The GeocodeModel type provides support for searching operations related to geographic information. 更多...
| import 语句： | import QtLocation 5.3 |
| Since: | Qt Location 5.5 |
The GeocodeModel type is used as part of a model/view grouping to match addresses or search strings with geographic locations. How the geographic locations generated are used or displayed is decided by any Views attached to the GeocodeModel (for example a MapItemView or ListView ).
像 Map and RouteModel , all the data for a GeocodeModel to work comes from a services plugin. This is contained in the plugin property, and this must be set before the GeocodeModel can do any useful work.
Once the plugin is set, the query property can be used to specify the address or search string to match. If autoUpdate is enabled, the Model will update its output automatically. Otherwise, the update method may be used. By default, autoUpdate 被禁用。
The data stored and returned in the GeocodeModel consists of 定位 objects, as a list with the role name "locationData". See the documentation for 定位 for further details on its structure and contents.
The following snippet is two-part, showing firstly the declaration of objects, and secondly a short piece of procedural code using it. We set the geocodeModel's autoUpdate property to false, and call update once the query is set up. In this case, as we use a string value in query , only one update would occur, even with autoUpdate enabled. However, if we provided an 地址 object we may inadvertently trigger multiple requests whilst setting its properties.
Plugin {
id: aPlugin
}
GeocodeModel {
id: geocodeModel
plugin: aPlugin
autoUpdate: false
}
{
geocodeModel.query = "53 Brandl St, Eight Mile Plains, Australia"
geocodeModel.update()
}
This property controls whether the Model automatically updates in response to changes in its attached query. The default value of this property is false.
If setting this value to 'true' and using an Address or coordinate as the query, note that any change at all in the object's properties will trigger a new request to be sent. If you are adjusting many properties of the object whilst autoUpdate is enabled, this can generate large numbers of useless (and later discarded) requests.
|
bounds : geoshape |
This property holds the bounding area used to limit the results to those within the area. This is particularly useful if query is only partially filled out, as the service will attempt to (reverse) geocode all matches for the specified data.
Accepted types are georectangle and geocircle .
This property holds how many locations the model currently has. Amongst other uses, you can use this value when accessing locations via the GeocodeModel::get -method.
This read-only property holds the latest error value of the geocoding request.
This read-only property holds the textual presentation of the latest geocoding error. If no error has occurred or the model has been reset, an empty string is returned.
An empty string may also be returned if an error occurred which has no associated textual representation.
This property holds the maximum number of results. The limit and offset values are only applicable with free string geocoding (that is they are not considered when using addresses or coordinates in the search query).
If limit is -1 the entire result set will be returned, otherwise at most limit results will be returned. The limit and offset results can be used together to implement paging.
This property tells not to return the first 'offset' number of the results. The limit and offset values are only applicable with free string geocoding (that is they are not considered when using addresses or coordinates in the search query).
The limit and offset results can be used together to implement paging.
|
plugin : Plugin |
This property holds the plugin that provides the actual geocoding service. Note that all plugins do not necessarily provide geocoding (could for example provide only routing or maps).
另请参阅 Plugin .
This property holds the data of the geocoding request. The property accepts three types of queries which determine both the data and the type of action to be performed:
This read-only property holds the current status of the model.
This signal is emitted when locations in the model have changed.
另请参阅 count .
Cancels any outstanding requests and clears errors. Model status will be set to either GeocodeModel .Null or GeocodeModel .Ready.
|
定位 get ( int ) |
返回 定位 at given index. Use count property to check the amount of locations available. The locations are indexed from zero, so the accessible range is 0...(count - 1).
If you access out of bounds, a zero (null object) is returned and a warning is issued.
Resets the model. All location data is cleared, any outstanding requests are aborted and possible errors are cleared. Model status will be set to GeocodeModel .Null
Instructs the GeocodeModel to update its data. This is most useful when autoUpdate is disabled, to force a refresh when the query has been changed.