Android 如何以编程方式释放声明的 USB 接口(interface)

Question

我在 AsyncTask 中运行 USB 连接。在某些情况下，如果我尝试使用连接，批量传输功能将永远不会返回。如果我终止 AsyncTask，除非我重新启动机器，否则连接将停止运行。

Log.d(TAG, "trying to connect");
boolean connected = con.claimInterface(device.getInterface(0), true);
Log.d(TAG, "connected: " + connected);

Log.d(TAG, "trying to transfer cmd");
int outGoingBytes = con.bulkTransfer(endPointOut, cmd, cmd.length, 0);
Log.d(TAG, "outGoingBytes: " + outGoingBytes);

永远不会到达最后一个日志。

有没有办法以编程方式释放接口(interface)以便重新建立连接？

这是 logcat 错误

E/UsbDeviceConnectionJNI: device is closed in native_claim_interface

Answer 1

尝试增加超时时间，您正在传递 0，输入 2000 毫秒或类似值。

con.bulkTransfer(endPointOut, cmd, cmd.length, 2000);

不太清楚，希望有经验的大神解答，不过释放通讯可以调用close()。

According to the documentation:

Releases all system resources related to the device. Once the object is closed it cannot be used again. The client must call openDevice(UsbDevice) again to retrieve a new instance to reestablish communication with the device.