内容

• 特性
• 信号
• 方法
• 详细描述

Playlist QML Type

用于指定要播放媒体的列表。 更多...

import 语句：	import QtMultimedia 5.8
Since:	Qt 5.6

• 所有成员列表，包括继承成员

特性

• currentIndex : int
• currentItemsource : url
• error : enumeration
• errorString : string
• itemCount : int
• playbackMode : enumeration
• readOnly : bool

信号

• itemAboutToBeInserted ( start , end )
• itemAboutToBeRemoved ( start , end )
• itemChanged ( start , end )
• itemInserted ( start , end )
• itemRemoved ( start , end )
• loadFailed ()
• loaded ()

方法

• bool addItem ( source )
• bool addItems ( sources )
• bool clear ()
• bool insertItem ( index , source )
• bool insertItems ( index , sources )
• url itemSource ( index )
• load ( location , format )
• bool moveItem ( from , to )
• next ()
• int nextIndex ( steps )
• previous ()
• int previousIndex ( steps )
• bool removeItem ( index )
• bool removeItems (int start , int end )
• bool save ( location , format )
• shuffle ()

详细描述

The Playlist type provides a way to play a list of media with the MediaPlayer , Audio and Video types. It can be used as a data source for view elements (such as ListView ) and other elements that interact with model data (such as Repeater). When used as a data model, each playlist item's source URL can be accessed using the source 角色。

Item {
    width: 400;
    height: 300;
    Audio {
        id: player;
        playlist: Playlist {
            id: playlist
            PlaylistItem { source: "song1.ogg"; }
            PlaylistItem { source: "song2.ogg"; }
            PlaylistItem { source: "song3.ogg"; }
        }
    }
    ListView {
        model: playlist;
        delegate: Text {
            font.pixelSize: 16;
            text: source;
        }
    }
    MouseArea {
        anchors.fill: parent;
        onPressed: {
            if (player.playbackState != Audio.PlayingState) {
                player.play();
            } else {
                player.pause();
            }
        }
    }
}
					

另请参阅 MediaPlayer , 音频 ，和 视频 .

特性文档编制

currentIndex : int

This property holds the position of the current item in the playlist.

currentItemsource : url

This property holds the source URL of the current item in the playlist.

error : enumeration

This property holds the error condition of the playlist.

值	描述
NoError	No errors
FormatError	Format error.
FormatNotSupportedError	Format not supported.
NetworkError	Network error.
AccessDeniedError	Access denied error.

errorString : string

This property holds a string describing the current error condition of the playlist.

itemCount : int

This property holds the number of items in the playlist.

playbackMode : enumeration

This property holds the order in which items in the playlist are played.

值	描述
CurrentItemOnce	The current item is played only once.
CurrentItemInLoop	The current item is played repeatedly in a loop.
Sequential	Playback starts from the current and moves through each successive item until the last is reached and then stops. The next item is a null item when the last one is currently playing.
Loop	Playback restarts at the first item after the last has finished playing.
Random	Play items in random order.

readOnly : bool

This property indicates if the playlist can be modified.

信号文档编制

itemAboutToBeInserted ( start , end )

This signal is emitted when items are to be inserted into the playlist at start and ending at end .

相应处理程序是 onItemAboutToBeInserted .

itemAboutToBeRemoved ( start , end )

This signal emitted when items are to be deleted from the playlist at start and ending at end .

相应处理程序是 onItemAboutToBeRemoved .

itemChanged ( start , end )

This signal is emitted after items have been changed in the playlist between start and end positions inclusive.

相应处理程序是 onItemChanged .

itemInserted ( start , end )

This signal is emitted after items have been inserted into the playlist. The new items are those between start and end 包括在内。

相应处理程序是 onItemInserted .

itemRemoved ( start , end )

This signal is emitted after items have been removed from the playlist. The removed items are those between start and end 包括在内。

相应处理程序是 onMediaRemoved .

loadFailed ()

This signal is emitted when the playlist loading failed. error and errorString can be checked for more information on the failure.

相应处理程序是 onLoadFailed .

loaded ()

This signal is emitted when the playlist loading succeeded.

相应处理程序是 onLoaded .

方法文档编制

bool addItem ( source )

追加 source URL to the playlist.

返回 true 若 source is added successfully.

bool addItems ( sources )

Appends the list of URLs in sources to the playlist.

返回 true 若 sources are added successfully.

This QML method was introduced in Qt 5.7.

bool clear ()

Removes all the items from the playlist.

Returns true if the operation is successful.

bool insertItem ( index , source )

插入 source URL to the playlist at the given index .

返回 true 若 source is added successfully.

bool insertItems ( index , sources )

Inserts the list of URLs in sources to the playlist at the given index .

返回 true 若 sources are added successfully.

This QML method was introduced in Qt 5.7.

url itemSource ( index )

Returns the source URL of the item at the given index in the playlist.

load ( location , format )

Loads a playlist from the given location 。若 format is specified, it is used, otherwise the format is guessed from the location name and the data.

New items are appended to the playlist.

onloaded() is emitted if the playlist loads successfully, otherwise onLoadFailed() is emitted with error and errorString defined accordingly.

bool moveItem ( from , to )

移动项按索引位置 from 到索引位置 to .

Returns true if the item is moved successfully.

This QML method was introduced in Qt 5.7.

next ()

Advances to the next item in the playlist.

int nextIndex ( steps )

Returns the index of the item in the playlist which would be current after calling next() steps times.

Returned value depends on the size of the playlist, the current position and the playback mode.

另请参阅 playbackMode and previousIndex() .

previous ()

Returns to the previous item in the playlist.

int previousIndex ( steps )

Returns the index of the item in the playlist which would be current after calling previous() steps times.

Returned value depends on the size of the playlist, the current position and the playback mode.

另请参阅 playbackMode and nextIndex() .

bool removeItem ( index )

Removed the item at the given index from the playlist.

返回 true 若 source is removed successfully.

bool removeItems ( int start , int end )

Removes items in the playlist from start to end 包括在内。

Returns true if the items are removed successfully.

This QML method was introduced in Qt 5.7.

bool save ( location , format )

Saves the playlist to the given location 。若 format is specified, it is used, otherwise the format is guessed from the location name.

Returns true if the playlist is saved successfully.

shuffle ()

Shuffles items in the playlist.