[ProgressView] Add the ProgressView component.

Summary:
Adds a ProgressView component. It displays determinate progress linearly.

Note: the README.md and API has previously been reviewed. Feel free to leave comments, but you can also skip for this review and focus on the implementation.

Test Plan: - Open Catalog > Progress View and verify looks.

Reviewers: randallli, junius, iangordon, O1 Material components iOS, ajsecord

Reviewed By: O1 Material components iOS, ajsecord

Tags: #material_components_ios

Differential Revision: http://codereview.cc/D1103

MaterialComponents.podspec

@@ -183,6 +183,14 @@ Pod::Spec.new do |s|
     ss.header_mappings_dir = "components/#{ss.base_name}/src"
   end
 
+  s.subspec "ProgressView" do |ss|
+    ss.public_header_files = "components/#{ss.base_name}/src/*.h"
+    ss.source_files = "components/#{ss.base_name}/src/*.{h,m}"
+    ss.header_mappings_dir = "components/#{ss.base_name}/src"
+
+    ss.dependency "MaterialComponents/private/RTL"
+  end
+
   s.subspec "RobotoFontLoader" do |ss|
     ss.public_header_files = "components/#{ss.base_name}/src/*.h"
     ss.source_files = "components/#{ss.base_name}/src/*.{h,m}", "components/#{ss.base_name}/src/private/*.{h,m}"

ROADMAP.md

@@ -4,6 +4,6 @@ components:
 - HUD
 - Textfields
 - ActivityIndicator
-- ProgressBar
+- ProgressView
 
 For suggestions, please [file a GitHub issue](https://github.com/google/material-components-ios/issues).

catalog/Podfile.lock

@@ -17,6 +17,7 @@ PODS:
     - MaterialComponents/PageControl (= 12.0.1)
     - MaterialComponents/Palettes (= 12.0.1)
     - MaterialComponents/private (= 12.0.1)
+    - MaterialComponents/ProgressView (= 12.0.1)
     - MaterialComponents/RobotoFontLoader (= 12.0.1)
     - MaterialComponents/ShadowElevations (= 12.0.1)
     - MaterialComponents/ShadowLayer (= 12.0.1)
@@ -113,6 +114,8 @@ PODS:
     - MaterialComponents/private/Color
     - MaterialComponents/ShadowElevations
     - MaterialComponents/ShadowLayer
+  - MaterialComponents/ProgressView (12.0.1):
+    - MaterialComponents/private/RTL
   - MaterialComponents/RobotoFontLoader (12.0.1):
     - MaterialComponents/FontDiskLoader
     - MaterialComponents/Typography
@@ -152,7 +155,7 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   CatalogByConvention: 0137d280781667dd3d856a14cdf507f5ac8eedc0
-  MaterialComponents: c9194c49be10b8ac59cb8f857bedecbb511705a8
+  MaterialComponents: ed704822f99f7286a3e5d2d4cc7ffdeac044c211
   MaterialComponentsCatalog: c2911e8ad9f380350107f124f88a43b9fe012d19
   MaterialComponentsUnitTests: 03755d2a184c1d21a66c86c0e333d7b087e2f662
 

components/ProgressView/.jazzy.yaml

@@ -0,0 +1,5 @@
+# Auto-generated by ./scripts/generate_jazzy_yamls.sh. Used primarily by scripts/external/arc-jazzy-linter.
+module: ProgressView
+umbrella_header: src/MaterialProgressView.h
+objc: true
+sdk: iphonesimulator

components/ProgressView/README.md

@@ -0,0 +1,166 @@
+---
+title:  "Progress View"
+layout: detail
+section: components
+excerpt: "Progress View is a determinate and linear progress indicator that implements Material Design animation and layout."
+---
+# Progress View
+
+<div class="ios-animation right" markdown="1">
+  <video src="docs/assets/progress_view.mp4" autoplay loop></video>
+  [![ScreenShot](docs/assets/progress_view.png)](docs/assets/progress_view.mp4)
+</div>
+
+This control is designed to be a drop-in replacement for `UIProgressView`, with a user experience
+influenced by [Material Design specifications](https://material.google.com/components/progress-activity.html#)
+for animation and layout. The API methods are the same as a `UIProgressView`, with the addition of a
+few key methods required to achieve the desired animation of the control.
+<!--{: .intro }-->
+
+### Material Design Specifications
+
+<ul class="icon-list">
+  <li class="icon-link"><a href="https://material.google.com/components/progress-activity.html">Progress & activity</a></li>
+</ul>
+
+### API Documentation
+
+<ul class="icon-list">
+  <li class="icon-link"><a href="/components/ProgressView/apidocs/Classes/MDCProgressView.html">MDCProgressView</a></li>
+</ul>
+
+- - -
+
+## Installation
+
+### Requirements
+
+- Xcode 7.0 or higher
+- iOS SDK version 7.0 or higher
+
+### Installation with CocoaPods
+
+To add this component to your Xcode project using CocoaPods, add the following to your `Podfile`:
+
+~~~ bash
+pod 'MaterialComponents/ProgressView'
+~~~
+
+Then, run the following command:
+
+~~~ bash
+$ pod install
+~~~
+
+- - -
+
+## Differences From UIProgressView
+
+This progress view provides an animation effect when showing and hidding it: it grows up (resp.
+shrinks down). Additionally, all animated changes APIs take an optional completion block, to
+synchronize multistep animations.
+
+- - -
+
+## Usage
+
+### Importing
+
+Before using Progress View, you'll need to import it:
+
+<!--<div class="material-code-render" markdown="1">-->
+#### Objective-C
+
+~~~ objc
+#import "MaterialProgressView.h"
+~~~
+
+#### Swift
+~~~ swift
+import MaterialComponents
+~~~
+<!--</div>-->
+
+Add the progress view to your view hierarchy like you would with any other view. Note that it works
+best when the progress view is added at the bottom of a view, as showing (resp. hiding) grows up
+(resp. shrinks down).
+
+### Step 1: Add the progress view to a view
+
+Add the progress view to a view and set the desired progress and hidden state.
+
+<!--<div class="material-code-render" markdown="1">-->
+#### Objective-C
+
+~~~ objc
+@implementation ViewController {
+  MDCProgressView *_progressView;
+}
+
+- (void)viewDidLoad {
+  [super viewDidLoad];
+
+  // Progress view configuration.
+  _progressView = [[MDCProgressView alloc] initWithFrame:myFrame];
+  _progressView.progress = 0;  // You can also set a greater progress for actions already started.
+  [self.view addSubview:_progressView];
+}
+
+~~~
+
+#### Swift
+
+~~~ swift
+class ProgressViewSwiftExampleViewController: UIViewController {
+
+  let progressView = MDCProgressView()
+
+  override func viewDidLoad() {
+    super.viewDidLoad()
+
+    progressView.progress = 0
+
+    let progressViewHeight = CGFloat(2)
+    progressView.frame = CGRectMake(0, view.bounds.height - progressViewHeight, view.bounds.width, progressViewHeight);
+    view.addSubview(progressView)
+  }
+
+~~~
+<!--</div>-->
+
+### Step 2: Change the progress and hidden state
+
+Both the progress and the hidden state can be animated, with a completion block.
+
+<!--<div class="material-code-render" markdown="1">-->
+#### Objective-C
+
+~~~ objc
+- (void)startAndShowProgressView {
+  _progressView.progress = 0;
+  [_progressView setHidden:NO animated:YES completion:nil];
+}
+
+- (void)completeAndHideProgressView {
+  [_progressView setProgress:1 animated:YES completion:^(BOOL finished){
+    [_progressView setHidden:YES animated:YES completion:nil];
+  }];
+}
+~~~
+
+#### Swift
+
+~~~ swift
+func startAndShowProgressView {
+  progressView.progress = 0
+  progressView.setHidden(false, animated: true)
+}
+
+func completeAndHideProgressView {
+  progressView.setProgress(1, animated: true) { BOOL finished in
+    progressView.setHidden(true, animated: true)
+  }
+}
+~~~
+
+<!--</div>-->