使用分隔符nsstring读取文本文件

Question

I have a text file like this

question1 question2 question3

I want to read only the first line into a nsstring

after that I want to mark the first line so the next time, skip the first line, but I don't know how to do it, I have this code for read but give me only the third line

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"qa" ofType:@"txt"];  

NSString *myText = [NSString  stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];   
NSArray *lines = [myText componentsSeparatedByString:@"\n"];    
for(myText in lines)
{

    texview.text = myText;  

}


}  

Ok I try this code, Do not work, what I am Doing wrong?

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString * const kKey = @"OneTimeKey";
NSObject  *keyValue = [defaults  objectForKey:kKey];



NSString *filePath = [[NSBundle mainBundle] pathForResource:@"qa" ofType:@"txt"];  

NSString *myText = [NSString  stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];   
NSArray *lines = [myText componentsSeparatedByString:@"|"];    



if (keyValue==nil) {
    for(myText in lines)

    {

        preguntadia.text = myText;  

        [defaults setBool:YES forKey:kKey];

    }



}

Answer 1

The problem is that your "for" is executed really fast, so fast that you can only see when the last element of the array is set to your text view.

What you can do is have a variable which specifies which one of the strings to show next and, with a timer, set a different string on your text view every number of seconds, so you can actually see the changes.

Bonus, you can make it cycle with something like this:

-(void)updateText{
    [textView setText:[lines objectAtIndex:currentIndex]];
    currentIndex++;
    currentIndex = currentIndex % [lines count];
}

So when it reaches the last string, it shows the first again.

Answer 2

You'll need to store a line counter locally to keep track, I think. That is easily accomplished with something like this to save:

[[NSUserDefaults standardDefaults] setInteger:lineCount forKey:@"lineCountKey"];

and fetch:

int lineCount = [[NSUserDefaults standardDefaults] integerForKey:@"lineCountKey"];

and then just read and discard lineCount lines when you open the file.

Now, splitting the line you want into multiple pieces, you can use the NSString method componentsSeparatedByString: , but be careful. If your "questions" are actually multi-word questions, you'll need to pick a separator other than space. Vertical bar (|) might be a good choice, then you can do something like this:

NSArray *questions = [line componentsSeparatedByString:@"|"];

NB: Code typed from memory; not compiled. :-)