QT-FlowLayout

记录一下流动布局 QT 中的 flowLayout ,该布局可以根据父 UI 组件窗口的宽度，调整每一行所能容纳的最大的元素个数。

示例代码如下：

# -*- coding:utf-8 -*-
# !/usr/bin/env python3
# Author: Mirror
# File: flowLayout
# Time: 2022-12-10 21:43
# Update： 2022-12-12 22:43
# Environment:PyCharm
# Blog: www.mirrorcg.com
# Description: flowLayout布局示例
# =========================================
import sys
from PySide2.QtWidgets import QApplication, QLayout, QSizePolicy, QWidget, QPushButton
from PySide2.QtCore import QPoint, QRect, QSize, Qt


class FlowLayout(QLayout):
    """流动布局"""
    def __init__(self, parent=None, margin=0, spacing=-1):
        super(FlowLayout, self).__init__(parent)

        if parent is not None:
            self.setContentsMargins(margin, margin, margin, margin)

        self.setSpacing(spacing)

        self.itemList = []

    def __del__(self):
        item = self.takeAt(0)
        while item:
            item = self.takeAt(0)

    def addItem(self, item):
        self.itemList.append(item)

    def count(self):
        return len(self.itemList)

    def itemAt(self, index):
        if index >= 0 and index < len(self.itemList):
            return self.itemList[index]

        return None

    def takeAt(self, index):
        if index >= 0 and index < len(self.itemList):
            return self.itemList.pop(index)

        return None

    def expandingDirections(self):
        return Qt.Orientations(Qt.Orientation(0))

    def hasHeightForWidth(self):
        return True

    def heightForWidth(self, width):
        height = self.doLayout(QRect(0, 0, width, 0), True)
        return height

    def setGeometry(self, rect):
        super(FlowLayout, self).setGeometry(rect)
        self.doLayout(rect, False)

    def sizeHint(self):
        return self.minimumSize()

    def minimumSize(self):
        size = QSize()

        for item in self.itemList:
            size = size.expandedTo(item.minimumSize())

        margin, _a, _b, _c = self.getContentsMargins()
        size += QSize(2 * margin, 2 * margin)
        return size

    def doLayout(self, rect, testOnly):
        x = rect.x()
        y = rect.y()
        lineHeight = 0

        for item in self.itemList:
            wid = item.widget()
            spaceX = self.spacing() + wid.style().layoutSpacing(QSizePolicy.PushButton,
                                                                QSizePolicy.PushButton, Qt.Horizontal)
            spaceY = self.spacing() + wid.style().layoutSpacing(QSizePolicy.PushButton,
                                                                QSizePolicy.PushButton, Qt.Vertical)
            nextX = x + item.sizeHint().width() + spaceX
            if nextX - spaceX > rect.right() and lineHeight > 0:
                x = rect.x()
                y = y + lineHeight + spaceY
                nextX = x + item.sizeHint().width() + spaceX
                lineHeight = 0

            if not testOnly:
                item.setGeometry(QRect(QPoint(x, y), item.sizeHint()))

            x = nextX
            lineHeight = max(lineHeight, item.sizeHint().height())

        return y + lineHeight - rect.y()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    win = QWidget()
    _layout = FlowLayout()
    win.setLayout(_layout)
    for i in range(10):
        item1 = QPushButton("%s" % i)
        win.layout().addWidget(item1)
    win.show()
    sys.exit(app.exec_())

示例结果：