Difference between revisions of "JSONListModel"

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JSONListModel is a pure-<span class="caps">QML</span> component that allows using <span class="caps">JSON</span> data as datasource for a <span class="caps">QML</span> ListView.
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{{LangSwitch}}
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[[Category:Snippets::QML]]
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[[Category:Developing with Qt::Qt Quick::QML]]
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JSONListModel is a pure-QML component that allows using JSON data as datasource for a QML ListView.  
  
==Code==
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See [https://wiki.qt.io/index.php?title=QJsonModel QJsonModel] for a pure Qt/C++ class based on QAbstractItemModel.
  
The JSONListModel code is Open Source and available under the <span class="caps">MIT</span> license at:
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== Code ==
  
[https://github.com/kromain/qml-utils github.com/kromain/qml-utils] ''[github.com]''
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The JSONListModel code is Open Source and available under the MIT license at:
  
==Features==
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[https://github.com/kromain/qml-utils github.com/kromain/qml-utils]
  
* mimics the XMLListModel component by providing similar <span class="caps">API</span> and properties
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== Features ==
* supports both source-based and string-based <span class="caps">JSON</span> data
 
* support complex <span class="caps">JSON</span> documents and queries via <span class="caps">JSONP</span>ath (XPath for <span class="caps">JSON</span>)
 
  
==Example==
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* mimics the XMLListModel component by providing similar API and properties
 +
* supports both source-based and string-based JSON data
 +
* support complex JSON documents and queries via JSONPath (XPath for JSON)
  
With a file '''jsonData.txt''' containing:<br />
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== Example ==
 +
 
 +
With a file '''jsonData.txt''' containing:
 +
<code>
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{ "store": {
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    "book": [
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      { "category": "reference",
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        "author": "Nigel Rees",
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        "title": "Sayings of the Century",
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        "price": 8.95
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      },
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      { "category": "fiction",
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        "author": "Evelyn Waugh",
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        "title": "Sword of Honour",
 +
        "price": 12.99
 +
      },
 +
      { "category": "fiction",
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        "author": "Herman Melville",
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        "title": "Moby Dick",
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        "isbn": "0-553-21311-3",
 +
        "price": 8.99
 +
      },
 +
      { "category": "fiction",
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        "author": "J. R. R. Tolkien",
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        "title": "The Lord of the Rings",
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        "isbn": "0-395-19395-8",
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        "price": 22.99
 +
      }
 +
    ],
 +
    "bicycle": {
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        "color": "red",
 +
        "price": 19.95
 +
    }
 +
  }
 +
}
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</code>
  
 
We can write:
 
We can write:
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 +
<code>
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    JSONListModel {
 +
        id: jsonModel1
 +
        source: "jsonData.txt"
 +
        // All books in the store object
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        query: "$.store.book[*]"
 +
    }
 +
 +
    JSONListModel {
 +
        id: jsonModel2
 +
        source: "jsonData.txt"
 +
        // Books less than $10
 +
        query: "$..book[?(@.price<10)]"
 +
    }
 +
 +
    JSONListModel {
 +
        id: jsonModel3
 +
        json: '[ \ 
 +
            {"label": "Answer", "value": "42"}, \
 +
            {"label": "Pastis", "value": "51"}, \
 +
            {"label": "Alsace", "value": "67"}, \
 +
            {"label": "Alsace", "value": "68"} \
 +
        ]'
 +
        // Labels starting with 'A'
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        query: "$[?(@.label.charAt(0)==='A')]"
 +
    }
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</code>
  
 
And use it in views and delegates like this:
 
And use it in views and delegates like this:
  
===Categories:===
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<code>
 +
    ListView {
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        model: jsonModel1.model
  
* [[:Category:Developing with Qt|Developing_with_Qt]]
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        delegate: Component {
** [[:Category:Developing with Qt::Qt-Quick|Qt Quick]]
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            Text {
* [[:Category:JSON|JSON]]
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                // Can be any of the JSON properties: model.author, model.price, etc.
* [[:Category:snippets|snippets]]
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                text: model.title
 +
            }
 +
        }
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</code>

Latest revision as of 21:43, 4 April 2017

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JSONListModel is a pure-QML component that allows using JSON data as datasource for a QML ListView.

See QJsonModel for a pure Qt/C++ class based on QAbstractItemModel.

Code

The JSONListModel code is Open Source and available under the MIT license at:

github.com/kromain/qml-utils

Features

  • mimics the XMLListModel component by providing similar API and properties
  • supports both source-based and string-based JSON data
  • support complex JSON documents and queries via JSONPath (XPath for JSON)

Example

With a file jsonData.txt containing: { "store": {

   "book": [
     { "category": "reference",
       "author": "Nigel Rees",
       "title": "Sayings of the Century",
       "price": 8.95
     },
     { "category": "fiction",
       "author": "Evelyn Waugh",
       "title": "Sword of Honour",
       "price": 12.99
     },
     { "category": "fiction",
       "author": "Herman Melville",
       "title": "Moby Dick",
       "isbn": "0-553-21311-3",
       "price": 8.99
     },
     { "category": "fiction",
       "author": "J. R. R. Tolkien",
       "title": "The Lord of the Rings",
       "isbn": "0-395-19395-8",
       "price": 22.99
     }
   ],
   "bicycle": {
       "color": "red",
       "price": 19.95
   }
 }

}

We can write:

   JSONListModel {
       id: jsonModel1
       source: "jsonData.txt"
       // All books in the store object
       query: "$.store.book[*]"
   }
   JSONListModel {
       id: jsonModel2
       source: "jsonData.txt"
       // Books less than $10
       query: "$..book[?(@.price<10)]"
   }
   JSONListModel {
       id: jsonModel3
       json: '[ \  
           {"label": "Answer", "value": "42"}, \
           {"label": "Pastis", "value": "51"}, \
           {"label": "Alsace", "value": "67"}, \
           {"label": "Alsace", "value": "68"} \
       ]'
       // Labels starting with 'A'
       query: "$[?(@.label.charAt(0)==='A')]"
   }

And use it in views and delegates like this:

   ListView {
       model: jsonModel1.model
       delegate: Component {
           Text {
               // Can be any of the JSON properties: model.author, model.price, etc.
               text: model.title
           }
       }