我是android新手并使用SQLite数据库。我无法找到在数据文件夹内的DDMS中创建的数据库表。这是我的代码，我也无法在数据库中插入值而数据库表也没有创建。
public class BookingOpenHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "BookingDB";
public static final String BOOKING_TABLE_NAME = "OnlineBooking";
public static final String NAME= "name";
public static final String QUANTITY = "quantity";
public static final String NOTE = "note";
public static final String NUMBER_OF_PIECES = "noofpieces";
public static final String DATE_AND_TIME = "dateandtime";
public static final String DELIVARY_ADDRESS = "delivaryaddress";
public static final int VERSION = 3;
public static final String CONTACT_NO = "contactno";
public static final String BOOKING_ID = "bookingid";
public static final String B_ID = "_id";
private static final String CREATE_BOOKING_TABLE = "create table onlinebooking(_id integer not null primary key autoincrement,name text null,contactnumber integer null,quantity text null,noofpcs integer null,dateandtime text null,delivaryaddress text null,note text null)";
public BookingOpenHelper(Context context, String name, CursorFactory factory, int version) {
super(context, name, factory, version);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db1) {
// TODO Auto-generated method stub
db1.execSQL(CREATE_BOOKING_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db1, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
onCreate(db1);
}
}
Adapter.java
package com.example.android;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
public class BookingAdapter {
SQLiteDatabase database_ob;
BookingOpenHelper openHelper_ob;
Context context;
public BookingAdapter(Context c) {// constructor
context = c;
}
public BookingAdapter opnToRead() {// method for open and read the database to perform the operations
openHelper_ob = new BookingOpenHelper(context, openHelper_ob.DATABASE_NAME, null, openHelper_ob.VERSION);
database_ob = openHelper_ob.getReadableDatabase();
return this;
}
public BookingAdapter opnToWrite() {// method for open and write the database to perform the operations
openHelper_ob = new BookingOpenHelper(context, openHelper_ob.DATABASE_NAME, null, openHelper_ob.VERSION);
database_ob = openHelper_ob.getWritableDatabase();
return this;
}
public void Close() {// method for closing the database
database_ob.close();
}
public long insertDetails(String name, String contactnumber,String quantity,String noofpieces,String dateandtime,String delivaryaddress,String note) {// insert method for steps
ContentValues contentValues = new ContentValues();
contentValues.put(openHelper_ob.NAME, name);
contentValues.put(openHelper_ob.CONTACT_NO,contactnumber );
contentValues.put(openHelper_ob.QUANTITY, quantity);
contentValues.put(openHelper_ob.NUMBER_OF_PIECES,noofpieces);
contentValues.put(openHelper_ob.DATE_AND_TIME, dateandtime);
contentValues.put(openHelper_ob.DELIVARY_ADDRESS,delivaryaddress);
contentValues.put(openHelper_ob.NOTE,note);
opnToWrite();
long val = database_ob.insert(openHelper_ob.BOOKING_TABLE_NAME, null, contentValues);
Close();
return val;
}
public Cursor queryForSteps() {// method to display the edit profile name and its related steps.
String[] cols = {openHelper_ob.BOOKING_ID, openHelper_ob.NAME, openHelper_ob.CONTACT_NO, openHelper_ob.QUANTITY,openHelper_ob.NUMBER_OF_PIECES,openHelper_ob.DATE_AND_TIME,openHelper_ob.DELIVARY_ADDRESS,openHelper_ob.NOTE };
opnToWrite();
Cursor c = database_ob.query(openHelper_ob.BOOKING_TABLE_NAME, cols,null, null, null, null, null);
return c;
}
public Cursor queryAll() {// method to display the edit profile
String[] cols = { openHelper_ob.BOOKING_ID, openHelper_ob.NAME, openHelper_ob.CONTACT_NO, openHelper_ob.QUANTITY,openHelper_ob.NUMBER_OF_PIECES,openHelper_ob.DATE_AND_TIME,openHelper_ob.DELIVARY_ADDRESS,openHelper_ob.NOTE };
opnToWrite();
Cursor c = database_ob.query(openHelper_ob.BOOKING_TABLE_NAME, cols,null, null, null, null, null);
return c;
}
public int getMaxID() {
int id = 0;
opnToWrite();
final String MY_QUERY = "SELECT MAX(_id) AS _id FROM onlinebooking";
Cursor cursor = database_ob.rawQuery(MY_QUERY, null);
if (cursor.moveToFirst()) {
id = cursor.getInt(0);
}
Close();
return id;
}
}
有些人可以帮助我解决这个问题。
09-03 05:01:42.880: E/AndroidRuntime(1016): FATAL EXCEPTION: main
09-03 05:01:42.880: E/AndroidRuntime(1016): java.lang.NullPointerException
090305:01:42.880:E/AndroidRuntime(1016):atcom.example.android.Online$1.onClick(Online.java:65)
09-03 05:01:42.880: E/AndroidRuntime(1016): at android.view.View.performClick(View.java:4204)
09-03 05:01:42.880: E/AndroidRuntime(1016): at android.view.View$PerformClick.run(View.java:17355)
online.java
package com.example.android;
import java.util.Calendar;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.FragmentActivity;
import android.text.format.DateFormat;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TimePicker;
public class Online extends FragmentActivity {
private Spinner quantitySpinner;
static EditText editDateTime;
Button nextButton,cancelButton;
EditText nameEdit,numberEdit,piecesEdit,delivaryEdit,noteEdit;
BookingAdapter adapter;
BookingOpenHelper helper_ob;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.online);
nameEdit=(EditText) findViewById(R.id.nameEdit);
numberEdit=(EditText) findViewById(R.id.contactNumber);
quantitySpinner=(Spinner) findViewById(R.id.spinner);
piecesEdit=(EditText) findViewById(R.id.editpieces);
editDateTime=(EditText) findViewById(R.id.editdate);
delivaryEdit=(EditText) findViewById(R.id.editaddress);
noteEdit=(EditText) findViewById(R.id.editnote);
nextButton=(Button) findViewById(R.id.nextformbtn);
cancelButton=(Button) findViewById(R.id.cancelformbutton);
nextButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
String name=nameEdit.getText().toString();
String contactnumber=numberEdit.getText().toString();
String quantity = String.valueOf(quantitySpinner.getSelectedItem());
String noofpieces=piecesEdit.getText().toString();
String dateandtime=editDateTime.getText().toString();
String delivaryaddress=delivaryEdit.getText().toString();
String note=noteEdit.getText().toString();
long vals=adapter.insertDetails(name, contactnumber, quantity, noofpieces, dateandtime, delivaryaddress, note);
}
});
cancelButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent(Online.this,HomeScreen.class));
}
});
quantitySpinner = (Spinner) findViewById(R.id.spinner);
addListenerOnSpinnerItemSelection();
editDateTime = (EditText) findViewById(R.id.editdate);
editDateTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
showTimePickerDialog(v);
showDatePickerDialog(v);
}
});
}
public void showDatePickerDialog(View v) {
DialogFragment newFragment = new DatePickerFragment();
newFragment.show(getSupportFragmentManager(), "datePicker");
}
public static class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current date as the default date in the picker
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
// Create a new instance of DatePickerDialog and return it
return new DatePickerDialog(getActivity(), this, year, month, day);
}
@Override
public void onDateSet(DatePicker arg0, int year, int month, int day) {
// TODO Auto-generated method stub
editDateTime.setText(day + "/" + (month + 1) + "/" + year);
}
}
public void showTimePickerDialog(View v) {
DialogFragment newFragment = new TimePickerFragment();
newFragment.show(getSupportFragmentManager(), "timePicker");
}
public static class TimePickerFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current time as the default values for the picker
final Calendar c = Calendar.getInstance();
int hour = c.get(Calendar.HOUR_OF_DAY);
int minute = c.get(Calendar.MINUTE);
// Create a new instance of TimePickerDialog and return it
return new TimePickerDialog(getActivity(), this, hour, minute, DateFormat.is24HourFormat(getActivity()));
}
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
// Do something with the time chosen by the user
editDateTime.setText(editDateTime.getText() + " -" + hourOfDay + ":" + minute);
}
}
private void addListenerOnSpinnerItemSelection() {
quantitySpinner.setOnItemSelectedListener(new CustomOnItemSelectedListener());
}
}
答案 0 :(得分：1)
更改此行
private static final String CREATE_BOOKING_TABLE =“create table onlinebooking（_id integer not null主键autoincrement，name text null，contactnumber integer null，quantity text null，noofpcs integer null，dateandtime text null，delivaryaddress text null，note text null） “;
将上一行替换为此
private static final String CREATE_BOOKING_TABLE =“create table onlinebooking（_id integer not null主键autoincrement，name text null，contactnumber integer null，quantity text null，noofpcs integer null，dateandtime text null，delivaryaddress text null，note text null） ;“;
答案 1 :(得分：0)
long vals=adapter.insertDetails(name, contactnumber, quantity, noofpieces, dateandtime, delivaryaddress, note);
你的一个或多个变量返回一个空值，这就是问题的根源。尝试打印所有变量的值，此调试将导致您的错误。
答案 2 :(得分：0)
创建＆＃34; adapter＆＃34;的实例使用前
adapter=new BookingAdapter (Context);//write this line starting of oncreate method
long vals=adapter.insertDetails(name, contactnumber, quantity, noofpieces, dateandtime, delivaryaddress, note);