TRTCCalling is an open-source class based on two closed-source SDKs: Tencent Cloud Real-Time Communication (TRTC) and Instant Messaging (IM). It supports one-to-one audio/video calls. For detailed instructions how to implement it, please see Real-Time Audio Call (Flutter).

• TRTC SDK: the TRTC SDK is used as a low-latency audio/video call component.
• IM SDK: the IM SDK is used to send and process signaling messages.

`TRTCCalling` API Overview

Basic SDK APIs

API	Description
sharedInstance	Gets a singleton.
destroySharedInstance	Destroys a singleton.
registerListener	Registers an event listener.
unRegisterListener	Unregisters an event listener.
destroy	Destroys an instance that is no longer needed.
login	Logs in. All features can be used only after login.
logout	Logs out. No calls can be made after logout.

Call operation APIs

API	Description
call	Makes a one-to-one call.
accept	Accepts the current call.
reject	Declines the current call.
hangup	Ends the current call.

Audio control APIs

API	Description
setMicMute	Mutes the local mic.
setHandsFree	Enables the hands-free mode.

`TRTCCallingDelegate` API Overview

Common event callback APIs

API	Description
onError	Callback for error.

Inviter callback APIs

API	Description
onReject	The call was declined.
onNoResp	The invitee did not answer.
onLineBusy	The line is busy.

Invitee callback APIs

API	Description
onInvited	An invitation was received.
onCallingCancel	The call was canceled.
onCallingTimeOut	The call timed out.

General callback APIs

API	Description
onUserEnter	A user joined the call.
onUserLeave	A user left the call.
onUserAudioAvailable	Whether a user is sending audio
onUserVoiceVolume	Call volume of the user
onCallEnd	The call ended.

Basic SDK APIs

sharedInstance

This API is used to get a singleton of the TRTCCalling component.

static Future<TRTCCalling> sharedInstance();

destroySharedInstance

This API is used to destroy a singleton of the TRTCCalling component.

static void destroySharedInstance();

destroy

This API is used to destroy an instance that is no longer needed.

void destroy();

registerListener

This API is used to register callbacks for TRTCCalling events. You can receive status notifications of TRTCCalling via TRTCCallingDelegate.

void registerListener(VoiceListenerFunc func);

unRegisterListener

This API is used to unregister event callbacks.

void unRegisterListener(VoiceListenerFunc func);

login

This API is used to log in to the component.

Future<ActionCallback> login(int sdkAppId, String userId, String userSig);

The parameters are as detailed below:

Parameter	Type	Description
sdkAppID	int	You can view the SDKAppID via Application Management > Application Info in the TRTC console.
userId	String	ID of the current user, which is a string that can contain only letters (a-z and A-Z), digits (0-9), hyphens (-), and underscores (_).
userSig	String	Tencent Cloud's proprietary security protection signature. For more information on how to get it, please see How to Calculate UserSig.

logout

This API is used to log out of the component.

Future<ActionCallback> logout();

Call Operation APIs

call

This API is used to make a one-to-one call. It can be called during a call to invite more users.

Future<ActionCallback> call(String userId, int type);

The parameters are as detailed below:

Parameter	Type	Description
userId	String	User ID of the callee
type	int	1: audio call; 2: video call

accept

This API is used to accept the current call. After receiving the onInvited() callback, the invitee can call this API to accept the call.

Future<ActionCallback> accept();

reject

This API is used to decline the current call. After receiving the onInvited() callback, the invitee can call this API to decline the call.

Future<ActionCallback> reject();

hangup

This API is used to end the current call.

void hangup();

Audio Control APIs

setMicMute

This API is used to mute the local mic.

void setMicMute(bool isMute);

The parameters are as detailed below:

Parameter	Type	Description
isMute	bool	true: mutes the mic; false: unmutes the mic.

setHandsFree

This API is used to enable the hands-free mode.

void setHandsFree(bool isHandsFree);

The parameters are as detailed below:

Parameter	Type	Description
isHandsFree	bool	true: enables the hands-free mode; false: disables the hands-free mode.

TRTCCallingDelegate Callback APIs

Common Event Callback APIs

onError

Callback for error.

Note：

This callback indicates that the SDK encountered an unrecoverable error. Such errors must be listened for, and UI reminders should be sent to users if necessary.

The parameters are as detailed below:

Parameter	Type	Description
code	int	Error code
msg	String	Error message

Inviter Callback APIs

onReject

The call was declined.

The parameters are as detailed below:

Parameter	Type	Description
userId	String	User ID of the invitee who declined the call

onNoResp

The invitee did not answer.

The parameters are as detailed below:

Parameter	Type	Description
userId	String	User ID of the invitee who did not answer

onLineBusy

The line is busy.

The parameters are as detailed below:

Parameter	Type	Description
userId	String	User ID of the invitee whose line is busy

Invitee Callback APIs

onInvited

A call invitation was received.

The parameters are as detailed below:

Parameter	Type	Description
sponsor	String	User ID of the inviter
userIds	List&dxlt;String&dxgt;	IDs of other users invited
isFromGroup	bool	Whether it is a group call
type	int	1: audio call; 2: video call

onCallingCancel

The call was canceled. The invitee will receive this callback if the inviter cancels the invitation before he or she handles it.

onCallingTimeOut

The call timed out.

General Callback APIs

onUserEnter

A user joined the call.

The parameters are as detailed below:

Parameter	Type	Description
userId	String	ID of the user who joined the call

onUserLeave

A user left the call.

The parameters are as detailed below:

Parameter	Type	Description
userId	String	ID of the user who left the call

onUserAudioAvailable

Whether a user is sending audio.

The parameters are as detailed below:

Parameter	Type	Description
userId	String	User ID
available	boolean	Whether the user has available audio

onUserVoiceVolume

Call volume of a user.

The parameters are as detailed below:

Parameter	Type	Description
userVolumes	List	Volume of every speaking user in the room. Value range: 0-100.
totalVolume	int	Total volume of all remote users. Value range: 0-100.

onCallEnd

The call ended.