The QGeoSatelliteInfoSource class is an abstract base class for the distribution of satellite information updates. 更多...
| 头： | #include <QGeoSatelliteInfoSource> |
| qmake: | QT += positioning |
| Since: | Qt 5.2 |
| 继承： | QObject |
该类在 Qt 5.2 引入。
| enum | Error { AccessError, ClosedError, NoError, UnknownSourceError } |
| virtual | ~QGeoSatelliteInfoSource () |
| virtual QGeoSatelliteInfoSource::Error | error () const = 0 |
| virtual int | minimumUpdateInterval () const = 0 |
| virtual void | setUpdateInterval (int msec ) |
| QString | sourceName () const |
| int | updateInterval () const |
| virtual void | requestUpdate (int timeout = 0) = 0 |
| virtual void | startUpdates () = 0 |
| virtual void | stopUpdates () = 0 |
| void | error (QGeoSatelliteInfoSource::Error satelliteError ) |
| void | requestTimeout () |
| void | satellitesInUseUpdated (const QList<QGeoSatelliteInfo> & satellites ) |
| void | satellitesInViewUpdated (const QList<QGeoSatelliteInfo> & satellites ) |
| QStringList | availableSources () |
| QGeoSatelliteInfoSource * | createDefaultSource (QObject * parent ) |
| QGeoSatelliteInfoSource * | createDefaultSource (const QVariantMap & 参数 , QObject * parent ) |
| QGeoSatelliteInfoSource * | createSource (const QString & sourceName , QObject * parent ) |
| QGeoSatelliteInfoSource * | createSource (const QString & sourceName , const QVariantMap & 参数 , QObject * parent ) |
The static function QGeoSatelliteInfoSource::createDefaultSource () creates a default satellite data source that is appropriate for the platform, if one is available. Otherwise, available QGeoPositionInfoSourceFactory plugins will be checked for one that has a satellite data source available.
调用 startUpdates () 和 stopUpdates () to start and stop regular updates, or requestUpdate () to request a single update. When an update is available, satellitesInViewUpdated () 和/或 satellitesInUseUpdated () 会被发射。
If regular satellite updates are required, setUpdateInterval () can be used to specify how often these updates should be emitted. If no interval is specified, updates are simply provided whenever they are available. For example:
// Emit updates every 10 seconds if available QGeoSatelliteInfoSource *source = QGeoSatelliteInfoSource::createDefaultSource(0); if (source) source->setUpdateInterval(10000);
To remove an update interval that was previously set, call setUpdateInterval () with a value of 0.
Note that the satellite source may have a minimum value requirement for update intervals, as returned by minimumUpdateInterval ().
The Error enumeration represents the errors which can occur.
| 常量 | 值 | 描述 |
|---|---|---|
QGeoSatelliteInfoSource::AccessError
|
0
|
The connection setup to the satellite backend failed because the application lacked the required privileges. |
QGeoSatelliteInfoSource::ClosedError
|
1
|
The satellite backend closed the connection, which happens for example in case the user is switching location services to off. This object becomes invalid and should be deleted. A new satellite source can be created by calling createDefaultSource () later on. |
QGeoSatelliteInfoSource::NoError
|
2
|
没有出现错误。 |
QGeoSatelliteInfoSource::UnknownSourceError
|
-1
|
发生无法识别的错误。 |
This property holds the minimum time (in milliseconds) required to retrieve a satellite update.
This is the minimum value accepted by setUpdateInterval () 和 requestUpdate ().
访问函数：
| virtual int | minimumUpdateInterval () const = 0 |
This property holds the requested interval in milliseconds between each update.
If the update interval is not set (or is set to 0) the source will provide updates as often as necessary.
If the update interval is set, the source will provide updates at an interval as close to the requested interval as possible. If the requested interval is less than the minimumUpdateInterval (), the minimum interval is used instead.
Changes to the update interval will happen as soon as is practical, however the time the change takes may vary between implementations. Whether or not the elapsed time from the previous interval is counted as part of the new interval is also implementation dependent.
The default value for this property is 0.
Note: Subclass implementations must call the base implementation of setUpdateInterval() so that updateInterval() returns the correct value.
访问函数：
| int | updateInterval () const |
| virtual void | setUpdateInterval (int msec ) |
[signal]
void
QGeoSatelliteInfoSource::
error
(
QGeoSatelliteInfoSource::Error
satelliteError
)
此信号被发射在发生错误之后。 satelliteError 参数描述发生错误的类型。
注意： 信号 error 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：
connect(geoSatelliteInfoSource, QOverload<QGeoSatelliteInfoSource::Error>::of(&QGeoSatelliteInfoSource::error), [=](QGeoSatelliteInfoSource::Error satelliteError){ /* ... */ });
[signal]
void
QGeoSatelliteInfoSource::
requestTimeout
()
Emitted if requestUpdate () was called and the current satellite information could not be retrieved within the specified timeout.
While the triggering of this signal may be considered an error condition, it does not imply the emission of the
error()
signal. Only the emission of
requestTimeout()
is required to indicate a timeout.
[pure virtual slot]
void
QGeoSatelliteInfoSource::
requestUpdate
(
int
timeout
= 0)
Attempts to get the current satellite information and emit satellitesInViewUpdated () 和 satellitesInUseUpdated () with this information. If the current satellite information cannot be found within the given timeout (in milliseconds) or if timeout is less than the value returned by minimumUpdateInterval (), requestTimeout () 被发射。
If the timeout is zero, the timeout defaults to a reasonable timeout period as appropriate for the source.
This does nothing if another update request is in progress. However it can be called even if startUpdates () has already been called and regular updates are in progress.
[signal]
void
QGeoSatelliteInfoSource::
satellitesInUseUpdated
(const
QList
<
QGeoSatelliteInfo
> &
satellites
)
若 startUpdates () 或 requestUpdate () is called, this signal is emitted when an update is available on the number 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.
satellites parameter holds the satellites currently in use.
[signal]
void
QGeoSatelliteInfoSource::
satellitesInViewUpdated
(const
QList
<
QGeoSatelliteInfo
> &
satellites
)
若 startUpdates () 或 requestUpdate () is called, this signal is emitted when an update is available on the satellites that are currently in view.
satellites parameter holds the satellites currently in view.
[pure virtual slot]
void
QGeoSatelliteInfoSource::
startUpdates
()
Starts emitting updates at regular intervals. The updates will be provided whenever new satellite information becomes available.
If satellite information cannot be retrieved or some other form of timeout has occurred the satellitesInViewUpdated () 和 satellitesInUseUpdated () signals may be emitted with empty parameter lists.
另请参阅 satellitesInViewUpdated () 和 satellitesInUseUpdated ().
[pure virtual slot]
void
QGeoSatelliteInfoSource::
stopUpdates
()
Stops emitting updates at regular intervals.
[virtual]
QGeoSatelliteInfoSource::
~QGeoSatelliteInfoSource
()
Destroys the satellite source.
[static]
QStringList
QGeoSatelliteInfoSource::
availableSources
()
Returns a list of available source plugins, including the default system backend if one is available.
[static]
QGeoSatelliteInfoSource
*QGeoSatelliteInfoSource::
createDefaultSource
(
QObject
*
parent
)
Creates and returns a source with the specified parent that reads from the system's default source of satellite update information, or the highest priority available plugin.
Returns 0 if the system has no default satellite source, no valid plugins could be found or the user does not have the permission to access the satellite data.
[static]
QGeoSatelliteInfoSource
*QGeoSatelliteInfoSource::
createDefaultSource
(const
QVariantMap
&
参数
,
QObject
*
parent
)
Creates and returns a satellite source with the given parent that reads from the system's default sources of satellite data, or the plugin with the highest available priority.
Returns nullptr if the system has no default satellite source, no valid plugins could be found or the user does not have the permission to access the satellite information.
This method passes 参数 to the factory to configure the source.
该函数在 Qt 5.14 引入。
[static]
QGeoSatelliteInfoSource
*QGeoSatelliteInfoSource::
createSource
(const
QString
&
sourceName
,
QObject
*
parent
)
Creates and returns a source with the given parent , by loading the plugin named sourceName .
Returns 0 if the plugin cannot be found.
[static]
QGeoSatelliteInfoSource
*QGeoSatelliteInfoSource::
createSource
(const
QString
&
sourceName
, const
QVariantMap
&
参数
,
QObject
*
parent
)
Creates and returns a satellite source with the given parent , by loading the plugin named sourceName .
Returns nullptr if the plugin cannot be found.
This method passes 参数 to the factory to configure the source.
该函数在 Qt 5.14 引入。
[pure virtual]
QGeoSatelliteInfoSource::Error
QGeoSatelliteInfoSource::
error
() const
返回上次发生的错误。
This signal is not emitted when a requestTimeout () has occurred.
Returns the unique name of the satellite source implementation in use.
This is the same name that can be passed to createSource () in order to create a new instance of a particular satellite source implementation.