToAnchor:backgroundCircleView
+                                                   .heightAnchor],
+      [backgroundCircleView.widthAnchor
+          constraintGreaterThanOrEqualToAnchor:label.widthAnchor
+                                      constant:labelMargin * 2]
+    ]];
+
+    // Start hidden.
+    self.alpha = 0.0;
+  }
+  return self;
+}
+
+#pragma mark - UIView
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  self.backgroundCircleView.layer.cornerRadius =
+      self.backgroundCircleView.bounds.size.height / 2.0f;
+}
+
+#pragma mark - public
+- (void)setNumber:(NSInteger)number animated:(BOOL)animated {
+  // If the previous number and current number match, do nothing.
+  if (self.displayNumber != number) {
+    self.displayNumber = number;
+    if (animated) {
+      [UIView animateWithDuration:kAnimationDuration
+                       animations:^{
+                         if (number > 0) {
+                           self.alpha = 1.0;
+                           // Only setting when > 0 as this makes the animation
+                           // look better than switching to 0 then fading out.
+                           self.label.text =
+                               [NSString stringWithFormat:@"%" PRIdNS, number];
+                         } else {
+                           self.alpha = 0.0;
+                         }
+                         [self setNeedsLayout];
+                         [self layoutIfNeeded];
+                       }];
+    } else {
+      self.label.text = [NSString stringWithFormat:@"%" PRIdNS, number];
+    }
+  }
+}
+
+- (void)setBackgroundColor:(UIColor*)backgroundColor animated:(BOOL)animated {
+  if (animated) {
+    [UIView animateWithDuration:kAnimationDuration
+                     animations:^{
+                       [self.backgroundCircleView
+                           setBackgroundColor:backgroundColor];
+                     }];
+  } else {
+    [self.backgroundCircleView setBackgroundColor:backgroundColor];
+  }
+}
+
+@end