IOS UI distinguish between NSBundle and NSURL (read file write file)

The example of this article is to distinguish NSBundle and NSURL, and the specific implementation content is as follows

Add a file to the project. aa.txt is added in this routine, and the content of the file is baidu: www.baidu.com. Now we need to use NSBundle and NSURL to get the content respectively.

//   Read file contents 
//   methods 1: Read by file path 
  NSString *pathBundle = [[NSBundle mainBundle]pathForResource:@"aa" ofType:@"txt"];
  NSString *outstringbundle = [NSString stringWithContentsOfFile:pathBundle encoding:NSUTF8StringEncoding error:nil];
  
//   methods 2: In accordance with the URL read 
  NSURL *pathUrl = [[NSBundle mainBundle]URLForResource:@"aa" withExtension:@"txt" subdirectory:nil];
  NSString *outstringUrl = [NSString stringWithContentsOfURL:pathUrl encoding:NSUTF8StringEncoding error:nil];
  
  NSLog(@"%@\n////////\n%@",outstringbundle,outstringUrl);

The output results are as follows:

2016-03-30 14:48:02.939  Sandbox mechanism and The file path [11786:518929]  baidu : www.baidu.com
 ////////
  baidu : www.baidu.com

Write to file:

First, create a new file:

NSString *newPath = [NSString stringWithFormat:@"%@/Documents/New",NSHomeDirectory()];
 //   Define the file path and file name first 
   NSString *newfile = [NSString stringWithFormat:@"%@/new.mp3",newPath];
 //   use createFileAtPath Create a file 
   [[NSFileManager defaultManager]createFileAtPath:newfile contents:nil attributes:nil];
   NSLog(@"%@",newPath);

After reading and writing:

//   Written to the file 
//  1 , use first data Read the data 
  NSData *data = [[NSData alloc]initWithContentsOfFile:pathBundle];
  NSLog(@"%@",data);
  
//  2 , to read data Write to the sandbox file, newfile Created in the sandbox file above mp3 file 
  [data writeToFile:newfile atomically:YES];

I hope it will be helpful for you to distinguish NSBundle from NSURL through a brief example.