android realizes the function of code scanning gun

The code scanning effect of the code scanning gun is equivalent to keyboard entry, which will call back the dispatchKeyEvent keyboard pressing event.

Development environment: wired code scanning gun, supporting 2-D code

Code

STEP 1 Receive data

 /**
     *  Code scanning processing of code scanning gun 
     */
    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            int keyCode = event.getKeyCode();
            char aChar = (char) event.getUnicodeChar();
            if (aChar != 0) {
                mStringBufferResult.append(aChar);
            }
            mHandler.removeCallbacks(mScanningFishedRunnable);
            // If it is Enter key, return directly 
            if (keyCode == KeyEvent.KEYCODE_ENTER) {
                mHandler.post(mScanningFishedRunnable);
            } else {
                // Delay post If 500ms Inside, there are other events 
                mHandler.postDelayed(mScanningFishedRunnable, 500L);
            }
            return true;
        }
        return super.dispatchKeyEvent(event);
    }

STEP 2 Process data

 /**
 * 2 Dimension code information object 
 */
   private QRCode qrCodeBean;
   /**
   * 2 Dimension code information original data container 
   */
   private StringBuilder mStringBufferResult = new StringBuilder();
   private Handler mHandler = new Handler();
   
   private Runnable mScanningFishedRunnable = new Runnable() {
        @Override
        public void run() {
            scanOk = false;
            String qrcode = mStringBufferResult.toString();
            if (!TextUtils.isEmpty(qrcode)) {
                //  Scan code to determine parameters 
                Gson gson = new Gson();
                try {
                    qrCodeBean = gson.fromJson(qrcode, QRCode.class);
                    //  Your code ...
                    //  If you want to support Chinese, the data can be used URLEncoder/URLDecoder Codec 
                } catch (JsonSyntaxException e) {
                    //  Parsing failed ...
                } catch (UnsupportedEncodingException e) {
                    //  Decoding failure ...
                } finally {
                    mStringBufferResult.setLength(0);
                }
            }
        }
    };

Reference: Android device Bluetooth connection scanning gun to obtain scanning content