将NSMutableString写入文件

Question

what is suppose to be wrong here with my code:

-(void)writetofile:(NSMutableString *)str{
    NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory,
                                                         NSUserDomainMask, YES);
    NSString *path = [paths objectAtIndex:0];
    NSString *filePath = [NSString stringWithFormat:@"%@/code.txt",path];

    NSStringEncoding *encode=NULL;

    [str writeToFile:filePath atomically:YES encoding:*encode error:nil];
}

Answer 1

try this:

NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory,
                                                     NSUserDomainMask, YES);
NSString *path = [paths objectAtIndex:0];
NSString *filePath = [path stringByAppendingPathComponent:@"code.txt"];
[str writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:nil];

Answer 2

You are dereferencing a NULL pointer:

NSStringEncoding *encode = NULL;

`... encoding:*encode ...`

Instead, just use NSUTF8StringEncoding :

[str writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:nil];