EX_25/3/3

在注册登录的练习里面，追加一个QListWidget 项目列表 要求：点击注册之后，将账号显示到 listWidget上面去 以及，在listWidget中双击某个账号的时候，将该账号删除

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QFile>
#include <QWidget>
#include <QListWidget>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
    void save_data(const QString& filename,const QString& data);
    QString load_data(const QString& filename);

private slots:

    void on_lineEdit_textChanged(const QString &arg1);

    void on_lineEdit_2_textChanged(const QString &arg1);

    void on_pushButton_3_pressed();

    void on_pushButton_3_released();



    void on_pushButton_clicked();



    void on_listWidget_itemDoubleClicked(QListWidgetItem *item);

private:
    Ui::Widget *ui;
    QFile file;
};
#endif // WIDGET_H

mian.cpp

#include "widget.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

widget.cpp

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);

    QString name=load_data("E:/name.txt");
    ui->lineEdit->setText(name);

    QString pswd=load_data("E:/pswd.txt");
    ui->lineEdit_2->setText(pswd);
}

Widget::~Widget()
{
    QString name=ui->lineEdit->text();
    save_data("E:/name.txt",name);

    QString pswd=ui->lineEdit_2->text();
    save_data("E:/pswd.txt",pswd);

    delete ui;
}

void Widget::save_data(const QString &filename, const QString &data)
{
    file.setFileName(filename);
    file.open(QFile::WriteOnly);

    file.write(data.toLocal8Bit());

    file.close();
}

QString Widget::load_data(const QString &filename)
{
    file.setFileName(filename);
    file.open(QFile::ReadOnly);

    QByteArray arr=file.readAll();
    QString str=QString::fromLocal8Bit(arr);

    file.close();
    return str;
}



void Widget::on_lineEdit_textChanged(const QString &arg1)
{
    QString name=ui->lineEdit->text();
    QString pswd=ui->lineEdit_2->text();
    if(name.isEmpty() || pswd.isEmpty())
    {
        ui->pushButton->setEnabled(0);
        ui->pushButton_2->setEnabled(0);
    }
    else
    {
        ui->pushButton->setEnabled(1);
        ui->pushButton_2->setEnabled(1);
    }
}


void Widget::on_lineEdit_2_textChanged(const QString &arg1)
{
    QString name=ui->lineEdit->text();
    QString pswd=ui->lineEdit_2->text();
    if(name.isEmpty() || pswd.isEmpty())
    {
        ui->pushButton->setEnabled(0);
        ui->pushButton_2->setEnabled(0);
    }
    else
    {
        ui->pushButton->setEnabled(1);
        ui->pushButton_2->setEnabled(1);
    }
}


void Widget::on_pushButton_3_pressed()
{
    ui->lineEdit_2->setEchoMode(QLineEdit::Normal);
}

void Widget::on_pushButton_3_released()
{
    ui->lineEdit_2->setEchoMode(QLineEdit::Password);
}


void Widget::on_pushButton_clicked()
{
    QString text = ui->lineEdit->text();
       if (!text.isEmpty()) {
           QListWidgetItem* item = new QListWidgetItem(text);
           ui->listWidget->addItem(item);
       }
}



void Widget::on_listWidget_itemDoubleClicked(QListWidgetItem *item)
{
    if (item) {
            delete ui->listWidget->takeItem(ui->listWidget->row(item));
        }
}

(关于勾选是否记住密码的操作并未执行)