pyqgis二次开发教程

https://zhuanlan.zhihu.com/p/629483254

安装好QGIS后，使用pycharm作为开发项目的编辑平台。现在在pycharm中进行配置。

新建项目，如下图所示。

坑：

报错1：

用pyuic5将.ui文件转化为.py文件出现报错，如下：

最终解决办法是：.ui文件名不能有空格。路径名称当中的文件夹名称也不能有空格；
比如你的.ui文件在 project program文件夹下面就不能实现转化，得把文件夹名称改为projectprogram

报错2：

不知道为什么由ui文件生成的py文件会带有C++的语法

报错3：

第一次运行python qt时显示：
This application failed to start because no Qt platform plugin could beinitialized Reinstalling the application may fix this problem
Available platform plugins are: direct2d, minimal, offscreen, windows。

from qgis.core import *
from qgis.gui import *
from qgis.PyQt.QtWidgets import *
from qgis.PyQt.QtGui import *
from qgis.PyQt.QtCore import *

from os.path import *
import sys


class MyWnd(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.resize(1200, 800)
        self.setWindowTitle("GIS软件")
        self.canvas = QgsMapCanvas()
        self.canvas.setCanvasColor(Qt.white)
        self.canvas.setVisible(True)
        self.canvas.xyCoordinates.connect(self.showXY)

        self.actionZoomIn = QAction("放大工具", self)
        self.actionZoomOut = QAction("缩小工具", self)
        self.actionPan = QAction("平移工具", self)
        self.actionOpenRas = QAction("打开影像", self)

        self.actionZoomIn.setCheckable(True)
        self.actionZoomOut.setCheckable(True)
        self.actionPan.setCheckable(True)

        self.actionZoomIn.triggered.connect(self.zoomIn)
        self.actionZoomOut.triggered.connect(self.zoomOut)
        self.actionPan.triggered.connect(self.pan)
        self.actionOpenRas.triggered.connect(self.openDialogRas)

        self.toolbar = QToolBar("Canvas actions")
        self.addToolBar(self.toolbar)
        self.toolbar.addAction(self.actionZoomIn)
        self.toolbar.addAction(self.actionZoomOut)
        self.toolbar.addAction(self.actionPan)
        self.toolbar.addAction(self.actionOpenRas)

        self.root = QgsProject.instance().layerTreeRoot()
        self.model = QgsLayerTreeModel(self.root, self)
        self.model.setFlag(QgsLayerTreeModel.AllowNodeReorder)
        self.model.setFlag(QgsLayerTreeModel.AllowNodeChangeVisibility)
        self.tocView = QgsLayerTreeView()
        self.tocView.setModel(self.model)
        self.tocView.setFixedWidth(200)
        self.bridge = QgsLayerTreeMapCanvasBridge(self.root, self.canvas, self)

        # create the map tools
        self.toolPan = QgsMapToolPan(self.canvas)
        self.toolPan.setAction(self.actionPan)
        self.toolZoomIn = QgsMapToolZoom(self.canvas, False)  # false = in
        self.toolZoomIn.setAction(self.actionZoomIn)
        self.toolZoomOut = QgsMapToolZoom(self.canvas, True)  # true = out
        self.toolZoomOut.setAction(self.actionZoomOut)

        centralWidget = QWidget()
        hLayout = QHBoxLayout()
        hLayout.addWidget(self.canvas)
        hLayout.addWidget(self.tocView)
        centralWidget.setLayout(hLayout)
        self.setCentralWidget(centralWidget)

        self.pan()

    def zoomIn(self):
        self.canvas.setMapTool(self.toolZoomIn)

    def zoomOut(self):
        self.canvas.setMapTool(self.toolZoomOut)

    def pan(self):
        self.canvas.setMapTool(self.toolPan)

    def openDialogRas(self):
        path_to_tif = QFileDialog.getOpenFileName()[0]
        if path_to_tif == "":
            return
        self.addRaster(path_to_tif)

    def openDialogVec(self):
        path_to_vec = QFileDialog.getOpenFileName()[0]
        if path_to_vec == "":
            return
        self.addVector(path_to_vec)

    def addRaster(self, path):
        layer = QgsRasterLayer(path, basename(path))
        if not layer.isValid():
            QMessageBox.information(self, '提示', '文件打开失败', QMessageBox.Ok)
            return
        layer.dataProvider().setNoDataValue(1, 0)
        QgsProject.instance().addMapLayers([layer])
        self.canvas.setLayers([layer])
        self.canvas.setExtent(layer.extent())
        self.canvas.refresh()

    def showXY(self, point):
        m_statusBar = self.statusBar()
        m_statusBar.showMessage("Coordinate:" + str(point.x()) + "," + str(point.y()))


if __name__ == "__main__":
    QgsApplication.setPrefixPath("./qgis_init", True)
    qgs = QgsApplication([], False)
    qgs.initQgis()

    w = MyWnd()
    w.show()
    sys.exit(qgs.exec_())

    qgs.exitQgis()