《PyQt5 快速开发与实战》 第九章代码Bug修正 DataGrid.py 最后一页下翻页 仍可点击的错误

# -*- coding: utf-8 -*- 

import sys
import re
from PyQt5.QtWidgets import (QWidget , QHBoxLayout , QVBoxLayout , QApplication, QPushButton, QLineEdit ,QLabel , QSplitter ,  QTableView , QHeaderView , QMessageBox )
from PyQt5.QtCore import Qt
from PyQt5.QtSql import QSqlDatabase  , QSqlQueryModel , QSqlQuery

def createTableAndInit():
    # 添加数据库
    db =  QSqlDatabase.addDatabase('QSQLITE')
    # 设置数据库名称
    db.setDatabaseName('./db/database.db')
    # 判断是否打开
    if not db.open():            
        return False

    # 声明数据库查询对象
    query = QSqlQuery()
    # 创建表
    query.exec("create table student(id int primary key, name vchar, sex vchar, age int, deparment vchar)")
    
    #添加记录
    query.exec("insert into student values(1,'张三1','男',20,'计算机')")
    query.exec("insert into student values(2,'李四1','男',19,'经管')")
    query.exec("insert into student values(3,'王五1','男',22,'机械')")
    query.exec("insert into student values(4,'赵六1','男',21,'法律')")
    query.exec("insert into student values(5,'小明1','男',20,'英语')")
    query.exec("insert into student values(6,'小李1','女',19,'计算机')")
    query.exec("insert into student values(7,'小张1','男',20,'机械')")
    query.exec("insert into student values(8,'小刚1','男',19,'经管')")
    query.exec("insert into student values(9,'张三2','男',21,'计算机')")
    query.exec("insert into student values(10,'张三3','女',20,'法律')")
    query.exec("insert into student values(11,'王五2','男',19,'经管')")
    query.exec("insert into student values(12,'张三4','男',20,'计算机')")
    query.exec("insert into student values(13,'小李2','男',20,'机械')")
    query.exec("insert into student values(14,'李四2','女',19,'经管')")
    query.exec("insert into student values(15,'赵六3','男',21,'英语')")
    query.exec("insert into student values(16,'李四2','男',19,'法律')")
    query.exec("insert into student values(17,'小张2','女',22,'经管')")
    query.exec("insert into student values(18,'李四3','男',21,'英语')")
    query.exec("insert into student values(19,'小李3','女',19,'法律')")
    query.exec("insert into student values(20,'王五3','女',20,'机械')")
    query.exec("insert into student values(21,'张三4','男',22,'计算机')")
    query.exec("insert into student values(22,'小李2','男',20,'法律')")
    query.exec("insert into student values(23,'张三5','男',19,'经管')")
    query.exec("insert into student values(24,'小张3','女',20,'计算机')")
    query.exec("insert into student values(25,'李四4','男',22,'英语')")
    query.exec("insert into student values(26,'赵六2','男',20,'机械')")
    query.exec("insert into student values(27,'小李3','女',19,'英语')")
    query.exec("insert into student values(28,'王五4','男',21,'经管')")
    db.close()
    return True        
                   
class DataGrid(QWidget):

    def __init__(self):
        super().__init__()
        self.setWindowTitle("分页查询例子")
        self.resize(750,300)
        
        # 查询模型        
        self.queryModel = None
        # 数据表
        self.tableView = None
        
        # 总数页文本
        self.totalPageLabel = None
        # 当前页文本
        self.currentPageLabel = None
        # 转到页输入框        
        self.switchPageLineEdit = None
        # 前一页按钮
        self.prevButton = None        
        # 后一页按钮
        self.nextButton = None
        # 转到页按钮
        self.switchPageButton = None    
        # 当前页    
        self.currentPage = 0
        # 总页数
        self.totalPage = 0        
        # 总记录数
        self.totalRecrodCount = 0
        # 每页显示记录数
        self.PageRecordCount  = 5            

        self.db = None
        self.initUI()

    def initUI(self):
        # 创建窗口
        self.createWindow()
        # 设置表格
        self.setTableView()
        
        # 信号槽连接
        self.prevButton.clicked.connect(self.onPrevButtonClick )        
        self.nextButton.clicked.connect(self.onNextButtonClick )    
        self.switchPageButton.clicked.connect(self.onSwitchPageButtonClick )    

    def closeEvent(self, event):
        # 关闭数据库
        self.db.close()

    
    # 创建窗口    
    def createWindow(self):
        # 操作布局
        operatorLayout = QHBoxLayout()
        self.prevButton = QPushButton("前一页")
        self.nextButton = QPushButton("后一页")
        self.switchPageButton = QPushButton("Go")
        self.switchPageLineEdit = QLineEdit()
        self.switchPageLineEdit.setFixedWidth(40)    
        
        switchPage =  QLabel("转到第")
        page = QLabel("页")
        operatorLayout.addWidget(self.prevButton)
        operatorLayout.addWidget(self.nextButton)
        operatorLayout.addWidget(switchPage)
        operatorLayout.addWidget(self.switchPageLineEdit)
        operatorLayout.addWidget(page)
        operatorLayout.addWidget(self.switchPageButton)
        operatorLayout.addWidget( QSplitter())
    
        # 状态布局
        statusLayout =  QHBoxLayout()
        self.totalPageLabel =  QLabel()
        self.totalPageLabel.setFixedWidth(70)
        self.currentPageLabel =  QLabel()
        self.currentPageLabel.setFixedWidth(70)
        
        self.totalRecordLabel =  QLabel()
        self.totalRecordLabel.setFixedWidth(70)
        
        statusLayout.addWidget(self.totalPageLabel)
        statusLayout.addWidget(self.currentPageLabel)
        statusLayout.addWidget( QSplitter() )    
        statusLayout.addWidget(self.totalRecordLabel)
        
        # 设置表格属性
        self.tableView = QTableView()
        # 表格宽度的自适应调整
        self.tableView.horizontalHeader().setStretchLastSection(True)
        self.tableView.horizontalHeader().setSectionResizeMode(QHeaderView.Stretch)
        
        # 创建界面
        mainLayout =  QVBoxLayout(self);
        mainLayout.addLayout(operatorLayout);
        mainLayout.addWidget(self.tableView);
        mainLayout.addLayout(statusLayout);
        self.setLayout(mainLayout)

    # 设置表格    
    def setTableView(self):    
        print('*** step2 SetTableView'  )
        self.db =  QSqlDatabase.addDatabase('QSQLITE')
        # 设置数据库名称
        self.db.setDatabaseName('./db/database.db')
        # 打开数据库
        self.db.open() 
    
        # 声明查询模型
        self.queryModel = QSqlQueryModel(self)
        # 设置当前页
        self.currentPage = 1;
        # 得到总记录数
        self.totalRecrodCount = self.getTotalRecordCount()
        # 得到总页数
        self.totalPage = self.getPageCount()
        # 刷新状态
        self.updateStatus()
        # 设置总页数文本
        self.setTotalPageLabel()
        # 设置总记录数
        self.setTotalRecordLabel()
        
        # 记录查询
        self.recordQuery(0)
        # 设置模型
        self.tableView.setModel(self.queryModel)

        print('totalRecrodCount=' + str(self.totalRecrodCount) )        
        print('totalPage=' + str(self.totalPage) )
                     
        # 设置表格表头
        self.queryModel.setHeaderData(0,Qt.Horizontal,"编号") 
        self.queryModel.setHeaderData(1,Qt.Horizontal,"姓名")
        self.queryModel.setHeaderData(2,Qt.Horizontal,"性别")
        self.queryModel.setHeaderData(3,Qt.Horizontal,"年龄")
        self.queryModel.setHeaderData(4,Qt.Horizontal,"院系")

    # 得到记录数    
    def getTotalRecordCount(self):            
        self.queryModel.setQuery("select * from student")
        rowCount = self.queryModel.rowCount()
        print('rowCount=' + str(rowCount) )
        return rowCount
            
    # 得到页数        
    def getPageCount(self):            
        if  self.totalRecrodCount % self.PageRecordCount == 0  :
            return (self.totalRecrodCount / self.PageRecordCount )
        else :
            return (int(self.totalRecrodCount / self.PageRecordCount) + 1)

    # 记录查询        
    def recordQuery(self, limitIndex ):    
        szQuery = ("select * from student limit %d,%d" % (  limitIndex , self.PageRecordCount ) )
        print('query sql=' + szQuery )
        self.queryModel.setQuery(szQuery)
        
    # 刷新状态        
    def updateStatus(self):                
        szCurrentText = ("当前第%d页" % self.currentPage )
        self.currentPageLabel.setText( szCurrentText )
        
        #设置按钮是否可用
        if self.currentPage == 1 :
            self.prevButton.setEnabled( False )
            self.nextButton.setEnabled( True )
        elif  self.currentPage == self.totalPage :
            self.prevButton.setEnabled( True )
            self.nextButton.setEnabled( False )
        else :
            self.prevButton.setEnabled( True )
            self.nextButton.setEnabled( True )

    # 设置总数页文本        
    def setTotalPageLabel(self):    
        szPageCountText  = ("总共%d页" % self.totalPage )
        self.totalPageLabel.setText(szPageCountText)

    # 设置总记录数        
    def setTotalRecordLabel(self):    
        szTotalRecordText  = ("共%d条" % self.totalRecrodCount )
        print('*** setTotalRecordLabel szTotalRecordText=' + szTotalRecordText )
        self.totalRecordLabel.setText(szTotalRecordText)
        
    # 前一页按钮按下        
    def onPrevButtonClick(self):    
        print('*** onPrevButtonClick ');
        limitIndex = (self.currentPage - 2) * self.PageRecordCount
        self.recordQuery( limitIndex) 
        self.currentPage -= 1 
        self.updateStatus() 

    # 后一页按钮按下    
    def onNextButtonClick(self):
        print('*** onNextButtonClick ');
        limitIndex =  self.currentPage * self.PageRecordCount
        self.recordQuery( limitIndex) 
        self.currentPage += 1
        self.updateStatus() 
        
    # 转到页按钮按下
    def onSwitchPageButtonClick(self):            
        # 得到输入字符串
        szText = self.switchPageLineEdit.text()
        #数字正则表达式        
        #pattern = re.compile(r'^[-+]?[0-9]+.[0-9]+$')
        #match = pattern.match(szText)
        try:
            match=None
            match=int(szText)
        except Exception as e:
            print(e)

        
        # 判断是否为数字
        if not match :
            QMessageBox.information(self, "提示", "请输入数字" )
            return
            
        # 是否为空
        if szText == '' :
            QMessageBox.information(self, "提示" , "请输入跳转页面" )
            return

        #得到页数
        pageIndex = int(szText)
        #判断是否有指定页
        if pageIndex > self.totalPage or pageIndex < 1 :
            QMessageBox.information(self, "提示", "没有指定的页面，请重新输入" )
            return
            
        #得到查询起始行号
        limitIndex = (pageIndex-1) * self.PageRecordCount            
            
        #记录查询
        self.recordQuery(limitIndex);
        #设置当前页
        self.currentPage = pageIndex
        #刷新状态
        self.updateStatus();
            
if __name__ == '__main__':
    app = QApplication(sys.argv)
    
    if createTableAndInit():            
        # 创建窗口
        example = DataGrid() 
        # 显示窗口
        example.show()   
    
    sys.exit(app.exec_())

效果图：

原代码中  最后一页的下翻页还是可以点击的，修改好这个BUG就解决了，问题在于总页数原代码中没有取整数。

同时，还修正了跳转页无效的问题，没有采用正则方式，而是采用了  int（XXX） 方法。

补充， 以上代码能够正常运行需要当前目录下面有  db 文件夹，这个需要自己新建一下就可以。

如下图：（空文件夹就行）