将输入改成摆放九个按钮

好的，根据您的要求，以下是将输入改为九个按钮的示例代码：

mainwindow.ui文件：

在界面设计器中，您需要移除原来的QLineEdit控件，并添加九个QPushButton控件，分别显示1到9的数字。

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Calculator</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <widget class="QPushButton" name="button1">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>60</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>1</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button2">
    <property name="geometry">
     <rect>
      <x>120</x>
      <y>60</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>2</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button3">
    <property name="geometry">
     <rect>
      <x>210</x>
      <y>60</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>3</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button4">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>100</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>4</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button5">
    <property name="geometry">
     <rect>
      <x>120</x>
      <y>100</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>5</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button6">
    <property name="geometry">
     <rect>
      <x>210</x>
      <y>100</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>6</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button7">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>140</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>7</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button8">
    <property name="geometry">
     <rect>
      <x>120</x>
      <y>140</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>8</string>
    </property>
   </widget>
   <widget class="QPushButton" name="button9">
    <property name="geometry">
     <rect>
      <x>210</x>
      <y>140</y>
      <width>75</width>
      <height>30</height>
     </rect>
    </property>
    <property name="text">
     <string>9</string>
    </property>
   </widget>
   <widget class="QPushButton" name="calculateButton">
    <property name="geometry">
     <rect>
      <x>300</x>
      <y>60</y>
      <width>75</width>
      <height>110</height>
     </rect>
    </property>
    <property name="text">
     <string>=</string>
    </property>
   </widget>
   <widget class="QLabel" name="resultLabel">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>20</y>
      <width>341</width>
      <height>31</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <pointsize>16</pointsize>
     </font>
    </property>
    <property name="text">
     <string>0</string>
    </property>
    <property name="alignment">
     <set>Qt::AlignRight</set>
    </property>
   </widget>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

mainwindow.h文件：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_button1_clicked();
    void on_button2_clicked();
    void on_button3_clicked();
    void on_button4_clicked();
    void on_button5_clicked();
    void on_button6_clicked();
    void on_button7_clicked();
    void on_button8_clicked();
    void on_button9_clicked();
    void on_calculateButton_clicked();

private:
    Ui::MainWindow *ui;
    QString input; // 记录输入的字符串
};
#endif // MAINWINDOW_H

mainwindow.cpp文件：

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    input = ""; // 初始化输入字符串为空
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_button1_clicked()
{
    input += "1";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button2_clicked()
{
    input += "2";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button3_clicked()
{
    input += "3";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button4_clicked()
{
    input += "4";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button5_clicked()
{
    input += "5";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button6_clicked()
{
    input += "6";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button7_clicked()
{
    input += "7";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button8_clicked()
{
    input += "8";
    ui->resultLabel->setText(input);
}

void MainWindow::on_button9_clicked()
{
    input += "9";
    ui->resultLabel->setText(input);
}

void MainWindow::on_calculateButton_clicked()
{
    // 计算
    QString result = QString::number(eval(input.toStdString().c_str()));

    // 输出结果
    ui->resultLabel->setText(result);

    // 清空输入
    input = "";
}

eval函数的实现可以与之前保持一致，这里不再赘述。

这样，您就可以在九个按钮上输入数字，点击“=”按钮进行计算了。