IngredientScale/app/src/main/java/com/sw/st/utils/ScanGunKeyEventHelper.java

package com.sw.st.utils;

import android.content.Context;
import android.hardware.input.InputManager;
import android.os.Handler;
import android.text.TextUtils;
import android.view.KeyEvent;

import static android.content.Context.INPUT_SERVICE;

public class ScanGunKeyEventHelper {
    private final static long MESSAGE_DELAY = 500;             //延迟500ms，判断扫码是否完成。
    private final StringBuffer mStringBufferResult;                  //扫码内容
    private boolean mCaps;                                     //大小写区分
    private final Handler mHandler;
    private final Runnable mScanningFishedRunnable;
    private OnScanSuccessListener mOnScanSuccessListener;
    private final Context mContext;

    //    private String mDeviceName = "TMC HIDKeyBoard";
    private String mDeviceName = "Linux 3.4.35 with ak-hsudc Composite Gadget (ACM + HID)";


    public ScanGunKeyEventHelper(Context context, OnScanSuccessListener onScanSuccessListener) {

        mContext = context;
        mOnScanSuccessListener = onScanSuccessListener;
        mStringBufferResult = new StringBuffer();
        mHandler = new Handler();
        mScanningFishedRunnable = this::performScanSuccess;
    }

    /**
     * 返回扫码成功后的结果
     */
    private void performScanSuccess() {
        String barcode = mStringBufferResult.toString();
        if (mOnScanSuccessListener != null && !TextUtils.isEmpty(barcode))
            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
     *
     * @param event
     * @return
     */
    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;
    }

    /**
     * 输入设备是否存在
     *
     * @param deviceName
     * @return
     */
    public boolean isInputDeviceExist(String deviceName) {

        InputManager inputManager = (InputManager) mContext.getSystemService(INPUT_SERVICE);
        int[] deviceIds = inputManager.getInputDeviceIds();
        for (int id : deviceIds) {
            if (inputManager.getInputDevice(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
     */
    public boolean isScanGunEvent(KeyEvent event) {
        L.e("event===" + event.getDevice().getName() +
                "===Char===" + event.getCharacters() +
                "===Action===" + event.getAction());
        return event.getDevice().getName().equals(mDeviceName);

//        return  true;
    }


}