項(xiàng)目中有一個(gè)新的需求，要求可以連接一個(gè)USB體溫槍责蝠，APP可以從體溫槍中讀取到體溫?cái)?shù)據(jù)俺附，一番搜尋之后發(fā)現(xiàn)一個(gè)封裝很棒的USB通信庫(kù)。
github地址：usb-serial-for-android
準(zhǔn)備工作
從 github 上 clone 這個(gè)庫(kù)的源文件
-
在Android Studio中引入模塊
import module 在build.gradle中添加依賴
compile project(path: ':usbSerialForAndroid')-
復(fù)制 device_filter.xml 到項(xiàng)目的 res/xml/ 文件夾下
設(shè)備列表 配置 AndroidManifest.xml 文件
<uses-feature android:name="android.hardware.usb.host" />
<application>
<activity
android:name="..."
...>
<intent-filter>
<action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
</intent-filter>
<meta-data
android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
android:resource="@xml/device_filter" />
</activity>
</application>
使用
示例代碼解析：
// 獲取系統(tǒng)服務(wù)得到UsbManager實(shí)例
UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
//查找所有插入的設(shè)備
List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
if (availableDrivers.isEmpty()) {
return;
}
// 打開設(shè)備抵栈，建立通信連接
UsbSerialDriver driver = availableDrivers.get(0);
UsbDeviceConnection connection = manager.openDevice(driver.getDevice());
if (connection == null) {
// You probably need to call UsbManager.requestPermission(driver.getDevice(), ..)
return;
}
//打開端口告材，設(shè)置端口參數(shù)，讀取數(shù)據(jù)
UsbSerialPort port = driver.getPorts().get(0);
try {
port.open(connection);
//四個(gè)參數(shù)分別是：波特率古劲，數(shù)據(jù)位斥赋，停止位，校驗(yàn)位
port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
byte buffer[] = new byte[16];
int numBytesRead = port.read(buffer, 1000);
Log.d(TAG, "Read " + numBytesRead + " bytes.");
} catch (IOException e) {
// Deal with error.
} finally {
port.close();
}
上述代碼是庫(kù)作者寫的一段示例代碼产艾，可以看出使用上非常簡(jiǎn)單疤剑，下面的代碼演示了如何將USB操作都封裝到一個(gè)類里。
public class TemperatureUsbControl {
private static final String TAG = TemperatureUsbControl.class.getSimpleName();
private static final String TEMPERATURE_USB_VENDOR_ID = "067B"; //供應(yīng)商id
private static final String TEMPERATURE_USB_PRODUCT_ID = "2303"; //產(chǎn)品id
private Context mContext;
private UsbManager mUsbManager; //USB管理器
private UsbSerialPort sTemperatureUsbPort = null; //接體溫槍的usb端口
private SerialInputOutputManager mSerialIoManager; //輸入輸出管理器（本質(zhì)是一個(gè)Runnable）
private final ExecutorService mExecutor = Executors.newSingleThreadExecutor(); //用于不斷從端口讀取數(shù)據(jù)
//數(shù)據(jù)輸入輸出監(jiān)聽器
private final SerialInputOutputManager.Listener mListener =
new SerialInputOutputManager.Listener() {
@Override
public void onRunError(Exception e) {
Log.d(TAG, "Runner stopped.");
}
@Override
public void onNewData(final byte[] data) {
Log.d(TAG, "new data.");
}
};
public TemperatureUsbControl(Context context) {
mContext = context;
}
public void initUsbControl() {
mUsbManager = (UsbManager) mContext.getSystemService(Context.USB_SERVICE);
//全部設(shè)備
List<UsbSerialDriver> usbSerialDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(mUsbManager);
//全部端口
List<UsbSerialPort> usbSerialPorts = new ArrayList<UsbSerialPort>();
for (UsbSerialDriver driver : usbSerialDrivers) {
List<UsbSerialPort> ports = driver.getPorts();
Log.d(TAG, String.format("+ %s: %s port%s",
driver, Integer.valueOf(ports.size()), ports.size() == 1 ? "" : "s"));
usbSerialPorts.addAll(ports);
}
String vendorId;
String productId;
//校驗(yàn)設(shè)備闷堡，設(shè)備是 2303設(shè)備
for (UsbSerialPort port : usbSerialPorts) {
UsbSerialDriver driver = port.getDriver();
UsbDevice device = driver.getDevice();
vendorId = HexDump.toHexString((short) device.getVendorId());
productId = HexDump.toHexString((short) device.getProductId());
if (vendorId.equals(TEMPERATURE_USB_VENDOR_ID) && productId.equals(TEMPERATURE_USB_PRODUCT_ID)) {
sTemperatureUsbPort = port;
}
}
if (sTemperatureUsbPort != null) {
//成功獲取端口隘膘，打開連接
UsbDeviceConnection connection = mUsbManager.openDevice(sTemperatureUsbPort.getDriver().getDevice());
if (connection == null) {
Log.e(TAG, "Opening device failed");
return;
}
try {
sTemperatureUsbPort.open(connection);
//設(shè)置波特率
sTemperatureUsbPort.setParameters(4800, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
} catch (IOException e) {
//打開端口失敗，關(guān)閉杠览！
Log.e(TAG, "Error setting up device: " + e.getMessage(), e);
try {
sTemperatureUsbPort.close();
} catch (IOException e2) {
// Ignore.
}
sTemperatureUsbPort = null;
return;
}
} else {
//提示未檢測(cè)到設(shè)備
}
}
public void onDeviceStateChange() {
//重新開啟USB管理器
stopIoManager();
startIoManager();
}
private void startIoManager() {
if (sTemperatureUsbPort != null) {
Log.i(TAG, "Starting io manager ..");
mSerialIoManager = new SerialInputOutputManager(sTemperatureUsbPort, mListener);
mExecutor.submit(mSerialIoManager); //實(shí)質(zhì)是用一個(gè)線程不斷讀取USB端口
}
}
private void stopIoManager() {
if (mSerialIoManager != null) {
Log.i(TAG, "Stopping io manager ..");
mSerialIoManager.stop();
mSerialIoManager = null;
}
}
public void onPause() {
stopIoManager();
if (sTemperatureUsbPort != null) {
try {
sTemperatureUsbPort.close();
} catch (IOException e) {
// Ignore.
}
sTemperatureUsbPort = null;
}
}
}
在Activity中使用：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_punch);
initUsbControl(); //初始化USB控制器
}
/**
* 初始化USB
*/
private void initUsbControl() {
mTemperatureUsbControl = new TemperatureUsbControl(mContext);
mTemperatureUsbControl.initUsbControl();
}
@Override
protected void onResume() {
super.onResume();
IntentFilter usbFilter = new IntentFilter();
usbFilter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
usbFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
registerReceiver(mUsbReceiver, usbFilter);
mTemperatureUsbControl.onDeviceStateChange();
}
@Override
protected void onPause() {
super.onPause();
mTemperatureUsbControl.onPause();
unregisterReceiver(mUsbReceiver);
}
/**
* 用于檢測(cè)usb插入狀態(tài)的BroadcasReceiver
*/
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
//設(shè)備插入
mTemperatureUsbControl.initUsbControl();
mTemperatureUsbControl.onDeviceStateChange();
Log.e(TAG, "ACTION_USB_DEVICE_ATTACHED");
} else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
//設(shè)備移除
mTemperatureUsbControl.onPause();
Log.e(TAG, "ACTION_USB_DEVICE_DETACHED");
}
}
};
讀到的數(shù)據(jù)如果需要在Activity中使用弯菊，可以使用EventBus來完成~
