為您的 iOS 應用程式新增進階功能

廣告插播

iOS Sender SDK 支援特定媒體串流中的廣告插播和隨播廣告。

如要進一步瞭解廣告插播的運作方式,請參閱網路接收器廣告插播總覽

雖然可以在傳送端和接收器上指定廣告插播,但還是建議您在網路接收器Android TV 接收器上指定廣告插播時間點,以便在不同平台間維持一致的行為。

在 iOS 上,使用 GCKAdBreakClipInfoGCKAdBreakInfo 在載入指令中指定廣告插播時間點:

Swift
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())
Objective-C
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]];

可變播放速率

應用程式可顯示及變更目前媒體項目的播放速率。您可以使用 GCKRemoteMediaClient-[setPlaybackRate:]-[setPlaybackRate:customData:] 設定速率,使用 GCKUIMediaControllerplaybackRateController 存取 GCKUIPlaybackRateController,並使用 GCKUIPlaybackRateControllerplaybackRate 顯示目前的播放速率。

程式碼範例

下列兩個檔案會實作 GCKUIPlaybackRateController,使用具有「標準」、「一半速度」和「雙倍速度」按鈕的分段控制項控製播放速率:

Swift
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
  }
}
Objective-C

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

新增自訂管道

Cast 架構提供兩種方式來建立頻道,以便將自訂訊息傳送至網路接收器:

  1. GCKCastChannel 應設為子類別,以實作具有相關狀態的非重要管道。
  2. GCKGenericChannel 可以做為子類別的替代方法,會將收到的訊息傳送至委派代表,以便其在其他位置處理。

以下是 GCKCastChannel 實作的範例:

Swift
class HGCTextChannel: GCKCastChannel {
  override func didReceiveTextMessage(_ message: String) {
    print("received message: \(message)")
  }
}
Objective-C

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

您隨時可以登錄管道。如果工作階段目前未處於連線狀態,當工作階段本身連線時,只要頻道的命名空間出現在 Web Receiver 應用程式中繼資料的受支援命名空間清單中,頻道就會自動連線。

每個自訂管道都是由不重複的命名空間定義,且開頭須為 urn:x-cast:,例如 urn:x-cast:com.example.custom。有可能擁有多個自訂管道,每個管道都有專屬的命名空間。Web Receiver 應用程式也可以使用相同的命名空間收發訊息

Swift
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)")
}
Objective-C
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);
}

如要提供需要在特定管道連線或中斷連線時執行的邏輯,請覆寫 -[didConnect]-[didDisconnect] 方法 (使用 GCKCastChannel),或是為 GCKGenericChannelDelegate-[castChannelDidConnect:]-[castChannelDidDisconnect:] 方法提供實作 (如果使用 GCKGenericChannel)。

支援自動播放功能

請參閱「自動播放及排入佇列 API」。

覆寫圖片選取與快取

此架構的各種元件 (包括「投放」對話方塊、迷你控制器、展開的控制器,以及 GCKUIMediaController 已設定) 會顯示目前投放媒體的圖片。圖片圖片的網址通常會包含在媒體的 GCKMediaMetadata 中,但傳送者應用程式可能會提供網址的替代來源。

GCKUIImagePicker 通訊協定會定義如何為特定用途和所需大小選取合適的圖片。其採用單一方法 -[getImageWithHints:fromMetadata:],該方法使用 GCKUIImageHints 物件和 GCKMediaMetadata 物件做為參數,並傳回 GCKImage 物件做為結果。架構提供 GCKUIImagePicker 的預設實作,一律選取 GCKMediaMetadata 物件圖片清單中的第一張圖片,但應用程式可以設定 GCKCastContext 單例模式的 imagePicker 屬性,提供另一種實作方式。

GCKUIImageCache 通訊協定也會定義一種方法,用來快取架構使用 HTTPS 下載的映像檔。該架構提供 GCKUIImageCache 的預設實作方式,會將下載的圖片檔儲存在應用程式的快取目錄中,但應用程式可以設定 GCKCastContext 單例模式的 imageCache 屬性,提供其他實作方式。

後續步驟

以上就是可新增至 iOS 發送端應用程式的功能。您現在可以為其他平台 (Android網頁版) 建構寄件者應用程式,或是建構 網路接收器