如何将QLineEdit背景变成进度条

该代码创建一个对话框QLineEdit and a QPushButton。 单击按钮时我想要QLineEdit变成一个进度条，显示按下按钮触发的过程的进度。当该过程完成时QLineEdit应该恢复到正常的“LineEdit”外观。如何实现这一目标？

这是 Photoshop 编辑的想法：

A progress bar could be a thin line at the bottom of QLineEdit:

from PyQt4 import QtCore, QtGui
import time

class Dialog(QtGui.QDialog):
    def __init__(self, parent=None):
        QtGui.QDialog .__init__(self, parent)
        mainLayout = QtGui.QVBoxLayout()
        lineEdit = QtGui.QLineEdit('ITEM 001')
        mainLayout.addWidget(lineEdit)
        button = QtGui.QPushButton('Push Button')
        button.clicked.connect(self.buttonClicked)
        mainLayout.addWidget(button)
        self.setLayout(mainLayout)

    def buttonClicked(self):
        print 'button clicked'
        for i in range(3):
            time.sleep(1)
            print '...processing %s'%i

if __name__ == '__main__':
    app = QtGui.QApplication([])
    window = Dialog()
    window.resize(300, 50)
    window.show()
    app.exec_()

在 PyQt4 中QLinearGradient获得水平方向。 而 PySide 似乎将其处理为垂直渐变。 该代码创建了一个QLineEdit其背景颜色通过设置palette.setBrush(QPalette.Base, QBrush(QLinearGradient))。按下按钮会将进度条值提高 10%。

from PyQt4 import QtCore, QtGui
import time


class Dialog(QtGui.QDialog):
    value = 0.001
    def __init__(self, parent=None):
        QtGui.QDialog .__init__(self, parent)
        mainLayout = QtGui.QVBoxLayout()

        self.lineedit = QtGui.QLineEdit()
        self.setValues()
        mainLayout.addWidget(self.lineedit)
        button = QtGui.QPushButton('Calculate')
        button.clicked.connect(self.buttonClicked)
        mainLayout.addWidget(button)
        self.setLayout(mainLayout)

    def setValues(self):
        self.lineedit.setText('progress %s'%self.value)
        palette = self.lineedit.palette()
        QRectF = QtCore.QRectF(self.lineedit.rect())
        gradient = QtGui.QLinearGradient(QRectF.topLeft(), QRectF.topRight())
        gradient.setColorAt(self.value-0.001, QtGui.QColor('#f99e41'))
        gradient.setColorAt(self.value, QtGui.QColor('#ffffff'))
        gradient.setColorAt(self.value+0.001, QtGui.QColor('#ffffff'))
        palette.setBrush(QtGui.QPalette.Base, QtGui.QBrush(gradient))
        self.lineedit.setPalette(palette)

    def buttonClicked(self):
        if self.value >0.9:
            self.value = 0.001
        else:
            self.value=self.value+0.1

        self.setValues()
        time.sleep(1)

if __name__ == '__main__':
    app = QtGui.QApplication([])
    window = Dialog()
    window.resize(300, 50)
    window.show()
    app.exec_()

对于 PySide，渐变可能是水平的：

import PySide.QtCore as QtCore
import PySide.QtGui as QtGui

class Dialog(QtGui.QDialog):
    value = 1.00
    def __init__(self, parent=None):
        QtGui.QDialog .__init__(self, parent)
        mainLayout = QtGui.QVBoxLayout()

        self.lineedit = QtGui.QLineEdit()
        self.setValues()
        mainLayout.addWidget(self.lineedit)
        button = QtGui.QPushButton('Calculate')
        button.clicked.connect(self.buttonClicked)
        mainLayout.addWidget(button)
        self.setLayout(mainLayout)

    def setValues(self):
        self.lineedit.setText('progress %s'%self.value)
        palette = self.lineedit.palette()
        QRectF = QtCore.QRectF(self.lineedit.rect())
        gradient = QtGui.QLinearGradient(QRectF.topLeft(), QRectF.topRight())
        gradient.setColorAt(self.value-0.001, QtGui.QColor('#ffffff'))
        gradient.setColorAt(self.value, QtGui.QColor('#f99e41'))
        gradient.setColorAt(self.value+0.001, QtGui.QColor('#f99e41'))
        palette.setBrush(QtGui.QPalette.Base, QtGui.QBrush(gradient))
        self.lineedit.setPalette(palette)

    def buttonClicked(self):
        if self.value <0.1:
            self.value = 1.00
        else:
            self.value=self.value-0.1

        self.setValues()


if __name__ == '__main__':
    app = QtGui.QApplication([])
    window = Dialog()
    window.resize(300, 50)
window.show()
app.exec_()