usb4java android,桌面java应用程序通过USB复制和传输android数据

比眉伴天荒 2023-01-24 04:25 33阅读 0赞

![Image 1][]

I have a desktop java app, and also an android app. Two app work together.

The user in desktop app have a button to launch the transfer between device data app to computer app and vice versa.

So I need to transfer data with a simple USB cable, and without internet connection/WiFi/Bluetooth/adb.

I found two Java MTP library that works on Windows to resolve my problem, and the USB Host/accesory fonctionnality of android:

jMTP successfully recognizes my Android devices, folder, and other things

I have success to transfer a file in computer ---> device, but i have an error when i try to transfer a file in device ---> computer

I put my code after the explaination.

jusbpmp but i don't have the possibility to transfer device ---> computer.

USB Host/accesory not usefull because transfer are launch from desktop app, and when i read on the android developper guide website, it seems to be not correspond from what i need, or maybe if the user start transfer from the device.

I try from 1 week to success in this task but it seems i need help.

Java + jMTP code

private static void jMTPeMethode()

PortableDeviceManager manager = new PortableDeviceManager();

PortableDevice device = manager.getDevices()\[0\];

// Connect to USB tablet

device.open();

System.out.println(device.getModel());

System.out.println("---------------");

// Iterate over deviceObjects

for (PortableDeviceObject object : device.getRootObjects())

// If the object is a storage object

if (object instanceof PortableDeviceStorageObject)

PortableDeviceStorageObject storage = (PortableDeviceStorageObject) object;

for (PortableDeviceObject o2 : storage.getChildObjects())

if(o2.getOriginalFileName().equalsIgnoreCase("Test"))

//Device to computer not working

PortableDeviceToHostImpl32 copy = new PortableDeviceToHostImpl32();

try

copy.copyFromPortableDeviceToHost(o2.getID(), "C:\\\\TransferTest", device);

\} catch (COMException ex)

// //Host to Device working

// BigInteger bigInteger1 = new BigInteger("123456789");

// File file = new File("c:/GettingJMTP.pdf");

// try \{

// storage.addAudioObject(file, "jj", "jj", bigInteger1);

// \} catch (Exception e) \{

// //System.out.println("Exception e = " + e);

// \}

System.out.println(o2.getOriginalFileName());

manager.getDevices()\[0\].close();

This is the result of the code and the error

Nexus 9

\---------------

Music

Podcasts

Ringtones

Alarms

Notifications

Pictures

Movies

Download

DCIM

Android

! Failed to get IStream (representing object data on the device) from IPortableDeviceResources, hr = 0x80070057

test

ReleveData

I read in internet 0x80070057 is a generic windows exception .

Edit:

Windows site say for the hr error

ERROR\_INVALID\_PARAMETER 0x80070057 :

The parameter supplied by the application is not valid.

But i don't see witch parameter is not valid

Here is the link of C class of the library use for transfer data device to computer, you can see my error line 230.

And this is the jMTP library i use.

Can you help me, or purpose an other way to do what i need(Usb4Java, libUSB) ? I shall be really grateful.

Thanks by advance.

解决方案

Ok, i found the problem.

The problem come from o2.getID() parameter give to the methode copy.copyFromPortableDeviceToHost.

Because o2 representing the folder, and not the file in the folder, so it's not possible to send folder, for success i need to send file in folder.

So i cast my PortableDeviceObject o2 to an PortableDeviceFolderObject, so that get a list of child Object with targetFolder.getChildObjects() in the PortableDeviceFolderObject representing files' and then i can iterate on any child objet from the folder.

And for each file i call the methode copy.copyFromPortableDeviceToHost, with the right id.

Here is the correction code, copy/transfer file from computer to device and device to computer.

I hope it's help.

public class USBTransfertMain \{

public static void main(String\[\] args) throws Throwable \{

jMTPeMethode();

private static void jMTPeMethode()

PortableDeviceFolderObject targetFolder = null;

PortableDeviceManager manager = new PortableDeviceManager();

PortableDevice device = manager.getDevices()\[0\];

// Connect to USB tablet

device.open();