基于QML的简单例子，包括listview调用数据库sqlite3增删改查，TCP客户端服务端通信，串口通信

#include "personlistviewmodel.h" PersonListViewModel::PersonListViewModel(SQLiteHelper *sqlhelper, QObject *parent) { Q_UNUSED(parent); sqlHelper=sqlhelper; //创建数据库 char *errmsg; //出错信息 const char *createPerson="create table IF NOT EXISTS Person(" "ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL," "Name varchar(30) NOT NULL, " "Age int NOT NULL" ");"; int res = sqlite3_exec(sqlHelper->sqldb, createPerson, NULL, NULL, &errmsg); if(res!=SQLITE_OK) { qDebug()<<"创建Person表失败："<<sqlite3_errcode(sqlHelper->sqldb)<<endl; qDebug()<<"创建Person表失败："<<sqlite3_errmsg(sqlHelper->sqldb)<<endl; qDebug()<<"创建Person表失败："<<errmsg; sqlite3_free(errmsg); } personList=getAllPerson(); } PersonListViewModel::~PersonListViewModel() { qDebug()<<"free person manage"; } QVariant PersonListViewModel::data(const QModelIndex &index, int role) const { switch(role){ case DataRoles::IDRole : return personList[index.row()]->getID(); case DataRoles::AgeRole : return personList[index.row()]->getAge(); case DataRoles::NameRole : return personList[index.row()]->getName(); default : break ; } return QVariant(); } QHash<int, QByteArray> PersonListViewModel::roleNames() const { QHash <int,QByteArray> temp ; temp.insert(DataRoles :: IDRole,"id"); temp.insert(DataRoles :: AgeRole,"age"); temp.insert(DataRoles :: NameRole,"name"); return temp ; } int PersonListViewModel::rowCount(const QModelIndex &parent) const { Q_UNUSED(parent); return personList.length(); } bool PersonListViewModel::setData(const QModelIndex &index, const QVariant &value, int role) { int row=index.row(); int col=index.column(); auto p=index.parent(); auto v=value.isValid(); if (!hasIndex(row,col, p) || !v) return false; Person *person = personList[index.row()]; if (role == DataRoles::NameRole) { person->setName(value.toString()); } else if (role == DataRoles::AgeRole) { person->setAge(value.toString().toInt()); } else { return false; } emit dataChanged(index, index, { role } ); return true ; } int PersonListViewModel::InsertPerson(Person *person) { char *errmsg; QString insertPerson=QString("INSERT INTO Person(NAME,AGE) VALUES('%1', %2)").arg(person->getName()).arg(person->getAge()); int res=sqlite3_exec(sqlHelper->sqldb, insertPerson.toUtf8(), NULL, NULL, &errmsg); if(res!=SQLITE_OK) { qDebug()<<sqlite3_errcode(sqlHelper->sqldb)<<endl; qDebug()<<sqlite3_errmsg(sqlHelper->sqldb)<<endl; qDebug()<<errmsg; sqlite3_free(errmsg); return -1; } else { char * zErrMsg = NULL; //错误信息指针的地址 char ** pResult = NULL; //用来指向sql执行结果的指针 int nrow = 0; //满足条件的记录数目 int ncolumn = 0; //每条记录包含的字段数据 QString selectPerson= "SELECT * FROM Person order by ID desc"; int result = sqlite3_get_table(sqlHelper->sqldb, selectPerson.toUtf8(), &pResult, &nrow, &ncolumn, &zErrMsg); if(result==SQLITE_OK) { return sqlHelper->getIntValue(pResult,ncolumn,0,0); } else { return -1; } } } void PersonListViewModel::deletePerson(int id) { char *errmsg; QString insertPerson=QString("DELETE FROM Person WHERE ID=%1").arg(id); int res=sqlite3_exec(sqlHelper->sqldb, insertPerson.toUtf8(), NULL, NULL, &errmsg); if(res!=SQLITE_OK) { qDebug()<<sqlite3_errcode(sqlHelper->sqldb)<<endl; qDebug()<<sqlite3_errmsg(sqlHelper->sqldb)<<endl; qDebug()<<errmsg; sqlite3_free(errmsg); } qDebug()<<"delete updata"; } void PersonListViewModel::updataPerson(int id, QString name, int age) { char *errmsg; QString insertPerson=QString("UPDATE Person SET NAME = '%1',Age = %2 WHERE ID = %3").arg(name).arg(age).arg(id); int res=sqlite3_exec(sqlHelper->sqldb, insertPerson.toUtf8(), NULL, NULL, &errmsg); if(res!=SQLITE_OK) { qDebug()<<sqlite3_errcode(sqlHelper->sqldb)<<endl; qDebug()<<sqlite3_errmsg(sqlHelper->sqldb)<<endl; qDebug()<<errmsg; sqlite3_free(errmsg); } else { if(personList.count()>0) { qDebug()<<"ID"<<id; for(int i=0;i<personList.size();i++) { if(personList[i]->getID()==id) { if(personList[i]->getAge()!=age) { setData(this->index(i) ,age,DataRoles::AgeRole); } if(personList[i]->getName()!=name) { setData(this->index(i),name,DataRoles::NameRole); } //personList.replace(i,personList[i]); //beginRemoveRows(QModelIndex(),i,i); //endRemoveRows(); break; } } } } } Person *PersonListViewModel::SelectPerson(int id) { char * zErrMsg = NULL; //错误信息指针的地址 char ** pResult = NULL; //用来指向sql执行结果的指针 int nrow = 0; //满足条件的记录数目 int ncolumn = 0; //每条记录包含的字段数据 QString selectPerson= QString("SELECT * FROM Person WHERE ID=%1").arg(id); int result = sqlite3_get_table(sqlHelper->sqldb, selectPerson.toUtf8(), &pResult, &nrow, &ncolumn, &zErrMsg); if(SQLITE_OK != result) { printf("执行sql语句失败\n"); return nullptr; } else { Person *person=new Person; person->setID(sqlHelper->getIntValue(pResult,ncolumn,0,0)); person->setName(sqlHelper->getQStringValue(pResult,ncolumn,0,1)); person->setAge(sqlHelper->getIntValue(pResult,ncolumn,0,2)); sqlite3_free_table(pResult); return person; } } QList<Person *> PersonListViewModel::getAllPerson() { QList<Person*> persons; char * zErrMsg = NULL; //错误信息指针的地址 char ** pResult = NULL; //用来指向sql执行结果的指针 int nrow = 0; //满足条件的记录数目 int ncolumn = 0; //每条记录包含的字段数据 QString selectPerson= QString("SELECT * FROM Person"); int result = sqlite3_get_table(sqlHelper->sqldb, selectPerson.toUtf8(), &pResult, &nrow, &ncolumn, &zErrMsg); if(SQLITE_OK != result) { qDebug()<<"执行sql语句失败"<<endl; } else { for(int i=0;i<nrow;i++) { Person *person=new Person; person->setID(sqlHelper->getIntValue(pResult,ncolumn,i,0)); person->setName(sqlHelper->getQStringValue(pResult,ncolumn,i,1)); person->setAge(sqlHelper->getIntValue(pResult,ncolumn,i,2)); persons.append(person); } sqlite3_free_table(pResult); } return persons; } void PersonListViewModel::addItem(QString name, int age) { Person *person=new Person(name,age); auto count=InsertPerson(person); qDebug()<<"count:"<<count; person->setID(count); beginInsertRows(QModelIndex(),rowCount(),rowCount()); personList.insert(personList.length(),person); endInsertRows(); } void PersonListViewModel::deleteItem(int id) { deletePerson(id); if(personList.count()>0) { qDebug()<<"ID"<<id;