数据未写入文件？

Question

我正在使用 FastttCamera 作为 AVFoundation 的包装器，以便在我的应用程序中实现相机。在我尝试使用以下代码保存捕获的图像之前，一切似乎都正常：

- (void)cameraController:(FastttCamera *)cameraController didFinishScalingCapturedImage:(FastttCapturedImage *)capturedImage
{
    //Use the image's data that is received
    pngData = UIImagePNGRepresentation(capturedImage.scaledImage);

    NSLog(@"1 The size of pngData should be %lu",(unsigned long)pngData.length);

    //Save the image someplace, and add the path to this transaction's picPath attribute
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory

    int timestamp = [[NSDate date] timeIntervalSince1970];

    NSString *timeTag = [NSString stringWithFormat:@"%d",timestamp];

    filePath = [documentsPath stringByAppendingString:timeTag]; //Add the file name


    NSLog(@"The picture was saved at %@",filePath);


    [self.imageWell setImage:capturedImage.scaledImage];
}

和

...
    [pngData writeToFile:filePath atomically:YES]; //Write the file

    NSLog(@"The pngData is written to file at %@",filePath);

    NSLog(@"2 The size of this file should be %lu",(unsigned long)pngData.length);

    self.thisTransaction.picPath = filePath;
...

我稍后尝试检索图片以在表格视图单元格中使用，但没有显示任何内容。所以我开始尝试跟踪哪里出了问题，显然数据实际上并没有写入文件路径指定的文件中。我从战略性放置的 NSLogs:

获得以下控制台读数

The pngData is written to file at /var/mobile/Containers/Data/Application/114FC402-83E0-4D15-B1E0-68E09DAB34DC/Documents1431292149
The size of this file should be 213633

和这个 return 来自文件路径的文件：

The size of fileSizeFromFilePath is 0

我已经看过很多 SO 问题，但一直没弄明白。有人可以告诉我哪里出错了吗？

Answer 1

pngData 写入了不存在的错误路径 /path/to/sandbox/Documents1431292149。

你应该替换

filePath = [documentsPath stringByAppendingString:timeTag];

和

filePath = [documentsPath stringByAppendingPathComponent:timeTag];

数据未写入文件？

Data not being written to file?

objective-c

filepath

ios

nsdocumentdirectory