我正在为学校项目创建一个应用程序，该应用程序必须将数据写入sqlite数据库。只要该应用程序处于活动状态，它就会起作用，但是一旦该应用程序关闭，我添加的数据就会消失，并且当我想读取此数据时，它将无法正常运行。我同时包含了loadData和saveData方法。这两个函数中的两个数据库路径相同，因此并不是在其他地方写数据。我真的找不到解决方案或问题。我什至在输出中获得插入成功，因此插入成功。
- (void) saveData:(id)sender{
NSString *sqldb = [[NSBundle mainBundle] pathForResource:@"PXLate" ofType:@"sqlite3"];
sqlite3_stmt *stmt;
NSString *queryInsert = @"INSERT INTO assignments (name, lesson, dueDate, notification, start, at) VALUES ('abc','abc', 'abc', 1, 'abc', 'abc')";
NSLog(@"%@",sqldb);
NSLog(@"%@",queryInsert);
if(sqlite3_open([sqldb UTF8String], &_PXLate) == SQLITE_OK)
{
sqlite3_prepare_v2(_PXLate, [queryInsert UTF8String], -1, &stmt, NULL);
if(sqlite3_step(stmt)==SQLITE_DONE)
{
NSLog(@"insert success");
}
else
{
NSLog(@"insert un success");
NSAssert1(0, @"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(_PXLate));
}
int success=sqlite3_step(stmt);
if (success == SQLITE_ERROR)
{
NSAssert1(0, @"Error: failed to insert into the database with message '%s'.", sqlite3_errmsg(_PXLate));
//[_PXLate save:&error];
} sqlite3_finalize(stmt);
}
sqlite3_close(_PXLate);
}
和我的
loadData函数- (void) loadData:(id)sender
{
//path for database
NSString *sqldb = [[NSBundle mainBundle] pathForResource:@"PXLate" ofType:@"sqlite3"];
//check if present
NSFileManager*fm=[NSFileManager defaultManager];
NSLog(@"path: %@", sqldb);
const char *dbpath = [sqldb UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &_PXLate) == SQLITE_OK)
{
NSString *querySQL = [NSString stringWithFormat: @"SELECT * FROM assignments WHERE name='abc'", _label.text];
const char *query_stmt = [querySQL UTF8String];
NSLog(@"name");
NSLog(querySQL);
int response = sqlite3_prepare_v2(_PXLate, query_stmt, -1, &statement, NULL);
NSLog(@"response %d", response);
if (response == SQLITE_OK)
{
NSLog(@"name");
if (sqlite3_step(statement) == SQLITE_ROW)
{
NSString *namefield = [[NSString alloc]
initWithUTF8String:
(const char *) sqlite3_column_text(
statement, 0)];
NSLog(@"name:%@", namefield);
_label.text = namefield;
} else {
_label.text = @"Match not found";
}
sqlite3_finalize(statement);
}
sqlite3_close(_PXLate);
}
}
最佳答案
您必须将sqlite复制到documents目录，然后使用它。例：
self.databaseName = @"databasename.sqlite";
// Get the path to the documents directory and append the databaseName
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
self.databasePath = [[NSString alloc]init];
self.databasePath = [documentsDir stringByAppendingPathComponent:self.databaseName];
[self checkAndCreateDatabase];
和创建方法：
-(void)checkAndCreateDatabase
{
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:self.databaseName];
[fileManager copyItemAtPath:databasePathFromApp toPath:self.databasePath error:nil];
}