Blackberry BarcodeScanner - barcodeDecode switch to MainScreen - blackberry

Question

Can somebody tell me how to close the Screen (which opened by the BarcodeScanner) and show the mainscreen again after the barcodeDecoded method was invoked?
I can't get it right. I tried a lot, one of them was this:
public void barcodeDecoded(String rawText) {
final String result = rawText;
try
{
final UiApplication ui = UiApplication.getUiApplication();
final MainScreen current = (MainScreen) ui.getActiveScreen();
System.out.println("Current: " + current.toString());
if (UiApplication.isEventDispatchThread()) {
getText(result);
ui.popScreen(current);
System.out.println("Close Window by active screen");
ui.pushScreen(_frm);
System.out.println("Push screen frmMain");
}else{
ui.invokeLater(new Runnable() {
public void run() {
getText(result); <-- Abstract method to use within the main app.
ui.popScreen(current);
ui.pushScreen(_frm);
}
});
}
}catch(Exception err){
System.out.println(err.getMessage());
}
}
the abstract method when i start the Scanner
private MenuItem mnuCamera = new MenuItem("Scan", 1, 1){
public void run(){
frmMain f = (frmMain)getScreen();
_decode = new BarcodeDecoderClass(f) {
public void getText(String tekst) {
setScannedText(tekst);
}
};
_decode.Start();
}
};

Answer 1

Ok, for the people who are stuck with the same problem. I found it out. Below you find the complete code:
The BarcodeScanner class:
public abstract class BarcodeDecoderClass implements BarcodeDecoderListener {
private Hashtable _hints;
private Vector _formats;
private BarcodeScanner _scanner;
private BarcodeDecoder _decoder;
private Field _viewFinder;
private MainScreen _screen;
public abstract void getText(String tekst, Screen screen);
public BarcodeDecoderClass(){
_hints = new Hashtable();
_formats = new Vector();
_formats.addElement(BarcodeFormat.QR_CODE);
_hints.put(DecodeHintType.POSSIBLE_FORMATS, _formats);
_decoder = new BarcodeDecoder(_hints);
try
{
_scanner = new BarcodeScanner(_decoder, this);
_scanner.getVideoControl().setDisplayFullScreen(true);
_viewFinder = _scanner.getViewfinder();
}catch(Exception err){
System.out.println(err.getMessage());
}
}
public void Start(){
try
{
_screen = new MainScreen();
_screen.add(_viewFinder);
UiApplication.getUiApplication().pushScreen(_screen);
_scanner.startScan();
}catch(Exception err){
System.out.println(err.getMessage());
}
}
public synchronized void Close(){
if(_scanner.isScanning()){
try{
_scanner.stopScan();
}catch(Exception err){
Dialog.alert(err.getMessage());
}
}
_scanner.getVideoControl().setVisible(false);
_scanner.getPlayer().close();
}
public void barcodeDecoded(String rawText) {
try
{
getText(rawText, _screen);
}catch(Exception err){
System.out.println(err.getMessage());
}
}
}
The MainScreen from which I start the BarcodeScanner (i just copied the method)
private MenuItem mnuCamera = new MenuItem("Scan", 1, 1){
public void run(){
final Screen f = getScreen();
_decode = new BarcodeDecoderClass() {
public void getText(String tekst, final Screen _screen) {
setScannedText(tekst);
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
_decode.Close();
_screen.close();
}
});
}
};
_decode.Start();
}
};

Answer 2

May be help full this code.
import java.util.Hashtable;
import java.util.Vector;
import net.rim.device.api.barcodelib.BarcodeDecoder;
import net.rim.device.api.barcodelib.BarcodeDecoderListener;
import net.rim.device.api.barcodelib.BarcodeScanner;
import net.rim.device.api.system.KeyListener;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.FieldChangeListener;
import net.rim.device.api.ui.Keypad;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.ButtonField;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.container.FullScreen;
import net.rim.device.api.ui.container.MainScreen;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.DecodeHintType;
public class BarcodeScanSample extends MainScreen{
private FullScreen _barcodeScreen;
private BarcodeScanner _scanner;
private LabelField lblBarcodeText;
private ButtonField btnScan;
public BarcodeScanSample(String barcodeText){
lblBarcodeText = new LabelField(barcodeText);
add(lblBarcodeText);
btnScan = new ButtonField("Scan");
btnScan.setChangeListener(new FieldChangeListener() {
public void fieldChanged(Field field, int context) {
scanBarcode();
}
});
add(btnScan);
}
private void scanBarcode() {
// If we haven't scanned before, we will set up our barcode scanner
if (_barcodeScreen == null) {
// First we create a hashtable to hold all of the hints that we can
// give the API about how we want to scan a barcode to improve speed
// and accuracy.
Hashtable hints = new Hashtable();
// The first thing going in is a list of formats. We could look for
// more than one at a time, but it's much slower. and set Barcode Format.
Vector formats = new Vector();
formats.addElement(BarcodeFormat.QR_CODE);
formats.addElement(BarcodeFormat.CODE_128);
formats.addElement(BarcodeFormat.CODE_39);
formats.addElement(BarcodeFormat.DATAMATRIX);
formats.addElement(BarcodeFormat.EAN_13);
formats.addElement(BarcodeFormat.EAN_8);
formats.addElement(BarcodeFormat.ITF);
formats.addElement(BarcodeFormat.PDF417);
formats.addElement(BarcodeFormat.UPC_A);
formats.addElement(BarcodeFormat.UPC_E);
hints.put(DecodeHintType.POSSIBLE_FORMATS, formats);
// We will also use the "TRY_HARDER" flag to make sure we get an
// accurate scan
hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
// We create a new decoder using those hints
BarcodeDecoder decoder = new BarcodeDecoder(hints);
// Finally we can create the actual scanner with a decoder and a
// listener that will handle the data stored in the barcode. We put
// that in our view screen to handle the display.
try {
_scanner = new BarcodeScanner(decoder, new MyBarcodeDecoderListener());
_barcodeScreen = new MyBarcodeScannerViewScreen(_scanner);
} catch (Exception e) {
System.out.println("Could not initialize barcode scanner: " + e);
return;
}
}
// If we get here, all the barcode scanning infrastructure should be set
// up, so all we have to do is start the scan and display the viewfinder
try {
_scanner.startScan();
UiApplication.getUiApplication().pushScreen(_barcodeScreen);
} catch (Exception e) {
System.out.println("Could not start scan: " + e);
}
}
/***
* MyBarcodeScannerViewScreen
* <p>
* This view screen is simply an extension of MainScreen that will hold our
* scanner's viewfinder, and handle cleanly stopping the scan if the user
* decides they want to abort via the back button.
*
* #author PBernhardt
*
*/
private class MyBarcodeScannerViewScreen extends MainScreen {
public MyBarcodeScannerViewScreen(BarcodeScanner scanner) {
super();
try {
// Get the viewfinder and add it to the screen
_scanner.getVideoControl().setDisplayFullScreen(true);
Field viewFinder = _scanner.getViewfinder();
this.add(viewFinder);
// Create and add our key listener to the screen
this.addKeyListener(new MyKeyListener());
} catch (Exception e) {
System.out.println("Error creating view screen: " + e);
}
}
/***
* MyKeyListener
* <p>
* This KeyListener will stop the current scan cleanly when the back
* button is pressed, and then pop the viewfinder off the stack.
*
* #author PBernhardt
*
*/
private class MyKeyListener implements KeyListener {
public boolean keyDown(int keycode, int time) {
// First convert the keycode into an actual key event, taking
// modifiers into account
int key = Keypad.key(keycode);
// From there we can compare against the escape key constant. If
// we get it, we stop the scan and pop this screen off the stack
if (key == Keypad.KEY_ESCAPE) {
try {
_scanner.stopScan();
} catch (Exception e) {
System.out.println("Error stopping scan: " + e);
}
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
UiApplication.getUiApplication().popScreen(_barcodeScreen);
}
});
return true;
}
// Otherwise, we'll return false so as not to consume the
// keyDown event
return false;
}
// We will only act on the keyDown event
public boolean keyChar(char key, int status, int time) {
return false;
}
public boolean keyRepeat(int keycode, int time) {
return false;
}
public boolean keyStatus(int keycode, int time) {
return false;
}
public boolean keyUp(int keycode, int time) {
return false;
}
}
}
/***
* MyBarcodeDecoderListener
* <p>
* This BarcodeDecoverListener implementation tries to open any data encoded
* in a barcode in the browser.
*
* #author PBernhardt
*
**/
private class MyBarcodeDecoderListener implements BarcodeDecoderListener {
public void barcodeDecoded(final String rawText) {
// First pop the viewfinder screen off of the stack so we can see
// the main app
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
UiApplication.getUiApplication().popScreen(_barcodeScreen);
}
});
_barcodeScreen.invalidate();
//Display this barcode on LabelField on BarcodeScanSample MainScreen we can also set whatever field here.
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
UiApplication.getUiApplication().popScreen();
UiApplication.getUiApplication().pushScreen(new BarcodeScanSample(rawText));
_barcodeScreen.close();
_barcodeScreen=null;
}
});
}
}
}