Android USB下的Accessory模式

发布时间:2016-12-6 22:15:34 编辑:www.fx114.net 分享查询网我要评论
本篇文章主要介绍了"Android USB下的Accessory模式",主要涉及到Android USB下的Accessory模式方面的内容,对于Android USB下的Accessory模式感兴趣的同学可以参考一下。

Android USB开发麻烦还是比较多的。 第一种:host模式 这种模式比较不错,由Android设备提供电源,然后与外部设备通信。举个例子来说:电脑连接USB设备,都是这个模式,非常常见的模式。 但是有一个万恶的问题,android接外部USB设备的时候,驱动怎么办?又有那款芯片敢说Android系统支持他们家的芯片,又有哪个厂家说不动android系统装上他们家的驱动,他们家的设备就可以在Android上使用,或许这点上Android很难超越windows。 造成想现状:想加外部设备,都要:重新自己做底层驱动程序--->编译系统--->刷机--->编写android程序--->接入硬件实现功能。 整个一套下来饭都吃好几顿了。还是希望以后android发展发展能向window一样支持多设备驱动吧。 第二种:Accessory模式 这个模式比较揪心,外部设备要供给电源,数据间通信:电脑---手机就是这种模式,手机作为Accessory设备,电脑供给它电源,同时进行数据通信。 恰巧我也是用了这种模式: 程序需要做的: (1)添加Action BoardCast private static final String ACTION_USB_PERMISSION ="com.ukey.USB_PERMISSION"; /***********************USB handling******************************************/ usbmanager = (UsbManager) context.getSystemService(Context.USB_SERVICE); mPermissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0); IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION); filter.addAction(UsbManager.ACTION_USB_ACCESSORY_DETACHED); context.registerReceiver(mUsbReceiver, filter); inputstream = null; outputstream = null; (2)编写对应的boradCaset信息 /***********USB broadcast receiver*******************************************/ private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (ACTION_USB_PERMISSION.equals(action)) { synchronized (this) { UsbAccessory accessory = (UsbAccessory) intent.getParcelableExtra(UsbManager.EXTRA_ACCESSORY); if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) { Toast.makeText(global_context, "Allow USB Permission", Toast.LENGTH_SHORT).show(); OpenAccessory(accessory); }else{ Toast.makeText(global_context, "Deny USB Permission", Toast.LENGTH_SHORT).show(); } mPermissionRequestPending = false; } } else if (UsbManager.ACTION_USB_ACCESSORY_DETACHED.equals(action)){ DestroyAccessory(true); }else{ Log.d("LED", "...."); } } };(3)又来一个比较麻烦的事 android每次使用Accessory的时候都会询问你是否允许设备访问,这会点击是或否的结果又(2)中代码 if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false))去获得,然后才能使用OpenAccessory功能。 public int OpenAccessory() { // Intent intent = getIntent(); if (inputstream != null && outputstream != null) { return 1; } UsbAccessory[] accessories = usbmanager.getAccessoryList(); if(accessories != null){ Toast.makeText(global_context, "Accessory Attached", Toast.LENGTH_SHORT).show(); }else{ // return 2 for accessory detached case return 2; } UsbAccessory accessory = (accessories == null ? null : accessories[0]); if (accessory != null) { if( -1 == accessory.toString().indexOf(ManufacturerString)){ Toast.makeText(global_context, "Manufacturer is not matched!", Toast.LENGTH_SHORT).show(); return 1; } if( -1 == accessory.toString().indexOf(ModelString1) && -1 == accessory.toString().indexOf(ModelString2)) { Toast.makeText(global_context, "Model is not matched!", Toast.LENGTH_SHORT).show(); return 1; }if( -1 == accessory.toString().indexOf(VersionString)) { Toast.makeText(global_context, "Version is not matched!", Toast.LENGTH_SHORT).show(); return 1; } Toast.makeText(global_context, "Manufacturer, Model & Version are matched!", Toast.LENGTH_SHORT).show(); if (usbmanager.hasPermission(accessory)) { OpenAccessory(accessory); }else{ synchronized (mUsbReceiver) { if (!mPermissionRequestPending) { Toast.makeText(global_context, "Request USB Permission", Toast.LENGTH_SHORT).show(); usbmanager.requestPermission(accessory,mPermissionIntent); mPermissionRequestPending = true; } } } } return 0; } 启动请求。 (4)openAccessory功能 /*destroy accessory*/ public void DestroyAccessory(boolean bConfiged){ if(true == bConfiged){ READ_ENABLE = false; // set false condition for handler_thread to exit waiting data loop writeusbdata[0] = 0; // send dummy data for instream.read going SendPacket(1, writeusbdata); }else{ SetConfig((int)9600,(byte)8,(byte)1,(byte)0,(byte)0); // send default setting data for config try{Thread.sleep(10);} catch(Exception e){} READ_ENABLE = false; // set false condition for handler_thread to exit waiting data loop writeusbdata[0] = 0; // send dummy data for instream.read going SendPacket(1, writeusbdata); } try{Thread.sleep(10);} catch(Exception e){} CloseAccessory(); } /*********************helper routines*************************************************/ public void OpenAccessory(UsbAccessory accessory) { filedescriptor = usbmanager.openAccessory(accessory); if(filedescriptor != null){ usbaccessory = accessory; FileDescriptor fd = filedescriptor.getFileDescriptor(); inputstream = new FileInputStream(fd); outputstream = new FileOutputStream(fd); /*check if any of them are null*/ if(inputstream == null || outputstream==null){ return; } if(READ_ENABLE == false){ READ_ENABLE = true; readThread = new read_thread(inputstream); readThread.start(); } } SetConfig((int)9600,(byte)8,(byte)1,(byte)0,(byte)0); } public void CloseAccessory() { try{ if(filedescriptor != null) filedescriptor.close(); }catch (IOException e){} try { if(inputstream != null) inputstream.close(); } catch(IOException e){} try { if(outputstream != null) outputstream.close(); }catch(IOException e){} /*FIXME, add the notfication also to close the application*/ filedescriptor = null; inputstream = null; outputstream = null; //System.exit(0); }

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