BarcodeManager null reference

  • TC55CH
    • 01.08.01G_3G build
    • Non GSM
    • Enterprise manager installed
    • 4.0 EMDK installed
  • Android Studio 1.5.1


Trying to establish a simple project that performs basic scanning using platform 23 as in Pietro's example

Adjusted the gradle file as the example indicates.  Compiles and transfers to handheld however the BarcodeManager is not instantiated for some reason.  Maybe you can see the error.


Null reference here in initializeScanner method which is called during onOpened


barcodeManager = (BarcodeManager) emdkManager.getInstance(FEATURE_TYPE.BARCODE);


There is an object reference to emdkManager.  Created a "libs' folder and copied the v16 of com.symbol.emdk.jar into it.

gradle file:

 apply plugin: ''   android {     compileSdkVersion 'Google Inc.:Google APIs:23'     buildToolsVersion "23.0.2"       defaultConfig {         applicationId "com.goroute.barcodescanning"         minSdkVersion 16         targetSdkVersion 23         versionCode 1         versionName "1.0"     }     buildTypes {         release {             minifyEnabled false             proguardFiles getDefaultProguardFile('proguard-android.txt'), ''         }     } }   dependencies {     compile fileTree(dir: 'libs', include: ['*.jar'], exclude: ['com.symbol.emdk.jar'] )     testCompile 'junit:junit:4.12'     compile ''     compile ''     provided fileTree(dir: 'libs', include: ['com.symbol.emdk.jar']) }       



Main code.  Null reference occurrs after onOpened calls initializeScanner. 

Any suggestions appreciated.  Project is attached.




package com.example.barcodescanning;   import android.os.AsyncTask; import android.os.Bundle; import; import; import; import; import android.view.View; import android.view.Menu; import android.view.MenuItem; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast;   import com.symbol.emdk.EMDKManager; import com.symbol.emdk.EMDKManager.EMDKListener; import com.symbol.emdk.EMDKResults; import com.symbol.emdk.barcode.BarcodeManager; import com.symbol.emdk.barcode.ScanDataCollection; import com.symbol.emdk.barcode.Scanner; import com.symbol.emdk.barcode.Scanner.DataListener; import com.symbol.emdk.barcode.Scanner.StatusListener; import com.symbol.emdk.barcode.ScannerException; import com.symbol.emdk.barcode.StatusData; import com.symbol.emdk.barcode.ScannerResults; import com.symbol.emdk.barcode.ScanDataCollection.ScanData; import com.symbol.emdk.barcode.ScanDataCollection.LabelType; import com.symbol.emdk.barcode.StatusData.ScannerStates; import com.symbol.emdk.EMDKManager.FEATURE_TYPE;   import java.util.ArrayList;   public class MainActivity extends AppCompatActivity implements EMDKListener, StatusListener, DataListener {   // Declare a variable to store EMDKManager object   private EMDKManager emdkManager = null;     // Declare a variable to store Barcode Manager object     private BarcodeManager barcodeManager = null;     // Declare a variable to hold scanner device to scan     private Scanner scanner = null;     // Text view to display status of EMDK and Barcode Scanning Operations     private TextView statusTextView = null;     // Edit Text that is used to display scanned barcode data     private EditText dataView = null;     boolean isScanning = false;       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         Toolbar toolbar = (Toolbar) findViewById(;         setSupportActionBar(toolbar);           // Reference to UI elements         statusTextView = (TextView) findViewById(;         dataView = (EditText) findViewById(;       // The EMDKManager object will be created and returned in the callback.         EMDKResults results = EMDKManager.getEMDKManager(                 getApplicationContext(), this);         // Check the return status of getEMDKManager and update the status Text         // View accordingly         if (results.statusCode != EMDKResults.STATUS_CODE.SUCCESS) {             statusTextView.setText("EMDKManager Request Failed");         }           FloatingActionButton fab = (FloatingActionButton) findViewById(;         fab.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)                         .setAction("Action", null).show();             }         });     }       // Method to initialize and enable Scanner and its listeners     private void initializeScanner() throws ScannerException {         if (scanner == null) {             // Get the Barcode Manager object             barcodeManager = (BarcodeManager) emdkManager.getInstance(FEATURE_TYPE.BARCODE);             // Get default scanner defined on the device             scanner = barcodeManager.getDevice(BarcodeManager.DeviceIdentifier.INTERNAL_LASER1);             // Add data and status listeners             scanner.addDataListener(this);             scanner.addStatusListener(this);             // Hard trigger. When this mode is set, the user has to manually             // press the trigger on the device after issuing the read call.             scanner.triggerType = Scanner.TriggerType.HARD;             // Enable the scanner             scanner.enable();             // Starts an asynchronous Scan. The method will not turn ON the             // scanner. It will, however, put the scanner in a state in which             // the scanner can be turned ON either by pressing a hardware             // trigger or can be turned ON automatically.   ;         }     }     @Override     public boolean onCreateOptionsMenu(Menu menu) {          // Inflate the menu; this adds items to the action bar if it is present.           getMenuInflater().inflate(, menu);         return true;     }       @Override     public boolean onOptionsItemSelected(MenuItem item) {         // Handle action bar item clicks here. The action bar will         // automatically handle clicks on the Home/Up button, so long         // as you specify a parent activity in AndroidManifest.xml.         int id = item.getItemId();           //noinspection SimplifiableIfStatement         if (id == {             return true;         }           return super.onOptionsItemSelected(item);     }       @Override     public void onData(ScanDataCollection scanDataCollection) {       }       @Override     protected void onDestroy() {         super.onDestroy();         if (emdkManager != null) {             // Clean up the objects created by EMDK manager             emdkManager.release();             emdkManager = null;         }     }         @Override     protected void onStop() {         super.onStop();         try {             if (scanner != null) {                 // releases the scanner hardware resources for other application                 // to use. You must call this as soon as you're done with the                 // scanning.                 scanner.disable();                 scanner = null;             }         } catch (ScannerException e) {             e.printStackTrace();         }     }       @Override     public void onOpened(EMDKManager emdkManager) {         this.emdkManager = emdkManager;           try {             // Call this method to enable Scanner and its listeners             initializeScanner();         } catch (ScannerException e) {             e.printStackTrace();         }           // Toast to indicate that the user can now start scanning         Toast.makeText(MainActivity.this,                 "Press Hard Scan Button to start scanning...",                 Toast.LENGTH_SHORT).show();     }       @Override     public void onClosed() {         // The EMDK closed abruptly. // Clean up the objects created by EMDK         // manager         if (this.emdkManager != null) {             this.emdkManager.release();             this.emdkManager = null;         }     }       @Override     public void onStatus(StatusData statusData) {         // process the scan status event on the background thread using         // AsyncTask and update the UI thread with current scanner state         new AsyncStatusUpdate().execute(statusData);     }       // Update the scan data on UI     int dataLength = 0;       // AsyncTask that configures the scanned data on background     // thread and updated the result on UI thread with scanned data and type of     // label     private class AsyncDataUpdate extends             AsyncTask<ScanDataCollection, Void, String> {           @Override         protected String doInBackground(ScanDataCollection... params) {               // Status string that contains both barcode data and type of barcode             //  that is being scanned                String statusStr = "";               try {                   // Starts an asynchronous Scan. The method will not turn ON the                 // scanner. It will, however, put the scanner in a state in                 // which                 // the scanner can be turned ON either by pressing a hardware                 // trigger or can be turned ON automatically.       ;                 ScanDataCollection scanDataCollection = params[0];                 // The ScanDataCollection object gives scanning result and the                 // collection of ScanData. So check the data and its status                 if (scanDataCollection != null && scanDataCollection.getResult() == ScannerResults.SUCCESS) {                       ArrayList<ScanData> scanData = scanDataCollection.getScanData();                       // Iterate through scanned data and prepare the statusStr                     for (ScanData data : scanData) {                         // Get the scanned data                         String barcodeDate = data.getData();                         // Get the type of label being scanned                         LabelType labelType = data.getLabelType();                         // Concatenate barcode data and label type                         statusStr = barcodeDate + " " + labelType;                     }                 }               } catch (ScannerException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }               // Return result to populate on UI thread             return statusStr;         }           @Override         protected void onPostExecute(String result) {             // Update the dataView EditText on UI thread with barcode data and             // its label type             if ( dataLength++ > 50) {                 // Clear the cache after 50 scans                 dataView.getText().clear();                 dataLength = 0;             }             dataView.append(result + "\n");         }     }         private class AsyncStatusUpdate extends AsyncTask<StatusData, Void, String>{           @Override         protected String doInBackground(StatusData... params) {             String statusStr = "";             // Get the current state of scanner in background             StatusData statusData = params[0];             ScannerStates state = statusData.getState();             // Different states of Scanner             switch (state) {                 // Scanner is IDLE                 case IDLE:                     statusStr = "The scanner enabled and its idle";                     break;                 // Scanner is SCANNING                 case SCANNING:                     statusStr = "Scanning..";                     break;                 // Scanner is waiting for trigger press                 case WAITING:                     statusStr = "Waiting for trigger press..";                     break;                 // Scanner is not enabled                 case DISABLED:                     statusStr = "Scanner is not enabled";                     break;                 default:                     break;             }               // Return result to populate on UI thread             return statusStr;         }           @Override         protected void onPostExecute(String s) {             super.onPostExecute(s);             statusTextView.setText(s);         }     } }                                                                                   


Message was edited by: Douglas Christensen It appears that when the EMDK 4.0 is installed on the device, DataWedge is also removed.  Is this by design?

Anonymous (not verified)
Hello Douglas,    There was

Hello Douglas,

    There was an issue with the EMDK Device runtime installer that was included with the EMDK 4.0 installer, which causes datawedge to be removed, this issue is covered in the release notes displayed after install.

To fix this issue download the EMDK OS update from here.  For your null reference error, could you provide an error log, nothing in the code is jumping out as an issue.

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Douglas Christensen
After install of fix,

After install of fix, DataWedge returned and scanner app worked.  Thanks for your help.

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