CODEWITHSUNDEEP
javaandroidjava.util.scanner
Ahmed I. Elsayed
Ahmed I. Elsayed

Reputation: 2130

what's the point of using scanners in java (android)

Let me explain in detail, I kept googling about scanners and I can't fully understand what are scanners exactly. I read many articles but all of them say

The java.util.Scanner class is a simple text scanner which can parse primitive types and strings using regular expressions

quoted from the official website, most websites took it and non of them said what a scanner is in english

Let me illustrate.

I have 3 views, a Button, EditText,TextView. I wanted to take the text from the EditView and put it in the TextView and I have 2 approaches, my question is what is the difference between them.

ALL THIS CODE GOES INTO THE ONCLICK LISTENER.

 Scanner sc = new Scanner(editText.getText().toString());
 String a = sc.next();
 txv.setText(a);

and this txv.setText(editText.getText().toString());

I got the data and it worked exactly the same in both cases and I can't seem to find anything useful.

Upvotes: 2

Views: 87

Answers (1)

OneCricketeer
OneCricketeer

Reputation: 191844

You shouldn't be using Scanner here, you should be using StringTokenizer, or just split("\\s+")[0] on the string.

But sc.next() will read the first consecutive non-whitespace characters of the Scanner's input string into the variable a, which gets set to the next textview.

For example 

Scanner sc = new Scanner("hello world");
String s = sc.next(); // == "hello"

Otherwise, in CLI applications Scanner is used for interactive inputs. Doesn't have much other use cases in production code that I can think of. Even for reading files, BufferedReader or the NIO API would be preferred

Upvotes: 4

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