你可以使用 ML Kit 翻譯語言之間的文字。ML Kit 能夠翻譯超過 50 種語言。
立即體驗
- 使用範例應用程式,查看這個 API 的使用範例。
事前準備
- 在 Podfile 中加入下列 ML Kit pod:
pod 'GoogleMLKit/Translate', '3.2.0'
- 安裝或更新專案的 Pod 後,請使用其
.xcworkspace
開啟 Xcode 專案。Xcode 12.4 以上版本支援 ML Kit。
翻譯文字字串
如何在兩種語言間翻譯字串:
建立
Translator
物件,並為其設定來源和譯文語言:Swift
// Create an English-German translator: let options = TranslatorOptions(sourceLanguage: .english, targetLanguage: .german) let englishGermanTranslator = Translator.translator(options: options)
Objective-C
// Create an English-German translator: MLKTranslatorOptions *options = [[MLKTranslatorOptions alloc] initWithSourceLanguage:MLKTranslateLanguageEnglish targetLanguage:MLKTranslateLanguageGerman]; MLKTranslator *englishGermanTranslator = [MLKTranslator translatorwithOptions:options];
如果您不知道輸入文字的語言,可以使用 Language Identification API 取得語言標記。接著將語言標記轉換為 ML Kit 列舉這些程式碼取決於您使用的語言:
- Swift:致電
TranslateLanguage.fromLanguageTag()
,取得TranslateLanguage
- 目標 C:呼叫
MLKTranslateLanguageForLanguageTag()
取得MLKTranslateLanguage
避免同時將過多語言模型在裝置上存放。
- Swift:致電
確認所需的翻譯模型已下載至裝置。 除非確認模型可用,否則不要呼叫
translate(_:completion:)
。Swift
let conditions = ModelDownloadConditions( allowsCellularAccess: false, allowsBackgroundDownloading: true ) englishGermanTranslator.downloadModelIfNeeded(with: conditions) { error in guard error == nil else { return } // Model downloaded successfully. Okay to start translating. }
Objective-C
MLKModelDownloadConditions *conditions = [[MLKModelDownloadConditions alloc] initWithAllowsCellularAccess:NO allowsBackgroundDownloading:YES]; [englishGermanTranslator downloadModelIfNeededWithConditions:conditions completion:^(NSError *_Nullable error) { if (error != nil) { return; } // Model downloaded successfully. Okay to start translating. }];
語言模型大約有 30 MB,因此請勿進行下載,除非使用者另外指定,否則只能透過 Wi-Fi 下載模型。您應刪除不再需要的模型。 請參閱明確管理翻譯模型一節。
確認模型下載完成後,請將原文語言的文字字串傳送至
translate(_:completion:)
:Swift
englishGermanTranslator.translate(text) { translatedText, error in guard error == nil, let translatedText = translatedText else { return } // Translation succeeded. }
Objective-C
[englishGermanTranslator translateText:text completion:^(NSString *_Nullable translatedText, NSError *_Nullable error) { if (error != nil || translatedText == nil) { return; } // Translation succeeded. }];
ML Kit 將文字轉譯為您設定的譯文語言,並將翻譯後的文字傳送至完成處理常式。
譯者生命週期是由 ARC 控管 (自動參考計算),這是 iOS 開發作業的建議慣例。移除所有強大的參考資料後,開發人員就能取消翻譯。
譯者在記憶體中載入後,會佔用 30 MB 至 150 MB 的空間。開發人員建立並行翻譯執行個體時,應考量裝置/應用程式的記憶體預算,並避免同時在裝置上使用過多語言模型。
明確管理翻譯模型
使用上述的 Translation API 時,ML Kit 會視需要自動將語言專屬的翻譯模型下載到裝置。您也可以使用 ML Kit 的翻譯模型管理 API 明確管理想要在裝置上使用的翻譯模型。如果想預先下載模型,或是從裝置中刪除不需要的模型,這項功能就能派上用場。
如何取得儲存在裝置上的翻譯模型:
Swift
let localModels = ModelManager.modelManager().downloadedTranslateModels
Objective-C
NSSet*localModels = [MLKModelManager modelManager].downloadedTranslateModels;
如要刪除模型:
Swift
// Delete the German model if it's on the device. let germanModel = TranslateRemoteModel.translateRemoteModel(language: .german) ModelManager.modelManager().deleteDownloadedModel(germanModel) { error in guard error == nil else { return } // Model deleted. }
Objective-C
// Delete the German model if it's on the device. MLKTranslateRemoteModel *germanModel = [MLKTranslateRemoteModel translateRemoteModelWithLanguage:MLKTranslateLanguageGerman]; [[MLKModelManager modelManager] deleteDownloadedModel:germanModel completion:^(NSError * _Nullable error) { if (error != nil) { return; } // Model deleted.
如何下載模型:
Swift
// Download the French model. let frenchModel = TranslateRemoteModel.translateRemoteModel(language: .french) // Keep a reference to the download progress so you can check that the model // is available before you use it. progress = ModelManager.modelManager().download( frenchModel, conditions: ModelDownloadConditions( allowsCellularAccess: false, allowsBackgroundDownloading: true ) )
如要透過 NotificationCenter
取得下載狀態,請為 mlkitModelDownloadDidSucceed
和 mlkitModelDownloadDidFail
註冊觀測器。請務必在觀察器區塊中使用 self
的弱參照,因為下載可能需要一些時間,而且在下載完成時可以釋出來源物件。例如:
NotificationCenter.default.addObserver( forName: .mlkitModelDownloadDidSucceed, object: nil, queue: nil ) { [weak self] notification in guard let strongSelf = self, let userInfo = notification.userInfo, let model = userInfo[ModelDownloadUserInfoKey.remoteModel.rawValue] as? TranslateRemoteModel, model == frenchModel else { return } // The model was downloaded and is available on the device } NotificationCenter.default.addObserver( forName: .mlkitModelDownloadDidFail, object: nil, queue: nil ) { [weak self] notification in guard let strongSelf = self, let userInfo = notification.userInfo, let model = userInfo[ModelDownloadUserInfoKey.remoteModel.rawValue] as? TranslateRemoteModel else { return } let error = userInfo[ModelDownloadUserInfoKey.error.rawValue] // ... }
Objective-C
// Download the French model. MLKModelDownloadConditions *conditions = [[MLKModelDownloadConditions alloc] initWithAllowsCellularAccess:NO allowsBackgroundDownloading:YES]; MLKTranslateRemoteModel *frenchModel = [MLKTranslateRemoteModel translateRemoteModelWithLanguage:MLKTranslateLanguageFrench]; // Keep a reference to the download progress so you can check that the model // is available before you use it. self.downloadProgress = [[MLKModelManager modelManager] downloadModel:frenchModel conditions:conditions];
如要透過 NSNotificationCenter
取得下載狀態,請為 MLKModelDownloadDidSucceedNotification
和 MLKModelDownloadDidFailNotification
註冊觀測器。請務必在觀察器區塊中使用 self
的弱參照,因為下載可能需要一點時間,而且在下載完成後就能釋出原始物件。
__block MyViewController *weakSelf = self; [NSNotificationCenter.defaultCenter addObserverForName:MLKModelDownloadDidSucceedNotification object:nil queue:nil usingBlock:^(NSNotification * _Nonnull note) { if (weakSelf == nil | note.userInfo == nil) { return; } MLKTranslateRemoteModel *model = note.userInfo[MLKModelDownloadUserInfoKeyRemoteModel]; if ([model isKindOfClass:[MLKTranslateRemoteModel class]] && model == frenchModel) { // The model was downloaded and is available on the device } }]; [NSNotificationCenter.defaultCenter addObserverForName:MLKModelDownloadDidFailNotification object:nil queue:nil usingBlock:^(NSNotification * _Nonnull note) { if (weakSelf == nil | note.userInfo == nil) { return; } NSError *error = note.userInfo[MLKModelDownloadUserInfoKeyError]; }];