ios copy项目文件到Documents目录下
NSFileManager*fileManager =[NSFileManager defaultManager];
NSError*error;
NSArray*paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString*documentsDirectory =[paths objectAtIndex:0];
NSString*txtPath =[documentsDirectory stringByAppendingPathComponent:@"txtFile.txt"];
if([fileManager fileExistsAtPath:txtPath]== NO){
NSString*resourcePath =[[NSBundle mainBundle] pathForResource:@"txtFile" ofType:@"txt"];
[fileManager copyItemAtPath:resourcePath toPath:txtPath error:&error];
}