Recreating multiple layers selection in QGIS Python plugin window

Question

I want to have a list of filtered layers (like only raster or vector ones) the user can select from like we have in QgsProcessingParameterMultipleLayers

yet without Processing algorithm script (in normal QDialog window)?

Answer 1

You can use a QListWidget with checkable items.

Example:

class LayerListWidget(QListWidget):
    def __init__(self, parent=None):
        QListWidget.__init__(self)
        self.populate()
        
    def populate(self):
        layers = [l for l in QgsProject.instance().mapLayers().values() if l.type() == QgsMapLayerType.VectorLayer]
        items = [f'{i.name()} [{i.crs().authid()}]' for i in layers]
        for s in items:
            i = QListWidgetItem(s)
            i.setFlags(i.flags() | Qt.ItemIsUserCheckable)
            i.setCheckState(Qt.Unchecked)
            self.addItem(i)
            
    def checked_layers(self):
        checked_items_text = []
        for n in range(self.count()):
            i = self.item(n)
            if i.checkState() == Qt.Checked:
                checked_items_text.append(i.text())
        layer_names = [t.split(' ')[0] for t in checked_items_text]
        layers = [l for l in QgsProject.instance().mapLayers().values() if isinstance(l, QgsVectorLayer) and l.name() in layer_names]
        return layers

class MainDialog(QDialog):
    def __init__(self):
        QDialog.__init__(self)
        self.setGeometry(300, 300, 500, 350)
        self.layout = QVBoxLayout()
        self.layer_list_widget = LayerListWidget(self)
        self.btn = QPushButton('Get checked layers', self)
        self.te = QTextEdit(self)
        self.layout.addWidget(self.layer_list_widget)
        self.layout.addWidget(self.btn)
        self.layout.addWidget(self.te)
        self.setLayout(self.layout)
        self.btn.clicked.connect(self.get_layers)
    
    def get_layers(self):
        self.te.setText(str(self.layer_list_widget.checked_layers()))

w = MainDialog()
w.show()

Results: