java – 在Android平板電腦和相機之間的USB bulkTransfer

public class MainActivity extends Activity {

private TextView text;
private int TIMEOUT = 1000;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text = (TextView) findViewById(R.id.txt);
usbTest();
}

private void usbTest() {
UsbDevice device = (UsbDevice) getIntent().getParcelableExtra(
UsbManager.EXTRA_DEVICE);
if (device == null)
text.setText("device null");
else
text.setText("device not null");

UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
text.setText(text.getText() + "\nDevices connected: "
+ deviceList.values().size());
Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();

while (deviceIterator.hasNext()) {
device = deviceIterator.next();
text.setText(text.getText() + "\nDevice name: "
+ device.getDeviceName());
text.setText(text.getText() + "\nDevice protocol: "
+ device.getDeviceProtocol());
text.setText(text.getText() + "\nDevice id: "
+ device.getDeviceId());
text.setText(text.getText() + "\nDevice product id: "
+ device.getProductId());
text.setText(text.getText() + "\nDevice vendor id: "
+ device.getVendorId());
text.setText(text.getText() + "\nDevice class: "
+ device.getDeviceClass());
text.setText(text.getText() + "\nDevice subclass: "
+ device.getDeviceSubclass());
text.setText(text.getText() + "\nDevice interface count: "
+ device.getInterfaceCount());
text.setText(text.getText() + "\n\n");
}

// communicate with device
UsbInterface intf = device.getInterface(0);
UsbEndpoint endpoint = intf.getEndpoint(0);
UsbDeviceConnection connection = manager.openDevice(device);
connection.claimInterface(intf, true);

for (int i = 0; i < intf.getEndpointCount(); i++) {
UsbEndpoint ep = intf.getEndpoint(i);
if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
if (ep.getDirection() == UsbConstants.USB_DIR_OUT) {
endpoint = ep;
text.setText("Found: "+i);
}
}
}


// byte[] opensession = { 0x0C, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02,
// 0x10,
// 0x00, 0x00, 0x00, 0x00 };
// connection.bulkTransfer(endpoint, opensession, opensession.length,
// TIMEOUT);

byte[] getEvent = { 0x0C, 0x00, 0x00, 0x00, 0x01, 0x00, toByte(0xC7),
toByte(0x90), 0x00, 0x00, 0x00, 0x00 };
int status = connection.bulkTransfer(endpoint, getEvent,
getEvent.length, TIMEOUT);
//text.setText("Status: " + status);

byte[] capture = { 0x14, 0x00, 0x00, 0x00, 0x10, 0x00, 0x0E, 0x10,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00 };
connection.bulkTransfer(endpoint, capture, capture.length, TIMEOUT);

// teminate communication
BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
UsbDevice device = (UsbDevice) intent
.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (device != null) {
// call your method that cleans up and closes
// communication with the device
}
}
}
};

}

public static byte toByte(int c) {
return (byte) (c <= 0x7f ? c : ((c % 0x80) - 0x80));
}

}

我懷疑你沒有正確地搜尋介面和端點.

見下面的說明.

建議：測試端點是否有效,並嘗試將其與裝置描述符進行匹配.

一個介面可以有多個設定.

AFAIK,對於相機,他們應該是相機介面的三個替代設定.

>零頻寬 – 內部沒有端點 – 最可能的替代設定0

>同步(如果相機支援它) – 等時端點在裡面

>批量 – 您感興趣的地方內的批量端點

(我不知道實際的USB相機規格,但是這應該適用於所有通過USB的流式傳輸協議(正如我在Audio Class中看到的)

您需要搜尋批量交替設定,然後在其中的端點上執行通訊.