QGIS Map Composer – How to Use Project Variables in Map Composer Templates

qgisqgis-variable

I need to insert project variable into map composer file (.qpt) for showing specific legend item. The item is a layer constructed from a URL query that I need to dynamically change based on a project variable.

When I open another project, the layer URL query in the legend has a fixed value and the legend does not display the symbol, only the layer title, because in that project the layer has a URL query with a dynamic variable and the legend does not "find" the corresponding layer in the project.

...<layer-tree-layer name="Some Name" id="query_where_obec_3D598259_text__objectIds__time__geometry__geometryType_...">
    <customproperties>
     <Option type="Map">
      <Option name="cached_name" type="QString" value="Území obce"/>
     </Option>
    </customproperties>
   </layer-tree-layer>
   <custom-order enabled="0"/>
  </layer-tree-group>...

In the "ID" option i need to insert the QGIS variable.

Is this possible or is there another solution for this problem?

EDIT: I must have auto update turned off for custom legend item settings.

REPRODUCIBLE EXAMPLE: Create a label in map composer, save as template (.qpt) and insert a qgis variable in the .qpt file somehow and after opening the template in a new map composer it should appear in the label.

Best Answer

The correct syntax is labelText="[% @myvar %]":

<layer-tree-layer name="Some Name" id="[% @myvar %]">
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