SoundEffect QML Type

The SoundEffect type provides a way to play sound effects in QML. 更多...

import 语句：	import QtMultimedia
实例化：	QSoundEffect

所有成员列表，包括继承成员

特性

loops : int
loopsRemaining : int
muted : bool
playing : bool
source : url
status : enumeration
volume : qreal

信号

方法

bool isLoaded ()
play ()
stop ()

详细描述

This type allows you to play uncompressed audio files (typically WAV files) in a generally lower latency way, and is suitable for "feedback" type sounds in response to user actions (e.g. virtual keyboard sounds, positive or negative feedback for popup dialogs, or game sounds). If low latency is not important, consider using the MediaPlayer type instead, since it support a wider variety of media formats and is less resource intensive.

Typically the sound effect should be reused, which allows all the parsing and preparation to be done ahead of time, and only triggered when necessary. This is easy to achieve with QML, since you can declare your SoundEffect instance and refer to it elsewhere.

The following example plays a WAV file on mouse click.

Text {
    text: "Click Me!";
    font.pointSize: 24;
    width: 150; height: 50;
    SoundEffect {
        id: playSound
        source: "soundeffect.wav"
    }
    MouseArea {
        id: playArea
        anchors.fill: parent
        onPressed: { playSound.play() }
    }
}

Since SoundEffect requires slightly more resources to achieve lower latency playback, the platform may limit the number of simultaneously playing sound effects.

特性文档编制

loops : int

This property holds the number of times the sound is played. A value of 0 or 1 means the sound will be played only once; set to SoundEffect .Infinite to enable infinite looping.

The value can be changed while the sound effect is playing, in which case it will update the remaining loops to the new value.

loopsRemaining : int [read-only]

This property contains the number of loops remaining before the sound effect stops by itself, or SoundEffect .Infinite if that's what has been set in loops .

muted : bool

This property provides a way to control muting. A value of true will mute this effect. Otherwise, playback will occur with the currently specified volume .

playing : bool [read-only]

This property indicates whether the sound effect is playing or not.

source : url

This property holds the url for the sound to play. For the SoundEffect to attempt to load the source, the URL must exist and the application must have read permission in the specified directory. If the desired source is a local file the URL may be specified using either absolute or relative (to the file that declared the SoundEffect ) pathing.

status : enumeration [read-only]

This property indicates the current status of the SoundEffect as enumerated within SoundEffect . Possible statuses are listed below.

值	描述
SoundEffect .Null	未设置源或源为 null。
SoundEffect .Loading	The SoundEffect 正试着加载源。
SoundEffect .Ready	源被加载并准备播放。
SoundEffect .Error	操作期间发生错误，譬如：源加载失败。

volume : qreal

This property holds the volume of the sound effect playback.

The volume is scaled linearly from 0.0 (无声) 到 1.0 (full volume). Values outside this range will be clamped.

默认音量为 1.0 .

UI volume controls should usually be scaled non-linearly. For example, using a logarithmic scale will produce linear changes in perceived loudness, which is what a user would normally expect from a volume control. See convertVolume () 了解更多细节。

信号文档编制

loadedChanged ()

The loadedChanged signal is emitted when the loading state has changed.

注意： 相应处理程序是 onLoadedChanged .

loopCountChanged ()

The loopCountChanged signal is emitted when the initial number of loops has changed.

注意： 相应处理程序是 onLoopCountChanged .

loopsRemainingChanged ()

The loopsRemainingChanged signal is emitted when the remaining number of loops has changed.

注意： 相应处理程序是 onLoopsRemainingChanged .

mutedChanged ()

The mutedChanged signal is emitted when the mute state has changed.

注意： 相应处理程序是 onMutedChanged .

playingChanged ()

The playingChanged signal is emitted when the playing property has changed.

注意： 相应处理程序是 onPlayingChanged .

sourceChanged ()

The sourceChanged signal is emitted when the source has been changed.

注意： 相应处理程序是 onSourceChanged .

statusChanged ()

The statusChanged signal is emitted when the status property has changed.

注意： 相应处理程序是 onStatusChanged .

volumeChanged ()

The volumeChanged signal is emitted when the volume has changed.

注意： 相应处理程序是 onVolumeChanged .

方法文档编制

bool isLoaded ()

Returns whether the sound effect has finished loading the source .

play ()

Start playback of the sound effect, looping the effect for the number of times as specified in the loops property.

This is the default method for SoundEffect .

SoundEffect {
    id: playSound
    source: "soundeffect.wav"
}
MouseArea {
    id: playArea
    anchors.fill: parent
    onPressed: { playSound.play() }
}

stop ()

Stop current playback.