python - 属性错误: 'QgsComposition' object has no attribute 'setMapCanvas'

Question

我正在尝试使用 QGis map 编辑器保存 map 及其图例。我已经有了模板。

这是Python代码。

layers =iface.legendInterface().layers()
canvas=iface.mapCanvas()

for layer in layers:
# myFile = r"C:\Users\craj\Downloads\GraduatedTheme.qpt"
    myFile = r"C:\Users\craj\Downloads\GraduatedTheme.qpt"
    myTemplateFile = file(myFile, 'rt')
    myTemplateContent = myTemplateFile.read()
    myTemplateFile.close()
    myDocument = QDomDocument()
    myDocument.setContent(myTemplateContent, False)
    newcomp = iface.createNewComposer()
    newcomp.composition().loadFromTemplate(myDocument)
    newcomp.composition().refreshItems()
    for a in iface.mapCanvas().layers():
        iface.legendInterface().setLayerVisible(a, False)
    iface.legendInterface().setLayerVisible(layer, True)
    newcomp.composition().refreshItems()
    map_item = newcomp.composition()
    map_item.getComposerItemById('map')
    map_item.setMapCanvas(canvas)
    map_item.zoomToExtent(canvas.extent())
    newcomp.composition().refreshItems()
    legend_item = newcomp.composition().getComposerItemById('legend')
    legend_item.updateLegend()
    newcomp.composition().refreshItems()
    imagePath ='C:/Users/craj/Downloads/'+layer.name()+'.png'
    image = newcomp.composition().printPageAsRaster(0)
    image.save(imagePath,'png')

执行Python代码时发生错误:

AttributeError: 'QgsComposition' object has no attribute 'setMapCanvas' 
Traceback (most recent call last):
  File "C:/Users/craj/.qgis2/python/plugins\JoinAttribute\Join_Attribute.py", line 436, in run
map_item.setMapCanvas(canvas)
AttributeError: 'QgsComposition' object has no attribute 'setMapCanvas'

Answer 1

如果你看docs QgsComposition 上没有 setMapCanvas。这个方法在其他几个类中，比如QgsComposerMap 。因此，根据调用 getComposerItemById() 的代码，您可能需要的是:

composition = newcomp.composition()
map_item = composition.getComposerItemById('map')
map_item.setMapCanvas(canvas)