尝试从包复制到文档目录时出错

Question

我已将一个 sqlite 文件添加到我的应用程序中，并试图将其从包中复制到文档目录中。我也将 sqlite 添加到目标应用程序。以下是我用来复制文件的代码：

NSString *destination = [[[Utils applicationDocumentsDirectory] absoluteString] stringByAppendingString:@"myapp.sqlite"];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if (![fileManager fileExistsAtPath:destination]) {
        NSString *source = [[NSBundle mainBundle] pathForResource:@"myapp" ofType:@"sqlite"];
        NSError *error = nil;
        [fileManager copyItemAtPath:source toPath:destination error:&error];
        if (error) {
            //
        }
    }

[Utils applicationDocumentsDirectory] 的代码：

+ (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

但是当执行这段代码时，我得到以下 error:

Error Domain=NSCocoaErrorDomain Code=4 "The file “myapp.sqlite” doesn’t exist." UserInfo={NSSourceFilePathErrorKey=/Users/harikrishnant/Library/Developer/CoreSimulator/Devices/8E531314-F1AE-417F-8E99-7AA92967CDC9/data/Containers/Bundle/Application/0A710929-475D-457C-8D2D-C2F2BBEB6B92/myapp.app/myapp.sqlite, NSUserStringVariant=( Copy ), NSDestinationFilePath=file:///Users/harikrishnant/Library/Developer/CoreSimulator/Devices/8E531314-F1AE-417F-8E99-7AA92967CDC9/data/Containers/Data/Application/13B22E15-D00C-433C-9F02-014B1F73D183/Documents/myapp.sqlite, NSFilePath=/Users/harikrishnant/Library/Developer/CoreSimulator/Devices/8E531314-F1AE-417F-8E99-7AA92967CDC9/data/Containers/Bundle/Application/0A710929-475D-457C-8D2D-C2F2BBEB6B92/myapp.app/myapp.sqlite, NSUnderlyingError=0x7faffe1b5cf0 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}

我使用终端检查了以下路径，发现 sqlite 文件确实存在于应用程序包中：

/Users/harikrishnant/Library/Developer/CoreSimulator/Devices/8E531314-F1AE-417F-8E99-7AA92967CDC9/data/Containers/Bundle/Application/0A710929-475D-457C-8D2D-C2F2BBEB6B92/myapp.app/myapp.sqlite

但我仍然收到此错误。我尝试了一切。我什至清理了构建文件夹并重新安装了应用程序，它仍然没有用。这可能是什么问题？如何解决？

Answer 1

我使用下面的代码将我的 SQLite 数据库从应用程序包复制到文档目录。
注意 'Database' 是文件夹名称。 'datasource' 是我的数据库名称，它的扩展名是 'db'

-(void)saveDatabase{
        //put bundle database to DocumentDirectory
        NSLog(@"%@",[self databasePath]);
        //Create Path For Destination
        NSString* path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
        path = [path stringByAppendingPathComponent:@"Database"];
        BOOL isExists=[[NSFileManager defaultManager]fileExistsAtPath:path];
        if(!isExists){
            NSError* error;
            BOOL isCreated = [[NSFileManager defaultManager]createDirectoryAtPath:path withIntermediateDirectories:NO attributes:nil error:&error];
            if(isCreated){
                path = [path stringByAppendingPathComponent:@"Datasource"];
                path = [path stringByAppendingPathExtension:@"db"];
                isExists = [[NSFileManager defaultManager]fileExistsAtPath:path];
                if(!isExists){
                    NSError* dbError;
                    NSString* bundle = [[NSBundle mainBundle]pathForResource:@"Datasource" ofType:@"db"];
                    isCreated = [[NSFileManager defaultManager]copyItemAtPath:bundle toPath:path error:&dbError];
                    if(isCreated){
                        NSLog(@"DatabasePath %@",path);
                    }else{
                        NSLog(@"ErrorCopying DB file %@",dbError.localizedDescription);
                    }
                }else{

                }

            }else{
                NSLog(@"Error While Creating Database Directory:->%@",error.localizedDescription);
            }
        }
    }
    - (NSString*)databasePath{
        NSString* path = [self documentDirectory];
        path = [path stringByAppendingPathComponent:@"Database"];
        path = [path stringByAppendingPathComponent:@"Datasource"];
        path = [path stringByAppendingPathExtension:@"db"];
        return path;
    }
    - (NSString*)documentDirectory{
        return [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
    }

Answer 2

确保您的文件在您使用的目标中的 Build Phases -> Copy Bundle Resources 中列出。尝试删除 Derived data。如果仍然不起作用，请转至 Derived data 并使用 Finder 检查文件。

Answer 3

您的代码几乎是正确的。此行有两个缺陷：

NSString *destination = [[[Utils applicationDocumentsDirectory] absoluteString] stringByAppendingString:@"myapp.sqlite"];

absoluteString 的使用不正确。这将以 file://path/to/Documents/ 的形式给出一个文件 URL。您需要使用 path 方法从 NSURL.

中获取文件路径（不是文件 URL）

然后您需要将文件名正确附加到路径中。您需要使用 stringByAppendingPathComponent: 而不是 stringByAppendingString:。

那一行应该是：

NSString *destination = [[[Utils applicationDocumentsDirectory] path] stringByAppendingPathComponent:@"myapp.sqlite"];

尝试从包复制到文档目录时出错

Error trying to copy from bundle to documents directory

objective-c

nsfilemanager

nsbundle

ios