Field Trip #31 CrossWord Puzzle By Keith Lynn

JApplet A JApplet is a top-level container in Java We will use the JApplet to contain two Jpanels The first JPanel will contain letters The second JPanel will contain words In order to load a JApplet, we create an HTML document The HTML document must contain an applet tag The applet tag must contain the applet's name, width, and height

Appletviewer An alternative to using a browser is to use the appletviewer program that is included in the JDK In order to use the appletviewer program, we create an HTML document where we include an applet tag The applet tag must contain the name of the class, the width and height

LayoutManager A LayoutManager defines how components will be placed onto a screen There are built-in layout managers in Java FlowLayout will put components in a row GridLayout will put components in a grid In this app, we will create a Jpanel to hold letters in buttons and put the buttons in a grid

String A String is a collection of individual characters We can obtain the character at a certain position in a String with the method charAt(int) The first character in a String is at position 0 We can determine the length of the String with the length() method We can concatenate characters to String with the += operator We can compare the content of two Strings with the equals or equalsIgnoreCase methods

Characters A character is a single character There is a special relationship between chars and ints in Java If you treat a char like an int, it is converted to its ASCII equivalent

JComboBox A JComboBox is a selection list It will contain a list of items In this app, we will create many JComboBoxes that contain the letters of the alphabet

JButton A JButton is a component that can be placed on a container The JButton can contain text or an image In this app, we will provide the user with button to give up

Events We can detect events and act on them by creating an event listener An event listener we can use with a button is the ActionListener ActionListener is an interface which contains the method actionPerformed If an ActionListener is registered with a button, then when the button is clicked, actionPerformed is called

Events, cont'd The event listener we will use with the JComboBoxes is the ItemListener The ItemListener interface contains the method itemStateChanged We can determine whether the state change was ItemEvent.SELECTED or ItemEvent.DESELECTED by using the method getStateChange Note that selecting an item in a JComboBox causes both a deselection and a selection event

Arrays Arrays are a collection of elements of the same type In our app, we will use a 2 dimensional array Java doesn't directly support 2 dimensional arrays But we can create an array of arrays We write a 2 dimensional array of 20 x 20 containing JcomboBoxes However, we will black out some boxes

Filling in Words We choose beforehand to black out certain boxes leaving only 26 positions to be filled with words Some of those words overlap We will load from a text file a list of words and definitions and choose 26 words randomly We make sure that we choose words that have the correct letters if the words overlap

The Game After the list of words and clues are loaded and we have chosen the words, we will display the clue for the word in a JComboBox The JComboBoxes corresponding to the word that goes with the clue will be highlighted in red If the user correctly chooses the letters, then the JComboBoxes are highlighted in green If the user gives up, then all of the words are displayed and all JComboBoxes that contains letters of words are highlighted in green