QT学习日记（一）

1.下载QT52.导入VS（添加QT的头文件路径，以及库文件路径）3.#include "testqt.h"#include <QPushButton>#include <QtWidgets/QApplication>#include <QlineEdit>#include <QCompleter>#include <QVBoxLayout>#include <QHBoxLayout>#include <QGridLayout>#include <QLabel>//#define BTN_1int main(int argc, char *argv[]){    QApplication a(argc, argv);    QWidget w;/*************QT的消息槽机制，类似与MFC的消息映射**********/#ifdef BTN_1    // 按钮的处理消息    QPushButton btn;    btn.setText("");    btn.setParent(&w);    btn.show();    // QT对c++的扩展(消息槽，信号和槽绑定)    QObject::connect(&btn, SIGNAL(clicked()), &w, SLOT(close()));#endif#ifdef EDIT_1    // 编辑框的处理    QLineEdit edit;    edit.setEchoMode(QLineEdit::PasswordEchoOnEdit);/*NoEcho,Password,PasswordEchoOnEdit*/;    //edit.text();  /*获取文字*/     //edit.setPlaceholderText("Please input text");    edit.show();    edit.setParent(&w);    QStringList list;    list.append("abb");    list.append("ccc");    list.append("112");    QCompleter completer(list);    completer.setFilterMode(Qt::MatchContains);    edit.setCompleter(&completer);#endif/******************************************************/    // 分层处理(QLayout的派生类)    /*    QVBoxLayout Layout;    Layout.addStretch(0);    Layout.addWidget(new QPushButton("button"), 0);    Layout.addSpacing(20);    Layout.addWidget(new QLineEdit(), 0);    Layout.addStretch(0);    */    QGridLayout GridLayout;    QLabel label1(QStringLiteral("用户名"));/*QStringLiteral用于将字符转换成UTF-8编码*/    QLabel label2(QStringLiteral("密码"));    QPushButton btn(QStringLiteral("确定"));    QPushButton btn1(QStringLiteral("取消"));    QLineEdit edit_psd;    edit_psd.setEchoMode(QLineEdit::Password);    edit_psd.setPlaceholderText("Please input text");    QLineEdit edit_user;    edit_user.setPlaceholderText("Please input text");    GridLayout.setColumnStretch(0,1);   /*注意行和宽要同步设置弹簧*/    GridLayout.setRowStretch(0, 1);    GridLayout.setColumnStretch(4, 1);    GridLayout.setRowStretch(4, 1);    GridLayout.addWidget(&label1, 1, 1);    GridLayout.addWidget(&label2, 2, 1);    GridLayout.addWidget(&edit_user, 1, 2);    GridLayout.addWidget(&edit_psd, 2, 2);    QHBoxLayout layout;    GridLayout.addLayout(&layout, 3, 2); /*层中层*/    layout.addStretch(1);    layout.addWidget(&btn);    layout.addWidget(&btn1);// 设置窗体大小    w.setGeometry(300, 300, 800, 600);    w.setLayout(&GridLayout);    w.setWindowTitle("hello world");    w.show();    return a.exec();     //此处类似win32以及mfc的消息循环机制，必须加上