写一个安卓UVC协议通信的例子,处理uvc的安键操作
时间: 2024-01-22 08:21:24 浏览: 24
UVC协议是一种用于USB摄像头的标准协议,可以让设备与主机之间进行视频、音频和控制数据的传输。在Android系统中,我们可以通过USB OTG接口连接UVC设备,并使用UVC协议进行通信。下面是一个简单的安卓UVC协议通信的例子,处理uvc的安键操作:
首先,我们需要在AndroidManifest.xml文件中添加以下权限:
```xml
<uses-feature android:name="android.hardware.usb.host" />
<uses-permission android:name="android.permission.USB_PERMISSION" />
```
然后,我们需要在Activity中获取USB设备的权限:
```java
private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
private UsbManager mUsbManager;
private UsbDevice mDevice;
private PendingIntent mPermissionIntent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
// 获取已连接的USB设备列表
HashMap<String, UsbDevice> deviceList = mUsbManager.getDeviceList();
for (UsbDevice device : deviceList.values()) {
// 判断是否是UVC设备
if (device.getVendorId() == UVC_VENDOR_ID && device.getProductId() == UVC_PRODUCT_ID) {
// 如果没有权限,则请求权限
if (!mUsbManager.hasPermission(device)) {
mDevice = device;
mUsbManager.requestPermission(device, mPermissionIntent);
return;
} else {
// 如果已有权限,则直接打开设备进行通信
openDevice(device);
}
}
}
}
// 接收USB设备权限的广播
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (ACTION_USB_PERMISSION.equals(action)) {
synchronized (this) {
UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
if (device != null && device.equals(mDevice)) {
// 如果已获取权限,则打开设备进行通信
openDevice(device);
}
} else {
Log.d(TAG, "USB permission denied");
}
}
}
}
};
// 打开UVC设备进行通信
private void openDevice(UsbDevice device) {
UsbInterface usbInterface = device.getInterface(0);
UsbEndpoint endpoint = usbInterface.getEndpoint(0);
UsbDeviceConnection connection = mUsbManager.openDevice(device);
if (connection == null) {
Log.d(TAG, "Failed to open USB device");
return;
}
// Claim interface
if (!connection.claimInterface(usbInterface, true)) {
Log.d(TAG, "Failed to claim interface");
connection.close();
return;
}
// Send UVC control command to start streaming
byte[] ctrlBuffer = new byte[1];
ctrlBuffer[0] = UVC_CTRL_START;
int sentBytes = connection.controlTransfer(UsbConstants.USB_TYPE_CLASS | UsbConstants.USB_RECIP_INTERFACE | UsbConstants.USB_DIR_OUT, UVC_CTRL_SET_CUR, (UVC_CTRL_SCANNING_MODE << 8) | 0x01, 0, ctrlBuffer, 1, 0);
if (sentBytes != 1) {
Log.d(TAG, "Failed to start UVC video streaming");
connection.releaseInterface(usbInterface);
connection.close();
return;
}
// Start reading USB data
byte[] buffer = new byte[endpoint.getMaxPacketSize()];
while (!Thread.currentThread().isInterrupted()) {
int bytesRead = connection.bulkTransfer(endpoint, buffer, buffer.length, TIMEOUT_MS);
if (bytesRead < 0) {
Log.d(TAG, "Failed to read USB data");
break;
}
// 处理UVC安键操作
handleUvcButtonAction(buffer, bytesRead);
}
// Send UVC control command to stop streaming
ctrlBuffer[0] = UVC_CTRL_STOP;
sentBytes = connection.controlTransfer(UsbConstants.USB_TYPE_CLASS | UsbConstants.USB_RECIP_INTERFACE | UsbConstants.USB_DIR_OUT, UVC_CTRL_SET_CUR, (UVC_CTRL_SCANNING_MODE << 8) | 0x01, 0, ctrlBuffer, 1, 0);
// Release interface and close connection
connection.releaseInterface(usbInterface);
connection.close();
}
// 处理UVC安键操作
private void handleUvcButtonAction(byte[] buffer, int length) {
// 查找安键操作的数据包
int index = 0;
while (index < length - 1) {
if (buffer[index] == UVC_BUTTON_DATA_PACKET_ID && buffer[index + 1] == UVC_BUTTON_DATA_PACKET_SIZE) {
// 获取安键操作的数据
byte buttonData = buffer[index + 2];
// 处理安键操作
switch (buttonData) {
case UVC_BUTTON_SHUTTER:
// 处理拍照按钮按下的操作
break;
case UVC_BUTTON_RECORD:
// 处理录像按钮按下的操作
break;
default:
break;
}
// 跳过当前数据包
index += UVC_BUTTON_DATA_PACKET_SIZE;
} else {
// 查找下一个数据包
index++;
}
}
}
```
在上面的代码中,我们首先通过USB Manager获取已连接的USB设备列表,并判断是否有UVC设备。如果有,则请求USB设备权限,如果已有权限,则直接打开设备进行通信。在打开设备后,我们通过USB接口发送UVC控制命令来启动视频流,然后使用bulkTransfer函数读取USB数据。在读取USB数据时,我们通过handleUvcButtonAction函数处理UVC安键操作。
在handleUvcButtonAction函数中,我们通过查找数据包ID和数据包大小来查找安键操作的数据包。然后,我们分析安键操作的数据,根据不同的按钮类型来执行相应的操作。例如,当拍照按钮按下时,我们可以调用相机API来拍照。
这就是一个简单的安卓UVC协议通信的例子,处理uvc的安键操作。