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 http://pietromaggi.com/2015/11/25/building-zebras-emdk-project-using-sd….
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: 'com.android.application' 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'), 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar'], exclude: ['com.symbol.emdk.jar'] ) testCompile 'junit:junit:4.12' compile 'com.android.support:appcompat-v7:23.1.1' compile 'com.android.support:design:23.1.1' provided fileTree(dir: 'libs', include: ['com.symbol.emdk.jar']) }
Main code. Null reference occurrs after onOpened calls initializeScanner.
Any suggestions appreciated. Project is attached.
Thanks.
package com.example.barcodescanning; import android.os.AsyncTask; import android.os.Bundle; import android.support.design.widget.FloatingActionButton; import android.support.design.widget.Snackbar; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; 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(R.id.toolbar); setSupportActionBar(toolbar); // Reference to UI elements statusTextView = (TextView) findViewById(R.id.textViewStatus); dataView = (EditText) findViewById(R.id.editText1); // 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(R.id.fab); 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. scanner.read(); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_main, 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 == R.id.action_settings) { 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 { @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. scanner.read(); 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 = 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{ @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?
2 Replies
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.
After install of fix, DataWedge returned and scanner app worked. Thanks for your help.