核心业务类：扫码类处理

app/src/main/java/com/miya/fastcashier/ui/PayActivity.kt

@@ -53,14 +53,21 @@ class PayActivity : BaseActivity() {
         })
         binding.clTitle.llBack.clickWithTrigger { finish() }
 
-        scanGunKeyEventHelper.setOnBarCodeCatchListener {
-            showProgressDialog("正在支付..")
-            viewModel.pay(price, it)
-        }
+        scanGunKeyEventHelper.setOnBarCodeCatchListener(object :
+            ScanGunKeyEventHelper.OnScanSuccessListener {
+            override fun onScanSuccess(barcode: String?) {
+                barcode?.let {
+                    showProgressDialog("正在支付..")
+                    viewModel.pay(price, it)
+                }
+            }
+        })
     }
 
     override fun dispatchKeyEvent(event: KeyEvent?): Boolean {
-        scanGunKeyEventHelper.analysisKeyEvent(event)
+        if (event != null) {
+            scanGunKeyEventHelper.analysisKeyEvent(event)
+        }
         return super.dispatchKeyEvent(event)
     }
 

app/src/main/java/com/miya/fastcashier/util/ScanGunKeyEventHelper.java

-package com.miya.fastcashier.util;
-
-import android.os.Handler;
-import android.text.TextUtils;
-import android.view.KeyEvent;
-
-
-/**
- * 扫码枪解码器
- * Created by fengyu on 2018/1/12.
- */
-
-public class ScanGunKeyEventHelper {
-
-    //延迟500ms，判断扫码是否完成。
-    private final static long MESSAGE_DELAY = 500;
-    //扫码内容
-    private final StringBuffer mStringBufferResult = new StringBuffer();
-    //大小写区分
-    private boolean mCaps;
-    private OnScanSuccessListener mOnScanSuccessListener;
-    private final Handler mHandler = new Handler();
-
-    private final Runnable mScanningFishedRunnable = new Runnable() {
-        @Override
-        public void run() {
-            performScanSuccess();
-        }
-    };
-
-    //返回扫描结果
-    private void performScanSuccess() {
-        String barcode = mStringBufferResult.toString();
-        if (mOnScanSuccessListener != null && !TextUtils.isEmpty(barcode))
-            mOnScanSuccessListener.onScanSuccess(barcode);
-        mStringBufferResult.setLength(0);
-    }
-
-    //key事件处理
-    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 (keyCode == KeyEvent.KEYCODE_ENTER) {
-                //若为回车键，直接返回
-                mHandler.removeCallbacks(mScanningFishedRunnable);
-                mHandler.post(mScanningFishedRunnable);
-            } else {
-                if (aChar != 0) {
-                    mStringBufferResult.append(aChar);
-                }
-                //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 {
-        public void onScanSuccess(String barcode);
-    }
-
-    public void setOnBarCodeCatchListener(OnScanSuccessListener onScanSuccessListener) {
-        mOnScanSuccessListener = onScanSuccessListener;
-    }
-
-    public void onDestroy() {
-        mHandler.removeCallbacks(mScanningFishedRunnable);
-        mOnScanSuccessListener = null;
-    }
-}

app/src/main/java/com/miya/fastcashier/util/ScanGunKeyEventHelper.kt

+package com.miya.fastcashier.util
+
+import android.os.Handler
+import android.text.TextUtils
+import android.view.KeyEvent
+
+/**
+ * 扫码枪解码器
+ * Created by fengyu on 2018/1/12.
+ */
+class ScanGunKeyEventHelper {
+    //扫码内容
+    private val mStringBufferResult = StringBuffer()
+
+    //大小写区分
+    private var mCaps = false
+    private var mOnScanSuccessListener: OnScanSuccessListener? = null
+    private val mHandler = Handler()
+    private val mScanningFishedRunnable = Runnable { performScanSuccess() }
+
+    //返回扫描结果
+    private fun performScanSuccess() {
+        val barcode = mStringBufferResult.toString()
+        if (mOnScanSuccessListener != null && !TextUtils.isEmpty(barcode)) mOnScanSuccessListener!!.onScanSuccess(
+            barcode
+        )
+        mStringBufferResult.setLength(0)
+    }
+
+    //key事件处理
+    fun analysisKeyEvent(event: KeyEvent) {
+        val keyCode = event.keyCode
+
+        //字母大小写判断
+        checkLetterStatus(event)
+        if (event.action == KeyEvent.ACTION_DOWN) {
+            val aChar = getInputCode(event)
+            if (keyCode == KeyEvent.KEYCODE_ENTER) {
+                //若为回车键，直接返回
+                mHandler.removeCallbacks(mScanningFishedRunnable)
+                mHandler.post(mScanningFishedRunnable)
+            } else {
+                if (aChar.toInt() != 0) {
+                    mStringBufferResult.append(aChar)
+                }
+                //延迟post，若500ms内，有其他事件
+                mHandler.removeCallbacks(mScanningFishedRunnable)
+                mHandler.postDelayed(mScanningFishedRunnable, MESSAGE_DELAY)
+            }
+        }
+    }
+
+    //检查shift键
+    private fun checkLetterStatus(event: KeyEvent) {
+        val keyCode = event.keyCode
+        if (keyCode == KeyEvent.KEYCODE_SHIFT_RIGHT || keyCode == KeyEvent.KEYCODE_SHIFT_LEFT) {
+            //true为按下shift键，表示大写
+            mCaps = (event.action == KeyEvent.ACTION_DOWN)
+        }
+    }
+
+    //获取扫描内容
+    private fun getInputCode(event: KeyEvent): Char {
+        val keyCode = event.keyCode
+        val aChar: Char
+        aChar =
+            if (keyCode >= KeyEvent.KEYCODE_A && keyCode <= KeyEvent.KEYCODE_Z) {
+                //字母
+                ((if (mCaps) 'A' else 'a').toInt() + keyCode - KeyEvent.KEYCODE_A).toChar()
+            } else if (keyCode >= KeyEvent.KEYCODE_0 && keyCode <= KeyEvent.KEYCODE_9) {
+                //数字
+                ('0'.toInt() + keyCode - KeyEvent.KEYCODE_0).toChar()
+            } else {
+                //其他符号
+                when (keyCode) {
+                    KeyEvent.KEYCODE_PERIOD -> '.'
+                    KeyEvent.KEYCODE_MINUS -> if (mCaps) '_' else '-'
+                    KeyEvent.KEYCODE_SLASH -> '/'
+                    KeyEvent.KEYCODE_BACKSLASH -> if (mCaps) '|' else '\\'
+                    else -> 0.toChar()
+                }
+            }
+        return aChar
+    }
+
+    interface OnScanSuccessListener {
+        fun onScanSuccess(barcode: String?)
+    }
+
+    fun setOnBarCodeCatchListener(onScanSuccessListener: OnScanSuccessListener?) {
+        mOnScanSuccessListener = onScanSuccessListener
+    }
+
+    fun onDestroy() {
+        mHandler.removeCallbacks(mScanningFishedRunnable)
+        mOnScanSuccessListener = null
+    }
+
+    companion object {
+        //延迟500ms，判断扫码是否完成。
+        private const val MESSAGE_DELAY: Long = 500
+    }
+}
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