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Added in API level 14

public abstract class

TextToSpeechService

extends Service

java.lang.Object
↳	android.content.Context
	↳	android.content.ContextWrapper
		↳	android.app.Service
			↳	android.speech.tts.TextToSpeechService

Class Overview

Abstract base class for TTS engine implementations. The following methods need to be implemented.

The first three deal primarily with language management, and are used to query the engine for it's support for a given language and indicate to it that requests in a given language are imminent.


        
         onSynthesizeText(SynthesisRequest, SynthesisCallback)

is central to the engine implementation. The implementation should synthesize text as per the request parameters and return synthesized data via the supplied callback. This class and its helpers will then consume that data, which might mean queueing it for playback or writing it to a file or similar. All calls to this method will be on a single thread, which will be different from the main thread of the service. Synthesis must be synchronous which means the engine must NOT hold on the callback or call any methods on it after the method returns


        
         onStop()

tells the engine that it should stop all ongoing synthesis, if any. Any pending data from the current synthesis will be discarded.

Summary

[Expand]

Inherited Constants

From class android.app.Service

From class android.content.Context

From interface android.content.ComponentCallbacks2

int	TRIM_MEMORY_BACKGROUND	Level for `onTrimMemory(int)` : the process has gone on to the LRU list.
int	TRIM_MEMORY_COMPLETE	Level for `onTrimMemory(int)` : the process is nearing the end of the background LRU list, and if more memory isn't found soon it will be killed.
int	TRIM_MEMORY_MODERATE	Level for `onTrimMemory(int)` : the process is around the middle of the background LRU list; freeing memory can help the system keep other processes running later in the list for better overall performance.
int	TRIM_MEMORY_RUNNING_CRITICAL	Level for `onTrimMemory(int)` : the process is not an expendable background process, but the device is running extremely low on memory and is about to not be able to keep any background processes running.
int	TRIM_MEMORY_RUNNING_LOW	Level for `onTrimMemory(int)` : the process is not an expendable background process, but the device is running low on memory.
int	TRIM_MEMORY_RUNNING_MODERATE	Level for `onTrimMemory(int)` : the process is not an expendable background process, but the device is running moderately low on memory.
int	TRIM_MEMORY_UI_HIDDEN	Level for `onTrimMemory(int)` : the process had been showing a user interface, and is no longer doing so.

Public Constructors
	TextToSpeechService ()

Public Methods
IBinder	onBind ( Intent intent) Return the communication channel to the service.
void	onCreate () Called by the system when the service is first created.
void	onDestroy () Called by the system to notify a Service that it is no longer used and is being removed.

Protected Methods
Set < String >	onGetFeaturesForLanguage ( String lang, String country, String variant) Queries the service for a set of features supported for a given language.
abstract String[]	onGetLanguage () Returns the language, country and variant currently being used by the TTS engine.
abstract int	onIsLanguageAvailable ( String lang, String country, String variant) Checks whether the engine supports a given language.
abstract int	onLoadLanguage ( String lang, String country, String variant) Notifies the engine that it should load a speech synthesis language.
abstract void	onStop () Notifies the service that it should stop any in-progress speech synthesis.
abstract void	onSynthesizeText ( SynthesisRequest request, SynthesisCallback callback) Tells the service to synthesize speech from the given text.

[Expand]

Inherited Methods

From class android.app.Service

void	dump ( FileDescriptor fd, PrintWriter writer, String[] args) Print the Service's state into the given stream.
final Application	getApplication () Return the application that owns this service.
abstract IBinder	onBind ( Intent intent) Return the communication channel to the service.
void	onConfigurationChanged ( Configuration newConfig) Called by the system when the device configuration changes while your component is running.
void	onCreate () Called by the system when the service is first created.
void	onDestroy () Called by the system to notify a Service that it is no longer used and is being removed.
void	onLowMemory () This is called when the overall system is running low on memory, and actively running processes should trim their memory usage.
void	onRebind ( Intent intent) Called when new clients have connected to the service, after it had previously been notified that all had disconnected in its `onUnbind(Intent)` .
void	onStart ( Intent intent, int startId) This method was deprecated in API level 5. Implement `onStartCommand(Intent, int, int)` instead.
int	onStartCommand ( Intent intent, int flags, int startId) Called by the system every time a client explicitly starts the service by calling `startService(Intent)` , providing the arguments it supplied and a unique integer token representing the start request.
void	onTaskRemoved ( Intent rootIntent) This is called if the service is currently running and the user has removed a task that comes from the service's application.
void	onTrimMemory (int level) Called when the operating system has determined that it is a good time for a process to trim unneeded memory from its process.
boolean	onUnbind ( Intent intent) Called when all clients have disconnected from a particular interface published by the service.
final void	startForeground (int id, Notification notification) Make this service run in the foreground, supplying the ongoing notification to be shown to the user while in this state.
final void	stopForeground (boolean removeNotification) Remove this service from foreground state, allowing it to be killed if more memory is needed.
final void	stopSelf () Stop the service, if it was previously started.
final void	stopSelf (int startId) Old version of `stopSelfResult(int)` that doesn't return a result.
final boolean	stopSelfResult (int startId) Stop the service if the most recent time it was started was `startId` .

From class android.content.ContextWrapper

From class android.content.Context

From class java.lang.Object

Object	clone () Creates and returns a copy of this `Object` .
boolean	equals ( Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize () Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class <?>	getClass () Returns the unique instance of `Class` that represents this object's class.
int	hashCode () Returns an integer hash code for this object.
final void	notify () Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll () Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString () Returns a string containing a concise, human-readable description of this object.
final void	wait () Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait (long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait (long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface android.content.ComponentCallbacks

From interface android.content.ComponentCallbacks2

Public Constructors

public TextToSpeechService ()

Added in API level 14

Public Methods

public IBinder onBind ( Intent intent)

Added in API level 14

Return the communication channel to the service. May return null if clients can not bind to the service. The returned IBinder is usually for a complex interface that has been described using aidl .

Note that unlike other application components, calls on to the IBinder interface returned here may not happen on the main thread of the process . More information about the main thread can be found in Processes and Threads .

Parameters

intent	The Intent that was used to bind to this service, as given to `Context.bindService` . Note that any extras that were included with the Intent at that point will not be seen here.

Returns

Return an IBinder through which clients can call on to the service.

public void onCreate ()

Added in API level 14

Called by the system when the service is first created. Do not call this method directly.

public void onDestroy ()

Added in API level 14

Called by the system to notify a Service that it is no longer used and is being removed. The service should clean up any resources it holds (threads, registered receivers, etc) at this point. Upon return, there will be no more calls in to this Service object and it is effectively dead. Do not call this method directly.

Protected Methods

protected Set < String > onGetFeaturesForLanguage ( String lang, String country, String variant)

Added in API level 15

Queries the service for a set of features supported for a given language.

Parameters

lang	ISO-3 language code.
country	ISO-3 country code. May be empty or null.
variant	Language variant. May be empty or null.

Returns

A list of features supported for the given language.

protected abstract String[] onGetLanguage ()

Added in API level 14

Returns the language, country and variant currently being used by the TTS engine. Can be called on multiple threads.

Returns

A 3-element array, containing language (ISO 3-letter code), country (ISO 3-letter code) and variant used by the engine. The country and variant may be "" . If country is empty, then variant must be empty too.

protected abstract int onIsLanguageAvailable ( String lang, String country, String variant)

Added in API level 14

Checks whether the engine supports a given language. Can be called on multiple threads. Its return values HAVE to be consistent with onLoadLanguage.

Parameters

lang	ISO-3 language code.
country	ISO-3 country code. May be empty or null.
variant	Language variant. May be empty or null.

Returns

Code indicating the support status for the locale. One of LANG_AVAILABLE , LANG_COUNTRY_AVAILABLE , LANG_COUNTRY_VAR_AVAILABLE , LANG_MISSING_DATA LANG_NOT_SUPPORTED .

protected abstract int onLoadLanguage ( String lang, String country, String variant)

Added in API level 14

Notifies the engine that it should load a speech synthesis language. There is no guarantee that this method is always called before the language is used for synthesis. It is merely a hint to the engine that it will probably get some synthesis requests for this language at some point in the future. Can be called on multiple threads. In <= Android 4.2 (<= API 17) can be called on main and service binder threads. In > Android 4.2 (> API 17) can be called on main and synthesis threads.

Parameters

lang	ISO-3 language code.
country	ISO-3 country code. May be empty or null.
variant	Language variant. May be empty or null.

Returns

Code indicating the support status for the locale. One of LANG_AVAILABLE , LANG_COUNTRY_AVAILABLE , LANG_COUNTRY_VAR_AVAILABLE , LANG_MISSING_DATA LANG_NOT_SUPPORTED .

protected abstract void onStop ()

Added in API level 14

Notifies the service that it should stop any in-progress speech synthesis. This method can be called even if no speech synthesis is currently in progress. Can be called on multiple threads, but not on the synthesis thread.

protected abstract void onSynthesizeText ( SynthesisRequest request, SynthesisCallback callback)

Added in API level 14

Tells the service to synthesize speech from the given text. This method should block until the synthesis is finished. Called on the synthesis thread.

Parameters

request	The synthesis request.
callback	The callback the the engine must use to make data available for playback or for writing to a file.

Results

Interfaces

Classes

TextToSpeechService

Class Overview

Summary

Public Constructors

public TextToSpeechService ()

Public Methods

public IBinder onBind ( Intent intent)

Parameters

Returns

public void onCreate ()

public void onDestroy ()

Protected Methods

protected Set < String > onGetFeaturesForLanguage ( String lang, String country, String variant)

Parameters

Returns

protected abstract String[] onGetLanguage ()

Returns

See Also

protected abstract int onIsLanguageAvailable ( String lang, String country, String variant)

Parameters

Returns

protected abstract int onLoadLanguage ( String lang, String country, String variant)

Parameters

Returns

protected abstract void onStop ()

protected abstract void onSynthesizeText ( SynthesisRequest request, SynthesisCallback callback)

Parameters