來源:http://www.bverhue.nl/g2dev/?p=65
Delphi Android USB Interface with the G2 Leave a reply I first tried to use Libusb to connect my Android tablet with the G2. I managed to compile the libusb sources for Android and call it from the application, only to run into the “No permissions” error on trying to open the device. There is no easy solution for this at the moment, other than havng to root the device and do other complex things, which very much narrows down the public who could eventually use the application. So I tried the other method, using the “Java native interface”, which turned out to be very easy. Here is an example application which uses this method to interface over USB. It involves 3 steps: Writting the JNI API header unit Writing the application Defining a device filter in the AndroidManifest.template.xml file There is one important requirement: the Android device must support “Host mode” and you should use a USB OTG cable to connect to the G2. Host mode means that the Android device can play the role of host to the usb slave device (the G2) and the OTG cable, because of special wiring, triggers the device into host mode. First the API header unit for the USB functions has to be created. I used the example over here: http://www.pclviewer.com/android/, which deals with the Bluetooth interface as an example. I’ve not exposed all classes or methods at the moment, just the ones I needed for my application.
unit Androidapi.JNI.USB; // (c) B.J.H. Verhue 2014 // JNI USB API converted from api-versions.xml interface uses Androidapi.JNIBridge, Androidapi.JNI.JavaTypes, Classes; type // ============================================================================= // // UsbEndPoint // // ============================================================================= JUsbEndPoint = interface; JUsbEndPointClass = interface(JObjectClass) ['{4B9757DB-9DF8-4E8A-B981-E318D099B0A1}'] end; [JavaSignature('android/hardware/usb/UsbEndpoint')] JUsbEndPoint = interface(JObject) ['{2D1BCC63-C184-41D0-A23A-78E256F8E1D4}'] function init:JUsbEndPoint; cdecl; function getAddress:integer; cdecl; function getAttributes:integer; cdecl; function getDirection:integer; cdecl; function getEndpointNumber:integer; cdecl; function getInterval:integer; cdecl; function getMaxPacketSize:integer; cdecl; function getType:integer; cdecl; end; TJUsbEndPoint = class(TJavaGenericImport<JUsbEndPointClass, JUsbEndPoint>) end; // ============================================================================= // // UsbInterface // // ============================================================================= JUsbInterface = interface; JUsbInterfaceClass = interface(JObjectClass) ['{245DC801-9BF6-4014-B84A-62F44A8C3DB9}'] end; [JavaSignature('android/hardware/usb/UsbInterface')] JUsbInterface = interface(JObject) ['{82D91C14-A4AA-47D7-BA6A-5B05B86F6856}'] function init:JUsbInterface; cdecl; function getEndpoint(i : integer): JUsbEndPoint; cdecl; function getEndpointCount: integer; cdecl; function getId: integer; cdecl; function getInterfaceClass: integer; cdecl; function getInterfaceProtocol: integer; cdecl; function getInterfaceSubclass: integer; cdecl; end; TJUsbInterface = class(TJavaGenericImport<JUsbInterfaceClass, JUsbInterface>) end; // ============================================================================= // // UsbDeviceConnection // // ============================================================================= JUsbDeviceConnection = interface; JUsbDeviceConnectionClass = interface(JObjectClass) ['{447D85BC-BA61-4BBA-A803-563071D90D85}'] end; [JavaSignature('android/hardware/usb/UsbDeviceConnection')] JUsbDeviceConnection = interface(JObject) ['{D613CA69-DD0E-404A-A064-828E09429145}'] function init:JUsbDeviceConnection; cdecl; function bulkTransfer(UsbEndpoint: JUsbEndpoint; data: TJavaArray<Byte>; length : integer; timeout : integer): integer; cdecl; function claimInterface(UsbInterface: JUsbInterface; ForceClaim: boolean): boolean; cdecl; procedure close; cdecl; function releaseInterface(UsbInterface: JUsbInterface): boolean; cdecl; end; TJUsbDeviceConnection = class(TJavaGenericImport<JUsbDeviceConnectionClass, JUsbDeviceConnection>) end; // ============================================================================= // // UsbDevice // // ============================================================================= JUsbDevice = interface; JUsbDeviceClass = interface(JObjectClass) ['{38F968EC-5B0B-4018-A302-4DC469509254}'] end; [JavaSignature('android/hardware/usb/UsbDevice')] JUsbDevice = interface(JObject) ['{35B16245-52F3-409B-86BF-259F3A8F4845}'] function getProductId:integer; cdecl; function getVendorId:integer; cdecl; function getInterface(i: integer):JUSBInterface; cdecl; function getInterfaceCount: integer; cdecl; end; TJUsbDevice = class(TJavaGenericImport<JUsbDeviceClass, JUsbDevice>) end; // ============================================================================= // // UsbManager // // ============================================================================= JUsbManager = interface; JUsbManagerClass = interface(JObjectClass) ['{D4A4DDAC-EE30-4123-A0BE-76F8E95FAC55}'] end; [JavaSignature('android/hardware/usb/UsbManager')] JUsbManager = interface(JObject) ['{5E8A5FA6-64DA-4C90-9D52-988D66E6728E}'] function getDeviceList:JHashMap; cdecl; function hasPermission(UsbDevice:JUsbDevice):boolean; cdecl; function openDevice(UsbDevice:JUsbDevice):JUsbDeviceConnection; cdecl; end; TJUsbManager = class(TJavaGenericImport<JUsbManagerClass, JUsbManager>) end; implementation end.
Second writing the application.
I’ve made a simple Android application in XE5 bases on a blank mobile form. The application has four buttons:
1.List devices, this lists all connected USB devices
2.Open, this opens the G2 devivce, if it is found
3.Message, this sends an “Init” message to the G2
4.Close, this closes the device
The messages are shown in a Memo control. Here is the code:
unit UnitUSBTestJNI; // (c) B.J.H. Verhue 2014 // G2 USB communication using JNI API DEMO interface uses System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Layouts, FMX.Memo, FMX.StdCtrls, Androidapi.JNIBridge, Androidapi.JNI.GraphicsContentViewText, Androidapi.JNI.JavaTypes, Androidapi.JNI.USB; type // Thread for receiving messages from G2 TUSBThread = class(TThread) private [Weak] FUsbDeviceConnection : JUSBDeviceConnection; [Weak] FUsbEPII : JUSBEndPoint; [Weak] FUsbEPBI : JUSBEndPoint; FLogMessage : string; FBytesRead : integer; FIBuffer, FBBuffer : TJavaArray<Byte>; protected procedure Execute; override; public constructor Create( CreateSuspended: Boolean); destructor Destroy; override; procedure ProcessMessage; procedure WriteLog; procedure DumpIMessage; procedure DumpBMessage; property UsbDeviceConnection : JUSBDeviceConnection read FUsbDeviceConnection write FUsbDeviceConnection; property UsbEPII : JUSBEndPoint read FUsbEPII write FUsbEPII; property UsbEPBI : JUSBEndPoint read FUsbEPBI write FUsbEPBI; end; TForm1 = class(TForm) Panel1: TPanel; bListDevices: TButton; Memo1: TMemo; bOpen: TButton; bMessage: TButton; bClose: TButton; procedure bListDevicesClick(Sender: TObject); procedure bOpenClick(Sender: TObject); procedure bCloseClick(Sender: TObject); procedure bMessageClick(Sender: TObject); private FUsbActive : boolean; FUsbThread : TUSBThread; FUsbManager : JUSBManager; FUsbDevice : JUSBDevice; FUsbInterface : JUSBInterface; FUsbEPII, FUsbEPBI, FUsbEPBO : JUSBEndPoint; FUsbDeviceConnection : JUSBDeviceConnection; function GetUsbActive: boolean; procedure SetUsbActive(const Value: boolean); procedure DumpMessage( data : TJavaArray<Byte>; size : integer); public property UsbActive : boolean read GetUsbActive write SetUsbActive; end; var Form1: TForm1; implementation uses FMX.Helpers.Android; {$R *.fmx} function CrcClavia( Seed: Integer; aVal: Integer): Word; var i : Integer; aCrc : Integer; k : Integer; begin // Calculates the G2 checksum for messages k := ((( Seed shr 8) xor aVal) and 255) shl 8; aCrc := 0; for i := 1 to 8 do begin if ( aCrc xor k) and $8000 <> 0 then aCrc := ( aCrc shl 1) xor $1021 else aCrc := aCrc shl 1; k := k shl 1; end; Result := (( Seed shl 8) xor aCrc) and $ffff; end; procedure TForm1.bListDevicesClick(Sender: TObject); var JavaObject : JObject; DeviceList : JHashMap; Device : JUSBDevice; i : Jiterator; s : JString; begin // Device discovery... // Get pointer to UsbManager JavaObject := SharedActivityContext.getSystemService(TJContext.JavaClass.USB_SERVICE); FUsbManager := TJUSBManager.Wrap((JavaObject as ILocalObject).GetObjectID); // Get a list of connected slave devices DeviceList := FUsbManager.getDeviceList; s := DeviceList.toString; Memo1.Lines.Add(jstringtostring(s)); // Get pointer to G2 Device FUsbDevice := nil; i := DeviceList.values.iterator; while i.hasNext do begin Device := TJUSBDevice.Wrap((i.next as ILocalObject).GetObjectID); if (Device.getVendorId = 4092) and (Device.getProductId = 2) then FUsbDevice := Device; Memo1.Lines.Add('VendorID ' + IntToStr(Device.getVendorId) + ', ProductID ' + IntToStr(Device.getProductId)); end; if assigned(FUsbDevice) then bOpen.Enabled := assigned(FUsbDevice); end; procedure TForm1.bCloseClick(Sender: TObject); begin if UsbActive then UsbActive := False; end; procedure TForm1.bMessageClick(Sender: TObject); var bytes_written, size, i : integer; crc : Word; Buffer : TJavaArray<Byte>; begin // Send "Init" message to G2 if assigned(FUsbDeviceConnection) then begin Buffer := TJavaArray<Byte>.Create(5); try Size := 1 + 2 + 2; Buffer.Items[0] := size div 256; Buffer.Items[1] := size mod 256; Buffer.Items[2] := $80; // Calc CRC Crc := 0; i := 2; while i < (Size-2) do begin Crc := CrcClavia(Crc, Buffer.Items[i]); inc(i); end; Buffer.Items[3] := crc div 256; Buffer.Items[4] := crc mod 256; bytes_written := FUsbDeviceConnection.bulkTransfer(FUsbEPBO, Buffer, Size, 100); finally Buffer.Free; end; end; end; procedure TForm1.bOpenClick(Sender: TObject); begin UsbActive := True; end; procedure TForm1.DumpMessage(data: TJavaArray<Byte>; size : integer); var p, i, c : integer; char_line, line : string; begin // Dump message in HEX and Char values Memo1.BeginUpdate; try c := 0; i := 0; p := 0; line := ''; char_line := '';; while (i<size) do begin if c < 16 then begin line := line + IntToHex(data.Items[i], 2) + ' '; if data.Items[i] >= 32 then char_line := char_line + chr(data.Items[i]) else char_line := char_line + '.'; inc(c); inc(i); end else begin Memo1.Lines.Add(IntToHex(p, 6) + ' - ' + line + ' ' + char_line); p := i; c := 0; line := ''; char_line := ''; end; end; if c <> 0 then Memo1.Lines.Add(IntToHex(p, 6) + ' - ' + line + stringofchar(' ', 16*3 - Length(line) + 1) + char_line); finally Memo1.EndUpdate; end; end; function TForm1.GetUsbActive: boolean; begin result := FUsbActive; end; procedure TForm1.SetUsbActive(const Value: boolean); begin if Value then begin // Activate the USB inteface with G2 // Get interface Memo1.Lines.Add('# Interfaces ' + IntToStr(FUsbDevice.getInterfaceCount)); FUsbInterface := FUsbDevice.getInterface(0); Memo1.Lines.Add('# Endpoints ' + IntToStr(FUsbInterface.getEndpointCount)); // Get 3 endpoints FUsbEPII := FUsbInterface.getEndpoint(0); Memo1.Lines.Add('Endpoint ' + IntToStr(FUsbEPII.getEndpointNumber)); FUsbEPBI := FUsbInterface.getEndpoint(1); Memo1.Lines.Add('Endpoint ' + IntToStr(FUsbEPBI.getEndpointNumber)); FUsbEPBO := FUsbInterface.getEndpoint(2); Memo1.Lines.Add('Endpoint ' + IntToStr(FUsbEPBO.getEndpointNumber)); // Check permisions if FUsbManager.hasPermission(FUsbDevice) then begin Memo1.Lines.Add('Permissions o.k.'); end else begin raise Exception.Create('No permission...'); end; // Open device FUsbDeviceConnection := FUsbManager.openDevice(FUsbDevice); if not assigned( FUsbDeviceConnection) then raise Exception.Create('Failed to open device.'); if not FUsbDeviceConnection.claimInterface(FUsbInterface, True) then raise Exception.Create('Failed to claim interface.'); FUsbActive := Value; // Start listening thread FUsbThread := TUsbThread.Create(True); FUsbThread.FUsbDeviceConnection := FUsbDeviceConnection; FUsbThread.FUsbEPII := FUsbEPII; FUsbThread.FUsbEPBI := FUsbEPBI; FUsbThread.Start; end else begin // Deactivate the USB connection FUsbActive := Value; if assigned(FUsbDeviceConnection) then begin // Release interface if not FUsbDeviceConnection.releaseInterface(FUsbInterface) then Memo1.Lines.Add('Failed to release the interface'); // Close device and free the thread if assigned(FUsbThread) then begin FUsbThread.Terminate; FUsbDeviceConnection.close; FUsbThread.DisposeOf; end else FUsbDeviceConnection.close; Memo1.Lines.Add('Device is closed'); end; end; end; { TUSBThread } constructor TUsbThread.Create( CreateSuspended: Boolean); begin FreeOnTerminate := False; inherited; FIBuffer := TJavaArray<Byte>.Create(16); FBBuffer := TJavaArray<Byte>.Create(8192); end; destructor TUsbThread.Destroy; begin FBBuffer.Free; FIBuffer.Free; end; procedure TUsbThread.Execute; var size : integer; begin FLogMessage := 'Thread started.'; synchronize(WriteLog); // The G2 sends first a short message over the interrupt endpoint of max 16 bytes // This may be followed by a longer message (extended message) while assigned(FUsbDeviceConnection) and (not Terminated) do begin FBytesRead := FUsbDeviceConnection.bulkTransfer(FUsbEPII, FIBuffer, 16, 0); if FBytesRead > 0 then begin synchronize(DumpIMessage); if FIBuffer.Items[0] and $f = 1 then begin // Extended message size := (FIBuffer.Items[1] shl 8) or FIBuffer.Items[2]; FLogMessage := 'Extended message, size ' + IntToStr(size); synchronize(WriteLog); FBytesRead := FUsbDeviceConnection.bulkTransfer(FUsbEPBI, FBBuffer, size, 0); FLogMessage := 'Extended message, bytes read ' + IntToStr(FBytesRead); synchronize(WriteLog); synchronize(DumpBMessage); end else begin // Embedded message end; end; sleep(10) end; FLogMessage := 'Thread terminated.'; synchronize(WriteLog); end; procedure TUsbThread.ProcessMessage; begin // Do something with the message... end; procedure TUsbThread.WriteLog; begin Form1.Memo1.Lines.Add(FLogMessage); end; procedure TUsbThread.DumpIMessage; begin Form1.DumpMessage(FIBuffer, FBytesRead); end; procedure TUsbThread.DumpBMessage; begin Form1.DumpMessage(FBBuffer, FBytesRead); end; end.
Finally we have to define a device filter in the “AndroidManifest.template.xml” file. This ensures that you get the necessary permissions for opening the device. Also, this enables automatic launch of the application when you plug in the device in your Android tablet!
First you have to make a little xml file, containing the vendor id and product id of the device. In case of the G2 synth, this file looks like this:
<?xml version="1.0" encoding="UTF-8"?> <resources> <usb-device vendor-id="4092" product-id="2" class="0" subclass="0" protocol="0" /> </resources>
Save this file as “device_filter.xml” and add it to the project.
You also have to deploy this file to the Android device, so put it into the Deployment manager, with remote path “res\xml”.
Next edit the file “AndroidManifest.template.xml” which should be in your project folder after compiling the application.
Put in
<meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" android:resource="@xml/device_filter" />
As a child in the “activity” element, and put
<action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
As a child to the “intent-filter” element. So the dile should look something like this:
<?xml version="1.0" encoding="utf-8"?> <!-- BEGIN_INCLUDE(manifest) --> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="%package%" android:versionCode="%versionCode%" android:versionName="%versionName%"> <!-- This is the platform API where NativeActivity was introduced. --> <uses-sdk android:minSdkVersion="%minSdkVersion%" /> <%uses-permission%> <application android:persistent="%persistent%" android:restoreAnyVersion="%restoreAnyVersion%" android:label="%label%" android:installLocation="%installLocation%" android:debuggable="%debuggable%" android:largeHeap="%largeHeap%" android:icon="%icon%" android:theme="%theme%"> <!-- Our activity is a subclass of the built-in NativeActivity framework class. This will take care of integrating with our NDK code. --> <activity android:name="com.embarcadero.firemonkey.FMXNativeActivity" android:label="%activityLabel%" android:configChanges="orientation|keyboardHidden"> <!-- Tell NativeActivity the name of our .so --> <meta-data android:name="android.app.lib_name" android:value="%libNameValue%" /> <meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" android:resource="@xml/device_filter" /> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" /> </intent-filter> </activity> <receiver android:name="com.embarcadero.firemonkey.notifications.FMXNotificationAlarm" /> </application> </manifest> <!-- END_INCLUDE(manifest) -->
Ok. So now you should be able to deploy the application to the Android device and connect to the G2.