我收到以下错误：没有这样的表：类别（代码1）:,编译时：SELECT * FROM categories。
我有一个活动，SplashActivity会加载第二个活动类别。在Category活动中，我正在加载一个微调器，其中包含数据库中表[categories]的数据。当用户在微调器上选择一个项目时，它应该加载一个QuestionsActivity，它根据微调器上的选择显示数据库中的问题。
正在从Assets文件夹复制数据库。当我把代码加载到'play'按钮上的Question活动时，它正在工作然后突然出现错误弹出。我已经从手机上卸载了应用程序来擦除数据并重新加载仍然会出现同样的错误。
这是我的logcat
06-17 21:15:16.610 16854-16854/zw.co.pindula.funsa E/SQLiteLog﹕ (1) no such table: categories
06-17 21:15:16.624 16854-16854/zw.co.pindula.funsa E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: zw.co.pindula.funsa, PID: 16854
java.lang.RuntimeException: Unable to start activity ComponentInfo{zw.co.pindula.funsa/zw.co.pindula.funsa.util.Category}: android.database.sqlite.SQLiteException: no such table: categories (code 1): , while compiling: SELECT * FROM categories
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: android.database.sqlite.SQLiteException: no such table: categories (code 1): , while compiling: SELECT * FROM categories
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1255)
at zw.co.pindula.funsa.db.DBHelper.getAllCategories(DBHelper.java:168)
at zw.co.pindula.funsa.util.Category.loadCategoryData(Category.java:70)
at zw.co.pindula.funsa.util.Category.onCreate(Category.java:37)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
这是我的DBHelper类
package zw.co.pindula.funsa.db;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import zw.co.pindula.funsa.quiz.Question;
/**
* Created by NKT on 03/06/2015.
*/
public class DBHelper extends SQLiteOpenHelper{
private static String DB_PATH;// = "/data/data/zw.co.pindula.funsa/databases/";
// Database Version
private static final int DATABASE_VERSION = 1;
private static String DB_NAME = "questionsDb";
//Category Table name
private static final String TABLE_CATEGORY = "categories";
private final Context myContext;
//private static String DB_PATH= Context.getDatabasePath(DB_NAME).getPath();
private SQLiteDatabase myDataBase;
public DBHelper(Context context) {
super(context, DB_NAME, null, DATABASE_VERSION);
this.myContext = context;
DB_PATH = myContext.getDatabasePath(DB_NAME).getPath();
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if(!dbExist)
{
//By calling this method an empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private boolean checkDataBase(){
/*
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH;// + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database doesn't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
*/
//New checkDataBase method
boolean checkdb = false;
try{
String myPath = myContext.getFilesDir().getAbsolutePath().replace("files", "databases")+ File.separator + DB_NAME;
File dbfile = new File(myPath);
checkdb = dbfile.exists();
}
catch(SQLiteException e){
System.out.println("Database doesn't exist");
}
return checkdb;
}
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH;// + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
//Open the database
String myPath = DB_PATH;// + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed, all data will be gone
//db.execSQL("DROP D IF EXISTS " + TABLE);
// Create tables again
//onCreate(db);
}
public List<Question> getQuestionSet(int difficulty, int numQ){
List<Question> questionSet = new ArrayList<Question>();
Cursor c = myDataBase.rawQuery("SELECT * FROM QUESTIONS WHERE DIFFICULTY=" + difficulty +
" ORDER BY RANDOM() LIMIT " + numQ, null);
while (c.moveToNext()){
//Log.d("QUESTION", "Question Found in DB: " + c.getString(1));
Question q = new Question();
q.setQuestion(c.getString(1));
q.setAnswer(c.getString(2));
q.setOption1(c.getString(3));
q.setOption2(c.getString(4));
q.setOption3(c.getString(5));
q.setRating(difficulty);
questionSet.add(q);
}
return questionSet;
}
/**
* Getting and return all the Categories
* */
public List<String> getAllCategories(){
List<String> myCategories = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CATEGORY;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
myCategories.add(cursor.getString(1));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning categories
return myCategories;
}
/*
* This method sets the questions using the categories
*/
public List<Question> getQuestionSetCategories(String cat, int difficulty, int numQ){
List<Question> questionSet = new ArrayList<Question>();
Cursor c = myDataBase.rawQuery("SELECT * FROM QUESTIONS WHERE CATEGORY=" + cat +
" ORDER BY RANDOM() LIMIT " + numQ, null);
while (c.moveToNext()){
//Log.d("QUESTION", "Question Found in DB: " + c.getString(1));
Question q = new Question();
q.setQuestion(c.getString(1));
q.setAnswer(c.getString(2));
q.setOption1(c.getString(3));
q.setOption2(c.getString(4));
q.setOption3(c.getString(5));
q.setRating(difficulty);
questionSet.add(q);
}
return questionSet;
}
}
这是类别活动
package zw.co.pindula.funsa.util;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.SQLException;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
import java.io.IOException;
import java.util.List;
import zw.co.pindula.funsa.R;
import zw.co.pindula.funsa.db.DBHelper;
import zw.co.pindula.funsa.quiz.Constants;
import zw.co.pindula.funsa.quiz.GamePlay;
import zw.co.pindula.funsa.quiz.Question;
public class Category extends Activity implements AdapterView.OnItemSelectedListener {
Spinner spinner;
String theCategory; //This is the String to hold the selected category
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_category);
spinner = (Spinner)findViewById(R.id.mySpinner);
loadCategoryData();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_category, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Function to load the spinner data from SQLite database
* */
private void loadCategoryData() {
// database handler
DBHelper db = new DBHelper(getApplicationContext());
// Spinner Drop down elements
List<String> lables = db.getAllCategories();
// Creating adapter for spinner
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, lables);
// Drop down layout style - list view with radio button
//dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter.setDropDownViewResource(android.R.layout.simple_list_item_single_choice);
// attaching data adapter to spinner
spinner.setAdapter(dataAdapter);
}
public void startGame(View view){
Spinner spinner = (Spinner)findViewById(R.id.mySpinner);
theCategory = spinner.getSelectedItem().toString();
if(theCategory==null){
Toast.makeText(this, "You didn't select anything: ",
Toast.LENGTH_SHORT).show();
}
else
{
Intent i;
List<Question> questions = getQuestionSetFromDb();
//Initialise Game with retrieved question set ///
GamePlay c = new GamePlay();
c.setQuestions(questions);
c.setNumRounds(getNumQuestions());
((FunsaApplication)getApplication()).setCurrentGame(c);
//Start Game Now.. //
i = new Intent(this, QuestionActivity.class);
startActivityForResult(i, Constants.PLAYBUTTON);
//break;
}
}
private List<Question> getQuestionSetFromDb() throws Error {
int diff = getDifficultySettings();
int numQuestions = getNumQuestions();
DBHelper myDbHelper = new DBHelper(this);
try {
myDbHelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
myDbHelper.openDataBase();
}catch(SQLException sqle){
throw sqle;
}
List<Question> questions = myDbHelper.getQuestionSetCategories(theCategory, diff, numQuestions);
myDbHelper.close();
return questions;
}
/**
* Method to return the difficulty settings
* @return
*/
private int getDifficultySettings() {
SharedPreferences settings = getSharedPreferences(Constants.SETTINGS, 0);
int diff = settings.getInt(Constants.DIFFICULTY, Constants.MEDIUM);
return diff;
}
/**
* Method to return the number of questions for the game
* @return
*/
private int getNumQuestions() {
SharedPreferences settings = getSharedPreferences(Constants.SETTINGS, 0);
int numRounds = settings.getInt(Constants.NUM_ROUNDS, 2); //This sets the number of rounds
return numRounds;
}
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
String selection =adapterView.getItemAtPosition(i).toString();//.getItemAtPosition(i).toString();
theCategory = selection;
// Showing selected spinner item
Toast.makeText(adapterView.getContext(), "You selected: " + selection,
Toast.LENGTH_SHORT).show();
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
}