下面的代码只是显示计算机驱动器的树状视图。每次选择新文件/文件夹时,视图都会滚动以使新选择可见。在
问题1:虽然这样做,但应用程序启动后的初始选择不会触发滚动。为什么?在
问题2:如果说明:
self.my_view.scrollTo(index, QAbstractItemView.EnsureVisible)
self.my_view.resizeColumnToContents(0)
倒置:
^{pr2}$第一列大小在初始显示时也不会调整,只有在之后。为什么?在
import sys
from PyQt5.QtCore import Qt, QModelIndex, QDir
from PyQt5.QtWidgets import QApplication, QTreeView, QMainWindow, QFileSystemModel, QAbstractItemView
class MyWindow(QMainWindow):
def __init__(self):
super().__init__()
# Instance variables
self.my_view = QTreeView()
self.my_model = QFileSystemModel()
# Init FS model to show all computer drives
model_root_path = str(self.my_model.myComputer())
self.my_model.setRootPath(model_root_path)
# Init tree view
self.my_view.setModel(self.my_model)
self.my_view.setRootIndex(self.my_model.index(model_root_path))
self.my_view.setSelectionMode(QAbstractItemView.SingleSelection)
self.my_view.setSelectionBehavior(QAbstractItemView.SelectRows)
# Connect selection change events to custom slot
select_model = self.my_view.selectionModel()
select_model.currentRowChanged.connect(self.current_row_changed)
# Main window
self.setCentralWidget(self.my_view)
self.setGeometry(200, 200, 800, 600)
# Select initial row on view
focus_path = QDir.currentPath()
focus_index = self.my_model.index(focus_path)
self.my_view.setCurrentIndex(focus_index)
def current_row_changed(self):
"""Current row of the model has changed"""
# Scroll view to new row
index = self.my_view.selectionModel().currentIndex()
self.my_view.scrollTo(index, QAbstractItemView.EnsureVisible)
self.my_view.resizeColumnToContents(0)
# Show path of current row in window title
absolute_path = self.my_model.filePath(index)
self.setWindowTitle(absolute_path)
def main():
a = QApplication(sys.argv)
mw = MyWindow()
mw.show()
sys.exit(a.exec_())
if __name__ == '__main__':
main()
`
编辑:在使用了@ekhurvo提供的好的解决方案之后,我上面的示例代码起作用了。然而,另一段代码仍然没有:
import os
import sys
from PyQt5.QtCore import pyqtSignal, QTimer, QDir, Qt
from PyQt5.QtWidgets import QMainWindow, QGridLayout, QWidget, QTreeView, QAbstractItemView, QFileSystemModel, \
QApplication
class AppWindow(QMainWindow):
default_folder_path = "."
def __init__(self):
super().__init__()
self.folder_view = FolderTreeView()
self.folder_view.folder_has_changed.connect(self.folder_changed)
self.build_ui()
self.show()
# Select initial folder
self.select_initial_folder()
def build_ui(self):
main_widget = QWidget()
layout = QGridLayout(main_widget)
layout.addWidget(self.folder_view)
self.setCentralWidget(main_widget)
self.setGeometry(200, 100, 800, 600)
def select_initial_folder(self):
folder_index = self.folder_view.get_index(AppWindow.default_folder_path)
if folder_index.isValid():
self.folder_view.select_folder(folder_index)
def folder_changed(self, folder_path):
if not os.path.isdir(folder_path):
print("Non existing folder:", folder_path)
return
class FolderTreeView(QTreeView):
folder_has_changed = pyqtSignal(str)
def __init__(self):
super().__init__()
self.folder_tree_model = FolderTreeModel()
self.setModel(self.folder_tree_model)
self.setSelectionMode(QAbstractItemView.SingleSelection)
self.setSelectionBehavior(QAbstractItemView.SelectRows)
def select_folder(self, folder_index):
self.setCurrentIndex(folder_index)
def currentChanged(self, current, previous):
super(FolderTreeView, self).currentChanged(current, previous)
# Scroll the view to current item and resize folder name column
QTimer.singleShot(50, lambda: self.delayed_scroll(current))
# Emit signal for other uses
self.folder_has_changed.emit(self.folder_tree_model.filePath(current))
def delayed_scroll(self, index):
self.scrollTo(index, QAbstractItemView.EnsureVisible)
self.resizeColumnToContents(0)
def get_index(self, folder_path):
return self.folder_tree_model.index(folder_path)
class FolderTreeModel(QFileSystemModel):
def __init__(self):
super().__init__()
self.setFilter(QDir.AllDirs | QDir.NoDotAndDotDot)
self.setRootPath("")
def main():
app = QApplication(sys.argv)
window = AppWindow()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
如果默认情况下,模型将其当前索引初始化到当前目录,则可能会导致第一个问题。这意味着,如果再次将其设置为相同的索引,则不会发出行更改信号(因为没有任何更改)。这可以通过直接调用行更改处理程序来解决:
至于第二个问题:当您调用
scrollTo
时,它可能需要扩展多个目录才能选择所需的索引。这显然会改变第一列的宽度,因此您应该始终在之后调用resizeColumnToContents
以获得正确的宽度。在更新:
我认为还有另一个问题是由时间问题引起的。
QFileSystemModel
必须在某种程度上异步工作,因为它必须从操作系统请求资源,然后等待响应。另外,在得到响应之前,它无法预先知道它将接收多少数据,因为文件系统可能在等待时已被更新。可能,响应可能包含来自包含数千个文件的巨大目录中的数据。因此,为了保持GUI的响应性,数据被成批处理,这些数据的大小足以填充当前视图。如果当前索引在窗口显示之前设置为,并且其所有小部件都已完全布局,则无法保证视图能够正确调整其列的大小。在这可以通过一个具有小延迟的一次性计时器显式地重新调用行更改处理程序来解决。这将允许视图正确地重新计算其列宽:
^{pr2}$相关问题 更多 >
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