Android 外接USB扫码器

Android外接USB扫码枪  https://www.jianshu.com/p/5c1bf3e968e6

USB扫码器实质就是一个外接键盘

客户问题：同一个二维码来扫描，一个视频是在谷歌输入法下测试的，每一次都有不同，另外一个视频是在原生输入法下测试的，没有什么误差

USB扫码器 在使用 GooglePinYin 输入法 打印数据 时会出现 少字符多换行字符等,
是因为输入法键盘符号、数字差异问题。

a.如果demo中用的 建议 自定义拦截键盘事件 不弹出输入法键盘
b.可以更新固件 这边找到合适的输入法了 要更新固件请提出需求

一.ScanKeyManager的拦截键盘事件并将它转化成需要的数据的管理类

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package com.gatsby.barcodescanner;   import android.view.KeyEvent;   public class ScanKeyManager {       private StringBuilder mResult;     public OnScanValueListener mListener;     private boolean mCaps;       public interface OnScanValueListener {         void onScanValue(String value);     }       public ScanKeyManager(OnScanValueListener listener) {         this.mListener = listener;         this.mResult = new StringBuilder();     }       /**      * 扫码设备事件解析      */     public void analysisKeyEvent(KeyEvent event) {         int keyCode = event.getKeyCode();         checkLetterStatus(event);         if (event.getAction() == KeyEvent.ACTION_DOWN) {             char aChar = getInputCode(mCaps, event.getKeyCode());             if (aChar != 0) {                 mResult.append(aChar);             }             if (keyCode == KeyEvent.KEYCODE_ENTER) {                 if (mListener != null) {                     mListener.onScanValue(mResult.toString());                 }                 mResult.delete(0, mResult.length());             }         }     }       /**      * 判断大小写      */     private void checkLetterStatus(KeyEvent event) {         int keyCode = event.getKeyCode();         if (keyCode == KeyEvent.KEYCODE_SHIFT_RIGHT || keyCode == KeyEvent.KEYCODE_SHIFT_LEFT) {             mCaps = event.getAction() == KeyEvent.ACTION_DOWN;         }     }       /**      * 将keyCode转为char      *      * @param caps    是不是大写      * @param keyCode 按键      * @return 按键对应的char      */     private char getInputCode(boolean caps, int keyCode) {         if (keyCode >= KeyEvent.KEYCODE_A && keyCode <= KeyEvent.KEYCODE_Z) {             return (char) ((caps ? 'A' : 'a') + keyCode - KeyEvent.KEYCODE_A);         } else {             return keyValue(caps, keyCode);         }     }       /**      * 按键对应的char表      */     private char keyValue(boolean caps, int keyCode) {         switch (keyCode) {             case KeyEvent.KEYCODE_0:                 return caps ? ')' : '0';             case KeyEvent.KEYCODE_1:                 return caps ? '!' : '1';             case KeyEvent.KEYCODE_2:                 return caps ? '@' : '2';             case KeyEvent.KEYCODE_3:                 return caps ? '#' : '3';             case KeyEvent.KEYCODE_4:                 return caps ? '$' : '4';             case KeyEvent.KEYCODE_5:                 return caps ? '%' : '5';             case KeyEvent.KEYCODE_6:                 return caps ? '^' : '6';             case KeyEvent.KEYCODE_7:                 return caps ? '&' : '7';             case KeyEvent.KEYCODE_8:                 return caps ? '*' : '8';             case KeyEvent.KEYCODE_9:                 return caps ? '(' : '9';             case KeyEvent.KEYCODE_NUMPAD_SUBTRACT:                 return '-';             case KeyEvent.KEYCODE_MINUS:                 return '_';             case KeyEvent.KEYCODE_EQUALS:                 return '=';             case KeyEvent.KEYCODE_NUMPAD_ADD:                 return '+';             case KeyEvent.KEYCODE_GRAVE:                 return caps ? '~' : '`';             case KeyEvent.KEYCODE_BACKSLASH:                 return caps ? '|' : '\\';             case KeyEvent.KEYCODE_LEFT_BRACKET:                 return caps ? '{' : '[';             case KeyEvent.KEYCODE_RIGHT_BRACKET:                 return caps ? '}' : ']';             case KeyEvent.KEYCODE_SEMICOLON:                 return caps ? ':' : ';';             case KeyEvent.KEYCODE_APOSTROPHE:                 return caps ? '"' : '\'';             case KeyEvent.KEYCODE_COMMA:                 return caps ? '<' : ',';             case KeyEvent.KEYCODE_PERIOD:                 return caps ? '>' : '.';             case KeyEvent.KEYCODE_SLASH:                 return caps ? '?' : '/';             default:                 return 0;         }     } }

 二.在activity中使用

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package com.gatsby.barcodescanner;   import android.os.Bundle; import android.util.Log; import android.view.KeyEvent;   import androidx.appcompat.app.AppCompatActivity;   public class MainActivity extends AppCompatActivity {       private ScanKeyManager scanKeyManager;       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);           //拦截扫码器回调,获取扫码内容         scanKeyManager = new ScanKeyManager(new ScanKeyManager.OnScanValueListener() {             @Override             public void onScanValue(String value) {                 Log.d("gatsby", "ScanValue->"+value);             }         });     }       /*监听键盘事件,除了返回事件都将它拦截,使用我们自定义的拦截器处理该事件*/     @Override     public boolean dispatchKeyEvent(KeyEvent event) {         if (event.getKeyCode() != KeyEvent.KEYCODE_BACK) {             scanKeyManager.analysisKeyEvent(event);             return true;         }         return super.dispatchKeyEvent(event);     }     }