Android的SQLite的：尝试重新打开已关闭的对象 [英] Android SQLite: attempt to re-open an already-closed object
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问题描述
我试图根据国际标准书号从我的库存表中获取一定的图书数据。
不过，我得到一个错误：尝试重新打开已关闭的对象。当我点击一个ListView对象，去一个不同的屏幕，返回到该页面通过完成（），然后尝试点击另一个ListView控件对象只出现此错误。我搬到了字符串searchEntries [] = InventoryAdapter.getInventoryEntriesByISBN（SEARCHQUERY，ISBN [位置]）; 从 onClickListener 来在previous的为前 onClickListener 循环的，现在它的作品。
为什么，如果我尝试通过getInventoryEntriesByISBN完成（），从另一个活动返回到本次活动后，它不工作？
在SearchResultsScreen发生错误：
字符串searchEntries [] = InventoryAdapter.getInventoryEntriesByISBN（SEARCHQUERY，ISBN [位置]）;
和推而广之，发生在InventoryAdapter：
光标光标= db.rawQuery（查询，新的String [] {ISBN}）;
SearchResultsScreen.java
//设置搜索阵列
的for（int i = 0; I＆LT; isbn.length;我++）
{
searchArray.add（新InventoryItem（ISBN [I]，InventoryAdapter.getTitleAndAuthorByISBN（ISBN由[i]）））;
}
Toast.makeText（getApplicationContext（），searchArray.size（）=+ searchArray.size（），Toast.LENGTH_LONG）.show（）; //添加自定义适配器数据
适配器=新CustomAdapter（这一点，R.layout.list，searchArray）;
DataList控件的ListView =（ListView控件）findViewById（R.id.list）;
dataList.setAdapter（适配器）; //在点击============================================== ==========
dataList.setOnItemClickListener（新OnItemClickListener（）{
@覆盖
公共无效onItemClick（适配器视图＆LT;＆GT;母公司，观景，INT位置，
长ID）{
字符串searchEntries [] = InventoryAdapter.getInventoryEntriesByISBN（SEARCHQUERY，ISBN [位置]）;
InventoryAdapter.java（最相关的部分）
公共字符串[] getInventoryEntriesByISBN（字符串搜索，字符串ISBN）
{
的String [] = searchEntry新的String [9];
//查询
查询字符串=从清单中选择*其中ISBN =？;
光标光标= db.rawQuery（查询，新的String [] {ISBN}）;
如果（cursor.getCount（）。1）//标题不存在
{
cursor.close（）;
的for（int i = 0; I＆LT; 9;我++）
searchEntry [I] =未找到;
返回searchEntry;
}
cursor.moveToFirst（）; //将数据放入相应的变量
INT发布= cursor.getInt（cursor.getColumnIndex（PUBLISH_DATE））;
字符串publishdate =（（整数）发布）的ToString（）;
字符串title = cursor.getString（cursor.getColumnIndex（TITLE））;
笔者字符串= cursor.getString（cursor.getColumnIndex（作者））;
串callNumber = cursor.getString（cursor.getColumnIndex（CALL_NUMBER））;
INT可用= cursor.getInt（cursor.getColumnIndex（AVAILABLE_COUNT））;
字符串availablecount =（（整数）可用）的ToString（）;
INT库存= cursor.getInt（cursor.getColumnIndex（INVENTORY_COUNT））;
字符串inventorycount =（（整数）存货）的ToString（）;
INT由于= cursor.getInt（cursor.getColumnIndex（DUE_PERIOD））;
字符串dueperiod =（（整数）因）的ToString（）;
INT checkoutcount = cursor.getInt（cursor.getColumnIndex（COUNT））;
字符串数=（（整数）checkoutcount）的ToString（）;
//合并变量放入一个阵列
searchEntry [0] = ISBN;
searchEntry [1] =称号;
searchEntry [2] =作者;
searchEntry [3] = publishdate;
searchEntry [4] = callNumber;
searchEntry [5] = availablecount;
searchEntry [6] = inventorycount;
searchEntry [7] = dueperiod;
searchEntry [8] =计数; cursor.close（）;
返回searchEntry;
}公共字符串getTitleAndAuthorByISBN（字符串ISBN）
{
INT entriesFound = getNumSearchEntries（ISBN）;
如果（entriesFound == 0）
entriesFound = 1;
串searchEntry;
//查询
查询字符串=从清单中选择*其中ISBN =？;
光标光标= db.rawQuery（查询，新的String [] {ISBN}）;
如果（cursor.getCount（）。1）//标题不存在
{
cursor.close（）;
searchEntry =未找到;
返回searchEntry;
}
cursor.moveToFirst（）;
//将数据放入相应的变量
字符串title = cursor.getString（cursor.getColumnIndex（TITLE））;
笔者字符串= cursor.getString（cursor.getColumnIndex（作者））;
//变量结合成一个字符串
searchEntry =标题+/+作者;
//关闭游标及返回
cursor.close（）;
返回searchEntry;
}
DataBaseHelper.java
公共类DataBaseHelper扩展SQLiteOpenHelper
{
//数据库版本
私有静态最终诠释DATABASE_VERSION = 1;//数据库名称
私有静态最后弦乐DATABASE_NAME =database.db;// ============================结束变量================== =========公共DataBaseHelper（上下文的背景下，字符串名称，CursorFactory工厂，INT版）
{
超（背景下，名称，厂家，版本）;
}公共DataBaseHelper（上下文的背景下）{
超（背景下，DATABASE_NAME，空，DATABASE_VERSION）;
}//当盘和辅助类的需求不存在的数据库调用
//创建一个新的。
@覆盖
公共无效的onCreate（SQLiteDatabase _db）
{
_db.execSQL（LoginDataBaseAdapter.USER_TABLE_CREATE）;
_db.execSQL（CheckOutDataBaseAdapter.CHECKOUT_TABLE_CREATE）;
_db.execSQL（InventoryAdapter.INVENTORY_TABLE_CREATE）;
_db.execSQL（StatisticsAdapter.STATISTICS_TABLE_CREATE）;
}
//当有一个数据库版本不匹配意味着该版本，称为
//在磁盘上的数据库需要升级到最新版本。
@覆盖
公共无效onUpgrade（SQLiteDatabase _db，诠释_oldVersion，诠释_newVersion）
{
//日志的版本升级。
Log.w（TaskDBAdapter，从版本升级+ _oldVersion +到+ _newVersion +，这将摧毁所有旧数据）;
//升级现有的数据库，以符合新的版本。多
// previous版本可以通过比较_oldVersion和_newVersion处理
//值。
//在升级旧的掉落表
_db.execSQL（DROP TABLE IF EXISTS+ LoginDataBaseAdapter.USER_TABLE_CREATE）;
_db.execSQL（DROP TABLE IF EXISTS+ CheckOutDataBaseAdapter.CHECKOUT_TABLE_CREATE）;
_db.execSQL（DROP TABLE IF EXISTS+ InventoryAdapter.INVENTORY_TABLE_CREATE）;
_db.execSQL（DROP TABLE IF EXISTS+ StatisticsAdapter.STATISTICS_TABLE_CREATE）; //创建一个新的。
的onCreate（_db）;
}}
解决方案
当我点击一个项目，去一个不同的屏幕，通过回到此页完成（），然后尝试单击只出现错误在另一个的ListView对象。
我感动字符串searchEntries [] = InventoryAdapter.getInventoryEntriesByISBN（SEARCHQUERY，ISBN [位置]）;从onClickListener到previous为onClickListener前环和现在的作品。
正确SearchResultsScreen是如下：
SearchResultsScreen.java
//设置搜索阵列
最终字符串项[] [] =新的String [isbn.length] [9];
的for（int i = 0; I＆LT; isbn.length;我++）
{
searchArray.add（新InventoryItem（ISBN [I]，InventoryAdapter.getTitleAndAuthorByISBN（ISBN由[i]）））;
参赛作品由[i] = InventoryAdapter.getInventoryEntriesByISBN（SEARCHQUERY，ISBN [I]）;
}
Toast.makeText（getApplicationContext（），searchArray.size（）=+ searchArray.size（），Toast.LENGTH_LONG）.show（）; //添加自定义适配器数据
适配器=新CustomAdapter（这一点，R.layout.list，searchArray）;
DataList控件的ListView =（ListView控件）findViewById（R.id.list）;
dataList.setAdapter（适配器）; //在点击============================================== ==========
dataList.setOnItemClickListener（新OnItemClickListener（）{
@覆盖
公共无效onItemClick（适配器视图＆LT;＆GT;母公司，观景，INT位置，
长ID）{
字符串searchEntries [] =条目[位置]
I'm trying to get certain book data from my Inventory table based on the ISBN.
However, I'm getting an error: "attempt to re-open an already-closed object". The error only occurs when I click a listView object, go to a different screen, go back to this page via "finish()", and then try to click on another listView object. I moved the String searchEntries[] = InventoryAdapter.getInventoryEntriesByISBN(searchQuery, isbn[position]); from the onClickListener to the previous for loop before the onClickListener and now it works.
Why does it not work if I try to getInventoryEntriesByISBN after returning to this activity from another activity via "finish()"?
The error occurs at SearchResultsScreen:
String searchEntries[] = InventoryAdapter.getInventoryEntriesByISBN(searchQuery, isbn[position]);
and by extension, occurs at InventoryAdapter:
Cursor cursor = db.rawQuery(query, new String[] {ISBN});
SearchResultsScreen.java
// Set up search array
for(int i = 0; i < isbn.length; i++)
{
searchArray.add(new InventoryItem(isbn[i], InventoryAdapter.getTitleAndAuthorByISBN(isbn[i])));
}
Toast.makeText(getApplicationContext(), "searchArray.size()="+searchArray.size(), Toast.LENGTH_LONG).show();
// add data in custom adapter
adapter = new CustomAdapter(this, R.layout.list, searchArray);
ListView dataList = (ListView) findViewById(R.id.list);
dataList.setAdapter(adapter);
// On Click ========================================================
dataList.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
String searchEntries[] = InventoryAdapter.getInventoryEntriesByISBN(searchQuery, isbn[position]);
InventoryAdapter.java (Most relevant parts)
public String[] getInventoryEntriesByISBN(String search, String ISBN)
{
String[] searchEntry = new String [9];
//Query
String query = "select * from INVENTORY where ISBN = ?";
Cursor cursor = db.rawQuery(query, new String[] {ISBN});
if(cursor.getCount()<1) // title Not Exist
{
cursor.close();
for(int i = 0; i < 9; i++)
searchEntry[i] = "Not Found";
return searchEntry;
}
cursor.moveToFirst();
//put data into respective variable
int publish = cursor.getInt(cursor.getColumnIndex("PUBLISH_DATE"));
String publishdate = ((Integer)publish).toString();
String title = cursor.getString(cursor.getColumnIndex("TITLE"));
String author = cursor.getString(cursor.getColumnIndex("AUTHOR"));
String callNumber = cursor.getString(cursor.getColumnIndex("CALL_NUMBER"));
int available = cursor.getInt(cursor.getColumnIndex("AVAILABLE_COUNT"));
String availablecount = ((Integer)available).toString();
int inventory = cursor.getInt(cursor.getColumnIndex("INVENTORY_COUNT"));
String inventorycount = ((Integer)inventory).toString();
int due = cursor.getInt(cursor.getColumnIndex("DUE_PERIOD"));
String dueperiod = ((Integer)due).toString();
int checkoutcount = cursor.getInt(cursor.getColumnIndex("COUNT"));
String count = ((Integer)checkoutcount).toString();
//combine variables into one array
searchEntry[0] = ISBN;
searchEntry[1] = title;
searchEntry[2] = author;
searchEntry[3] = publishdate;
searchEntry[4] = callNumber;
searchEntry[5] = availablecount;
searchEntry[6] = inventorycount;
searchEntry[7] = dueperiod;
searchEntry[8] = count;
cursor.close();
return searchEntry;
}
public String getTitleAndAuthorByISBN(String ISBN)
{
int entriesFound = getNumSearchEntries(ISBN);
if(entriesFound==0)
entriesFound = 1;
String searchEntry;
//Query
String query = "select * from INVENTORY where ISBN = ?";
Cursor cursor = db.rawQuery(query, new String[] {ISBN});
if(cursor.getCount()<1) // title Not Exist
{
cursor.close();
searchEntry = "Not Found";
return searchEntry;
}
cursor.moveToFirst();
//put data into respective variable
String title = cursor.getString(cursor.getColumnIndex("TITLE"));
String author = cursor.getString(cursor.getColumnIndex("AUTHOR"));
//combine variables into one String
searchEntry = title + " / " + author;
//close cursor and return
cursor.close();
return searchEntry;
}
DataBaseHelper.java
public class DataBaseHelper extends SQLiteOpenHelper
{
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "database.db";
// ============================ End Variables ===========================
public DataBaseHelper(Context context, String name, CursorFactory factory, int version)
{
super(context, name, factory, version);
}
public DataBaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Called when no database exists in disk and the helper class needs
// to create a new one.
@Override
public void onCreate(SQLiteDatabase _db)
{
_db.execSQL(LoginDataBaseAdapter.USER_TABLE_CREATE);
_db.execSQL(CheckOutDataBaseAdapter.CHECKOUT_TABLE_CREATE);
_db.execSQL(InventoryAdapter.INVENTORY_TABLE_CREATE);
_db.execSQL(StatisticsAdapter.STATISTICS_TABLE_CREATE);
}
// Called when there is a database version mismatch meaning that the version
// of the database on disk needs to be upgraded to the current version.
@Override
public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion)
{
// Log the version upgrade.
Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ", which will destroy all old data");
// Upgrade the existing database to conform to the new version. Multiple
// previous versions can be handled by comparing _oldVersion and _newVersion
// values.
// on upgrade drop older tables
_db.execSQL("DROP TABLE IF EXISTS " + LoginDataBaseAdapter.USER_TABLE_CREATE);
_db.execSQL("DROP TABLE IF EXISTS " + CheckOutDataBaseAdapter.CHECKOUT_TABLE_CREATE);
_db.execSQL("DROP TABLE IF EXISTS " + InventoryAdapter.INVENTORY_TABLE_CREATE);
_db.execSQL("DROP TABLE IF EXISTS " + StatisticsAdapter.STATISTICS_TABLE_CREATE);
// Create a new one.
onCreate(_db);
}
}
解决方案
The error only occurs when I click an item, go to a different screen, go back to this page via "finish()", and then try to click on another listView object.
I moved the String searchEntries[] = InventoryAdapter.getInventoryEntriesByISBN(searchQuery, isbn[position]); from the onClickListener to the previous for loop before the onClickListener and now it works.
The correct SearchResultsScreen is below:
SearchResultsScreen.java
// Set up search array
final String Entries[][] = new String[isbn.length][9];
for(int i = 0; i < isbn.length; i++)
{
searchArray.add(new InventoryItem(isbn[i], InventoryAdapter.getTitleAndAuthorByISBN(isbn[i])));
Entries[i] = InventoryAdapter.getInventoryEntriesByISBN(searchQuery, isbn[i]);
}
Toast.makeText(getApplicationContext(), "searchArray.size()="+searchArray.size(), Toast.LENGTH_LONG).show();
// add data in custom adapter
adapter = new CustomAdapter(this, R.layout.list, searchArray);
ListView dataList = (ListView) findViewById(R.id.list);
dataList.setAdapter(adapter);
// On Click ========================================================
dataList.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
String searchEntries[] = Entries[position];
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