android中如何通过扫码枪读取手机二维码

这篇文章主要介绍了android中如何通过扫码枪读取手机二维码，具有一定借鉴价值，感兴趣的朋友可以参考下，希望大家阅读完这篇文章之后大有收获，下面让小编带着大家一起了解一下。

1.引入扫码设备辅助类

public class ScanGunKeyEventHelper {     private final static long MESSAGE_DELAY = 500;             //延迟500ms，判断扫码是否完成。    private StringBuffer mStringBufferResult;                  //扫码内容    private boolean mCaps;                                     //大小写区分    private final Handler mHandler;    private final BluetoothAdapter mBluetoothAdapter;    private final Runnable mScanningFishedRunnable;    private OnScanSuccessListener mOnScanSuccessListener;    private String mDeviceName;     public ScanGunKeyEventHelper(OnScanSuccessListener onScanSuccessListener) {        mOnScanSuccessListener = onScanSuccessListener ;        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();        mStringBufferResult = new StringBuffer();        mHandler = new Handler();        mScanningFishedRunnable = new Runnable() {            @Override            public void run() {                performScanSuccess();            }        };    }      /**     * 返回扫码成功后的结果     */    private void performScanSuccess() {        String barcode = mStringBufferResult.toString();        if (mOnScanSuccessListener != null)            mOnScanSuccessListener.onScanSuccess(barcode);        mStringBufferResult.setLength(0);    }      /**     * 扫码枪事件解析     * @param event     */    public void analysisKeyEvent(KeyEvent event) {         int keyCode = event.getKeyCode();         //字母大小写判断        checkLetterStatus(event);         if (event.getAction() == KeyEvent.ACTION_DOWN) {             char aChar = getInputCode(event);;             if (aChar != 0) {                mStringBufferResult.append(aChar);            }             if (keyCode == KeyEvent.KEYCODE_ENTER) {                //若为回车键，直接返回                mHandler.removeCallbacks(mScanningFishedRunnable);                mHandler.post(mScanningFishedRunnable);            } else {                //延迟post，若500ms内，有其他事件                mHandler.removeCallbacks(mScanningFishedRunnable);                mHandler.postDelayed(mScanningFishedRunnable, MESSAGE_DELAY);            }         }    }    //检查shift键    private void checkLetterStatus(KeyEvent event) {        int keyCode = event.getKeyCode();        if (keyCode == KeyEvent.KEYCODE_SHIFT_RIGHT || keyCode == KeyEvent.KEYCODE_SHIFT_LEFT) {            if (event.getAction() == KeyEvent.ACTION_DOWN) {                //按着shift键，表示大写                mCaps = true;            } else {                //松开shift键，表示小写                mCaps = false;            }        }    }     //获取扫描内容    private char getInputCode(KeyEvent event) {         int keyCode = event.getKeyCode();         char aChar;         if (keyCode >= KeyEvent.KEYCODE_A && keyCode <= KeyEvent.KEYCODE_Z) {            //字母            aChar = (char) ((mCaps ? 'A' : 'a') + keyCode - KeyEvent.KEYCODE_A);        } else if (keyCode >= KeyEvent.KEYCODE_0 && keyCode <= KeyEvent.KEYCODE_9) {            //数字            aChar = (char) ('0' + keyCode - KeyEvent.KEYCODE_0);        } else {            //其他符号            switch (keyCode) {                case KeyEvent.KEYCODE_PERIOD:                    aChar = '.';                    break;                case KeyEvent.KEYCODE_MINUS:                    aChar = mCaps ? '_' : '-';                    break;                case KeyEvent.KEYCODE_SLASH:                    aChar = '/';                    break;                case KeyEvent.KEYCODE_BACKSLASH:                    aChar = mCaps ? '|' : '\\';                    break;                default:                    aChar = 0;                    break;            }        }         return aChar;     }     public interface OnScanSuccessListener {        void onScanSuccess(String barcode);    }      public void onDestroy() {        mHandler.removeCallbacks(mScanningFishedRunnable);        mOnScanSuccessListener = null;    }      //部分手机如三星，无法使用该方法//    private void hasScanGun() {//        Configuration cfg = getResources().getConfiguration();//        return cfg.keyboard != Configuration.KEYBOARD_NOKEYS;//    } //    /**//     * 扫描枪是否连接//     * @return//     *///    public boolean hasScanGun() {////        if (mBluetoothAdapter == null) {//            return false;//        }////        Set blueDevices = mBluetoothAdapter.getBondedDevices();////        if (blueDevices == null || blueDevices.size() <= 0) {//            return false;//        }////        for (Iterator iterator = blueDevices.iterator(); iterator.hasNext(); ) {//            BluetoothDevice bluetoothDevice = iterator.next();////            if (bluetoothDevice.getBluetoothClass().getMajorDeviceClass() == BluetoothClass.Device.Major.PERIPHERAL) {//                mDeviceName = bluetoothDevice.getName();//                return isInputDeviceExist(mDeviceName);//            }////        }////        return false;////    }     /**     * 输入设备是否存在     * @param deviceName     * @return     */    private boolean isInputDeviceExist(String deviceName) {        int[] deviceIds = InputDevice.getDeviceIds();         for (int id : deviceIds) {            if (InputDevice.getDevice(id).getName().equals(deviceName)) {                return true;            }        }        return false;    }     /**     * 是否为扫码枪事件(部分机型KeyEvent获取的名字错误)     * @param event     * @return     */    @Deprecated    public boolean isScanGunEvent(KeyEvent event) {        return event.getDevice().getName().equals(mDeviceName);    } }

2. active里面实现代理方法

 //实现上述类接口'public class MainActivity extends AppCompatActivity implements        ScanGunKeyEventHelper.OnScanSuccessListener//重写扫码枪识别返回数据@Override       public void onScanSuccess(String barcode) {         barCode = barcode;        if (barcode != null && recordPrice > 0 && payString.equals                ("readyPay")) {            payDishs();        }    } //重写捕捉到扫码枪事件    @Override    public boolean dispatchKeyEvent(KeyEvent event) {     mScanGunKeyEventHelper.analysisKeyEvent(event);        return true;    }

dispatchKeyEvent里面分发事件一定设置 return true，否则扫码枪事件传递到屏幕其他按钮上

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