Zxing應用程序和SQLite數據庫

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我按照在線教程，創建了一個使用ZXing庫掃描條形碼和QR碼的應用程序，並將所有信息存儲在數據庫中。我跟着一步一步做的事，但在我的代碼.The數據不能在數據庫存儲，並保持部隊密切Zxing應用程序和SQLite數據庫

Calledspot_pay.java

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; 
    } 



}

ProductDatabase.java

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; 
    } 
}

AddProduct.java

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() > 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(); 
    } 
}

有人有什麼錯誤？

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

來源

2012-10-17 fewer

您的ONE_HUNDRED變量爲空。

private static final BigDecimal ONE_HUNDRED = null;

你可以試試：

private static final BigDecimal ONE_HUNDRED = new BigDecimal(100);

來源

2012-10-17 10:35:47

我無法理解你的短信.. –

什麼需要改變？是否意味着ONE_HUNDRED變量不能爲空？ – fewer

真的很抱歉再次問同樣的問題，因爲我無法理解你的評論。您是否在問如何將值分配給ONE_HUNDRED變量或需要將哪個值分配給該變量？ –

Zxing應用程序和SQLite數據庫

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