Qt 信号槽错误：QMetaObject::connectSlotsByName: No matching signal for on_modeComboBox_currentIndexChanged(int) 解决方法

#include #include #include #include #include #include "sqlite.h"

Sqlite::Sqlite() {

}

void Sqlite::sqlite_init() { // 先关闭重复的数据库连接 if (QSqlDatabase::contains("qt_sql_default_connection")) { QSqlDatabase::removeDatabase("qt_sql_default_connection"); } QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("../Smarthome_Client/database/database.db"); if(!db.open()) { qDebug() << "无法打开数据库！"; } else{ qDebug() << "数据库打开成功！"; } }

// 更新智能家居状态表中的数据 void updateSmartHomeStatus(int userId, QString deviceName, QString devicestate,QString newValue) { Sqlite::sqlite_init(); // 执行更新操作 QSqlQuery query; query.prepare("SELECT * FROM Status WHERE uid = :userId"); query.bindValue(":userId", userId); if (!query.exec()) { qDebug() << "查询id失败：" << query.lastError().text(); } QString sql = QString("INSERT INTO Status (uid, device_name, device_state, value) VALUES (%1, '%2', '%3', '%4')") .arg(userId).arg(deviceName).arg(devicestate).arg(newValue); query.prepare(sql); if (!query.exec()) { qDebug() << "插入数据失败：" << query.lastError().text(); return; } }

bool statusUid(int userId) { Sqlite::sqlite_init(); QSqlQuery query; // 查询智能家居状态表，获取用户对应的状态 query.prepare("SELECT * FROM status WHERE uid = :userId"); query.bindValue(":userId", userId); qDebug() << query.exec(); if (!query.next()) { qDebug() << "Failed to execute query!" << query.lastError().text(); return false; }else{ qDebug() << "Successed to execute query!"; return true; } }

-- 创建智能家居状态表 CREATE TABLE IF NOT EXISTS Status ( sid INTEGER PRIMARY KEY AUTOINCREMENT, uid INTEGER , device_name varchar(10), device_state varchar(10), value varchar(10), mode varchar(10), FOREIGN KEY (uid) REFERENCES users (uid) );

-- 创建用户表 CREATE TABLE IF NOT EXISTS users ( uid INTEGER PRIMARY KEY AUTOINCREMENT, username varchar(10), passwd varchar(10) );

-- 创建智能家居状态表 CREATE TABLE IF NOT EXISTS Status ( sid INTEGER PRIMARY KEY AUTOINCREMENT, uid INTEGER , device_name varchar(10), device_state varchar(10), value varchar(10), mode varchar(10), FOREIGN KEY (uid) REFERENCES users (uid) );

SELECT device_state FROM Status WHERE uid = 123 AND device_name = '智能灯'; SELECT device_state FROM Status WHERE uid = 123 AND device_name = '智能灯' ORDER BY sid DESC LIMIT 1; UPDATE Status SET value = '12' , device_state = '开启' WHERE uid = 123 AND device_name = '智能灯';