SatelliteSource QML Type

The SatelliteSource class provides the satellite information. 更多...

import 语句：	import QtPositioning 6.5
Since:	Qt 6.5

所有成员列表，包括继承成员

特性

active : bool
name : string
参数 : list<PluginParameter>
satellitesInUse : list<geoSatelliteInfo>
satellitesInView : list<geoSatelliteInfo>
sourceError : enumeration
updateInterval : int
valid : bool

方法

var backendProperty (string name )
bool setBackendProperty (string name , var value )
start ()
stop ()
update (int timeout )

详细描述

The SatelliteSource class provides information about satellites in use and satellites in view. This class is a QML representation of QGeoSatelliteInfoSource .

Like its C++ equivalent, the class supports different plugins. Use the name property to specify the name of the plugin to be used, and provide PluginParameter s, if required. If the name property is not set, a default plugin will be used. See Qt Positioning 插件 for more information on the available plugins.

使用 valid property to check the SatelliteSource state.

使用 updateInterval property to indicate how often your application wants to receive the satellite information updates. The start (), stop () 和 update () methods can be used to control the operation of the SatelliteSource, as well as the active property, which when set is equivalent to calling start () 或 stop ().

When the SatelliteSource is active, satellite information updates can be retrieved using the satellitesInView and satellitesInUse 特性。

If an error happens during satellite information updates, use the sourceError property to get the actual error code.

用法范例

The following example shows a SatelliteSource which is using the NMEA plugin to receive satellite information updates every second and print the amount of satellites in view and satellites in use to the console.

SatelliteSource {
    id: source
    name: "nmea"
    active: true
    updateInterval: 1000
    PluginParameter { name: "nmea.source"; value: "serial:/dev/ttyACM0" }
    onSatellitesInUseChanged: {
        console.log("Satellites in use:", source.satellitesInUse.length)
    }
    onSatellitesInViewChanged: {
        console.log("Satellites in view:", source.satellitesInView.length)
    }
}

另请参阅 QGeoSatelliteInfoSource , PluginParameter ，和 geoSatelliteInfo .

特性文档编制

active : bool

This property indicates whether the satellite source is active. Setting this property to false equals calling stop , and setting this property to true equals calling start .

另请参阅 start , stop ，和 update .

name : string

This property holds the unique internal name for the plugin currently providing satellite information.

Setting the property causes the SatelliteSource to use a particular backend plugin. If the SatelliteSource is active at the time that the name property is changed, it will become inactive. If the specified backend cannot be loaded the satellite source will become invalid.

Changing the name property may cause the updateInterval property to change as well.

[default] 参数 : list < PluginParameter >

This property holds the list of plugin parameters.

另请参阅 PluginParameter .

[read-only] satellitesInUse : list < geoSatelliteInfo >

This property holds the list of satellites that are currently in use. These are the satellites that are used to get a "fix" - that is, those used to determine the current position.

[read-only] satellitesInView : list < geoSatelliteInfo >

This property holds the list of satellites that are currently in view.

[read-only] sourceError : enumeration

This property holds the error which last occurred with the backend data provider.

SatelliteSource .AccessError - The connection setup to the satellite backend failed because the application lacked the required privileges.
SatelliteSource .ClosedError - The satellite backend closed the connection, which happens for example in case the user is switching location services to off.
SatelliteSource . NoError - No error has occurred.
SatelliteSource .UnknownSourceError - An unidentified error occurred.
SatelliteSource .UpdateTimeoutError - The satellite information could not be retrieved within the specified timeout.

updateInterval : int

This property holds the desired interval between updates in milliseconds.

[read-only] valid : bool

此特性是 true 若 SatelliteSource object has acquired a valid backend plugin to provide data, and false 否则。

Applications should check this property to determine whether providing satellite information is available and enabled on the runtime platform, and react accordingly.

方法文档编制

var backendProperty ( string name )

Returns the value of the backend-specific property named name , if present. Otherwise, including if called on an uninitialized SatelliteSource , the return value will be invalid.

另请参阅 setBackendProperty ().

bool setBackendProperty ( string name , var value )

Sets the backend-specific property named name to value . Returns true on success, false otherwise, including if called on an uninitialized SatelliteSource .

另请参阅 backendProperty ().

start ()

Requests updates from the satellite source. Uses updateInterval if set, default interval otherwise. If there is no source available, this method has no effect.

另请参阅 stop , update ，和 active .

stop ()

Stops updates from the satellite source. If there is no source available or it is not active, this method has no effect.

另请参阅 start , update ，和 active .

update ( int timeout = 0)

A convenience method to request a single update from the satellite source. If there is no source available, this method has no effect.

If the satellite source is not active, it will be activated for as long as it takes to receive an update, or until the request times out. The request timeout period is plugin-specific.

The timeout is specified in milliseconds. If the timeout is zero (the default value), it defaults to a reasonable timeout period as appropriate for the source.

另请参阅 start , stop ，和 active .