一、QMap深度解析
1、QMap是一个以升序键顺序存储键值对的数据结构
（1）QMap原型为class QMap<K, T>模板
（2）、QMap中的键值对根据key进行了排序
（3）、QMap中的key类型必须重载operator < (小于操作符)
2、QMap使用实例一
3、QMap使用实例二
4、QMap的注意事项
（1）、通过key获取Value时
A、当key存在，返回对应的Value
B、当key不存在，返回值类型所对应的“零”值
（2）、插入键值对时
A、当key存在，更新Value的值
B、当key不存在，插入新的键值对
#include <QtCore/QCoreApplication>
#include <QDebug>
#include <QMap>
#include<QMapIterator>//迭代器
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QMap<QString, int> map;
map["key 2"] = 2;
map["key 0"] = 0;
map.insert("key 1", 1);
//map.insert("key 1", 4);//前面已有key 1，所有这里会更新key的键值为4
QList<QString> list = map.keys();
for(int i=0; i<list.count(); i++)
{
qDebug() << list[i];//打印排序好的key 0、key 1、key 2
}
QList<int> vlist = map.values();
for(int i=0; i<vlist.count(); i++)
{
qDebug() << vlist[i];//打印0、1、2
}
QMapIterator<QString,int> it(map);//it指向第一个元素之前的位置
while(it.hasNext())
{
it.next();
qDebug() << it.key() << ":" << it.value() ;
}
return a.exec();
}
QMap.cpp
二、QHash深度解析
1、QHash是Qt中的哈希数据结构
（1）、QHash原型为class QHash<K, T>模板
（2）、QHash中的键值对在内部无序排列
（3）、QHash中的Key类型必须重载operator ==
（4）、QHash中的Key对象必须重载全局哈希函数（qHash()）
2、QHash使用示例
#include <QtCore/QCoreApplication>
#include <QDebug>
#include <QHash>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QHash<QString, int> map;
map["key 2"] = 2;
map["key 0"] = 0;
map.insert("key 1", 1);
//map.insert("key 1", 4);//前面已有key 1，所有这里会更新key的键值为4
QList<QString> list = map.keys();
for(int i=0; i<list.count(); i++)
{
qDebug() << list[i];//打印排序好的key 0、key 1、key 2
}
QList<int> vlist = map.values();
for(int i=0; i<vlist.count(); i++)
{
qDebug() << vlist[i];//打印0、1、2
}
QHash<QString,int>::const_iterator i;
for(i=map.constBegin(); i!=map.constEnd(); ++i)
{
qDebug() << i.key() << ":" << i.value() ;
}
return a.exec();
}
QHash.cpp
三、QMap和QHash的对比分析
1、QMap和QHash的接口相同，可直接替换使用
（1）、QHash的查找速度明显快于QMap
（2）、QHash占用的存储空间明显多于QMap
（3）、QHash以任意的方式存储元素
（4）、QMap以Key顺序存储元素
（5）、QHash的键类型必须提供operator == () 和 qHash(key)函数
（6）、QMap的键类型必须提供operator <
QString MainWindow::showFileDialog(QFileDialog::AcceptMode mode, QString title)
{
QString ret = "";
QFileDialog fd;
QStringList filters;
QMap<QString, QString> map;
const char* fileArray[][2]=
{
{"Text(*.txt)", ".txt"},
{"All Files(*.*)", "*" },
{NULL, NULL}
};
for(int i=0; fileArray[i][0] != NULL; i++)
{
filters.append(fileArray[i][0]);
map.insert(fileArray[i][0], fileArray[i][1]);
}
fd.setWindowTitle(title);
fd.setAcceptMode(mode);
fd.setNameFilters(filters);
if(mode==QFileDialog::AcceptOpen)
{
fd.setFileMode(QFileDialog::ExistingFile);
}
if(fd.exec()==QFileDialog::Accepted)
{
ret = fd.selectedFiles()[0];
QString posix = map[fd.selectedNameFilter()];//把下拉中选中的后缀对应键值取出
if(posix != "*" && !ret.endsWith(posix))
{
ret += posix;
}
}
return ret;
}
自动加入后缀名
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMenuBar>
#include <QMenu>
#include <QAction>
#include <QString>
#include <QtGui/QMainWindow>
#include <QToolBar>
#include <QIcon>
#include <QSize>
#include <QStatusBar>
#include <QLabel>
#include <QPlainTextEdit>
#include <QFileDialog>
class MainWindow : public QMainWindow
{
Q_OBJECT
private:
QPlainTextEdit mainEdit;
QLabel statusLabel;
QString m_filePath;//记得在构造函数里初始化
bool m_isTextChanged;//构造函数里初始化为false
MainWindow(QWidget *parent = 0);
MainWindow(const MainWindow& obj);
MainWindow* operator = (const MainWindow& obj);
bool construct();
bool initMenuBar();//菜单栏
bool initToolBar();//工具栏
bool initStatusBar();//状态栏
bool initinitMainEditor();//编辑窗口
bool initFileMenu(QMenuBar* mb);//文件菜单
bool initEditMenu(QMenuBar* mb);//编辑菜单
bool initFormatMenu(QMenuBar* mb);//格式菜单
bool initViewMenu(QMenuBar* mb);//视图菜单
bool initHelpMenu(QMenuBar* mb);//帮助菜单
bool initFileToolItem(QToolBar* tb);//工具选项
bool initEditToolItem(QToolBar* tb);
bool initFormatToolItem(QToolBar* tb);
bool initViewToolItem(QToolBar* tb);
bool makeAction(QAction*& action,QMenu* menu, QString text, int key);//菜单项
bool makeAction(QAction*& action,QToolBar* tb, QString tip, QString icon);
QString showFileDialog(QFileDialog::AcceptMode mode, QString title);//文件对话框
void showErrorMessage(QString message);//错误消息对话框
int showQuesstionMessage(QString message);//问题消息对话框
QString saveCurrentData(QString path = "");
void preEditorChanged();
private slots:
void onFileNew();
void onFileOpen();
void onFlieSave();
void onFileSaveAs();
void onTextChanged();
public:
static MainWindow* NewInstance();
~MainWindow();
};
#endif // MAINWINDOW_H
MainWindow.h
#include "MainWindow.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent), statusLabel(this)
{
m_filePath = "";
m_isTextChanged = false;
setWindowTitle("NotePad-[New]");
}
bool MainWindow::construct()
{
bool ret = true;
ret = ret && initMenuBar();
ret = ret && initToolBar();
ret = ret && initStatusBar();
ret = ret && initinitMainEditor();
return ret;
}
MainWindow* MainWindow::NewInstance()
{
MainWindow* ret = new MainWindow();
if((ret==NULL) || (!ret->construct()))
{
delete ret;
ret = NULL;
}
return ret;
}
bool MainWindow::initMenuBar()//菜单栏
{
bool ret = true;
QMenuBar* mb = menuBar();//一定要注意是menuBar()，这是普通成员函数，不是构造函数
ret = ret && initFileMenu(mb);//传一个参数是为了在initFileMenu()函数将menu加入菜单栏
ret = ret && initEditMenu(mb);
ret = ret && initFormatMenu(mb);
ret = ret && initViewMenu(mb);
ret = ret && initHelpMenu(mb);
return ret;
}
bool MainWindow::initToolBar()//工具栏
{
bool ret = true;
QToolBar* tb = addToolBar("Tool Bar");
//tb->setMovable(false);
//tb->setFloatable(false);
tb->setIconSize(QSize(16,16));
ret = ret && initFileToolItem(tb);
tb->addSeparator();
ret = ret && initEditToolItem(tb);
tb->addSeparator();
ret = ret && initFormatToolItem(tb);
tb->addSeparator();
ret = ret && initViewToolItem(tb);
return ret;
}
bool MainWindow::initStatusBar()//状态栏
{
bool ret = true;
QStatusBar* sb = statusBar();
QLabel* label = new QLabel("Made By LGC");
if(label != NULL)
{
statusLabel.setMinimumWidth(200);
statusLabel.setAlignment(Qt::AlignHCenter);
statusLabel.setText("Ln:1 Col:1");
label->setMinimumWidth(200);
label->setAlignment(Qt::AlignHCenter);
sb->addPermanentWidget(new QLabel());//单纯加入分隔符
sb->addPermanentWidget(&statusLabel);
sb->addPermanentWidget(label);
}
else
{
ret = false;
}
return ret;
}
bool MainWindow::initinitMainEditor()//编辑窗口
{
bool ret = true;
mainEdit.setParent(this);
setCentralWidget(&mainEdit);
connect(&mainEdit, SIGNAL(textChanged()), this, SLOT(onTextChanged()));
return ret;
}
/************************************************文件菜单********************************************************/
bool MainWindow::initFileMenu(QMenuBar* mb)
{
bool ret = true;
QMenu* menu = new QMenu("File(&F)");//创建文件菜单，（&F）是为了可以Alt+F打开
ret = (menu != NULL);
if(ret)
{
QAction* action = NULL;
//New
ret = ret && makeAction(action, menu, "New(&N)",Qt::CTRL + Qt::Key_N);
if(ret)
{
connect(action, SIGNAL(triggered()), this, SLOT(onFileNew()));
menu->addAction(action);
}
menu->addSeparator();
//Open
ret = ret && makeAction(action, menu,"Open(&O)...",Qt::CTRL + Qt::Key_O);
if(ret)
{
connect(action, SIGNAL(triggered()), this, SLOT(onFileOpen()));
menu->addAction(action);
}
menu->addSeparator();
//Save
ret = ret && makeAction(action, menu,"Save(&S)",Qt::CTRL + Qt::Key_S);
if(ret)
{
connect(action, SIGNAL(triggered()), this ,SLOT(onFlieSave()));
menu->addAction(action);
}
menu->addSeparator();
//Save As
ret = ret && makeAction(action, menu, "Save As(&A)...",0);
if(ret)
{
connect(action, SIGNAL(triggered()), this, SLOT(onFileSaveAs()));
menu->addAction(action);
}
menu->addSeparator();
//print
ret = ret && makeAction(action, menu, "Print(&P)...",Qt::CTRL + Qt::Key_P);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Exit
ret = ret && makeAction(action, menu,"Exit(&X)",0);
if(ret)
{
menu->addAction(action);//将菜单项加入到菜单
}
}
if(ret)
{
mb->addMenu(menu);//将菜单加入到菜单栏
}
else
{
delete mb;
}
return ret;
}
/************************************************编辑菜单********************************************************/
bool MainWindow::initEditMenu(QMenuBar* mb)
{
bool ret = true;
QMenu* menu = new QMenu("Edit(&E)");
ret = (menu != NULL);
if(ret)
{
QAction* action = NULL;
//Undo
ret = ret && makeAction(action, menu,"Undo(&U)",Qt::CTRL + Qt::Key_Z);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Redo
ret = ret && makeAction(action, menu,"Redo(&R)...",Qt::CTRL + Qt::Key_Y);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Cut
ret = ret && makeAction(action, menu,"Cut(&T)",Qt::CTRL + Qt::Key_X);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Copy
ret = ret && makeAction(action, menu,"Copy(&C)...",Qt::CTRL + Qt::Key_C);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Pase
ret = ret && makeAction(action, menu,"Pase(&P)...",Qt::CTRL + Qt::Key_V);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Delete
ret = ret && makeAction(action, menu, "Delete(&L)",Qt::Key_Delete);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Find
ret = ret && makeAction(action, menu,"Find(&F)...",Qt::CTRL + Qt::Key_F);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Replace
ret = ret && makeAction(action, menu,"Replace(&R)...",Qt::CTRL + Qt::Key_H);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Goto
ret = ret && makeAction(action, menu,"Goto(&G)",Qt::CTRL + Qt::Key_G);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Select All
ret = ret && makeAction(action, menu, "Select All(&A)",Qt::CTRL + Qt::Key_A);
if(ret)
{
menu->addAction(action);
}
}
if(ret)
{
mb->addMenu(menu);
}
else
{
delete mb;
}
return ret;
}
/************************************************格式菜单********************************************************/
bool MainWindow::initFormatMenu(QMenuBar* mb)
{
bool ret = true;
QMenu* menu = new QMenu("Format(&O)");
ret = (menu != NULL);
if(ret)
{
QAction* action = NULL;
//Auto Wrap
ret = ret && makeAction(action, menu,"Auto Wrap(&W)",0);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Font
ret = ret && makeAction(action, menu,"Font(&F)...",0);
if(ret)
{
menu->addAction(action);
}
}
if(ret)
{
mb->addMenu(menu);
}
else
{
delete mb;
}
return ret;
}
/************************************************视图菜单********************************************************/
bool MainWindow::initViewMenu(QMenuBar* mb)
{
bool ret = true;
QMenu* menu = new QMenu("View(&V)");
ret = (menu != NULL);
if(ret)
{
QAction* action = NULL;
//Tool Bar
ret = ret && makeAction(action, menu,"Tool Bar(&T)",0);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//Status Bar
ret = ret && makeAction(action, menu,"Status Bar(&S)",0);
if(ret)
{
menu->addAction(action);
}
}
if(ret)
{
mb->addMenu(menu);
}
else
{
delete mb;
}
return ret;
}
/************************************************帮助菜单********************************************************/
bool MainWindow::initHelpMenu(QMenuBar* mb)
{
bool ret = true;
QMenu* menu = new QMenu("Help(&H)");
ret = (menu != NULL);
if(ret)
{
QAction* action = NULL;
//User Manual
ret = ret && makeAction(action, menu,"User Manual",0);
if(ret)
{
menu->addAction(action);
}
menu->addSeparator();
//About NotePad
ret = ret && makeAction(action, menu,"About NotePad...",0);
if(ret)
{
menu->addAction(action);
}
}
if(ret)
{
mb->addMenu(menu);
}
else
{
delete mb;
}
return ret;
}
/*****************************************工具************************************************************/
bool MainWindow::initFileToolItem(QToolBar* tb)
{
bool ret = true;
QAction* action = NULL;
ret = ret && makeAction(action, tb, "New", ":/Res/pic/new.png");
if(ret)
{
connect(action, SIGNAL(triggered()), this, SLOT(onFileNew()));
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Open", ":/Res/pic/open.png");
if(ret)
{
connect(action, SIGNAL(triggered()), this, SLOT(onFileOpen()));
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Save", ":/Res/pic/save.png");
if(ret)
{
connect(action, SIGNAL(triggered()), this ,SLOT(onFlieSave()));
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Save As", ":/Res/pic/saveas.png");
if(ret)
{
connect(action, SIGNAL(triggered()), this, SLOT(onFileSaveAs()));
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Print", ":/Res/pic/print.png");
if(ret)
{
tb->addAction(action);
}
return ret;
}
bool MainWindow::initEditToolItem(QToolBar* tb)
{
bool ret = true;
QAction* action = NULL;
ret = ret && makeAction(action, tb,"Undo", ":/Res/pic/undo.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Redo", ":/Res/pic/redo.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb, "Cut", ":/Res/pic/cut.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Copy", ":/Res/pic/copy.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Paste", ":/Res/pic/paste.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Find", ":/Res/pic/find.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Replace", ":/Res/pic/replace.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Goto", ":/Res/pic/goto.png");
if(ret)
{
tb->addAction(action);
}
return ret;
}
bool MainWindow::initFormatToolItem(QToolBar* tb)
{
bool ret = true;
QAction* action = NULL;
ret = ret && makeAction(action, tb, "Auto Wrap", ":/Res/pic/wrap.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Font", ":/Res/pic/font.png");
if(ret)
{
tb->addAction(action);
}
return ret;
}
bool MainWindow::initViewToolItem(QToolBar* tb)
{
bool ret = true;
QAction* action = NULL;
ret = ret && makeAction(action, tb,"Tool Bar", ":/Res/pic/tool.png");
if(ret)
{
tb->addAction(action);
}
ret = ret && makeAction(action, tb,"Status Bar", ":/Res/pic/status.png");
if(ret)
{
tb->addAction(action);
}
return ret;
}
bool MainWindow::makeAction(QAction*& action,QMenu* menu, QString text, int key)//菜单项
{
bool ret = true;
action = new QAction(text, menu);
if(action != NULL)
{
action->setShortcut(QKeySequence(key));//创建快捷键
}
else
{
ret = false;
}
return ret;
}
bool MainWindow::makeAction(QAction*& action,QToolBar* tb, QString tip, QString icon)
{
bool ret = true;
action = new QAction("", tb);
if(action != NULL)
{
action->setToolTip(tip);
action->setIcon(QIcon(icon));
}
else
{
ret = false;
}
return ret;
}
MainWindow::~MainWindow()
{
}
MainWindowUI.cpp
#include <QFileDialog>
#include <QStringList>
#include <QFile>
#include <QDebug>
#include <QMessageBox>
#include "MainWindow.h"
#include <QMap>
QString MainWindow::showFileDialog(QFileDialog::AcceptMode mode, QString title)
{
QString ret = "";
QFileDialog fd;
QStringList filters;
QMap<QString, QString> map;
const char* fileArray[][2]=
{
{"Text(*.txt)", ".txt"},
{"All Files(*.*)", "*" },
{NULL, NULL}
};
for(int i=0; fileArray[i][0] != NULL; i++)
{
filters.append(fileArray[i][0]);
map.insert(fileArray[i][0], fileArray[i][1]);
}
fd.setWindowTitle(title);
fd.setAcceptMode(mode);
fd.setNameFilters(filters);
if(mode==QFileDialog::AcceptOpen)
{
fd.setFileMode(QFileDialog::ExistingFile);
}
if(fd.exec()==QFileDialog::Accepted)
{
ret = fd.selectedFiles()[0];
QString posix = map[fd.selectedNameFilter()];//把下拉中选中的后缀对应键值取出
if(posix != "*" && !ret.endsWith(posix))
{
ret += posix;
}
}
return ret;
}
void MainWindow::showErrorMessage(QString message)
{
QMessageBox mb(this);
mb.setWindowTitle("Quession");
mb.setText(message);
mb.setIcon(QMessageBox::Critical);
mb.setStandardButtons(QMessageBox::Ok);
mb.exec();
}
int MainWindow::showQuesstionMessage(QString message)
{
QMessageBox mb(this);
mb.setWindowTitle("Error");
mb.setText(message);
mb.setIcon(QMessageBox::Question);
mb.setStandardButtons(QMessageBox::Yes | QMessageBox::No | QMessageBox::Cancel);
return mb.exec();
}
QString MainWindow::saveCurrentData(QString path)
{
QString ret = path;
if(ret == "")
{
ret = showFileDialog(QFileDialog::AcceptSave, "Save");
}
if(ret != "")
{
QFile file(ret);
if(file.open(QIODevice::WriteOnly | QIODevice::Text))
{
QTextStream out(&file);
out << QString(mainEdit.toPlainText());
file.close();
setWindowTitle("NotePad - [" + ret + "]");
m_isTextChanged = false;//保存后修改状态值
}
else
{
showErrorMessage(QString("Open file Error!\n\n") + "\"" + m_filePath + "\"");
ret = "";
}
}
return ret;
}
void MainWindow::preEditorChanged()
{
if(m_isTextChanged)
{
int r = showQuesstionMessage("Do you want to Save?");
switch (r)
{
case QMessageBox::Yes:
saveCurrentData(m_filePath);
break;
case QMessageBox::No:
m_isTextChanged = false;
break;
case QMessageBox::Cancel:
break;
}
}
}
void MainWindow::onFileNew()
{
preEditorChanged();
if(!m_isTextChanged)
{
mainEdit.clear();
m_filePath = "";
m_isTextChanged = false;
setWindowTitle("NotePad-[New]");
}
}
void MainWindow::onFileOpen()
{
preEditorChanged();
if(!m_isTextChanged)
{
QString path = showFileDialog(QFileDialog::AcceptOpen, "open");
if(path != "")
{
QFile file(path);
if(file.open(QIODevice::ReadOnly | QIODevice::Text))
{
mainEdit.setPlainText(QString(file.readAll()));
file.close();
m_filePath = path;//报存当前文件路径
setWindowTitle("NotePad - [" + m_filePath + "]");
}
else
{
showErrorMessage(QString("Open file Error!\n\n") + "\"" + m_filePath + "\"");
}
}
}
}
void MainWindow::onFlieSave()
{
QString path = saveCurrentData(m_filePath);
if(path != "")
{
m_filePath = path;
}
}
void MainWindow::onFileSaveAs()
{
QString path = saveCurrentData();//使用默认参数
if(path != "")
{
m_filePath = path;
}
}
void MainWindow::onTextChanged()
{
if(!m_isTextChanged)
{
setWindowTitle("*" + windowTitle());
}
m_isTextChanged = true;
}
MainWindowSlots.cpp
#include <QtGui/QApplication>
#include "MainWindow.h"
#include <QTextCodec>
int main(int argc, char *argv[])
{
QTextCodec::setCodecForLocale(QTextCodec::codecForName("GBK")); //路径名支持中文
QTextCodec::setCodecForTr(QTextCodec::codecForName("GBK")); //QString支持中文
QTextCodec::setCodecForCStrings(QTextCodec::codecForName("GBK")); //string支持中文
QApplication a(argc, argv);
MainWindow* w = MainWindow::NewInstance();
int ret = -1;
if(w != NULL)
{
w->show();
ret = a.exec();
}
delete w;
return ret;
}
main.cpp
四、小结
（1）、Qt中提供了用于存储键值的类模板
（2）、QHash与QMap遵循了相同的使用接口
（3）、QHash的查找速度快于QMap
（4）、QMap需要的内存少于QHash
（5）、QHash对于Key类型的要求高于QMap
时间： 2024-12-24 16:04:15