Plugins: Access project custom metadata key from qml extension

Advanced Use & Customization
1

Hi there,

In qgis we can set custom metadata key at project level

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image693×193 18.7 KB

Which reads in a qgs file as

... a21b3e2c-260f-4702-a665-c7039758a80f

My question is, can we access this from a app Extension (in qml)? I’ve searched through the header files but could not find anything about reading project metadata.

Many thanks!

Toni

2

Hi Toni,

you can get a keyword’s value using the ExpressionEvaluator:

import org.qfield

ExpressionEvaluator {
    id: exprEval
    expressionText: "@project_keywords['keyword']" //replace 'keyword' with your keyword's concept/key
    project: qgisProject
}

and then exprEval.evaluate() returns the value of the specified keyword.

Depending on your use case, you could also use custom project/expression variables instead, since they are super easy to access from within a QField plugin and also editable natively via the QField user interface.

import org.qfield

let projectVariables = ExpressionContextUtils.projectVariables(qgisProject);
for (var key in projectVariables) {
    iface.logMessage(key + ": " + projectVariables[key]);
}

Hope this helps!

2 Likes
3

Wonderful! This helps! Thanks a lot!