3

以下是代码：

NSData * imageData = [NSData dataWithContentsOfURL:imageURL];                

 [imageData writeToFile:savedImagePath options:NSDataWritingAtomic error:&error];
                            if(error != nil)
 NSLog(@"write error %@", error);

错误：

 write error Error Domain=NSCocoaErrorDomain Code=4 "The operation couldn’t be completed. (Cocoa error 4.)" UserInfo=0x8b7b850 {NSUnderlyingError=0x8b7d7c0 "The operation couldn’t be completed. No such file or directory", NSFilePath=/Users/alfa-1/Library/Application Support/iPhone Simulator/6.0/Applications/C24B228A-599E-4249-97A7-17775E8A546B/Library/Caches/ChannelListImages/http:/direct.domain.com/files/icons/1-all-cb.jpg, NSUserStringVariant=Folder}
4

2 回答 2

5

在将数据写入文件之前。您需要创建文件夹。按着这些次序

#define APPLICATION_DATA_DIRECTORY @"Application Data"
+ (NSString *)cachesDirectoryPath
// Returns the path to the caches directory.  This is a class method because it's
// used by +applicationStartup.
{
    NSString *      result;
    NSArray *       paths;

    result = nil;
    paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    if ( (paths != nil) && ([paths count] != 0) ) {
        assert([[paths objectAtIndex:0] isKindOfClass:[NSString class]]);
        result = [paths objectAtIndex:0];
    }
    result = [result stringByAppendingPathComponent:APPLICATION_DATA_DIRECTORY];
    if (![[NSFileManager defaultManager] fileExistsAtPath:result]) {
        [[NSFileManager defaultManager] createDirectoryAtPath:result withIntermediateDirectories:YES attributes:nil error:NULL];
    }

    return result;
}

在这之后：#define kPhotosDirectoryName @"ApplicationDocuments"

    NSMutableString *savePath = [NSMutableString string];
    [savePath appendFormat:@"%@/%@",[YOURClass cachesDirectoryPath],kPhotosDirectoryName];

    [savePath appendFormat:@"/%@",YOUR_FILE_NAME];

    if (![[NSFileManager defaultManager] fileExistsAtPath:savePath]) {
        //write the data to file here
    }
于 2013-02-21T12:56:48.000 回答
1

试试这个样本。这个对我有用。

在 .h 文件中声明 -(NSString*) 数据文件路径

-(NSString *) datafilepath{
NSArray *path=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documents=[path objectAtIndex:0];
return [documents stringByAppendingFormat:@"/sample.plist"];
}

任何你想执行写功能的地方

NSData * imageData = [NSData dataWithContentsOfURL:imageURL];                
[imageData writeToFile:[self datafilepath]atomically:YES];
 if(error != nil)
 NSLog(@"write error %@", error);

希望这可以帮助！！！

于 2013-02-21T12:50:50.870 回答