在此页

• 特性
• Media action types
• 描述
• 范例
• 规范
• 浏览器兼容性
• 范例
• 规范
• 浏览器兼容性
• 相关话题

Media Session API' s MediaSessionActionDetails dictionary is the type used by the sole input parameter into the callback which is executed when a media session action 出现。 It specifies the type of action which needs to be performed as well as the data needed to perform the action.

特性

action

A Media Session action type string taken from the MediaSessionAction enumerated type, indicating which type of action needs to be performed. See Media action types below for possible values.

fastSeek 可选

An seekto action may optionally include this property, which is a Boolean value indicating whether or not to perform a "fast" seek. A "fast" seek is a seek being performed in a rapid sequence, such as when fast-forwarding or reversing through the media, rapidly skipping through it. This property can be used to indicate that you should use the shortest possible method to seek the media. fastSeek is not included on the final action in the seek sequence in this situation.

seekOffset 可选

若 action 是 seekforward or seekbackward and this property is present, it is a floating point value which indicates the number of seconds to move the play position forward or backward. If this property isn't present, those actions should choose a reasonable default distance to skip forward or backward (such as 7 or 10 seconds).

seekTime 可选

若 action is seekto , this property must be present and must be a floating-point value indicating the absolute time within the media to move the playback position to, where 0 indicates the beginning of the media. This property is not present for other action types.

Media action types

A media session action's type is specified using a string from the MediaSessionAction enumerated type.

值

Each of the actions is a common media session control request. Implement support for each of these in order to allow that type of action to be performed. The following strings identify the currently available types of media session action:

nexttrack

Advances playback to the next track.

pause

暂停媒体回放。

play

Begins (or resumes) playback of the media.

previoustrack

Moves back to the previous track.

seekbackward

Seeks backward through the media from the current position. The MediaSessionActionDetails property seekOffset specifies the amount of time to seek backward.

seekforward

Seeks forward from the current position through the media. The MediaSessionActionDetails property seekOffset specifies the amount of time to seek forward.

seekto

Moves the playback position to the specified time within the media. The time to which to seek is specified in the MediaSessionActionDetails property seekTime . If you intend to perform multiple seekto operations in rapid succession, you can also specify the MediaSessionActionDetails property fastSeek property with a value of true . This lets the browser know it can take steps to optimize repeated operations, and is likely to result in improved performance.

skipad

Skips past the currently playing advertisement or commercial. This action may or may not be available, depending on the platform and 用户代理 , or may be disabled due to subscription level or other circumstances.

stop

Halts playback entirely.

描述

A media session action may be generated by any media session action source; these sources include anything from UI widgets within the browser itself to media control keys on the user's keyboard to buttons on the user's headset or earbuds.

范例

Adding action handlers

This example implements seek forward and backward actions for an audio player by setting up the seekforward and seekbackward action handlers.

let skipTime = 10; // Time to skip in seconds
navigator.mediaSession.setActionHandler('seekforward', evt => {
 // User clicked "Seek Forward" media notification icon.
 audio.currentTime = Math.min(audio.currentTime + skipTime,
               audio.duration);
});
navigator.mediaSession.setActionHandler('seekbackward', evt => {
 // User clicked "Seek Backward" media notification icon.
 audio.currentTime = Math.max(audio.currentTime - skipTime, 0);
});
					

Supporting multiple actions in one handler function

You can also, if you prefer, use a single function to handle multiple action types, by checking the value of the MediaSessionActionDetails 对象的 action 特性：

let skipTime = 7;
navigator.mediaSession.setActionHandler("seekforward", handleSeek);
navigator.mediaSession.setActionHandler("seekbackward", handleSeek);
function handleSeek(details) {
  switch(details.action) {
    case "seekforward":
      audio.currentTime = Math.min(audio.currentTime + skipTime,
              audio.duration);
      break;
    case "seekbackward":
      audio.currentTime = Math.max(audio.currentTime - skipTime, 0);
      break;
  }
}
					

在这里， handleSeek() function handles both seekbackward and seekforward actions.

规范

规范	状态	注释
Media Session Standard The definition of 'Media Session action types' in that specification.	草案	初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

No compatibility data found. Please contribute data for "api.MediaSessionAction" (depth: 1) to the MDN 兼容性数据存储库 .

范例

Adding action handlers

This example implements seek forward and backward actions for an audio player by setting up the seekforward and seekbackward action handlers.

let skipTime = 10; // Time to skip in seconds
navigator.mediaSession.setActionHandler('seekforward', details => {
 // User clicked "Seek Forward" media notification icon.
 audio.currentTime = Math.min(audio.currentTime + skipTime,
               audio.duration);
});
navigator.mediaSession.setActionHandler('seekbackward', details => {
 // User clicked "Seek Backward" media notification icon.
 audio.currentTime = Math.max(audio.currentTime - skipTime, 0);
});
				

In this case, both the seekforward and seekbackward handlers are using a fixed distance, ignoring the time specified by the MediaSessionActionDetails passed into the handler.

Supporting multiple actions in one handler function

You can also, if you prefer, use a single function to handle multiple action types, by checking the value of the MediaSessionActionDetails 对象的 action 特性：

let skipTime = 7;
navigator.mediaSession.setActionHandler("seekforward", handleSeek);
navigator.mediaSession.setActionHandler("seekbackward", handleSeek);
function handleSeek(details) {
  switch(details.action) {
    case "seekforward":
      audio.currentTime = Math.min(audio.currentTime + skipTime,
              audio.duration);
      break;
    case "seekbackward":
      audio.currentTime = Math.max(audio.currentTime - skipTime, 0);
      break;
  }
}
				

在这里， handleSeek() function handles both seekbackward and seekforward actions.

Using data provided by MediaSessionActionDetails

In this example, instead of seeking a specified distance, the seekforward and seekbackward handlers use the time specified in the MediaSessionActionDetails 对象的 seekOffset 特性。

navigator.mediaSession.setActionHandler("seekforward", handleSeek);
navigator.mediaSession.setActionHandler("seekbackward", handleSeek);
function handleSeek(details) {
  switch(details.action) {
    case "seekforward":
      audio.currentTime = Math.min(audio.currentTime + details.seekOffset,
                                   audio.duration);
      break;
    case "seekbackward":
      audio.currentTime = Math.max(audio.currentTime - details.seekOffset, 0);
      break;
  }
});
				

规范

规范	状态	注释
Media Session Standard The definition of 'MediaSessionActionDetails' in that specification.	草案	初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

No compatibility data found. Please contribute data for "api.MediaSessionActionDetails" (depth: 1) to the MDN 兼容性数据存储库 .

元数据

• 最后修改： Aug 6, 2020

相关话题

1. 媒体会话 API
2. MediaSessionActionDetails
3. 特性

   1. action
   2. fastSeek
   3. seekOffset
   4. seekTime
4. Related pages for Media Session API

   1. MediaMetadata
   2. MediaSession