In iOS, when QLPreviewController is used to open a file and process txt files with garbled characters, qlpreviewcontroller

In iOS, when QLPreviewController is used to open a file and process txt files with garbled characters, qlpreviewcontroller
In iOS, QLPreviewController is used to open a file and process Garbled text files.

Main Code:

-(Id <QLPreviewItem>) previewController :( QLPreviewController *) controller previewItemAtIndex :( NSInteger) index {// handle the case where the txt format content is garbled NSData * fileData = [NSData dataWithContentsOfFile: self. files]; // determines whether it is UNICODE-encoded NSString * isUNICODE = [[NSString alloc] initWithData: fileData encoding: NSUTF8StringEncoding]; // or ANSI-encoded (-2147483623,-2147482591, -2147482062,-2147481296) encoding: select either of the following options: NSString * isANSI = [[NSString alloc] initWithData: fileData encoding:-2147483623]; if (isUNICODE) {NSString * retStr = [[NSString alloc] initWithCString: [isUNICODE UTF8String] encoding: NSUTF8StringEncoding]; NSData * data = [retStr dataUsingEncoding: callback]; [data writeToFile: self. files atomically: YES];} else if (isANSI) {NSData * data = [isANSI dataUsingEncoding: NSUTF16StringEncoding]; [data writeToFile: self. files atomically: YES];} return [NSURL fileURLWithPath: self. files];}