Text Areas

Den här förmiddagen roar jag mig med den här sidan; How to use Text Areas.

Tänkte lägga upp koden men internet strular på den andra datorn (ja jag sitter med två datorer samtidigt, hehe).

TextField, layout, text&graphics

Lecture 21.

TextField, Layout (Grid and Table) and Text & Graphics. Again a lecture with a lot of code. I am going to dive right into that any second now.

Interactors( GUI)

Lecture 20.

GUI - Graphical User Interface
Interactors

A lot of coding in this lecture. I had to change a lot in his code because i don't have access to the Stanfords own library (which what I understand has  a lot of methods already written in it to simplify for the students). Anyhow, interactors are buttons, sliders, checkboxes, radio buttons, combo box and text box.

Don't forget to create an instance variable if you need to keep track of the variable between methodcalles.
Ex.
   pick = new JComboBox();
......
}
private JComboBox pick;

Iterator

Lecture 19.

Iterator
  -> lists through set of values

ArrayList

ArrayList<String> name new ArrayList<String>( );
Iterator<String> it = names.iterator( );

//Always ask if there are any values left
   while(it.hasNext()){
       println(it.next());
 }

HashMap

Don't have the values in order.

//You ask for the key and not the corresponding value
   Iterator<String> i = phonebook.keySet( ).iterator( );
//And then use the whileloop

If you don't want to create the iterator there is a new way of writing:
   for (String name : phonebook.keySet()){
          println(name)
}

Interface, Map and HashMap

Lecture 19.
Interface
-> set of methods
-> common functionality among a set of classes

Syntax: public class ClassName implements InterfaceName


Interface is more general than extends.

Map (interface)
Key
Value


An association between a key and a value. Always keysensitive.
Ex. Dictionary - a map
      words - key
      defintions - value
Ex. Phonebook - a map
      names - key
      numbers - value

HashMap (class)
     -> implements Map
template -> 2 types ( one type for your keys and one for your values)

HashMap<String, Integer> phonebook = new HashMap<String, Integer>( );

Methods most commonly used: put and get, but also remove, containskey and size.

phonebook.put("Mehran", 7236059);
phonebook.put("Jenny", 8675309);

Integer MehranNumber = phonebook.get("Mehran");

phonebook.remove(key); //removes key AND value
phonebook.containskey(key); // returns a boolean

THINK of it as a bag where you put things in pairs. No order.

Debugging

Lecture 18.

Design - Architect
Coding - Engineer
Testing - Vandal!
Debugging - Detective

Always be a vandal! 

Bad values, faulty logic and unwarranted assumptions (ex. feet instead of meters) causes bugs.

- Most of the problems are SIMPLE
- Be systematic
- Don't make assumptions about the problem(s)
- Be critical (< instead of >)
And don't panic!

Use println to find bugs. Ex. before and after a method or writing out variables.
Unit test - test one unit at the time (with values you give)

Arraylist vs array

Lecture 18.
Arraylist

+ dynamic resized
+ other operations

- less efficient than an array
- syntax is bulky (more errors can occur)
- pre version 5.0

If you have a fixed size (almost) always use an array!