SQLite插入上的java空指针异常
好的,我现在正试图将数据插入到sqlite数据库中。它崩溃了,因为它说我的数据库是空的。我想我没有在我的Additem类中初始化(或者可能是另一个术语…基本上是为了识别我在另一个类中所做的事情),但不确定如何解决,以及为什么
指针
另外。阶级
public class AddItem extends Activity implements OnClickListener {
private final String TAG = "Main Activity";
View v;
SQLiteDatabase db;
DbHelper dbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_item);
Log.i(TAG, "OnCreate");
}
@Override
public void onClick(View v) {
Log.i(TAG, "Extracting Data");
DatePicker datePicker1 = (DatePicker) findViewById(R.id.datePicker1);
AutoCompleteTextView autoCompleteSubCat = (AutoCompleteTextView) findViewById(R.id.autoCompleteSubCat);
EditText editItem = (EditText) findViewById(R.id.editItem);
EditText editPrice = (EditText) findViewById(R.id.editPrice);
EditText editQuantity = (EditText) findViewById(R.id.editQuantity);
EditText editWeight = (EditText) findViewById(R.id.editWeight);
EditText editVolume = (EditText) findViewById(R.id.editVolume);
//CheckBox checkSale = (CheckBox) findViewById(R.id.checkSale);
AutoCompleteTextView autoCompleteStore = (AutoCompleteTextView) findViewById(R.id.autoCompleteStore);
EditText editExtra = (EditText) findViewById(R.id.editExtra);
String subcat,item,store,extra;
Integer day,month,year;
Double price,quantity,weight,volume,sale;
Log.i(TAG, "Converting to String and Int");
day = datePicker1.getDayOfMonth();
month = datePicker1.getMonth();
year = datePicker1.getYear();
subcat = autoCompleteSubCat.getText().toString();
item = editItem.getText().toString();
extra = editExtra.getText().toString();
price = Double.parseDouble(editPrice.getText().toString());
quantity = Double.parseDouble(editQuantity.getText().toString());
weight = Double.parseDouble(editWeight.getText().toString());
volume = Double.parseDouble(editVolume.getText().toString());
// sale = checkSale;
store = autoCompleteStore.getText().toString();
db = dbHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(DbPrice.SUBCAT, subcat);
cv.put(DbPrice.ITEM, item);
cv.put(DbPrice.PRICE, price);
cv.put(DbPrice.QUANTITY, quantity);
cv.put(DbPrice.WEIGHT, weight);
cv.put(DbPrice.VOLUME, volume);
// cv.put(DbPrice.SALE, sale);
cv.put(DbPrice.STORE, store);
cv.put(DbPrice.EXTRA, extra);
db.insert(DbPrice.TABLE_NAME, null, cv);
dbHelper.close();
Log.i(TAG, "Starting New Activity");
Intent allItemsActivity = new Intent (AddItem.this, AllItems.class);
startActivity(allItemsActivity);
}
DbPrice。阶级
public class DbPrice extends Activity {
public static final String DATABASE_NAME = "data";
public static final String TABLE_NAME = "price_table";
public static final String C_ID = "_id";
public static final String DAY = "day";
public static final String MONTH = "month";
public static final String YEAR = "year";
public static final String SUBCAT = "subcategory";
public static final String ITEM = "item";
public static final String PRICE = "price";
public static final String QUANTITY = "quantity";
public static final String WEIGHT = "weight";
public static final String VOLUME = "volume";
public static final String SALE = "sale";
public static final String STORE = "store";
public static final String EXTRA = "extra";
public static final int VERSION = 1;
Context context;
DbHelper dbHelper;
SQLiteDatabase db;
public DbPrice(Context context) {
this.context = context;
dbHelper = new DbHelper(context);
}
public Cursor query() {
db = dbHelper.getReadableDatabase();
Cursor cursor = db.query(DbPrice.TABLE_NAME,null, null, null, null, null, SUBCAT + " DESC");
return cursor;
}
class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, VERSION);
}
private final String createDb = "create table if not exists " + TABLE_NAME+ " ( "
+ C_ID + " integer primary key autoincrement, "
// + DAY + " integer, "
// + MONTH + " integer, "
// + YEAR + " integer, "
+ SUBCAT + " text, "
+ ITEM + " text, "
+ PRICE + " integer, "
+ QUANTITY + " integer, "
+ WEIGHT + " integer, "
+ VOLUME + " integer, "
// + SALE + " text, "
+ STORE + " text, "
+ EXTRA + " text) ";
@Override
public void onCreate(SQLiteDatabase db) {
Log.d("DbPrice", "Oncreate with SQL"+ createDb);
db.execSQL(createDb);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldversion, int newversion) {
db.execSQL("drop table if exists " + TABLE_NAME);
onCreate(db);
}
}
}
在我的杂货店里。课堂(活动课,我做了这个)
public class GroceryApp extends Application {
static final String TAG = "GroceryApp";
DbPrice dbPrice;
@Override
public void onCreate() {
super.onCreate();
dbPrice = new DbPrice(this);
Log.d(TAG, "OnCreated GroceryApp");
}
}
这是我的日志,仅供参考
01-10 06:18:38.763: E/AndroidRuntime(1119): java.lang.IllegalStateException: Could not execute method of the activity
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.view.View$1.onClick(View.java:3814)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.view.View.performClick(View.java:4424)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.view.View$PerformClick.run(View.java:18383)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.os.Handler.handleCallback(Handler.java:733)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.os.Handler.dispatchMessage(Handler.java:95)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.os.Looper.loop(Looper.java:137)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.app.ActivityThread.main(ActivityThread.java:4998)
01-10 06:18:38.763: E/AndroidRuntime(1119): at java.lang.reflect.Method.invokeNative(Native Method)
01-10 06:18:38.763: E/AndroidRuntime(1119): at java.lang.reflect.Method.invoke(Method.java:515)
01-10 06:18:38.763: E/AndroidRuntime(1119): at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
01-10 06:18:38.763: E/AndroidRuntime(1119): at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:593)
01-10 06:18:38.763: E/AndroidRuntime(1119): at dalvik.system.NativeStart.main(Native Method)
01-10 06:18:38.763: E/AndroidRuntime(1119): Caused by: java.lang.reflect.InvocationTargetException
01-10 06:18:38.763: E/AndroidRuntime(1119): at java.lang.reflect.Method.invokeNative(Native Method)
01-10 06:18:38.763: E/AndroidRuntime(1119): at java.lang.reflect.Method.invoke(Method.java:515)
01-10 06:18:38.763: E/AndroidRuntime(1119): at 安卓.view.View$1.onClick(View.java:3809)
01-10 06:18:38.763: E/AndroidRuntime(1119): ... 11 more
01-10 06:18:38.763: E/AndroidRuntime(1119): Caused by: java.lang.NullPointerException
01-10 06:18:38.763: E/AndroidRuntime(1119): at com.unsuccessfulstudent.grocerypricehistory.AddItem.onClick(AddItem.java:73)
# 1 楼答案
你忘了初始化
DbHelper dbHelper;
在
onCreate
但你有
我想你需要看看医生。还有更多的错误
你正在创建一个activity类的实例,这是非常错误的
编辑:
价格如下
在活动中