Field Trip #26 Create a Find a Word Puzzle in Java By Keith Lynn

JPanel A JPanel is a lightweight container that can be placed inside of other containers It can have its own layout For this app, we will make the layout of a JPanel a grid

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

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

Character 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

Events Events can be detected and acted on by creating listeners In this app, we will have three different kind of event listeners We will attach an ActionListener to a single button that will start the puzzle For each button in the grid, we will attach both a MouseListener and MouseMotionListener The MouseListener will be use to determine when we let up on the mouse The MouseMotionListener will be use to determine when we drag the mouse

Color In this app, when a word has been found, we will change the background color of the button to red We will change the text color to white

Fonts Fonts allows us to change the appearance of text We will display a list of words the user will find When a user correctly finds one, the font of the word will be changed to strikethrough

Arrays Arrays are a collection of elements of the same type In this app, we will consider what is actually a 2 dimensional array Java doesn't directly support 2 dimensional arrays so we will create an array of arrays The array will hold all of the buttons The buttons contain letters

Subclasses In this app, we will also make use of the ability to create subclasses If a class is not declared final, then we can create a new class called a subclass We can add additional functionality to the subclass

The game The idea behind the game to choose randomly words from a list We create a grid of 400 letters and randomly choose locations to place those words in the grid After we have placed those words, we fill the other buttons in with random letters The words hidden are displayed in a list

The game, cont'd The player will search through the grid trying to locate the words When a player thinks they have found the word, they will hold down the mouse on the first letter and drag the mouse to the last letter When the player begins dragging the mouse, a MouseMotionEvent is fired We record the buttons that the user drags the mouse over

The game, cont'd When the user lets up on the mouse, a MouseEvent is fired We then collect the letters from the buttons the user selected We create a String from the letters and check to see if it is in the list If it is, then we change the font of the word to strikethrough If the user wants to start over, we provide a button to reset the grid