[NSBundle mainBundle]pathForResource返回空

Question

我正在尝试将我的应用程序连接到SQLite数据库，但收到的消息告诉我数据库已创建，但没有表。

我调试了程序，发现[[NSBundle mainBundle] pathForResource]总是返回nil

NSString* file = [[NSBundle mainBundle]pathForResource:_databaseName ofType:_databaseType];

为什么会发生这种情况？请帮帮我!

Answer 1

首先:确保您的数据库在应用程序包中。

然后，您需要实现将路径复制到文档目录.as的方法

-(NSString *) getDBPath:(NSString*)databaseName {
// search for the existed paths
NSArray *paths = NSSearchPathForDirectoriesInDomains(  NSDocumentDirectory , NSUserDomainMask, YES);
  NSString *documentsDir = [paths objectAtIndex:0];


return [documentsDir stringByAppendingPathComponent:databaseName];

}

- (void) InstantiateYourDatabase:(NSString *)DatabaseName {


//Using NSFileManager we can perform many file system operations.

NSFileManager *fileManager = [NSFileManager defaultManager];

NSError *error;
NSString *dpname=DatabaseName;

_dbPath = [self getDBPath:dpname];

BOOL success = [fileManager fileExistsAtPath:_dbPath];

NSLog(@"success == %i",success);

if( !success) {

    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] 
                               stringByAppendingPathComponent:DatabaseName];
    success = [fileManager copyItemAtPath:defaultDBPath toPath:_dbPath error:&error];

}  

}

告诉我这有没有帮助！

Answer 2

尝试使用以下代码查找数据库路径

    NSString *databaseName = @"your_db_name.sql";
    NSString *databasePath;
    // Get the path to the documents directory and append the databaseName
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [documentPaths objectAtIndex:0];
    databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
    NSLog(@"Database Path is: %@",databasePath);

您想了解有关iOS中Sqllite数据库连接的更多详细信息，请尝试此tutorial

欢迎!

Answer 3

如果您创建了一个sqlite db文件并将其拖到xcode3中的项目中，则它在运行时位于应用程序文档文件夹中。

NSString *databaseName = @"cartoon.db";
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentDir = [documentPaths objectAtIndex:0];
NSString *databasePath = [documentDir stringByAppendingPathComponent:databaseName];