Loading Projects

本章节讲述如导入已有工程

有时候你需要加载一个已经存在的工程，为了加载一个已有的QGIS应用，你需要QgsProject的实例instance()并且调用它的read（）方法读取对应路径的工程。

# If you are not inside a QGIS console you first need to import
# qgis and PyQt4 classes you will use in this script as shown below:
from qgis.core import QgsProject
from qgis.PyQt.QtCore import QFileInfo
# Get the project instance
project = QgsProject.instance()
# Print the current project file name (might be empty in case no projects have been loaded)
print(project.fileName())
u'/home/user/projects/my_qgis_project.qgs'
# Load another project
project.read(QFileInfo('/home/user/projects/my_other_qgis_project.qgs'))
print(project.fileName())
u'/home/user/projects/my_other_qgis_project.qgs'

如果你需要对工程做一些修改，可以通过write（）方法来读取工程实例：

# Save the project to the same
project.write()
# ... or to a new file
project.write(QFileInfo('/home/user/projects/my_new_qgis_project.qgs'))

read（）和write（）都返回一个是否加载成功的布尔值。