client *q = new client; q->show();什么意思
时间: 2024-03-19 10:45:37 浏览: 7
这段代码定义了一个指向 client 类对象的指针 q,并且使用 new 操作符在堆上动态地创建了一个 client 对象,然后通过指针 q 调用 show() 函数。
具体而言,new 操作符会在堆上分配一块内存,用于存储 client 类对象,并且返回一个指向该内存地址的指针。这个指针被赋值给了 q 变量,因此 q 指向了堆上分配的 client 对象。然后通过指针 q 调用 show() 函数,实现对 client 对象的访问和操作。
需要注意的是,在使用完动态分配的内存后,需要使用 delete 操作符将其释放,以免出现内存泄漏。例如:
```
client *q = new client;
q->show();
delete q;
```
相关问题
//该函数用于在收到文件名UDP消息时判断是否接收该文件 void Widget::hasPendingFile(QString usrname, QString srvaddr, QString clntaddr, QString filename) { QString ipAddr = getIP(); if (ipAddr == clntaddr) { int btn = QMessageBox::information(this, tr("接收文件"), tr("来自%1(%2)的文件:%3,是否接收?") .arg(usrname) .arg(srvaddr) .arg(filename), QMessageBox::Yes,QMessageBox::No); if (btn == QMessageBox::Yes) { QString name = QFileDialog::getSaveFileName(0, tr("保存文件"),filename); if(!name.isEmpty()) { Client *clnt = new Client(this); clnt->setFileName(name); clnt->setHostAddr(QHostAddress(srvaddr)); clnt->show(); }else{ sndMsg(Refuse, srvaddr); } } } }
这是一段 C++ 代码,用于实现 Widget 类中的 hasPendingFile() 函数。该函数用于在收到文件名 UDP 消息时,判断是否接收该文件,并根据用户的选择进行相应的操作。
具体来说,该函数首先获取本机的 IP 地址,然后判断该消息的发送者 IP 是否与本机 IP 相同。如果相同,则弹出一个询问框,询问用户是否接收来自发送者的文件,并显示文件名、发送者 IP 和发送者用户名。如果用户选择接收,就弹出一个文件保存对话框,让用户选择保存文件的路径和文件名。如果用户选择保存,就创建一个 Client 类对象 clnt,设置文件名和发送者 IP 地址,并显示该对象。如果用户选择不保存,则向发送者发送一个 Refuse 类型的消息,表示拒绝接收文件。
需要注意的是,该函数中使用了 QFileDialog 类来实现文件保存对话框的功能,使用了 Client 类来实现文件接收功能。另外,该函数应该是在 Widget 类中的一个槽函数,当接收到文件名 UDP 消息时,会自动触发该函数的执行。
Qt freerdp 示例代码
以下是一个使用Qt和FreeRDP实现远程桌面连接的示例代码,仅供参考:
```cpp
#include <QApplication>
#include <QWidget>
#include <QPushButton>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QLineEdit>
#include <QLabel>
#include <QThread>
#include <freerdp/client.h>
#include <freerdp/freerdp.h>
#include <freerdp/channels/channels.h>
class RdpClient : public QThread
{
Q_OBJECT
public:
RdpClient(QString hostname, QString username, QString password, QWidget* parent = nullptr) :
QThread(parent),
m_hostname(hostname),
m_username(username),
m_password(password)
{
}
void run() override
{
FreeRDP* instance;
DWORD flags;
RDP_CLIENT_ENTRY_POINTS clientEntryPoints;
memset(&clientEntryPoints, 0, sizeof(RDP_CLIENT_ENTRY_POINTS));
clientEntryPoints.Size = sizeof(RDP_CLIENT_ENTRY_POINTS);
freerdp_client_load_addins(&clientEntryPoints);
instance = freerdp_new();
instance->PreConnect = rdp_pre_connect;
instance->PostConnect = rdp_post_connect;
instance->Authenticate = rdp_authenticate;
instance->SendChannelData = rdp_send_channel_data;
instance->ReceiveChannelData = rdp_receive_channel_data;
instance->ReceiveChannelData = rdp_receive_channel_data;
instance->Update = rdp_update;
instance->ContextSize = sizeof(MyContext);
instance->ContextNew = rdp_context_new;
instance->ContextFree = rdp_context_free;
instance->ContextUpdate = rdp_context_update;
instance->settings = freerdp_settings_new(clientEntryPoints.GetDefaultSettings);
instance->settings->hostname = strdup(m_hostname.toStdString().c_str());
instance->settings->username = strdup(m_username.toStdString().c_str());
instance->settings->password = strdup(m_password.toStdString().c_str());
instance->settings->domain = strdup("");
instance->settings->width = 1024;
instance->settings->height = 768;
instance->settings->color_depth = 16;
instance->settings->fullscreen = false;
instance->settings->performance_flags = PERF_DISABLE_WALLPAPER | PERF_DISABLE_FULLWINDOWDRAG | PERF_DISABLE_MENUANIMATIONS | PERF_DISABLE_THEMING | PERF_ENABLE_FONT_SMOOTHING;
instance->settings->encryption = true;
instance->settings->encryption_method = ENCRYPTION_METHOD_SSL;
instance->settings->ignore_certificate = true;
instance->settings->cert_auto_accept = true;
instance->settings->nego_security_layer = true;
instance->settings->remote_app = false;
instance->settings->multimon = false;
instance->settings->audio_mode = AUDIO_MODE_REDIRECT;
instance->settings->audio_capture_mode = false;
instance->settings->audio_playback_mode = true;
instance->settings->redirect_printer = false;
instance->settings->redirect_com_ports = false;
instance->settings->redirect_smartcards = false;
instance->settings->redirect_clipboard = true;
instance->settings->async_input = true;
instance->settings->mouse_motion = true;
instance->settings->window_title = strdup("Remote Desktop Connection");
if (freerdp_client_settings_parse_command_line(instance->settings, argc, argv, FALSE) == -1)
{
printf("error parsing command line arguments\n");
exit(1);
}
if (freerdp_client_settings_command_line_status_print(instance->settings, argc, argv, 0, FALSE) == 1)
{
exit(0);
}
if (!freerdp_client_load_settings(instance->settings, instance->settings->connection_file, false))
{
printf("error loading settings\n");
exit(1);
}
flags = FREERDP_PASSIVE | FREERDP_SILENT;
instance->ContextExtra = (void*) this;
if (!freerdp_client_start(instance))
{
printf("error starting client\n");
exit(1);
}
freerdp_client_stop(instance);
freerdp_client_free(instance);
freerdp_channels_global_uninit();
freerdp_keyboard_uninit();
}
signals:
void connected();
void disconnected();
void error(QString message);
private:
QString m_hostname;
QString m_username;
QString m_password;
static BOOL rdp_pre_connect(freerdp* instance)
{
return TRUE;
}
static BOOL rdp_post_connect(freerdp* instance)
{
RdpClient* client = static_cast<RdpClient*>(instance->ContextExtra);
emit client->connected();
return TRUE;
}
static BOOL rdp_authenticate(freerdp* instance, char** username, char** password, char** domain)
{
RdpClient* client = static_cast<RdpClient*>(instance->ContextExtra);
if (client) {
*username = strdup(client->m_username.toStdString().c_str());
*password = strdup(client->m_password.toStdString().c_str());
*domain = strdup("");
}
return TRUE;
}
static BOOL rdp_send_channel_data(freerdp* instance, UINT16 channelId, BYTE* data, int size)
{
return TRUE;
}
static BOOL rdp_receive_channel_data(freerdp* instance, UINT16 channelId, BYTE* data, int size, int flags, int totalSize)
{
return TRUE;
}
static BOOL rdp_update(freerdp* instance)
{
return TRUE;
}
typedef struct _my_context
{
int status;
} MyContext;
static void* rdp_context_new(freerdp* instance)
{
MyContext* context = new MyContext();
context->status = 0;
return context;
}
static void rdp_context_free(freerdp* instance, void* context)
{
delete static_cast<MyContext*>(context);
}
static BOOL rdp_context_update(freerdp* instance, void* context)
{
MyContext* myContext = static_cast<MyContext*>(context);
return TRUE;
}
};
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
QWidget* mainWidget = new QWidget();
QVBoxLayout* mainLayout = new QVBoxLayout();
QHBoxLayout* hostnameLayout = new QHBoxLayout();
QLabel* hostnameLabel = new QLabel("Hostname:");
QLineEdit* hostnameLineEdit = new QLineEdit();
hostnameLineEdit->setText("192.168.0.1");
hostnameLayout->addWidget(hostnameLabel);
hostnameLayout->addWidget(hostnameLineEdit);
QHBoxLayout* usernameLayout = new QHBoxLayout();
QLabel* usernameLabel = new QLabel("Username:");
QLineEdit* usernameLineEdit = new QLineEdit();
usernameLineEdit->setText("user");
usernameLayout->addWidget(usernameLabel);
usernameLayout->addWidget(usernameLineEdit);
QHBoxLayout* passwordLayout = new QHBoxLayout();
QLabel* passwordLabel = new QLabel("Password:");
QLineEdit* passwordLineEdit = new QLineEdit();
passwordLineEdit->setEchoMode(QLineEdit::Password);
passwordLayout->addWidget(passwordLabel);
passwordLayout->addWidget(passwordLineEdit);
QPushButton* connectButton = new QPushButton("Connect");
connectButton->setEnabled(true);
mainLayout->addLayout(hostnameLayout);
mainLayout->addLayout(usernameLayout);
mainLayout->addLayout(passwordLayout);
mainLayout->addWidget(connectButton);
mainWidget->setLayout(mainLayout);
mainWidget->show();
QObject::connect(connectButton, &QPushButton::clicked, [=]() {
connectButton->setEnabled(false);
RdpClient* client = new RdpClient(hostnameLineEdit->text(), usernameLineEdit->text(), passwordLineEdit->text(), mainWidget);
QObject::connect(client, &RdpClient::connected, [=]() {
mainWidget->close();
// Remote desktop connected, do something else here
});
QObject::connect(client, &RdpClient::disconnected, [=]() {
connectButton->setEnabled(true);
});
QObject::connect(client, &RdpClient::error, [=](QString message) {
connectButton->setEnabled(true);
// Handle error here
});
client->start();
});
return app.exec();
}
```
在这个示例代码中,我们首先创建了一个Qt界面,包括一个文本框用于输入主机名、用户名、密码,以及一个按钮用于连接远程桌面。当用户点击按钮时,我们创建了一个 `RdpClient` 对象,并将其启动。在 `RdpClient` 类中,我们使用FreeRDP库实现了远程桌面连接的逻辑。在 `run` 方法中,我们首先创建了一个FreeRDP实例,并将其设置为Passive和Silent模式,然后设置一些远程桌面连接的参数,如主机名、用户名、密码等。接下来,我们启动FreeRDP客户端,等待连接成功。在连接成功或失败时,我们向主线程发出信号,以便主线程可以更新界面或处理错误。
需要注意的是,由于FreeRDP是一个C库,而Qt是一个C++库,因此在连接FreeRDP和Qt时需要特别注意类型的转换。在示例代码中,我们使用了一些C++11的特性,如Lambda表达式和信号-槽机制,以简化代码。
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