Regarding EMDK Barcode Scanning APIs
Zebra strongly recommends the use of DataWedge for all applications that require barcode scanning. While Zebra will continue to support EMDK Barcode APIs, the efficiency and feature richness of intent-based interfaces make it a simpler alternative to app development using EMDK Barcode APIs.
DataWedge facts:
- DataWedge APIs have the same capabilities currently available in EMDK Barcode APIs.
- DataWedge intent-based APIs are easier and faster to implement than EMDK Barcode APIs.
- New features are added to DataWedge before being considered for EMDK Barcode APIs.
Learn About DataWedge
Overview
This guide walks through creation of an app using the Barcode/Scanning APIs introduced in EMDK-A 3.0 to perform additional options along with scanning operations on Zebra Android devices without using Profile Wizard. The API uses Barcode Manager, which is the primary object to access barcode scanning feature.
This tutorial focuses on scanning barcodes using the soft scan trigger implemented as a button in the app, not the hard scan trigger on the device.
Note: The Profile Wizard is not required to use the Barcode/Scanning APIs; everything is configured programmatically.
The following features are configured:
Device Types - gets the scanning devices supported by a specific Zebra device (i.e. Serial SSI Scanner, Camera Scanner etc.)
Decoder Params - used to configure various types of decoders through apps for scanning specific types of scanners (i.e. Code 11, Code 39, UPCA etc.).
Reader Params - used to configure reader-specific options of a particular scanning device. This tutorial configures Illumination Mode for the Camera Scanner.
Note: "Illumination Mode" is available only for the camera scanner device.
- Scan Params - class that provides access to scanning parameters available for all decoders.
This tutorial configures the following scanning params:
- Vibration is used to configure Vibration of the scanner device when scanning barcodes.
- Scan Tone is used to set scan tone while scanning barcodes. We can apply various media, notification or alarm tones to the device while scanning barcodes. We can also keep a silent tone by not passing any parameter to this attribute. In this tutorial, we will provide a list of Scan Tones for the user to select including silent mode where we won't pass any parameter to Scan Tone attribute.
Creating The Project
Note: Provide "AdvancedScanningTutorial" as the project name for this tutorial.
Create a new project with Android Studio, click here.
Enabling Android Permissions
Modify the Application's Manifest.xml to use the EMDK library and to set permission for the EMDK to scan the barcodes.
You must first enable permissions for 'com.symbol.emdk.permission.EMDK':
<uses-permission android:name="com.symbol.emdk.permission.EMDK" />
Then you must enable the library for EMDK:
<uses-library android:name="com.symbol.emdk" />
When done, your manifest.xml should look like:
Adding Some Code
Now we will start to add some code.
First you must add references to the libraries:
import com.symbol.emdk.EMDKManager; import com.symbol.emdk.EMDKManager.EMDKListener; import com.symbol.emdk.barcode.ScanDataCollection; import com.symbol.emdk.barcode.Scanner.DataListener; import com.symbol.emdk.barcode.Scanner.StatusListener; import com.symbol.emdk.barcode.StatusData;
Then you must extend the activity to implement EMDKListener.
After that you also need to implement
StatusListener
for notifying client applications to notify scan events. Override itsonStatus
function.Implement
DataListener
for notifying client applications when the scan data is available. Override itsonData
function.Finally, we will implement
OnCheckedChangeListener
that has an overriden methodonCheckedChanged
, which gets called whenever the user checks or unchecks any checkbox. We will be using checkboxes for various decoders that user can check or uncheck based on the requirement.public class MainActivity extends Activity implements EMDKListener, StatusListener, DataListener, OnCheckedChangeListener {
@Override public void onClosed() { // TODO Auto-generated method stub } @Override public void onOpened(EMDKManager arg0) { // TODO Auto-generated method stub } @Override public void onData(ScanDataCollection scanDataCollection) { // TODO Auto-generated method stub } @Override public void onStatus(StatusData statusData) { // TODO Auto-generated method stub } @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { // TODO Auto-generated method stub } }.. .. .. .. .. .. ...
Note: To organize imports in Android Studio, press CTRL+ALT+O or CMD+ALT+O.
We will now create some global variables to hold the instance objects of EMDKManager, BarcodeManager and Scanner. These variables would be used throughout the code.
It will have some UI elements such as Checkboxes to
We will then add some UI elements starting with a TextView to display the status of scanning operation and then EditText to populate scanned barcode data.
We will also declare a boolean variable to call setProfile() method only when required avoiding scanner exceptions while setting profile.
// 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; // Button to scan barcodes through the app using soft trigger private Button scanButton; // 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; // CheckBox to set Decoder Param Code 11; private CheckBox checkBoxCode11; // CheckBox to set Decoder Param Code 39; private CheckBox checkBoxCode39; // CheckBox to set Decoder Param Code 128; private CheckBox checkBoxCode128; // CheckBox to set Decoder Param Code UPCA; private CheckBox checkBoxCodeUPCA; // CheckBox to set Decoder Param EAN 8; private CheckBox checkBoxEAN8; // CheckBox to set Decoder Param EAN 13; private CheckBox checkBoxEAN13; // CheckBox to set Reader Param Illumination Mode; private CheckBox checkBoxIlluminationMode; // CheckBox to set Scan Param Vibration Mode (decodeHapticFeedback); private CheckBox checkBoxVibrationMode; // Drop Down for selecting scanner devices private Spinner deviceSelectionSpinner; // Drop Down for selecting the type of streaming on which the scan beep // should // be played private Spinner scanToneSpinner; // Array Adapter to hold arrays that are used in various drop downs private ArrayAdapter<String> spinnerDataAdapter; // List of supported scanner devices private List<ScannerInfo> deviceList; // Provides current scanner index in the device Selection Spinner private int scannerIndex = 0; // Boolean to avoid calling setProfile() method again in the scan tone // listener private boolean isScanToneFirstTime;
The code till here looks like:
and the remaining part looks like:
Note: Due to more variables, it has been divided into multiple screen captures.
Now, let us design the simple UI that has fields for each of the features mentioned above starting with Spinner to display list of scanner devices and scan tones at the bottom. It will then have some Checkboxes to display decoder params, reader params and scan params for scanner. We then have a Button that would be set as a soft trigger in the app to scan barcodes later in this tutorial as we are not using the hard scan trigger of the device. Finally the screen has a TextView to display the status of scanning operation and above that an EditText to populate scanned barcode data. Since the UI has lots of elements, we need to embed it in a ScrollView to view all the UI elements.
So, remove all the code, inside "res/layout/activity_main.xml" and add following XML layout code for UI.
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:paddingBottom="5dip" >
</ScrollView><RelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content" > <TextView android:id="@+id/device_Selection" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="5dip" android:text="Select Scanner Device Type:" android:textSize="16sp" android:textStyle="bold" /> <Spinner android:id="@+id/device_selection_spinner" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/device_Selection" android:layout_margin="5dip" /> <TextView android:id="@+id/decoder_selection" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/device_selection_spinner" android:layout_margin="5dip" android:text="Select Decoder Params:" android:textSize="16sp" android:textStyle="bold" /> <RelativeLayout android:id="@+id/decoder_layout" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/decoder_selection" android:layout_margin="5dip" > <CheckBox android:id="@+id/checkBoxCode39" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_margin="3dip" android:checked="true" android:text="Code 39" android:textSize="14sp" /> <CheckBox android:id="@+id/checkBoxCode128" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="3dip" android:layout_toRightOf="@+id/checkBoxCode39" android:checked="true" android:text="Code 128" android:textSize="14sp" /> <CheckBox android:id="@+id/checkBoxUPCA" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="3dip" android:layout_toRightOf="@+id/checkBoxCode128" android:checked="true" android:text="UPCA" android:textSize="14sp" /> <CheckBox android:id="@+id/checkBoxCode11" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_below="@+id/checkBoxCode39" android:layout_margin="3dip" android:checked="true" android:text="Code 11" android:textSize="14sp" /> <CheckBox android:id="@+id/checkBoxEan8" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/checkBoxCode128" android:layout_margin="3dip" android:layout_toRightOf="@+id/checkBoxCode11" android:checked="true" android:text="EAN 8" android:textSize="14sp" /> <CheckBox android:id="@+id/checkBoxEan13" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/checkBoxUPCA" android:layout_marginLeft="25dip" android:layout_marginTop="3dip" android:layout_toRightOf="@+id/checkBoxEan8" android:checked="true" android:text="EAN 13" android:textSize="14sp" /> </RelativeLayout> <TextView android:id="@+id/reader_selection" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/decoder_layout" android:layout_margin="5dip" android:text="Select Reader Params:" android:textSize="16sp" android:textStyle="bold" /> <CheckBox android:id="@+id/illumination" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_below="@+id/reader_selection" android:layout_margin="3dip" android:checked="false" android:text="Illumination Mode" android:textSize="14sp" /> <TextView android:id="@+id/scan_selection" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/illumination" android:layout_margin="5dip" android:text="Select Scan Params:" android:textSize="16sp" android:textStyle="bold" /> <RelativeLayout android:id="@+id/scan_layout" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/scan_selection" android:layout_margin="5dip" > <CheckBox android:id="@+id/vibration" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_margin="3dip" android:checked="false" android:text="Vibration" android:textSize="14sp" /> <TextView android:id="@+id/scan_tone" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/vibration" android:layout_margin="5dip" android:text="Select Scan Tone:" android:textSize="14sp" /> <Spinner android:id="@+id/scan_tone_spinner" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/scan_tone" android:layout_margin="5dip" /> </RelativeLayout> <Button android:id="@+id/btn_scan" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/scan_layout" android:layout_centerHorizontal="true" android:layout_margin="5dip" android:text="Scan" /> <EditText android:id="@+id/editText1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/btn_scan" android:layout_centerHorizontal="true" android:ems="10" android:fadeScrollbars="true" android:focusableInTouchMode="false" android:inputType="none|textMultiLine" /> <TextView android:id="@+id/textViewStatusTitle" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/editText1" android:layout_centerHorizontal="true" android:text="Status:" /> <TextView android:id="@+id/textViewStatus" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/textViewStatusTitle" android:layout_centerHorizontal="true" android:layout_marginBottom="10dip" android:text="" /> </RelativeLayout>
The code till here looks like:
In the
onCreate
method, we take reference of UI elements that are declared inres/layout/activity_main.xml
in order to use them in our Activity. We would then setOnCheckedChangeListener
for all the checkboxes followed bysetOnTouchListener
for the "Scan" button that we have declared in UI.We will also set the Spinner Adapter to hold the list of Scanner devices and Scan Tones followed by the listener calls for both spinners.
We then call getEMDKManager so that the EMDK can be initialized and checked to see if it is ready.
// Reference to UI elements statusTextView = (TextView) findViewById(R.id.textViewStatus); dataView = (EditText) findViewById(R.id.editText1); checkBoxCode11 = (CheckBox) findViewById(R.id.checkBoxCode11); checkBoxCode39 = (CheckBox) findViewById(R.id.checkBoxCode39); checkBoxCode128 = (CheckBox) findViewById(R.id.checkBoxCode128); checkBoxCodeUPCA = (CheckBox) findViewById(R.id.checkBoxUPCA); checkBoxEAN8 = (CheckBox) findViewById(R.id.checkBoxEan8); checkBoxEAN13 = (CheckBox) findViewById(R.id.checkBoxEan13); checkBoxIlluminationMode = (CheckBox) findViewById(R.id.illumination); checkBoxVibrationMode = (CheckBox) findViewById(R.id.vibration); checkBoxCode11.setOnCheckedChangeListener(this); checkBoxCode39.setOnCheckedChangeListener(this); checkBoxCode128.setOnCheckedChangeListener(this); checkBoxCodeUPCA.setOnCheckedChangeListener(this); checkBoxEAN8.setOnCheckedChangeListener(this); checkBoxEAN13.setOnCheckedChangeListener(this); checkBoxIlluminationMode.setOnCheckedChangeListener(this); checkBoxVibrationMode.setOnCheckedChangeListener(this); deviceSelectionSpinner = (Spinner) findViewById(R.id.device_selection_spinner); scanToneSpinner = (Spinner) findViewById(R.id.scan_tone_spinner); // Adapter to hold the list of scan tone options spinnerDataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, getResources() .getStringArray(R.array.scan_tone_array)); spinnerDataAdapter .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); // Set adapter to scan tone drop down scanToneSpinner.setAdapter(spinnerDataAdapter); // Add onClick listener for scan button to enable soft scan through app addScanButtonListener(); // On Item Click Listener of Scanner Devices Spinner addSpinnerScannerDevicesListener(); // On Item Click Listener of Scan Tone Spinner addSpinnerScanToneListener(); // 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"); }
So the complete
onCreate
method looks like:You will see some errors, which we need to get rid of. So first, we need to provide
scan_tone_array
to the spinner data adapter. So createarrays.xml
file underres/values
folder and write following code of array in<resources>
tag. This will remove the adapter error.<!-- Array of type of streaming on which the scan beep should be played --> <string-array name="scan_tone_array"> <item>NONE (Silent Mode)</item> <item>Adara.ogg</item> <item>Antimony.ogg</item> <item>Xenon.ogg</item> <item>Vega.ogg</item> <item>decode-short.wav</item> <item>decode.wav</item> </string-array>
So the complete
arrays.xml
code looks like:Next, We need to add listeners for
Scanner Devices
andScan Tone
spinners. The listener for scanner devices spinner will disable the scanner if there is any usingdeInitScanner
method and create new scanner instance of scanner device selected from this spinner with the help of index stored inscannerIndex
usinginitializeScanner
method. It will then callsetProfile
method which will set whatever the parameters are enabled in the User interface for various features.Note: We need to re-initialize the scanner and set the properties as we change the device type.
The listener for scan tone will simply call
setProfile
method, which will set the parameters selected by user on the User Interface.Note: For scan tone spinner listener, we don't need to re-initialize scanner as we are not changing scanner device.
// Listener for Scanner Device Spinner private void addSpinnerScannerDevicesListener() { deviceSelectionSpinner .setOnItemSelectedListener(new OnItemSelectedListener() {
} // Listener for Scan Tone Spinner private void addSpinnerScanToneListener() {@Override public void onItemSelected(AdapterView<?> parent, View arg1, int position, long arg3) { scannerIndex = position; try { deInitScanner(); initializeScanner(); setProfile(); } catch (ScannerException e) { e.printStackTrace(); } } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } });
}scanToneSpinner.setOnItemSelectedListener(new OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View arg1, int position, long arg3) { // Ignore Scan Tone spinner firing of for the first time, which // is not required if (isScanToneFirstTime) setProfile(); else isScanToneFirstTime = true; } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } });
Note: The purpose of
isScanToneFirstTime
boolean is to simply avoid callingsetProfile
again in the scan tone spinner initially, as it has already been set in the device spinner.This is how it looks like:
We will now add the
setOnTouchListener
for Scan button. The purpose behind this is to scan barcodes by callingread
method when user presses the Scan button and stop scanning by canceling any pending asynchronous read calls usingcancelRead
method when user releases the Scan button. Theread
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. This is determined by theScanner.TriggerType
. In order to scan barcodes using button through our application, we need to set the trigger type toTriggerType.SOFT_ONCE
where the scan beam will come up automatically without having to press the hard scan trigger on the device after issuing the read call.// Listener for scan button that uses soft scan to scan barcodes through app private void addScanButtonListener() { Button scanButton = (Button) findViewById(R.id.btn_scan); // On Touch listener for scan button that scans barcodes when pressed // and stops // scanning when the button is released scanButton.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { // Scan Button Press Event if (event.getAction() == MotionEvent.ACTION_DOWN) { try { // Enable Soft scan scanner.triggerType = TriggerType.SOFT_ONCE; // cancel any pending reads before reading barcodes if (scanner.isReadPending()) scanner.cancelRead(); // Puts the device in a state where it can scan barcodes scanner.read(); } catch (ScannerException e) { e.printStackTrace(); } // Scan Button Release Event } else if (event.getAction() == MotionEvent.ACTION_UP) { try { // cancel any pending reads before reading barcodes if (scanner.isReadPending()) scanner.cancelRead(); } catch (ScannerException e) { e.printStackTrace(); } } return false; } }); }
It will still show few errors as we have not specified the required methods yet. So first we will add
deInitScanner()
method that cancels any pending read operations, removes all status and data listeners, disables the existing scanner instance and sets the scanner instance toNULL
.// Disable the scanner instance private void deInitScanner() {
}if (scanner != null) { try { scanner.cancelRead(); scanner.removeDataListener(this); scanner.removeStatusListener(this); scanner.disable(); } catch (ScannerException e) { // TODO Auto-generated catch block statusTextView.setText("Status: " + e.getMessage()); } scanner = null; }
This is how
deInitScanner
method looks like:Next, we will write a method
initializeScanner
to initialize and enable the scanner and its listeners such as status, data etc. by using Barcode Manager object. Theenable
method enables the scanner hardware. This method does not make the scanner to scan or turn on the laser. Basically it will make the scanner device available for your application. If the same of scanner is enabled by other applications, this will throws ScannerExceptions. You must calldisable()
when you are done the scanning, otherwise it will remain locked and be unavailable to other applications.In case of any errors, the
statusTextView
will display a failure message to notify user.// Method to initialize and enable Scanner and its listeners private void initializeScanner() throws ScannerException {
}if (deviceList.size() != 0) { scanner = barcodeManager.getDevice(deviceList.get(scannerIndex)); } else { statusTextView .setText("Status: " + "Failed to get the specified scanner device! Please close and restart the application."); } if (scanner != null) { // Add data and status listeners scanner.addDataListener(this); scanner.addStatusListener(this); try { // Enable the scanner scanner.enable(); } catch (ScannerException e) { // TODO Auto-generated catch block statusTextView.setText("Status: " + e.getMessage()); } }
This is how
initializeScanner
method looks like:Now, we will add
setProfile
method. This method will create an instance of ScannerConfig, which will allow us to modify scanner properties (Ex. Decoder Params, Reader Params, Scan Params etc.) and set the changes back to the scanner instance. Here, we will read the checkboxes and spinner values and set them accordingly to the scanner instance through ScannerConfig.config
is name of ScannerConfig instance.Initially we will cancel any pending asynchronous read calls before applying profile and reading barcodes using
cancelRead
method on thescanner
instance.config.decoderParams
allows us to set all the decoder params such ascode11
,code39
etc.readerParams.readerSpecific.cameraSpecific.illuminationMode
enables user to set Illumination Mode, which is available only for CameraSpecific devices.config.scanParams.decodehapticfeedback
lets you set Vibration Mode of the scanning device.config.scanParams.decodeAudioFeedbackUri
will accept a URI for the Audio Tone that user needs to set while scanning a barcode.Note: An empty URI (Ex.
config.scanParams.decodeAudioFeedbackUri = "";
) indicates that there will not be any scan tone while scanning a barcode. In other words, it would be your silent mode.// Sets the user selected Barcode scanning Profile public void setProfile() { try {
}// cancel any pending asynchronous read calls before applying profile // and start reading barcodes if (scanner.isReadPending()) scanner.cancelRead(); ScannerConfig config = scanner.getConfig(); // Set code11 if (checkBoxCode11.isChecked()) { config.decoderParams.code11.enabled = true; } else { config.decoderParams.code11.enabled = false; } // Set code39 if (checkBoxCode39.isChecked()) { config.decoderParams.code39.enabled = true; } else { config.decoderParams.code39.enabled = false; } // Set code128 if (checkBoxCode128.isChecked()) { config.decoderParams.code128.enabled = true; } else { config.decoderParams.code128.enabled = false; } // set codeUPCA if (checkBoxCodeUPCA.isChecked()) { config.decoderParams.upca.enabled = true; } else { config.decoderParams.upca.enabled = false; } // set EAN8 if (checkBoxEAN8.isChecked()) { config.decoderParams.ean8.enabled = true; } else { config.decoderParams.ean8.enabled = false; } // set EAN13 if (checkBoxEAN13.isChecked()) { config.decoderParams.ean13.enabled = true; } else { config.decoderParams.ean13.enabled = false; } // set Illumination Mode, which is available only for // INTERNAL_CAMERA1 device type if (checkBoxIlluminationMode.isChecked() && deviceSelectionSpinner.getSelectedItem().toString() .contains("Camera")) { config.readerParams.readerSpecific.cameraSpecific.illuminationMode = IlluminationMode.ON; } else { config.readerParams.readerSpecific.cameraSpecific.illuminationMode = IlluminationMode.OFF; } // set Vibration Mode (decodeHapticFeedback) if (checkBoxVibrationMode.isChecked()) { config.scanParams.decodeHapticFeedback = true; } else { config.scanParams.decodeHapticFeedback = false; } // Set the Scan Tone selected from the Scan Tone Spinner config.scanParams.audioStreamType = AudioStreamType.RINGER; String scanTone = scanToneSpinner.getSelectedItem().toString(); if (scanTone.contains("NONE")) // Silent Mode (No scan tone will be played) config.scanParams.decodeAudioFeedbackUri = ""; else // Other selected scan tones from the drop-down config.scanParams.decodeAudioFeedbackUri = "system/media/audio/notifications/" + scanTone; scanner.setConfig(config); // 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(); Toast.makeText(MainActivity.this, "Changes Appplied. Press Scan Button to start scanning...", Toast.LENGTH_SHORT).show(); } catch (ScannerException e) { statusTextView.setText(e.toString()); }
The
setProfile
method looks like:Whenever the user checks or unchecks any checkbox, we update the settings to the scanner instance at runtime by calling
setProfile()
method throughonCheckedChanged
method of theOnCheckedChangeListener
that we implemented earlier. So add the method call inonCheckedChanged()
method.setProfile();
This looks like:
Now we need to use the
onOpened
method to get a reference to the EMDKManager. The EMDKListener interface will trigger this event when the EMDK is ready to be used. The EMDKListener interface must be implemented in order to get a reference to the EMDKManager APIs. This event will pass the EMDKManager instance and we assign it to the global variableemdkManager
that we created in the earlier steps. We have used that instance to get an instance of Barcode Manager to enable scanning.Once that is done, we need to get all the scanner devices that a Symbol Android device supports with the default one selected first using
enumerateScannerDevices()
that we will declare in the next step. We are not callinginitializeScanner()
andsetProfile
methods here as we have already called them in the device selection spinner listener.Note: Rename the argument of
onOpened
method fromarg0
toemdkManager
this.emdkManager = emdkManager; // Get the Barcode Manager object barcodeManager = (BarcodeManager) this.emdkManager .getInstance(FEATURE_TYPE.BARCODE); // Get the supported scanner devices enumerateScannerDevices();
Your complete
onOpened
method should now look like this:To get rid of error, we will create
enumerateScannerDevices
that will get all the scanner devices that a Symbol Android device supports with the default one selected first. It usesgetSupportedDevicesInfo
method onbarcodeManager
instance that returns a list of supported scanner devices for that particular Symbol device. We will then iterate through this list, get the friendly names of each scanner device and add them to our list with those names to show user in Device Spinner.// Go through and get the available scanner devices private void enumerateScannerDevices() {
}if (barcodeManager != null) { List<String> friendlyNameList = new ArrayList<String>(); int spinnerIndex = 0; // Set the default selection in the spinner int defaultIndex = 0; deviceList = barcodeManager.getSupportedDevicesInfo(); if (deviceList.size() != 0) { Iterator<ScannerInfo> it = deviceList.iterator(); while (it.hasNext()) { ScannerInfo scnInfo = it.next(); friendlyNameList.add(scnInfo.getFriendlyName()); if (scnInfo.isDefaultScanner()) { defaultIndex = spinnerIndex; } ++spinnerIndex; } } else { statusTextView .setText("Status: " + "Failed to get the list of supported scanner devices! Please close and restart the application."); } spinnerDataAdapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_item, friendlyNameList); spinnerDataAdapter .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); deviceSelectionSpinner.setAdapter(spinnerDataAdapter); deviceSelectionSpinner.setSelection(defaultIndex); }
Your complete
enumerateScannerDevices
method should now look like this:As mentioned earlier that whenever a barcode is scanned, its data will be received in a callback
onData
method upon data availability. So we need to get that data, process it in the format we want and populate in the EditText of UI.The received data should be processed on a background thread not to block the UI thread. Hence we will use Android's own AsyncTask to process the scanned data on background thread. So we create AsyncTask
AsyncDataUpdate
that takes ScanDataCollection, which has the scanned data. It then processes this object indoInBackground
method to filter the barcode data and label type in strings, which is then passed to the UI thread inonPostExecute
method of AsyncTask to Populate.// 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) { ScanDataCollection scanDataCollection = params[0];
} @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"); } @Override protected void onPreExecute() { } @Override protected void onProgressUpdate(Void... values) { } }// Status string that contains both barcode data and type of barcode // that is being scanned String statusStr = ""; // 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; } } // Return result to populate on UI thread return statusStr;
We call this AsyncTask in overridden
onData
method, by creating an instance ofAsyncDataUpdate
and passing thescanDataCollection
for further processing.// Use the scanned data, process it on background thread using AsyncTask // and update the UI thread with the scanned results new AsyncDataUpdate().execute(scanDataCollection);
So the
onData
method andAsyncDataUpdate
looks like:Whether we scan the barcode by pressing the hard scan key or keep it idle, it returns the status of the scanner at specific point of time in the overridden
onStatus
method of implementedStatusListener
interface. Since we are also displaying the status along with barcode data, we will make use of this method and populate the status.Just like scanned data, we are also processing the scanner status on a background thread. Hence we will create another AsyncTask named
AsyncStatusUpdate
that takes StatusData and processes it indoInBackground
method to retrieve state in string format which is populated in status Text View on UI thread inonPostExecute
method of the AsyncTask.// AsyncTask that configures the current state of scanner on background // thread and updates the result on UI thread private class AsyncStatusUpdate extends AsyncTask<StatusData, Void, String> { @Override protected String doInBackground(StatusData... params) { // Get the current state of scanner in background StatusData statusData = params[0]; String statusStr = ""; ScannerStates state = statusData.getState(); // Different states of Scanner switch (state) { // Scanner is IDLE case IDLE: statusStr = "The scanner enabled and its idle"; isScanning = false; break; // Scanner is SCANNING case SCANNING: statusStr = "Scanning.."; isScanning = true; 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 result) { // Update the status text view on UI thread with current scanner // state statusTextView.setText(result); } @Override protected void onPreExecute() { } @Override protected void onProgressUpdate(Void... values) { } }
We call this AsyncTask in overridden
onStatus
method, by creating an instance ofAsyncStatusUpdate
and passing theStatusData
for further processing.// process the scan status event on the background thread using // AsyncTask and update the UI thread with current scanner state new AsyncStatusUpdate().execute(statusData);
So the
onStatus
method andAsyncStatusUpdate
looks like:Now let's override the
onDestroy
method so we can release the EMDKManager and BarcodeManager resources:@Override protected void onDestroy() { super.onDestroy();
}if (barcodeManager != null) barcodeManager = null; if (emdkManager != null) { // Clean up the objects created by EMDK manager emdkManager.release(); emdkManager = null; }
Your
onDestroy
method should now look like this:When we are done with scanning, we must release the scanner hardware resources for other applications to use. So override
onStop
method and disable the scanner by callingdeInitScanner
method to release it.@Override protected void onStop() { // TODO Auto-generated method stub super.onStop(); deInitScanner(); }
Your
onStop
method should now look like this:Finally, Clean up the objects created by EMDK manager in
onClosed
method, if EMDK closed abruptly.// The EMDK closed abruptly. // Clean up the objects created by EMDK // manager if (this.emdkManager != null) {
}this.emdkManager.release(); this.emdkManager = null;
Your
onClosed
method should now look like this:
That's it!!! We are done with all the coding part that will let us perform some advanced barcode scanning operations on our Symbol Android device using Barcode/Scanning APIs introduced in EMDK V 3.0. Now let us run the application.
Running the Application
Connect the device to a USB port.
Run the application.
You can see a Toast, which indicates that the Scanner has been enabled and you can start scanning by pressing hard scan button of the device.
Now if you press and hold the Scan button on the UI, the status listener in the code starts working and current status of Scanner is displayed in Status TextView, which is
Scanning
. The "Scanner Device Type" Spinner shows Serial SSI Scanner as it is the default scanner for Symbol TC55 device. All the decoders are checked, which means current configuration scan supports all of these decoder types. But Scan Tone isNONE
, which means there won't be any tone/sound while scanning a barcode.The scanner status is always updated on the status text view below the Edit Text at the bottom.
Lets us change some configurations starting with the device type. We will change it to Camera Scanner.
It will display a success toast when the changes are applied each time you change any scanner configuration just for your knowledge.
Next check the Vibration checkbox and select some scan tone from the Select Scan Tone spinner.
Now once again scan a barcode and this time it will open your device's camera to scan the barcode.
This is how Barcode/Scanning APIs introduced in EMDK V 3.0 can be used to perform some of the Advanced Scanning operations using soft scan key through application on your Symbol devices without using Profile Wizard.
Important Programming Tips
The following changes in the application's
AndroidManifest.xml
are required:Note:
- Include the permission for EMDK:
<uses-permission android:name="com.symbol.emdk.permission.EMDK"/>
Note:
- Use the EMDK library:
<uses-library android:name="com.symbol.emdk"/>
Use DataWedge v1.7.12 or higher to test the
ProfileManager.processProfile()
method for DataWedge profiles.Optionally, the example below shows how to convert raw data (byte array) into hex format:
byte[] rawData = data.getRawData(); StringBuilder builder = new StringBuilder(); for(byte b : rawData) { builder.append(String.format("%02x", b)); } return builder.toString();