广告插播时间点
iOS Sender SDK 支持给定媒体流中的广告插播时间点和随播广告。
如需详细了解广告插播时间点的运作方式,请参阅网络接收器广告插播概览。
虽然可以在发送端和接收端上同时指定广告插播时间点,但建议在网络接收器和 Android TV 接收器中指定中断,以确保各个平台的行为保持一致。
在 iOS 上,使用 GCKAdBreakClipInfo
和 GCKAdBreakInfo
在加载命令中指定广告插播时间点:
let breakClip1Builder = GCKAdBreakClipInfoBuilder(adBreakClipID: "bc0") breakClip1Builder.title = "Clip title" if let posterUrl = URL(string: "https://www.some.url") { breakClip1Builder.posterURL = posterUrl } breakClip1Builder.duration = 60 breakClip1Builder.whenSkippable = 5 // Set this field so that the ad is skippable let breakClip1 = breakClip1Builder.build() let breakClip2 = ... let breakClip3 = ... let break1 = GCKAdBreakInfoBuilder(adBreakID: "b0", adBreakClipIds: ["bc0", "bc1", "bc2"]).build() let mediaInfoBuilder = GCKMediaInformationBuilder(entity: "entity") ... mediaInfoBuilder.adBreaks = [break1] mediaInfoBuilder.adBreakClips = [breakClip1, breakClip2, breakClip3] ... mediaInformation = mediaInfoBuilder.build() let mediaLoadRequestDataBuilder = GCKMediaLoadRequestDataBuilder() mediaLoadRequestDataBuilder.mediaInformation = mediaInformation sessionManager.currentSession?.remoteMediaClient?.loadMedia(with: mediaLoadRequestDataBuilder.build())
GCKAdBreakClipInfoBuilder *breakClipInfoBuilder = [[GCKAdBreakClipInfoBuilder alloc] initWithAdBreakClipID:@"bc0"]; breakClipInfoBuilder.title = @"Clip title"; breakClipInfoBuilder.posterURL = [[NSURL alloc] initWithString:@"https://www.some.url"]; breakClipInfoBuilder.duration = 60; breakClipInfoBuilder.whenSkippable = 5; GCKAdBreakClipInfo *breakClip1 = breakClipInfoBuilder.build; GCKAdBreakClipInfo *breakClip2 = ... GCKAdBreakClipInfo *breakClip3 = ... GCKAdBreakInfo *break1 = [[GCKAdBreakInfoBuilder alloc] initWithAdBreakID:@"b0" adBreakClipIds:@[@"bc0", @"bc1", @"bc2"]].build; GCKMediaInformationBuilder *mediaInfoBuilder = [[GCKMediaInformationBuilder alloc] initWithEntity:@"entity"]; ... mediaInfoBuilder.adBreaks = @[break1]; mediaInfoBuilder.adBreakClips = @[breakClip1, breakClip2, breakClip3]; ... self.mediaInformation = [mediaInfoBuilder build]; GCKMediaLoadRequestDataBuilder *mediaLoadRequestDataBuilder = [[GCKMediaLoadRequestDataBuilder alloc] init]; mediaLoadRequestDataBuilder.mediaInformation = self.mediaInformation; // Send a load request to the remote media client. GCKRequest *request = [self.sessionManager.currentSession.remoteMediaClient loadMediaWithLoadRequestData:[mediaLoadRequestDataBuilder build]];
可变播放速率
您的应用可以显示和更改当前媒体项的播放速率。您可以使用 GCKRemoteMediaClient
的 -[setPlaybackRate:]
或 -[setPlaybackRate:customData:]
设置速率,使用 GCKUIMediaController
的 playbackRateController
访问 GCKUIPlaybackRateController
,以及使用 GCKUIPlaybackRateController
的 playbackRate
显示当前播放速率。
示例代码
以下两个文件实现了 GCKUIPlaybackRateController
,它使用包含“正常”“半速”和“双倍速”按钮的分段控件来控制播放速率:
import GoogleCast /** * An implementation of GCKUIPlaybackRateController that controls playback rate * using a segmented control that has "normal", "half speed", and "double speed" * buttons. */ class SegmentedButtonPlaybackRateController: GCKUIPlaybackRateController { static let kSegmentNormal = 0; static let kSegmentHalfSpeed = 1; static let kSegmentDoubleSpeed = 2; var segmentedControl: UISegmentedControl! override var playbackRate: Float { didSet { var buttonIndex = 0 // Map the playback rate to one of our three supported speeds. if playbackRate == 1.0 { buttonIndex = SegmentedButtonPlaybackRateController.kSegmentNormal } else if playbackRate < 1.0 { buttonIndex = SegmentedButtonPlaybackRateController.kSegmentHalfSpeed } else { buttonIndex = SegmentedButtonPlaybackRateController.kSegmentDoubleSpeed } segmentedControl?.selectedSegmentIndex = buttonIndex } } override var inputEnabled: Bool { didSet { segmentedControl?.isEnabled = inputEnabled } } /** * Designated initializer. * * @param segmentedControl The segmented control for changing/displaying the * playback rate. */ convenience init(_ segmentedControl: UISegmentedControl) { self.init() self.segmentedControl = segmentedControl; segmentedControl.addTarget(self, action: #selector(segmentedControlTapped(sender:)), for: UIControl.Event.valueChanged) } @objc func segmentedControlTapped(sender: UISegmentedControl) { var playbackRate: Float = 1.0 switch segmentedControl?.selectedSegmentIndex { case SegmentedButtonPlaybackRateController.kSegmentHalfSpeed: playbackRate = 0.5; case SegmentedButtonPlaybackRateController.kSegmentDoubleSpeed: playbackRate = 2.0; case SegmentedButtonPlaybackRateController.kSegmentNormal: fallthrough default: playbackRate = 1.0; } self.playbackRate = playbackRate } }
SegmentedButtonPlaybackRateController.h
#import <GoogleCast/GoogleCast.h> #import <UIKit/UIKit.h> /** * An implementation of GCKUIPlaybackRateController that controls playback rate * using a segmented control that has "normal", "half speed", and "double speed" * buttons. */ @interface SegmentedButtonPlaybackRateController : GCKUIPlaybackRateController /** * Designated initializer. * * @param segmentedControl The segmented control for changing/displaying the * playback rate. */ - (instancetype)initWithSegmentedControl:(UISegmentedControl *)segmentedControl; @end
SegmentedButtonPlaybackRateController.m
#import "SegmentedButtonPlaybackRateController.h" @interface SegmentedButtonPlaybackRateController () { UISegmentedControl *_segmentedControl; } @end static const NSInteger kSegmentNormal = 0; static const NSInteger kSegmentHalfSpeed = 1; static const NSInteger kSegmentDoubleSpeed = 2; @implementation SegmentedButtonPlaybackRateController - (instancetype)initWithSegmentedControl:(UISegmentedControl *)segmentedControl { if (self = [super init]) { _segmentedControl = segmentedControl; [_segmentedControl addTarget:self action:@selector(segmentedControlTapped:) forControlEvents:UIControlEventValueChanged]; } return self; } - (void)setPlaybackRate:(float)playbackRate { [super setPlaybackRate:playbackRate]; NSInteger buttonIndex = 0; // Map the playback rate to one of our three supported speeds. if (playbackRate == 1.0) { buttonIndex = kSegmentNormal; } else if (playbackRate < 1.0) { buttonIndex = kSegmentHalfSpeed; } else { buttonIndex = kSegmentDoubleSpeed; } _segmentedControl.selectedSegmentIndex = buttonIndex; } - (void)setInputEnabled:(BOOL)inputEnabled { _segmentedControl.enabled = inputEnabled; [super setInputEnabled:inputEnabled]; } - (void)segmentedControlTapped:(id)sender { float playbackRate; switch (_segmentedControl.selectedSegmentIndex) { case kSegmentHalfSpeed: playbackRate = 0.5; break; case kSegmentDoubleSpeed: playbackRate = 2.0; break; case kSegmentNormal: default: playbackRate = 1.0; break; } self.playbackRate = playbackRate; } @end
添加自定义渠道
Cast 框架提供了两种方法来创建用于将自定义消息发送到网络接收器的通道:
GCKCastChannel
旨在实现子类化,以实现具有关联状态的重要通道。GCKGenericChannel
作为子类化的替代方案;它会将接收到的消息传递给代理,以便在其他位置处理这些消息。
下面是一个 GCKCastChannel
实现示例:
class HGCTextChannel: GCKCastChannel { override func didReceiveTextMessage(_ message: String) { print("received message: \(message)") } }
HGCTextChannel.h
#import <GoogleCast/GCKCastChannel.h> @interface HGCTextChannel : GCKCastChannel @end
HGCTextChannel.m
#import "HGCTextChannel.h" @implementation HGCTextChannel - (void)didReceiveTextMessage:(NSString*)message { NSLog(@"received message: %@", message); } @end
通道可以随时注册;如果会话当前未处于已连接状态,则该通道会在会话本身连接时自动连接,前提是该通道的命名空间存在于 Web Receiver 应用元数据的受支持命名空间列表中。
每个自定义渠道都由唯一的命名空间定义,且必须以前缀 urn:x-cast:
开头,例如 urn:x-cast:com.example.custom
。您可以拥有多个自定义渠道,每个渠道都有一个唯一的命名空间。Web 接收器应用还可以使用同一命名空间收发消息。
var error: GCKError? let textChannel = HGCTextChannel.init(namespace: "urn:x-cast:com.google.cast.sample.helloworld") sessionManager.currentCastSession?.add(textChannel) textChannel.sendTextMessage("Hello World", error: &error) if error != nil { print("Error sending text message \(error.debugDescription)") }
NSError *error; HGCTextChannel *textChannel = [[HGCTextChannel alloc] initWithNamespace:@"urn:x-cast:com.google.cast.sample.helloworld"]; [sessionManager.currentCastSession addChannel:textChannel]; [textChannel sendTextMessage:@"Hello World" error:&error]; if (error != nil) { NSLog(@"Error sending text message: %@", error); }
如需提供在特定频道连接或断开连接时需要执行的逻辑,请替换 -[didConnect]
和 -[didDisconnect]
方法(如果使用 GCKCastChannel
),或为 GCKGenericChannelDelegate
的 -[castChannelDidConnect:]
和 -[castChannelDidDisconnect:]
方法提供实现(如果使用 GCKGenericChannel
)。
支持自动播放
请参阅 Autoplay API 和 Queueing API。
替换图片选择和缓存
框架的各个组件(即“投射”对话框、迷你控制器、展开的控制器以及 GCKUIMediaController
(如果已配置)将显示当前投射媒体的海报图片。图片图片的网址通常包含在媒体的 GCKMediaMetadata
中,但发送器应用可能有备用网址来源。
GCKUIImagePicker
协议定义了根据给定用途和所需大小选择合适图片的方法。它只有一个方法 -[getImageWithHints:fromMetadata:]
,该方法接受 GCKUIImageHints
对象和 GCKMediaMetadata
对象作为参数,并返回一个 GCKImage
对象作为结果。框架提供了 GCKUIImagePicker
的默认实现,它会始终选择 GCKMediaMetadata
对象内图片列表中的第一张图片,但应用可以通过设置 GCKCastContext
单例的 imagePicker
属性来提供备用实现。
GCKUIImageCache
协议还定义了一种对框架使用 HTTPS 下载的图片进行缓存的方法。框架提供了 GCKUIImageCache
的默认实现,它会将下载的图片文件存储在应用的缓存目录中,但应用可以通过设置 GCKCastContext
单例的 imageCache
属性来提供替代实现。
后续步骤
以上就是可添加到 iOS“发送者”应用中的功能。现在,你可以针对其他平台(Android 或 Web)构建发送器应用,或者构建网络接收器。