学习了上一篇博客关于QLineEdit的一些重要的成员函数和信号的用法之后，我们写一个小程序来熟练下这些函数.
这里是程序完成后的图片.
首先，我们现在ui设计师里拖拽出以下的布局:
注意箭头处还有个QLabel部件.
以下是”c.cpp”下的代码:
#include "c.h"c::c(QWidget *parent)
: QWidget(parent)
{
ui.setupUi(this); //设置标题为"QLineEdit"
this->setWindowTitle("QQ"); //设置图标.
this->setWindowIcon(QIcon("pixmap.jpg")); //设置为伙伴.
ui.accountLabel->setBuddy(ui.accountLineEdit);
ui.passwordLabel->setBuddy(ui.passwordLineEdit); //设置头像.
ui.pixmapLabel->setPixmap(QPixmap("pixmap.jpg")); //让label完整的放下图片.根据比例缩减.
ui.pixmapLabel->setScaledContents(true); //设置密码输入框的显示模式为:密码显示模式.
ui.passwordLineEdit->setEchoMode(QLineEdit::Password); //设置激活两个输入框的清空按钮.
ui.accountLineEdit->setClearButtonEnabled(true);
ui.passwordLineEdit->setClearButtonEnabled(true); //设置两个输入框的最大长度
ui.accountLineEdit->setMaxLength(10);
ui.passwordLineEdit->setMaxLength(10); //设置账号输入框允许拖拽.
ui.accountLineEdit->setDragEnabled(true); //设置密码输入框不接受拖拽的文本.
ui.passwordLineEdit->setAcceptDrops(false); //设置两个输入框的占位符.
ui.accountLineEdit->setPlaceholderText(QString::fromLocal8Bit("必须为纯数字"));
ui.passwordLineEdit->setPlaceholderText(QString::fromLocal8Bit("两位字母+纯数字")); //设置账号输入框的整数验证器，并且设定输入的范围.
QIntValidator *account = new QIntValidator;
account->setBottom(0);
ui.accountLineEdit->setValidator(account); //设置密码输入框的验证器，用了正则表达式来规定:前面1-2个必须是字母，后面8-9个必须是0-9内的数字.
QRegExp password("[A-Za-z]{2}[0-9]{8，9}");
ui.passwordLineEdit->setValidator(new QRegExpValidator(password, this)); //设置密码输入框中，按鼠标右键无菜单显示.和QQ一样.有心的小伙伴可以去试一下.
ui.passwordLineEdit->setContextMenuPolicy(Qt::NoContextMenu); //但是对于Ctrl+V粘贴的快捷操作还没有屏蔽.有兴趣的可以去自己试试.这里不展开了.
//连接信号与槽.
connect(ui.showAccountButton, SIGNAL(clicked()), this, SLOT(showAccountNameSlot()));
connect(ui.showPasswordButton, SIGNAL(clicked()), this, SLOT(showPasswordSlot()));
connect(ui.pushButton, SIGNAL(clicked()), this, SLOT(showEntryDialogSlot()));
connect(ui.passwordLineEdit, SIGNAL(returnPressed()), ui.pushButton, SIGNAL(clicked()));
}
c::~c()
{
}void c::showAccountNameSlot()
{
QMessageBox::information(this, QString::fromLocal8Bit("账号:"), ui.accountLineEdit->text());
}void c::showPasswordSlot()
{ //注意text()返回的是本身的文本，而displayText()返回的是显示的文本.
QMessageBox::information(this, QString::fromLocal8Bit("密码:"), ui.passwordLineEdit->text());
}void c::showEntryDialogSlot()
{ //这里只是为了演示QLineEdit的用法，就没有实现注册，登录等功能.所以这是简单的登陆下.
if ((ui.accountLineEdit->text() == "123456") && (ui.passwordLineEdit->text() == "qw123456"))
{
QMessageBox::information(this, QString::fromLocal8Bit("登录"), QString::fromLocal8Bit("登录成功"));
} else
{
QMessageBox::warning(this, QString::fromLocal8Bit("登录"), QString::fromLocal8Bit("登录失败"));
}
}12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879以下是”c.h”内的代码:
#ifndef C_H#define C_H#include <QtWidgets/QWidget>#include "ui_c.h"#include <QMessageBox>#include <QLineEdit>#include <QLabel>#include <QPushButton>#include <QValidator>#include <QRegExp>#include <QMessageBox>#include <QPixmap>class c : public QWidget{
Q_OBJECTpublic:
c(QWidget *parent = 0);
~c();private slots: void showAccountNameSlot(); void showPasswordSlot(); void showEntryDialogSlot();private:
Ui::cClass ui;
};#endif // C_H1234567891011121314151617181920212223242526272829303132最后是”main.cpp”内的代码:
#include "c.h"#include <QtWidgets/QApplication>int main(int argc, char *argv[])
{
QApplication a(argc, argv);
c w;
w.show(); return a.exec();
}
