Question

Using java in android studio, I need help in making a barcode scanner
thanks for the help

Answer 1

Step 1 – Create New Android Project with Application name “Barcode Reader” and Minimum SDK, API9: Android 2.3 (Gingerbread).
Step 2 – Complete the code in activity_main.xml file:
Create a button for pressing to scan.

<Button android:id="@+id/scan_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:text="@string/scan" />

Add two Text Views to display the scanned information.

<TextView
    android:id="@+id/scan_format"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textIsSelectable="true"
    android:layout_centerHorizontal="true"
    android:layout_below="@id/scan_button" />
<TextView
    android:id="@+id/scan_content"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textIsSelectable="true"
    android:layout_centerHorizontal="true"
    android:layout_below="@id/scan_format" />

Step 3 – Add the button text “Scan” to strings.xml file

<string name="scan">Scan</string>

Step 4 – Create New Package with name
“com.google.zxing.integration.android”.
Step 5 – Create New Java Class with name “IntentIntegrator“.
Step 6 – Create New Java Class with name “IntentResult“

Step 7 – Complete the code in MainActivity.java

package com.example.toyo.barcodereader;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import com.google.zxing.integration.android.IntentIntegrator;

/*Download ZXing-2.2 https://code.google.com/p/zxing/downloads/list */

import com.google.zxing.integration.android.IntentResult;
/*Encapsulates the result of a barcode scan invoked through IntentIntegrator.*/
import android.content.Intent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements OnClickListener {
    private Button scanBtn;
    private TextView formatTxt, contentTxt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        scanBtn = (Button)findViewById(R.id.scan_button);
        formatTxt = (TextView)findViewById(R.id.scan_format);
        contentTxt = (TextView)findViewById(R.id.scan_content);

        scanBtn.setOnClickListener(this);
    }

    public void onClick(View v){
        if(v.getId()==R.id.scan_button){
            IntentIntegrator scanIntegrator = new IntentIntegrator(this);
            scanIntegrator.initiateScan();
        }
    }

    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
        if (scanningResult != null) {
            String scanContent = scanningResult.getContents();
            String scanFormat = scanningResult.getFormatName();
            formatTxt.setText("FORMAT: " + scanFormat);
            contentTxt.setText("CONTENT: " + scanContent);
        }
        else{
            Toast toast = Toast.makeText(getApplicationContext(),
                    "No scan data received!", Toast.LENGTH_SHORT);
            toast.show();
        }
    }
}

Step 8 – Complete the code in IntentIntegrator.java

package com.google.zxing.integration.android;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.ActivityNotFoundException;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;

public class IntentIntegrator {

    public static final int REQUEST_CODE = 0x0000c0de; // Only use bottom 16 bits
    private static final String TAG = IntentIntegrator.class.getSimpleName();

    public static final String DEFAULT_TITLE = "Install Barcode Scanner?";
    public static final String DEFAULT_MESSAGE =
            "This application requires Barcode Scanner. Would you like to install it?";
    public static final String DEFAULT_YES = "Yes";
    public static final String DEFAULT_NO = "No";

    private static final String BS_PACKAGE = "com.google.zxing.client.android";
    private static final String BSPLUS_PACKAGE = "com.srowen.bs.android";

    // supported barcode formats
    public static final Collection<String> PRODUCT_CODE_TYPES = list("UPC_A", "UPC_E", "EAN_8", "EAN_13", "RSS_14");
    public static final Collection<String> ONE_D_CODE_TYPES =
            list("UPC_A", "UPC_E", "EAN_8", "EAN_13", "CODE_39", "CODE_93", "CODE_128",
                    "ITF", "RSS_14", "RSS_EXPANDED");
    public static final Collection<String> QR_CODE_TYPES = Collections.singleton("QR_CODE");
    public static final Collection<String> DATA_MATRIX_TYPES = Collections.singleton("DATA_MATRIX");

    public static final Collection<String> ALL_CODE_TYPES = null;

    public static final List<String> TARGET_BARCODE_SCANNER_ONLY = Collections.singletonList(BS_PACKAGE);
    public static final List<String> TARGET_ALL_KNOWN = list(
            BS_PACKAGE, // Barcode Scanner
            BSPLUS_PACKAGE, // Barcode Scanner+
            BSPLUS_PACKAGE + ".simple" // Barcode Scanner+ Simple
            // What else supports this intent?
    );

    private final Activity activity;
    private String title;
    private String message;
    private String buttonYes;
    private String buttonNo;
    private List<String> targetApplications;
    private final Map<String,Object> moreExtras;

    public IntentIntegrator(Activity activity) {
        this.activity = activity;
        title = DEFAULT_TITLE;
        message = DEFAULT_MESSAGE;
        buttonYes = DEFAULT_YES;
        buttonNo = DEFAULT_NO;
        targetApplications = TARGET_ALL_KNOWN;
        moreExtras = new HashMap<String,Object>(3);
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public void setTitleByID(int titleID) {
        title = activity.getString(titleID);
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public void setMessageByID(int messageID) {
        message = activity.getString(messageID);
    }

    public String getButtonYes() {
        return buttonYes;
    }

    public void setButtonYes(String buttonYes) {
        this.buttonYes = buttonYes;
    }

    public void setButtonYesByID(int buttonYesID) {
        buttonYes = activity.getString(buttonYesID);
    }

    public String getButtonNo() {
        return buttonNo;
    }

    public void setButtonNo(String buttonNo) {
        this.buttonNo = buttonNo;
    }

    public void setButtonNoByID(int buttonNoID) {
        buttonNo = activity.getString(buttonNoID);
    }

    public Collection<String> getTargetApplications() {
        return targetApplications;
    }

    public final void setTargetApplications(List<String> targetApplications) {
        if (targetApplications.isEmpty()) {
            throw new IllegalArgumentException("No target applications");
        }
        this.targetApplications = targetApplications;
    }

    public void setSingleTargetApplication(String targetApplication) {
        this.targetApplications = Collections.singletonList(targetApplication);
    }

    public Map<String,?> getMoreExtras() {
        return moreExtras;
    }

    public final void addExtra(String key, Object value) {
        moreExtras.put(key, value);
    }


    public final AlertDialog initiateScan() {
        return initiateScan(ALL_CODE_TYPES);
    }

    public final AlertDialog initiateScan(Collection<String> desiredBarcodeFormats) {
        Intent intentScan = new Intent(BS_PACKAGE + ".SCAN");
        intentScan.addCategory(Intent.CATEGORY_DEFAULT);

        // check which types of codes to scan for
        if (desiredBarcodeFormats != null) {
            // set the desired barcode types
            StringBuilder joinedByComma = new StringBuilder();
            for (String format : desiredBarcodeFormats) {
                if (joinedByComma.length() > 0) {
                    joinedByComma.append(',');
                }
                joinedByComma.append(format);
            }
            intentScan.putExtra("SCAN_FORMATS", joinedByComma.toString());
        }


        String targetAppPackage = findTargetAppPackage(intentScan);
        if (targetAppPackage == null) {
            return showDownloadDialog();
        }
        intentScan.setPackage(targetAppPackage);
        intentScan.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        intentScan.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
        attachMoreExtras(intentScan);
        startActivityForResult(intentScan, REQUEST_CODE);
        return null;
    }


    protected void startActivityForResult(Intent intent, int code) {
        activity.startActivityForResult(intent, code);
    }

    private String findTargetAppPackage(Intent intent) {
        PackageManager pm = activity.getPackageManager();
        List<ResolveInfo> availableApps = pm.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
        if (availableApps != null) {
            for (ResolveInfo availableApp : availableApps) {
                String packageName = availableApp.activityInfo.packageName;
                if (targetApplications.contains(packageName)) {
                    return packageName;
                }
            }
        }
        return null;
    }

    private AlertDialog showDownloadDialog() {
        AlertDialog.Builder downloadDialog = new AlertDialog.Builder(activity);
        downloadDialog.setTitle(title);
        downloadDialog.setMessage(message);
        downloadDialog.setPositiveButton(buttonYes, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                String packageName = targetApplications.get(0);
                Uri uri = Uri.parse("market://details?id=" + packageName);
                Intent intent = new Intent(Intent.ACTION_VIEW, uri);
                try {
                    activity.startActivity(intent);
                } catch (ActivityNotFoundException anfe) {
                    // Hmm, market is not installed
                    Log.w(TAG, "Google Play is not installed; cannot install " + packageName);
                }
            }
        });
        downloadDialog.setNegativeButton(buttonNo, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {}
        });
        return downloadDialog.show();
    }

    public static IntentResult parseActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == REQUEST_CODE) {
            if (resultCode == Activity.RESULT_OK) {
                String contents = intent.getStringExtra("SCAN_RESULT");
                String formatName = intent.getStringExtra("SCAN_RESULT_FORMAT");
                byte[] rawBytes = intent.getByteArrayExtra("SCAN_RESULT_BYTES");
                int intentOrientation = intent.getIntExtra("SCAN_RESULT_ORIENTATION", Integer.MIN_VALUE);
                Integer orientation = intentOrientation == Integer.MIN_VALUE ? null : intentOrientation;
                String errorCorrectionLevel = intent.getStringExtra("SCAN_RESULT_ERROR_CORRECTION_LEVEL");
                return new IntentResult(contents,
                        formatName,
                        rawBytes,
                        orientation,
                        errorCorrectionLevel);
            }
            return new IntentResult();
        }
        return null;
    }

    public final AlertDialog shareText(CharSequence text, CharSequence type) {
        Intent intent = new Intent();
        intent.addCategory(Intent.CATEGORY_DEFAULT);
        intent.setAction(BS_PACKAGE + ".ENCODE");
        intent.putExtra("ENCODE_TYPE", type);
        intent.putExtra("ENCODE_DATA", text);
        String targetAppPackage = findTargetAppPackage(intent);
        if (targetAppPackage == null) {
            return showDownloadDialog();
        }
        intent.setPackage(targetAppPackage);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
        attachMoreExtras(intent);
        activity.startActivity(intent);
        return null;
    }

    private static List<String> list(String... values) {
        return Collections.unmodifiableList(Arrays.asList(values));
    }

    private void attachMoreExtras(Intent intent) {
        for (Map.Entry<String,Object> entry : moreExtras.entrySet()) {
            String key = entry.getKey();
            Object value = entry.getValue();
            // Kind of hacky
            if (value instanceof Integer) {
                intent.putExtra(key, (Integer) value);
            } else if (value instanceof Long) {
                intent.putExtra(key, (Long) value);
            } else if (value instanceof Boolean) {
                intent.putExtra(key, (Boolean) value);
            } else if (value instanceof Double) {
                intent.putExtra(key, (Double) value);
            } else if (value instanceof Float) {
                intent.putExtra(key, (Float) value);
            } else if (value instanceof Bundle) {
                intent.putExtra(key, (Bundle) value);
            } else {
                intent.putExtra(key, value.toString());
            }
        }
    }
}

Step 9 – Complete the code in IntentResult.java

package com.google.zxing.integration.android;


public final class IntentResult {

    private final String contents;
    private final String formatName;
    private final byte[] rawBytes;
    private final Integer orientation;
    private final String errorCorrectionLevel;

    IntentResult() {
        this(null, null, null, null, null);
    }

    IntentResult(String contents,
                 String formatName,
                 byte[] rawBytes,
                 Integer orientation,
                 String errorCorrectionLevel) {
        this.contents = contents;
        this.formatName = formatName;
        this.rawBytes = rawBytes;
        this.orientation = orientation;
        this.errorCorrectionLevel = errorCorrectionLevel;
    }


    public String getContents() {
        return contents;
    }


    public String getFormatName() {
        return formatName;
    }


    public byte[] getRawBytes() {
        return rawBytes;
    }


    public Integer getOrientation() {
        return orientation;
    }


    public String getErrorCorrectionLevel() {
        return errorCorrectionLevel;
    }

    @Override
    public String toString() {
        StringBuilder dialogText = new StringBuilder(100);
        dialogText.append("Format: ").append(formatName).append('\n');
        dialogText.append("Contents: ").append(contents).append('\n');
        int rawBytesLength = rawBytes == null ? 0 : rawBytes.length;
        dialogText.append("Raw bytes: (").append(rawBytesLength).append(" bytes)\n");
        dialogText.append("Orientation: ").append(orientation).append('\n');
        dialogText.append("EC level: ").append(errorCorrectionLevel).append('\n');
        return dialogText.toString();
    }

}

Step 10 – Export app from Android Studio.
Run the exported app on a device instead of an emulator and can scan any barcode.