在下面的代码中，getLatestCorrect（）和getLatestIncorrect（）方法都会导致错误并捕获异常。我在StackOverflow上查看了一些类似的问题，发现没有我认为适用于这种情况的解决方案。
ManipulateDatabase类的LogCat输出和（相关）代码清单（包含上面提到的两个问题方法）。
logcat的
01-28 19:50:31.204: I/System.out(535): BUTTON CLICKED!
01-28 19:50:31.204: I/System.out(535): Inside case 2
01-28 19:50:31.216: I/System.out(535): Words in input: 22
01-28 19:50:31.216: I/System.out(535): Words in ideal: 15
01-28 19:50:31.216: I/System.out(535): Input: Harper Lee call us to do what is right and face the consequences - as she has done with the whole novel
01-28 19:50:31.216: I/System.out(535): Ideal: Courage is portrayed as persistence where defeat is inevitable instead of heroic and bold actions
01-28 19:50:31.216: I/System.out(535): A match has been found for:is
01-28 19:50:31.216: I/System.out(535): A match has been found for:as
01-28 19:50:31.224: I/System.out(535): A match has been found for:is
01-28 19:50:31.224: I/System.out(535): A match has been found for:and
01-28 19:50:31.224: I/System.out(535): 11
01-28 19:50:31.224: I/System.out(535): 11
01-28 19:50:31.224: I/System.out(535): 19
01-28 19:50:31.224: I/System.out(535): 73
01-28 19:50:31.224: I/System.out(535): 121
01-28 19:50:31.234: I/System.out(535): similarLength
01-28 19:50:31.324: E/CursorWindow(535): Failed to read row 0, column -1 from a CursorWindow which has 1 rows, 1 columns.
01-28 19:50:31.354: I/System.out(535): Caught excption from getLastCorrect
01-28 19:50:31.354: E/CursorWindow(535): Failed to read row 0, column -1 from a CursorWindow which has 1 rows, 1 columns.
01-28 19:50:31.384: I/System.out(535): Caught exception from getLastIncorrect
ManipulateDatabase代码
/**
* Contains SQL statements and manages connections
*
* @author Daniel Lawson
* @version 29/12/13
*/
package com.lawson.englishlitrevision;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.res.AssetManager;
import java.sql.Date;
import java.util.ArrayList;
import java.util.Scanner;
import java.io.File;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class ManipulateDatabase {
/** String representing the name of the database */
private static final String databaseName = "EnglishDatabase.db";
/** Int representing the current version of the database */
private static final int databaseVersion = 113;
// ----------------------------------------------------------------------------------
/**
* String representing the table that stores the name of the piece and
* whether it is a play or not.
*/
private static final String pieceTable = "pieceTable";
/**
* String representing the table that stores the name of the point made,
* which piece it belongs to, and which element it pertains to.
*/
private static final String specificTable = "specificTable";
/**
* String representing the table that stores the element, the piece it
* belongs to, and whether or not it is a character.
*/
private static final String elementTable = "elementTable";
/**
* String representing the table that stores the quote and the point it
* links to.
*/
private static final String quoteTable = "quoteTable";
/**
* String representing the table that stores the piece and the
* correct/incorrect responses on various dates
*/
private static final String statsTable = "statsTable";
// ----------------------------------------------------------------------------------
/** String representing the piece field of the piece table */
private static final String pieceField = "piece";
/** String representing the type field of the piece table */
private static final String typeField = "isPlay";
/** String representing the point field of the specific table */
private static final String pointField = "point";
/** String representing the element field of the element table */
private static final String elementField = "element";
/** String representing the elType field of the element table */
private static final String elTypeField = "isCharacter";
/** String representing the quote field of the quote table */
private static final String quoteField = "quote";
/** String representing the ID field of the stats table */
private static final String idField = "statId";
/** String representing the correct field of the stats table */
private static final String correctField = "correct";
/** String representing the incorrect field of the stats table */
private static final String incorrectField = "incorrect";
/** String representing the date field of the stats table */
private static final String dateField = "date";
// ----------------------------------------------------------------------------------
/** String array representing all the fields of the piece table */
private static final String[] pieceTableFields = { pieceField, typeField };
/** String array representing all the fields of the specific table */
private static final String[] specificTableFields = { pointField,
elementField };
/** String array representing all the fields of the quote table */
private static final String[] quoteTableFields = { quoteField, pointField };
/** String array representing all the fields of the element table */
private static final String[] elementTableFields = { elementField,
pieceField, elTypeField };
/** String array representing all the fields of the stats table */
private static final String[] statsTableFields = { idField, pieceField,
correctField, incorrectField, dateField };
// ----------------------------------------------------------------------------------
/** SQL statement to create the piece table. */
private static final String createPieceTable = "CREATE TABLE " + pieceTable
+ " (" + pieceField + " TEXT NOT NULL PRIMARY KEY, " + typeField
+ " INTEGER);";
/** SQL statement to create the specific table. */
private static final String createSpecificTable = "CREATE TABLE "
+ specificTable + "(" + pointField + " TEXT NOT NULL PRIMARY KEY,"
+ elementField + " TEXT NOT NULL);";
/** SQL statement to create the quotes table. */
private static final String createQuoteTable = "CREATE TABLE " + quoteTable
+ " (" + quoteField + " TEXT NOT NULL, " + pointField
+ " TEXT NOT NULL, PRIMARY KEY (" + quoteField + ", " + pointField
+ "));";
/** SQL statement to create the element table. */
private static final String createElementTable = "CREATE TABLE "
+ elementTable + "(" + elementField + " TEXT NOT NULL PRIMARY KEY,"
+ pieceField + " TEXT NOT NULL," + elTypeField + " INTEGER);";
/** SQL statement to create the stats table. */
private static final String createStatsTable = "CREATE TABLE " + statsTable
+ "(" + idField + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ pieceField + " TEXT NOT NULL," + correctField + " INTEGER,"
+ incorrectField + " INTEGER," + dateField + " LONG);";
// ----------------------------------------------------------------------------------
/**
* SQL statement to search the piece table - replace [columnName] and
* [value] with field to be searched and what value to look for.
*/
private static final String searchPieceTable = "SELECT * FROM "
+ pieceTable + " WHERE [columnName] = '[value]';";
/**
* SQL statement to search the specific table - replace [columnName] and
* [value] with field to be searched and what value to look for.
*/
private static final String searchSpecificTable = "SELECT * FROM "
+ specificTable + " WHERE [columnName] = '[value]';";
/**
* SQL statement to search the quote table - replace [columnName] and
* [value] with field to be searched and what value to look for.
*/
private static final String searchQuoteTable = "SELECT * FROM "
+ quoteTable + " WHERE [columnName] = '[value]';";
/**
* SQL statement to search the element table - replace [columnName] and
* [value] with field to be searched and what value to look for.
*/
private static final String searchElementTable = "SELECT * FROM "
+ elementTable
+ " WHERE [columnName] = '[value]' AND [columnName2] = '[value2]';";
/**
* SQL statement to search the stats table - replace [columnName] and
* [value] with field to be searched and what value to look for.
*/
private static final String searchStatsTable = "SELECT * FROM "
+ statsTable + " WHERE [columnName] = '[value]'";
/**
* SQL statement to delete from the piece table - replace [condition] the
* condition where if true, this deletion should be applied.
*/
private static final String deleteFromPieceTable = "DELETE FROM "
+ pieceTable + " WHERE [condition]";
/**
* SQL statement to delete from the specific table - replace [condition] the
* condition where if true, this deletion should be applied.
*/
private static final String deleteFromSpecificTable = "DELETE FROM "
+ specificTable + " WHERE [condition]";
/**
* SQL statement to delete from the quote table - replace [condition] the
* condition where if true, this deletion should be applied.
*/
private static final String deleteFromQuoteTable = "DELETE FROM "
+ quoteTable + " WHERE [condition]";
/**
* SQL statement to delete from the element table - replace [condition] the
* condition where if true, this deletion should be applied.
*/
private static final String deleteFromElementTable = "DELETE FROM "
+ elementTable + " WHERE [condition]";
/**
* SQL statement to delete from the stats table - replace [condition] the
* condition where if true, this deletion should be applied.
*/
private static final String deleteFromStatsTable = "DELETE FROM "
+ statsTable + " WHERE [condition]";
// ----------------------------------------------------------------------------------
/**
* SQL statement to insert into the piece table - replace [values] with the
* values to be inserted.
*/
private static final String insertIntoPieceTable = "INSERT INTO "
+ pieceTable + " VALUES ([values]);";
/**
* SQL statement to insert into the specific table - replace [values] with
* the values to be inserted.
*/
private static final String insertIntoSpecificTable = "INSERT INTO "
+ specificTable + " VALUES ([values])";
/**
* SQL statement to insert into the quote table - replace [values] with the
* values to be inserted.
*/
private static final String insertIntoQuoteTable = "INSERT INTO "
+ quoteTable + " VALUES ([values])";
/**
* SQL statement to insert into the element table - replace [values] with
* the values to be inserted.
*/
private static final String insertIntoElementTable = "INSERT INTO "
+ elementTable + " VALUES ([values])";
/**
* SQL statement to insert into the quote table - replace [values] with the
* values to be inserted.
*/
private static final String insertIntoStatsTable = "INSERT INTO "
+ statsTable + " VALUES ([values])";
// ----------------------------------------------------------------------------------
/**
* SQLiteDatabase representing the English database
*/
private SQLiteDatabase dataBase;
/**
* Instance of DatabaseHelper class utilised to 'access' database
*/
private DatabaseHelper baseHelper;
/**
* Content of the Database Manipulator (ManipulateDatabase class)
*/
private Activity context;
/**
* Boolean to store whether or not this is the first time this base/version
* has been launched
*/
private boolean initialLaunch = false;
/**
* File for the BufferedReader to read into Database
*/
private File pieceList;
/**
* Method to get pieceList file from assets for BufferedReader to use
*
* @param ctx
* @throws IOException
*/
private InputStream getPieceTextFile(Activity ctx) throws IOException {
try {
AssetManager manager = ctx.getAssets();
InputStream pieceStream = manager.open("pieceList.txt");
return pieceStream;
} catch (Exception e) {
System.out.println("Asset Manager/IS not work.");
e.printStackTrace();
return null;
}
}
/**
* Method to get specificList file from assets for BufferedReader to use
*
* @param ctx
* @throws IOException
*/
private InputStream getSpecificTextFile(Activity ctx) throws IOException {
try {
AssetManager manager = ctx.getAssets();
InputStream specificStream = manager.open("specificList.txt");
return specificStream;
} catch (Exception e) {
System.out.println("Asset Manager/IS not work.");
e.printStackTrace();
return null;
}
}
/**
* Method to get elementList file from assets for BufferedReader to use
*
* @param ctx
* @throws IOException
*/
private InputStream getElementTextFile(Activity ctx) throws IOException {
try {
AssetManager manager = ctx.getAssets();
InputStream elementStream = manager.open("elementList.txt");
return elementStream;
} catch (Exception e) {
System.out.println("Asset Manager/IS not work.");
e.printStackTrace();
return null;
}
}
/**
* Method to get quoteList file from assets for BufferedReader to use
*
* @param ctx
* @throws IOException
*/
private InputStream getQuoteTextFile(Activity ctx) throws IOException {
try {
AssetManager manager = ctx.getAssets();
InputStream quoteStream = manager.open("quoteList.txt");
return quoteStream;
} catch (Exception e) {
System.out.println("Asset Manager/IS not work.");
e.printStackTrace();
return null;
}
}
/**
* Method to open the database
*/
private void openSesame() {
try {
dataBase = baseHelper.getWritableDatabase();
} catch (SQLiteException e) {
System.out.println("Database couldn't be opened");
e.printStackTrace();
}
}
/**
* Method to close the database
*/
private void closeSesame() {
baseHelper.close();
}
/**
*
* @param typePiece
* The type of the piece (a play or novel) to fetch from
* database, represented as 1 or 0 respectively.
*
* @return pieces ArrayList containing the Strings to be returned (data
* items that fulfill the criteria)
*/
public ArrayList<String> getPieces(String typePiece) {
try {
openSesame();
ArrayList<String> pieces = new ArrayList<String>();
String command = searchPieceTable
.replace("[columnName]", typeField);
command = command.replace("[value]", typePiece);
Cursor cursor = dataBase.rawQuery(command, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
pieces.add(cursor.getString(cursor.getColumnIndex(pieceField)));
System.out
.println(cursor.getString(cursor
.getColumnIndex(pieceField))
+ " HAS JUST BEEN ADDED TO PIECE ARRAYLIST FETCHED FROM DB");
cursor.moveToNext();
}
closeSesame();
return pieces;
} catch (SQLiteException e) {
e.printStackTrace();
System.out.println("SQL Problem");
ArrayList<String> defaultReturn = new ArrayList<String>();
defaultReturn.add("There is default item.");
defaultReturn.add("Because the proper ArrayList");
defaultReturn.add("Wasn't filled properly");
return defaultReturn;
}
}
/**
*
* @param namePiece
* String representing the piece which the elements wanted are
* from
* @param typeElement
* String representing the type of element to extract
* (character/theme)
*
* @param appendage
* String representing the additional criteria that might want to
* be added to the SQL SELECT statement
*
* @return elements ArrayList containing the Strings of the elements
*
*/
public ArrayList<String> getElements(String namePiece, String typeElement,
String appendage) {
try {
openSesame();
ArrayList<String> elements = new ArrayList<String>();
String command = searchElementTable.replace("[columnName]",
pieceField);
command = command.replace("[value]", namePiece);
command = command.replace("[columnName2]", elTypeField);
command = command.replace("[value2]", typeElement);
Cursor cursor = dataBase.rawQuery(command, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
elements.add(cursor.getString(cursor
.getColumnIndex(elementField)));
System.out
.println(cursor.getString(cursor
.getColumnIndex(elementField))
+ " HAS JUST BEEN ADDED TO ELEMENT ARRAYLIST FETCHED FROM DB");
cursor.moveToNext();
}
closeSesame();
return elements;
} catch (SQLiteException e) {
e.printStackTrace();
System.out.println("SQL Problem");
ArrayList<String> defaultReturn = new ArrayList<String>();
defaultReturn.add("There is default item.");
defaultReturn.add("Because the proper ArrayList");
defaultReturn.add("Wasn't filled properly");
return defaultReturn;
}
}
/**
*
* @param nameElement
* String representing the element to which the points belong
*
*
* @param appendage
* String representing the additional criteria that might want to
* be added to the SQL SELECT statement
*
* @return points ArrayList containing the Strings of the points
*
*/
public ArrayList<String> getPoints(String nameElement, String appendage) {
try {
openSesame();
ArrayList<String> points = new ArrayList<String>();
String command = searchSpecificTable.replace("[columnName]",
elementField);
command = command.replace("[value]", nameElement);
command = command.concat(appendage);
Cursor cursor = dataBase.rawQuery(command, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
points.add(cursor.getString(cursor.getColumnIndex(pointField)));
System.out
.println(cursor.getString(cursor
.getColumnIndex(pointField))
+ " HAS JUST BEEN ADDED TO ELEMENT ARRAYLIST FETCHED FROM DB");
cursor.moveToNext();
}
closeSesame();
return points;
} catch (SQLiteException e) {
e.printStackTrace();
System.out.println("SQL Problem");
ArrayList<String> defaultReturn = new ArrayList<String>();
defaultReturn.add("There is default item.");
defaultReturn.add("Because the proper ArrayList");
defaultReturn.add("Wasn't filled properly");
return defaultReturn;
}
}
/**
*
* @param namePoint
* String representing the point to which the quote belongs
*
*
*
* @return points ArrayList containing the Strings of the points
*
*/
public ArrayList<String> getQuotes(String namePoint) {
try {
openSesame();
ArrayList<String> quotes = new ArrayList<String>();
String command = searchQuoteTable.replace("[columnName]",
pointField);
command = command.replace("[value]", namePoint);
Cursor cursor = dataBase.rawQuery(command, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
String adjustedQuote = '"' + cursor.getString(cursor
.getColumnIndex(quoteField)) + '"';
String unadjustedQuote = cursor.getString(cursor
.getColumnIndex(quoteField));
Tester test = new Tester();
if (test.isNeedQuoteMarks()) {
quotes.add(adjustedQuote);
} else {
quotes.add(unadjustedQuote);
}
System.out
.println(cursor.getString(cursor
.getColumnIndex(quoteField))
+ " HAS JUST BEEN ADDED TO ELEMENT ARRAYLIST FETCHED FROM DB");
cursor.moveToNext();
}
closeSesame();
return quotes;
} catch (SQLiteException e) {
e.printStackTrace();
System.out.println("SQL Problem");
ArrayList<String> defaultReturn = new ArrayList<String>();
defaultReturn.add("There is default item.");
defaultReturn.add("Because the proper ArrayList");
defaultReturn.add("Wasn't filled properly");
return defaultReturn;
}
}
public int getLatestCorrect(String namePiece) {
try {
openSesame();
String command = "SELECT MAX(correct) FROM statsTable WHERE piece = '"
+ namePiece + "';";
Cursor cursor = dataBase.rawQuery(command, null);
cursor.moveToFirst();
int value = (cursor.getInt(cursor.getColumnIndex(correctField)));
closeSesame();
return value;
} catch (Exception e) {
System.out.println("Caught excption from getLastCorrect");
return 0;
}
}
public int getLatestIncorrect(String namePiece) {
try {
openSesame();
String command = "SELECT MAX(incorrect) FROM statsTable WHERE piece = '"
+ namePiece + "';";
Cursor cursor = dataBase.rawQuery(command, null);
cursor.moveToFirst();
int value = (cursor.getInt(cursor.getColumnIndex(incorrectField)));
closeSesame();
return value;
} catch (Exception e) {
System.out.println("Caught exception from getLastIncorrect");
return 0;
}
}
public void addPiece(String namePiece, String isDrama) {
openSesame();
ContentValues adPi = new ContentValues();
adPi.put(pieceField, namePiece);
System.out.println(pieceField + ": " + namePiece);
adPi.put(typeField, (Integer.parseInt(isDrama)));
System.out.println(typeField + ": " + (isDrama));
dataBase.insert(pieceTable, null, adPi);
System.out.println("INSERTED " + namePiece + " IS D: " + isDrama);
closeSesame();
}
public void deletePiece(String namePiece) {
openSesame();
String command = deleteFromPieceTable.replace("[condition]", pieceField
+ "= '" + namePiece + "';");
dataBase.execSQL(command);
closeSesame();
}
public void addElement(String nameElement, String namePiece, String isChar) {
openSesame();
ContentValues adEl = new ContentValues();
adEl.put(elementField, nameElement);
adEl.put(pieceField, namePiece);
adEl.put(elTypeField, (Integer.parseInt(isChar)));
dataBase.insert(elementTable, null, adEl);
System.out.println("INSERTED " + nameElement + "FROM " + namePiece
+ " IS C: " + isChar);
closeSesame();
}
public void deleteElement(String nameElement) {
openSesame();
String command = deleteFromElementTable.replace("[condition]",
elementField + "= '" + nameElement + "';");
dataBase.execSQL(command);
closeSesame();
}
public void addPoint(String namePoint, String nameElement) {
openSesame();
ContentValues adPo = new ContentValues();
adPo.put(pointField, namePoint);
adPo.put(elementField, nameElement);
dataBase.insert(specificTable, null, adPo);
System.out.println("INSERTED " + namePoint + "FOR " + nameElement);
closeSesame();
}
public void deletePoint(String namePoint) {
openSesame();
String command = deleteFromSpecificTable.replace("[condition]",
pointField + "= '" + namePoint + "';");
dataBase.execSQL(command);
closeSesame();
}
public void addQuote(String nameQuote, String namePoint) {
System.out.println("INSIDE INSERT QUOTE");
openSesame();
ContentValues adQu = new ContentValues();
adQu.put(quoteField, nameQuote);
adQu.put(pointField, namePoint);
dataBase.insert(quoteTable, null, adQu);
System.out.println("INSERTED " + nameQuote + " FOR " + namePoint);
closeSesame();
}
public void deleteQuote(String nameQuote) {
openSesame();
String command = deleteFromQuoteTable.replace("[condition]", quoteField
+ "= '" + nameQuote + "';");
dataBase.execSQL(command);
closeSesame();
}
public void addStat(String pieceName, int correct, int incorrect, long date) {
openSesame();
ContentValues adSt = new ContentValues();
adSt.put(pieceField, pieceName);
adSt.put(correctField, correct);
adSt.put(incorrectField, incorrect);
adSt.put(dateField, date);
dataBase.insert(statsTable, null, adSt);
System.out.println("INSERTED " + correct + " correct and " + incorrect
+ " incorrect FOR " + pieceName);
closeSesame();
}
答案 0 :(得分：2)
您的光标有一行“MAX（不正确）”，您试图选择“不正确”列
您需要为列添加“MAX（不正确）”等别名，然后它才能正常工作。