Zxing app and SQLite database
<p>i follow the tutorial online , created an app for scanning barcodes and QR code using the ZXing library, and store all the information inside the database . I follow step by step to do it ,but something in my code .The data cannot store in database , and keep force close </p>

<p>Calledspot_pay.java</p>

<pre><code>package com.example.zxing_android_products;

import java.math.BigDecimal;



import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.support.v4.app.NavUtils;

public class Calledspot_pay extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_calledspot_pay);
        Button addButton=(Button)findViewById(R.id.addMenuButton);
        addButton.setOnClickListener (new OnClickListener(){
            public void onClick (View v){
                startActivity(new Intent(Calledspot_pay .this, AddProduct.class));
            }
            });
    }  






    static final class ProductData {
        String barcode;
        String format;
        String title;
        BigDecimal price;
    }



}
</code></pre>

<p>ProductDatabase.java</p>

<pre><code>package com.example.zxing_android_products;

import java.math.BigDecimal;

import com.example.zxing_android_products.Calledspot_pay.ProductData;

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class ProductDatabase {
  private static final String PRODUCT_TABLE="products";
  private static final String DATABASE_NAME="spot_pay.db";
  private static final int DATABASE_VERSION=1;
private static final BigDecimal ONE_HUNDRED = null;

  private SQLiteDatabase db;

  private static class ProductDatabaseHelper extends SQLiteOpenHelper {

        private static final String TAG = null;

        public ProductDatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {            
               StringBuilder sql = new StringBuilder();

                sql.append("create table ").append(PRODUCT_TABLE)
                    .append("(  ")
                    .append("   _id integer primary key,")
                    .append("   barcode text,")
                    .append("   format text,")
                    .append("   title text,")
                    .append("   price currency")
                    .append(")  ");

                db.execSQL(sql.toString());    

                Log.d(TAG, PRODUCT_TABLE + "table created");       
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {            
            db.execSQL("drop table if exists " + PRODUCT_TABLE);                    
            onCreate(db);
        }

      }



  public ProductDatabase(Context context) {
        ProductDatabaseHelper helper = new ProductDatabaseHelper(context);
        db = helper.getWritableDatabase();
    }

  public boolean insert(ProductData product) {
        ContentValues vals = new ContentValues();
        vals.put("barcode", product.barcode);
        vals.put("format", product.format);
        vals.put("title", product.title);
        vals.put("price", product.price.multiply(ONE_HUNDRED).longValue());

        return db.insert(PRODUCT_TABLE, null, vals) != -1;
    }
}
</code></pre>

<p>AddProduct.java</p>

<pre><code>package com.example.zxing_android_products;

import java.math.BigDecimal;

import com.example.zxing_android_products.Calledspot_pay.ProductData;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class AddProduct extends Activity  implements OnClickListener{
    private static final int REQUEST_BARCODE=0;
    private static final ProductData mProductData=new ProductData();
    EditText mBarcodeEdit;
    EditText mFormatEdit;
    EditText mTitleEdit;
      EditText mPriceEdit;
      private Button mScanButton;
        private Button mAddButton;
    //private ProductDatabase mProductDb;
     ProductDatabase mProductDb;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_product);


        mBarcodeEdit = (EditText) findViewById(R.id.barcodeEdit);
        mFormatEdit = (EditText) findViewById(R.id.codeFormatEdit);
        mTitleEdit = (EditText) findViewById(R.id.titleEdit);
        mPriceEdit = (EditText) findViewById(R.id.priceEdit);
        mScanButton = (Button) findViewById(R.id.scanButton);
        mScanButton.setOnClickListener(this);
        mAddButton = (Button) findViewById(R.id.addButton);
        mAddButton.setOnClickListener(this);
         mProductDb = new ProductDatabase(this); // not yet shown

}
    public void onClick(View v) {
    // TODO Auto-generated method stub
           switch (v.getId()) {
            case R.id.scanButton:
                Intent intent = new Intent("com.google.zxing.client.android.SCAN");
                intent.putExtra("SCAN_MODE", "PRODUCT_MODE");
                startActivityForResult(intent, REQUEST_BARCODE);
                break;


            case R.id.addButton:
                String barcode = mBarcodeEdit.getText().toString();
                String format = mFormatEdit.getText().toString();
                String title = mTitleEdit.getText().toString();
                String price = mPriceEdit.getText().toString();

                String errors = validateFields(barcode, format, title, price);
                if (errors.length() &gt; 0) {
                    showInfoDialog(this, "Please fix errors", errors);
                } else {
                    mProductData.barcode = barcode;
                    mProductData.format = format;
                    mProductData.title = title;
                    mProductData.price = new BigDecimal(price);

              mProductDb.insert(mProductData);
                    showInfoDialog(this, "Success", "Product saved successfully");
                    resetForm();
                }
                break;
            }   
        }



    private void showInfoDialog(Context context, String title, String information) {
        new AlertDialog.Builder (context)
        .setMessage(information)
        .setTitle(title)
        .setPositiveButton("OK", new DialogInterface.OnClickListener() {


            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();

            }
        }).show();  
    }
private void resetForm() {
    // TODO Auto-generated method stub
      mBarcodeEdit.getText().clear();
      mFormatEdit.getText().clear();
      mTitleEdit.getText().clear();
      mPriceEdit.getText().clear();
}





public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (requestCode == REQUEST_BARCODE) {
        if (resultCode == RESULT_OK) {
            String barcode = intent.getStringExtra("SCAN_RESULT");
            mBarcodeEdit.setText(barcode);

            String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
            mFormatEdit.setText(format);
        } else if (resultCode == RESULT_CANCELED) {
            finish();
        }
    }
}

private static String validateFields(String barcode, String format, 
        String title, String price) {
        StringBuilder errors = new StringBuilder();

        if (barcode.matches("^\\s*$")) {
            errors.append("Barcode required\n");
        }

        if (format.matches("^\\s*$")) {
            errors.append("Format required\n");
        }

        if (title.matches("^\\s*$")) {
            errors.append("Title required\n");
        }

        if (!price.matches("^-?\\d+(.\\d+)?$")) {
            errors.append("Need numeric price\n");
        }

        return errors.toString();
    }
}
</code></pre>

<p>anybody what is the error ? </p>

<pre><code>10-17 10:21:37.746: D/AndroidRuntime(18643): Shutting down VM
10-17 10:21:37.746: W/dalvikvm(18643): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
10-17 10:21:37.746: E/AndroidRuntime(18643): Uncaught handler: thread main exiting due to uncaught exception
10-17 10:21:37.767: E/AndroidRuntime(18643): java.lang.NullPointerException
10-17 10:21:37.767: E/AndroidRuntime(18643):    at java.math.BigDecimal.multiply(BigDecimal.java:1025)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.example.zxing_android_products.ProductDatabase.insert(ProductDatabase.java:69)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.example.zxing_android_products.AddProduct.onClick(AddProduct.java:74)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.View.performClick(View.java:2364)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.View.onTouchEvent(View.java:4179)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.widget.TextView.onTouchEvent(TextView.java:6541)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.View.dispatchTouchEvent(View.java:3709)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.os.Handler.dispatchMessage(Handler.java:99)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.os.Looper.loop(Looper.java:123)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at android.app.ActivityThread.main(ActivityThread.java:4363)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at java.lang.reflect.Method.invokeNative(Native Method)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at java.lang.reflect.Method.invoke(Method.java:521)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
10-17 10:21:37.767: E/AndroidRuntime(18643):    at dalvik.system.NativeStart.main(Native Method)
10-17 10:21:37.776: I/dalvikvm(18643): threadid=7: reacting to signal 3
10-17 10:21:37.776: E/dalvikvm(18643): Unable to open stack trace file '/data/anr/traces.txt': Permission denied
10-17 10:21:39.636: I/Process(18643): Sending signal. PID: 18643 SIG: 9
</code></pre>
