如何在Android中正确关闭游标 [英] How to properly close a cursor in android
本文介绍了如何在Android中正确关闭游标的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个使用sqlite的数据库，我在关闭游标时遇到了问题，它说Application did not close the cursor or database object that was opened here这是logcat
I have this database using sqlite, and I'm having problem with closing the cursor its saying that Application did not close the cursor or database object that was opened here here's the logcat
10-18 08:40:56.354: E/Cursor(331): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
10-18 08:40:56.354: E/Cursor(331): at android.database.sqlite.SQLiteCursor.<init>(SQLiteCursor.java:210)
10-18 08:40:56.354: E/Cursor(331): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53)
10-18 08:40:56.354: E/Cursor(331): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
10-18 08:40:56.354: E/Cursor(331): at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
10-18 08:40:56.354: E/Cursor(331): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
10-18 08:40:56.354: E/Cursor(331): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
10-18 08:40:56.354: E/Cursor(331): at standard.internet.marketing.mymovingfriend.SQLHandler.checkMove(SQLHandler.java:1094)
10-18 08:40:56.354: E/Cursor(331): at standard.internet.marketing.mymovingfriend.ListMovingNames$3.onKey(ListMovingNames.java:98)
10-18 08:40:56.354: E/Cursor(331): at android.view.View.dispatchKeyEvent(View.java:3735)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1667)
10-18 08:40:56.354: E/Cursor(331): at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1102)
10-18 08:40:56.354: E/Cursor(331): at android.app.Activity.dispatchKeyEvent(Activity.java:2063)
10-18 08:40:56.354: E/Cursor(331): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441)
10-18 08:40:56.354: E/Cursor(331): at android.view.ViewRoot.handleMessage(ViewRoot.java:1735)
10-18 08:40:56.354: E/Cursor(331): at android.os.Handler.dispatchMessage(Handler.java:99)
10-18 08:40:56.354: E/Cursor(331): at android.os.Looper.loop(Looper.java:123)
10-18 08:40:56.354: E/Cursor(331): at android.app.ActivityThread.main(ActivityThread.java:4627)
10-18 08:40:56.354: E/Cursor(331): at java.lang.reflect.Method.invokeNative(Native Method)
10-18 08:40:56.354: E/Cursor(331): at java.lang.reflect.Method.invoke(Method.java:521)
10-18 08:40:56.354: E/Cursor(331): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
10-18 08:40:56.354: E/Cursor(331): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
10-18 08:40:56.354: E/Cursor(331): at dalvik.system.NativeStart.main(Native Method)
这个问题困扰了我3天.
this issue's been bugging me for 3 days.
此处是一些相关代码:
public class SQLHandler {
public static final String KEY_MOVENAME = "movename";
public static final String KEY_ID1 = "_id";
public static final String KEY_ID5 = "_id";
public static final String KEY_MOVEDATE = "movedate";
public static final String KEY_TOTALMOVEWEIGHT = "totalmoveweight";
public static final String KEY_TOTALITEM = "totalitem";
private static final String DATABASE_NAME = "mymovingfriend";
private static final int DATABASE_VERSION = 1;
public static final String KEY_LISTITEMNAME = "listitemname";
public static final String KEY_LISTITEMWEIGHT = "listitemweight";
public static final String KEY_LISTITEMROOM = "listitemroom";
private static final String DATABASE_TABLE1 = "movingname";
private static final String DATABASE_TABLE5 = "listitem";
public static final String CREATE_TABLE_1 = "CREATE TABLE " + DATABASE_TABLE1 + " (" +
KEY_ID1 + " INTEGER PRIMARY KEY AUTOINCREMENT," +
KEY_MOVEDATE + " TEXT NOT NULL, " +
KEY_TOTALMOVEWEIGHT + " TEXT NOT NULL, " +
KEY_TOTALITEM + " INTEGER NOT NULL, " +
KEY_MOVENAME + " TEXT NOT NULL);";
public static final String CREATE_TABLE_2 = "CREATE TABLE " + DATABASE_TABLE2 + " (" +
KEY_ID2 + " INTEGER PRIMARY KEY AUTOINCREMENT," +
KEY_ROOMMOVEHOLDER + " TEXT NOT NULL, " +
KEY_ROOMWEIGHT + " TEXT NOT NULL, " +
KEY_ROOM + " TEXT NOT NULL);";
public static final String CREATE_TABLE_5 = "CREATE TABLE " + DATABASE_TABLE5 + " (" +
KEY_ID5 + " INTEGER PRIMARY KEY AUTOINCREMENT," +
KEY_LISTITEMNAME + " TEXT NOT NULL, " +
KEY_LISTITEMWEIGHT + " TEXT NOT NULL, " +
KEY_LISTITEMROOM + " TEXT NOT NULL);";
private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;
private static class DbHelper extends SQLiteOpenHelper{
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(CREATE_TABLE_1);
db.execSQL(CREATE_TABLE_2);
db.execSQL(CREATE_TABLE_3);
db.execSQL(CREATE_TABLE_4);
db.execSQL(CREATE_TABLE_5);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldversion, int newversion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE1);
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE2);
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE3);
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE4);
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE5);
onCreate(db);
}
}
public SQLHandler(Context c){
ourContext = c;
}
public SQLHandler open() throws SQLException{
ourHelper = new DbHelper(ourContext);
ourDatabase = ourHelper.getWritableDatabase();
return this;
}
public void close(){
ourDatabase.close();
ourHelper.close();
}
public long createMove(String smovename){
ContentValues cv = new ContentValues();
cv.put(KEY_MOVENAME, smovename);
cv.put(KEY_MOVEDATE, "Not yet set");
cv.put(KEY_TOTALMOVEWEIGHT, "0");
cv.put(KEY_TOTALITEM, 0);
return ourDatabase.insert(DATABASE_TABLE1, null, cv);
}
public void createList(){
String[] sroom = new String[]{"Kitchen", "Bedroom", "Dinning Room"};
String[] sitem = new String[]{"Dishwasher", "Bed", "Table"};
String[] sweight = new String[]{"40", "25", "15"};
for (int i = 0; i < sroom.length; i++) {
cv.put(KEY_LISTITEMROOM, sroom[i]);
cv.put(KEY_LISTITEMNAME, sitem[i]);
cv.put(KEY_LISTITEMWEIGHT, sweight[i]);
ourDatabase.insert(DATABASE_TABLE5, null, cv);
}
}
public void setMoveDate(String smovedate, String smovename){
ContentValues cv = new ContentValues();
cv.put(KEY_MOVEDATE, smovedate);
ourDatabase.update(DATABASE_TABLE1, cv, KEY_MOVENAME + "='" + smovename + "'", null);
}
public void setMoveWeight(String smoveweight, String smovename){
ContentValues cv = new ContentValues();
cv.put(KEY_TOTALMOVEWEIGHT, smoveweight);
ourDatabase.update(DATABASE_TABLE1, cv, KEY_MOVENAME + "='" + smovename + "'", null);
}
public void setTotalItem(String smovename, int imoveitem){
ContentValues cv = new ContentValues();
cv.put(KEY_TOTALITEM, imoveitem);
ourDatabase.update(DATABASE_TABLE1, cv, KEY_MOVENAME + "='" + smovename + "'", null);
}
public void renameRoom(String movename, String roomname, String currentroom){
ContentValues cv = new ContentValues();
cv.put(KEY_ROOM, roomname);
ourDatabase.update(DATABASE_TABLE2, cv, KEY_ROOMMOVEHOLDER + "='" + movename + "'" + " AND " + KEY_ROOM + "='" + currentroom + "'", null);
}
public void setRoomWeight(String sroomweight, String smovename, String sroomname){
ContentValues cv = new ContentValues();
cv.put(KEY_ROOMWEIGHT, sroomweight);
ourDatabase.update(DATABASE_TABLE2, cv, KEY_ROOMMOVEHOLDER + "='" + smovename + "'" + " AND " + KEY_ROOM + "='" + sroomname + "'", null);
}
public long addRooms(String sroommoveholder, String sroom){
ContentValues cv = new ContentValues();
cv.put(KEY_ROOMMOVEHOLDER, sroommoveholder);
cv.put(KEY_ROOM, sroom);
cv.put(KEY_ROOMWEIGHT, "0");
return ourDatabase.insert(DATABASE_TABLE2, null, cv);
}
public long addNewItems(String sitemmoveholder, String sroomholder, String sitemname, String sitemvalue, String sitemweight){
ContentValues cv = new ContentValues();
cv.put(KEY_ITEMMOVEHOLDER, sitemmoveholder);
cv.put(KEY_ROOMHOLDER, sroomholder);
cv.put(KEY_ITEMNAME, sitemname);
cv.put(KEY_ITEMVALUE, sitemvalue);
cv.put(KEY_ITEMWEIGHT, sitemweight);
return ourDatabase.insert(DATABASE_TABLE3, null, cv);
}
public void updateItems(String sitemmoveholder, String sroomholder, String sitemname, String sitemvalue, String sitemweight){
ContentValues cv = new ContentValues();
cv.put(KEY_ITEMVALUE, sitemvalue);
cv.put(KEY_ITEMWEIGHT, sitemweight);
ourDatabase.update(DATABASE_TABLE3, cv, KEY_ITEMMOVEHOLDER + "='" + sitemmoveholder + "'" + " AND " +
KEY_ROOMHOLDER + "='" + sroomholder + "'" + " AND " + KEY_ITEMNAME + "='" + sitemname + "'", null);
}
public Cursor getMove(){
String[] columns = new String[]{KEY_ID1, KEY_MOVENAME};
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE1, columns, null, null, null, null, null);
} catch (Exception e) {
c.close();
}
return c;
}
public String getTotalWeight(String m) throws SQLException{
String[] columns = new String[]{KEY_ID1, KEY_MOVENAME, KEY_MOVEDATE, KEY_TOTALMOVEWEIGHT};
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE1, columns, KEY_MOVENAME + "= '" + m + "'", null, null, null, null);
if (c != null) {
c.moveToFirst();
String totalWeight = c.getString(3);
return totalWeight;
}
} catch (Exception e) {
c.close();
}
return null;
}
public String getTotalWeightLBS(String m) throws SQLException{
String[] columns = new String[]{KEY_ID1, KEY_MOVENAME, KEY_MOVEDATE, KEY_TOTALMOVEWEIGHT};
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE1, columns, KEY_MOVENAME + "= '" + m + "'", null, null, null, null);
if (c != null) {
c.moveToFirst();
int x = Integer.parseInt(c.getString(3)) * 7;
String totalWeight = "" + x + " lbs";
return totalWeight;
}
} catch (Exception e) {
c.close();
}
return null;
}
public String getDateMove(String md){
String[] columns = new String[]{KEY_ID1, KEY_MOVENAME, KEY_MOVEDATE};
Cursor c = null;try {
c = ourDatabase.query(DATABASE_TABLE1, columns, KEY_MOVENAME + "= '" + md + "'", null, null, null, null);
if (c != null) {
c.moveToFirst();
String moveDate = c.getString(2);
return moveDate;
}
} catch (Exception e) {
c.close();
}
return null;
}
public ArrayList<String> loadRooms(String mn) throws SQLException{
String[] columns = new String[]{KEY_ID2, KEY_ROOMMOVEHOLDER, KEY_ROOM};
ArrayList<String> array = new ArrayList<String>();
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE2, columns,KEY_ROOMMOVEHOLDER + "='" + mn + "'",
null, null, null, null);
int iroom = c.getColumnIndex(KEY_ROOM);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
array.add(c.getString(iroom));
}
} catch (Exception e) {
c.close();
}
return array;
}
public void deleteMove(String m) throws SQLException{
ourDatabase.delete(DATABASE_TABLE1, KEY_MOVENAME + "='" + m + "'", null);
ourDatabase.delete(DATABASE_TABLE2, KEY_ROOMMOVEHOLDER + "='" + m + "'", null);
ourDatabase.delete(DATABASE_TABLE3, KEY_ITEMMOVEHOLDER + "='" + m + "'", null);
ourDatabase.delete(DATABASE_TABLE4, KEY_TODOMOVE + "='" + m + "'", null);
}
public ArrayList<String> getitems(){
String[] columns = new String[]{KEY_ID5, KEY_ITEMNAME};
ArrayList<String> items;
items = new ArrayList<String>();
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE5, columns, null, null, null, null, null);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
items.add(c.getString(1));
}
} catch (Exception e) {
c.close();
}
return items;
}
public ArrayList<String> getitemweight(){
String[] columns = new String[]{KEY_ID5, KEY_ITEMWEIGHT};
ArrayList<String> items = new ArrayList<String>();
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE5, columns, null, null, null, null, null);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
items.add(c.getString(1));
}
} catch (Exception e) {
c.close();
}
return items;
}
public ArrayList<String> getitemclass(){
String[] columns = new String[]{KEY_ID5, KEY_LISTITEMROOM};
ArrayList<String> items = new ArrayList<String>();
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE5, columns, null, null, null, null, null);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
items.add(c.getString(1));
}
} catch (Exception e) {
c.close();
}
return items;
}
}
推荐答案
您没有关闭getDateMove，getTotalWeightLBS，loadRooms，...
You're not closing cursor in getDateMove, getTotalWeightLBS, loadRooms,...
在不再需要光标的任何地方都将其关闭.在那些使用try-finally的方法中，即使发生抛出异常，也可以保证在finally块中执行代码.
Everywhere where cursor is not needed anymore close it. In those methods use try-finally, it will guarantee to execute code in finally block even when thrown exception occur.
在此方法中更改代码:
try{
// get data from cursor
} catch (Exception e) {
c.close();
}
对此:
try {
// get data from cursor
} catch (Exception e) {
// exception handling
} finally {
if(c != null){
c.close();
}
}
这篇关于如何在Android中正确关闭游标的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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