问题描述
在 QWidget 中拖动 QPushButton 时,它会直到它消失,一旦它通过(跨过)MainWindow (QWidget) 的边界
我想限制这个 QPushButton 不越过它的容器的边界,而是在 QWidget 中保持可见
from PyQt5.QtWidgets import QApplication,QWidget,QPushButton
from PyQt5.QtCore import Qt
class DragButton(QPushButton):
def mousepressEvent(self,event):
self.__mousepressPos = None
self.__mouseMovePos = None
if event.button() == Qt.LeftButton:
self.__mousepressPos = event.globalPos()
self.__mouseMovePos = event.globalPos()
super(DragButton,self).mousepressEvent(event)
def mouseMoveEvent(self,event):
if event.buttons() == Qt.LeftButton:
# adjust offset from clicked point to origin of widget
currPos = self.mapToGlobal(self.pos())
globalPos = event.globalPos()
diff = globalPos - self.__mouseMovePos
newPos = self.mapFromGlobal(currPos + diff)
self.move(newPos)
self.__mouseMovePos = globalPos
super(DragButton,self).mouseMoveEvent(event)
def mouseReleaseEvent(self,event):
if self.__mousepressPos is not None:
moved = event.globalPos() - self.__mousepressPos
if moved.manhattanLength() > 3:
event.ignore()
return
super(DragButton,self).mouseReleaseEvent(event)
def clicked():
print ("click as normal!")
if __name__ == "__main__":
app = QApplication([])
w = QWidget()
w.resize(800,600)
button = DragButton("Drag",w)
button.clicked.connect(clicked)
w.show()
app.exec_()
有没有办法做到这一点?
解决方法
由于要求确保子级在父级的边界内,因此您需要检查子级 rect()
(翻译到新位置)是否在该区域内,之前 移动它。
请注意,要实现“自我”运动,不必连续平移全局位置。
class DragButton(QPushButton):
def mousePressEvent(self,event):
self.__mousePressPos = None
self.__mouseMovePos = None
if event.button() == Qt.LeftButton:
self.__mousePressPos = event.globalPos()
self.__mouseMovePos = event.pos()
super(DragButton,self).mousePressEvent(event)
def mouseMoveEvent(self,event):
if event.buttons() == Qt.LeftButton:
delta = event.pos() - self.__mouseMovePos
newPos = self.pos() + delta
if self.parent():
geo = self.rect().translated(newPos)
parentRect = self.parent().rect()
if geo.x() < 0:
geo.moveLeft(0)
elif geo.right() > parentRect.right():
geo.moveRight(parentRect.right())
if geo.y() < 0:
geo.moveTop(0)
elif geo.bottom() > parentRect.bottom():
geo.moveBottom(parentRect.bottom())
self.move(geo.topLeft())
else:
self.move(newPos)
super(DragButton,self).mouseMoveEvent(event)
还要考虑拖动已启用的按钮不是一个好主意,因为它可能会导致不需要的、不直观的和意外的行为。您的实现显示了这一点,因为如果按钮移动到超过 3 像素的限制,它将保持按下状态。