数据不会保存到桌面

Question

I am trying to pull a PDF file from Parse through Simulator and save it onto my Desktop when a button is clicked on my app. Problem is that no matter what i do file doesn't show up on Desktop nor anywhere else. I am using this method for my download button

-(void) Savefile {
    NSFileManager *filemanager = [NSFileManager defaultManager];
    [self.downloadfile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
        if (error)  {

        }
        else if (data) {
            [filemanager createFileAtPath:@"file:///Users/Danny/Desktop" contents:data attributes:nil];
            [data writeToFile:@"file:///Users/Danny/Desktop" atomically:NO ];
            NSLog(@"Downloading file...");
        }
    }];

}

downloadFile is a PFFile property that stores the index of my PDFfile as i move it through segue. Its declared as this:

@property (retain,nonatomic) PFFile * downloadfile;

this here is the segue:

detailVC.downloadfile=[[PDFArray objectAtIndex:indexPath.row]objectForKey:@"PDFFile"];

can't get it to save to desktop.

Answer 1

The path in which you are trying to download Pdf file does not exist in iOS Device, if you want to download file in your device you can try like this :-

-(void) Savefile {

    [self.downloadfile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
        if (error)
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Wooopss!" message:@"Download failed. Try Again..." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
            [alert show];
        }
        else if (data)
        {
            NSString *downloadFilePath = [NSString stringWithFormat:@"%@/Documents/PDFFile/hello_%@.pdf", NSHomeDirectory(),[self getCurrentDate]];

            if( ![[NSFileManager defaultManager] fileExistsAtPath:downloadFilePath] )
            {
                NSLog(@"File don't exist at that path");
            }
            else
            {
                NSError *error = nil;
                [[NSFileManager defaultManager] removeItemAtPath:downloadFilePath error:&error];
            }

            [[NSFileManager defaultManager] createFileAtPath:downloadFilePath contents:nil attributes:nil];

            NSLog(@"Downloading file...");

            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Downloading" message:@"File is being downloaded..." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
            [alert show];
        }
    }];

}
//Below method will return you current timestamp through which you can download new PDF with new name

-(NSString *)getCurrentDate
{

    NSDateFormatter *dateFormatter = [NSDateFormatter new];
    [dateFormatter setDateFormat:@"MMddYYYYmmss"];

    NSString *date = [dateFormatter stringFromDate:[NSDate date]];

    return date;
}

Hope this will help you Happy Coding :)

Answer 2

iOS devices don't have a desktop. If iOS did have a desktop, an app would't be able to write to it anyway as iOS apps are sandboxed so they cannot write outside of their own data storage area.

Even when running on the simulator, you cannot write to the OSX Desktop, because the app is sandboxed into the Simulator file storage. You can save the file to your app sandbox and then access the simulator storage from finder -

Is there any way to see the file system on the iOS simulator?