我用qt/c++首次亮相，我使用ubuntu os。我搜索了一个程序示例，它可以帮助我将libusb1.0与qt一起使用。
该计划应：显示连接的 USB 设备，从 USB 设备读取/写入数据。
拜托，我需要你的帮助。
感谢和问候
我尝试了这个例子qt_lisbusb
当我连接USB设备（例如闪存盘）时，程序会检测到但无法打开它。
我使用的代码：
void Qt_libusb::listview_populate_usb_devices() {
ui->listWidget->clear(); //clearing the list view
libusb_device_handle *device_handle; //handle to USB device
libusb_device_descriptor device_descriptor; //the device descriptor
libusb_device **device_list; //to store all found USB devices
libusb_context *ctx; //a libusb context for library intialization
ssize_t i; //for the device iterator for loop
ssize_t device_count; //holding number of devices in list
QString list_entry; //for using library outputs in char * in Qt framework
int r; //for return values
int progress_bar_value = 0;
int progress_bar_correction = 0;
char device_open = 0; //for checking whether a device was opened or not
unsigned char string_buffer_manufacturer[4096]; //for storing manufacturer descriptor
unsigned char string_buffer_product[4096]; //for storing product descriptor
const char *cc_manufacturer; //for the casting to use the string output from libusb in Qt
const char *cc_product; //for the casting to use the string output from libusb in Qt
r = libusb_init(&ctx); //initializing the library
//inform error on status bar
if(r < 0) ui->statusBar->showMessage("Error: Initializing libusb");
else
{
//detecting all the connected devices
device_count = libusb_get_device_list(ctx, &device_list);
//inform error on status bar
if(device_count <= 0) ui->statusBar->showMessage("Info: No device found");
else
{
//resetting the progress bar
ui->progressBar->reset();
//for loop iterating through found devices
for(i=0;i<device_count;i++)
{
//getting device descriptor
r = libusb_get_device_descriptor(device_list[i], &device_descriptor);
//inform error on status bar
if(r < 0) ui->statusBar->showMessage("Error: Failed to get device descriptor");
else
{
//opening the device
r = libusb_open(device_list[i],&device_handle);
if(r < 0)
{
//inform error on status bar
ui->statusBar->showMessage("Error: Opening USB device");
//indicating that device is not open
device_open = 0;
}
else
{
//indicating that device is open
device_open = 1;
//getting the ASCII text value from the descriptor field
r = libusb_get_string_descriptor_ascii(device_handle,device_descriptor.iManufacturer,string_buffer_manufacturer,sizeof(string_buffer_manufacturer));
if(r < 0)
{
//reporting error on the list entry
ui->listWidget->addItem("Error: Converting descriptor to ASCII [iManufacturer]");
ui->listWidget->item(ui->listWidget->count() - 1)->setForeground(Qt::white);
ui->listWidget->item(ui->listWidget->count() - 1)->setBackground(Qt::red);
}
else
{
//getting the ASCII text value from the descriptor field
r = libusb_get_string_descriptor_ascii(device_handle,device_descriptor.iProduct,string_buffer_product,sizeof(string_buffer_product));
if(r < 0)
{
//reporting error on the list entry
ui->listWidget->addItem("Error: Converting descriptor to ASCII [iProduct]");
ui->listWidget->item(ui->listWidget->count() - 1)->setForeground(Qt::white);
ui->listWidget->item(ui->listWidget->count() - 1)->setBackground(Qt::red);
}
else
{
//converting the string to const char*
cc_manufacturer = (const char*)string_buffer_manufacturer;
QString manufacturer(cc_manufacturer);
//converting the string to const char*
cc_product = (const char*)string_buffer_product;
QString product(cc_product);
//constructing the string for list entry
list_entry = manufacturer + " " + product;
ui->listWidget->horizontalScrollBar();
ui->listWidget->verticalScrollBar();
ui->listWidget->addItem(list_entry); //adding the list entry
//closing opened USB device
if (device_open == 1)
{
//closing the deivce
libusb_close(device_handle);
//indicating that device is open
device_open = 0;
}
//calculate and set the progress bar value
progress_bar_value = (i+1) * (100/device_count);
//correcting value
if ( (i+1) == device_count)
{
progress_bar_correction = 100 - progress_bar_value;
progress_bar_value = progress_bar_value + progress_bar_correction;
}
//setting the value
ui->progressBar->setValue(progress_bar_value);
}
}
}
}
}
//closing opened USB device
if (device_open == 1)
{
//closing the deivce
libusb_close(device_handle);
//indicating that device is open
device_open = 0;
}
}
} }