问题描述
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我有一个打开了4或5个sql表的应用程序。
当用户点击主页按钮并调用applicationDidEnterBackground时,我将所有脏记录保存到表中:
[self.shoppingListArray makeObjectsPerformSelector:@selector(saveAllData)];
...
- (void)saveAllData {
if(isDirty) {
if(updateStmt == nil) {
const char *sql = \"UPDATE ShoppingList SET Section = ?,Question = ?,Checked = ?,Modified = ? WHERE ID = ?\";
if(sqlite3_prepare_v2(database,sql,-1,&updateStmt,NULL) != sqlITE_OK)
NSAssert1(0,@\"Error while creating update statement. \'%s\'\",sqlite3_errmsg(database));
}
NSLog(@\"DIRTY Item Was Updated: %@\",Question);
sqlite3_bind_text(updateStmt,1,[Section UTF8String],sqlITE_TRANSIENT);
sqlite3_bind_text(updateStmt,2,[Question UTF8String],3,isChecked ? [@\"YES\" UTF8String]:[@\"NO\" UTF8String],4,isModified ? [@\"YES\" UTF8String]:[@\"NO\" UTF8String],sqlITE_TRANSIENT);
sqlite3_bind_int(updateStmt,5,ID);
if(sqlITE_DONE != sqlite3_step(updateStmt))
NSAssert1(0,@\"Error while updating. \'%s\'\",sqlite3_errmsg(database));
sqlite3_reset(updateStmt);
isDirty = NO;
}
//Reclaim all memory here.
[Section release];
Section = nil;
[Question release];
Question = nil;
isDetailViewHydrated = NO;
}
然后,我完成语句并关闭数据库:
[ShoppingListinformation finalizeStatements];
...
+ (void) finalizeStatements {
if(database) sqlite3_close(database);
if(deleteStmt) sqlite3_finalize(deleteStmt);
if(updateStmt) sqlite3_finalize(updateStmt);
if(addStmt) sqlite3_finalize(addStmt);
}
所以,问题是当调用applicationWillEnterForeground时该怎么办?
我是否重新打开数据库,重新填充数组并重新加载表视图?
如何做到这一点并且不丢失用户数据,还原状态等的最佳实践是什么?
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解决方法
我建议不要关闭db或finalize语句,除非应用程序正在关闭(applicationWillTerminate :)。然后,您将以离开应用程序的状态回到应用程序,无需执行任何操作。我不太肯定这是最有效的方法,但对我有用。