CategoryModel QML Type

The CategoryModel type provides a model of the categories supported by a Plugin . 更多...

import 语句：	import QtLocation 5.3
Since:	Qt Location 5.5

所有成员列表，包括继承成员

特性

hierarchical : bool
plugin : Plugin
status : enumeration

信号

dataChanged ()

方法

string errorString ()

详细描述

The CategoryModel type provides a model of the categories that are available from the current Plugin . The model supports both a flat list of categories and a hierarchical tree representing category groupings. This can be controlled by the hierarchical 特性。

The model supports the following roles:

角色	类型	描述
category	Category	Category object for the current item.
parentCategory	Category	Parent category object for the current item. If there is no parent, null is returned.

The following example displays a flat list of all available categories:

import QtQuick 2.0
import QtPositioning 5.5
import QtLocation 5.6
ListView {
    model: CategoryModel {
        plugin: myPlugin
        hierarchical: false
    }
    delegate: Text { text: category.name }
}

To access the hierarchical category model it is necessary to use a DelegateModel to access the child items.

特性文档编制

hierarchical : bool

This property holds whether the model provides a hierarchical tree of categories or a flat list. The default is true.

plugin : Plugin

This property holds the provider Plugin used by this model.

status : enumeration

This property holds the status of the model. It can be one of:

CategoryModel .Null	No category fetch query has been executed. The model is empty.
CategoryModel .Ready	No error occurred during the last operation, further operations may be performed on the model.
CategoryModel .Loading	The model is being updated, no other operations may be performed until complete.
CategoryModel .Error	An error occurred during the last operation, further operations can still be performed on the model.

信号文档编制

dataChanged ()

This signal is emitted when significant changes have been made to the underlying datastore.

Applications should act on this signal at their own discretion. The data provided by the model could be out of date and so the model should be reupdated sometime, however an immediate reupdate may be disconcerting to users if the categories change without any action on their part.

相应处理程序是 onDataChanged .

方法文档编制

string errorString () const

This read-only property holds the textual presentation of the latest category model error. If no error has occurred, an empty string is returned.

An empty string may also be returned if an error occurred which has no associated textual representation.