INDEX
Symbols
+ (addition operator), 12
= (assignment operator), 13–15, 245, 276
{ } (braces), 23
+ (concatenation operator), 12–13, 27, 30, 130–131
-- (decrement operator), 130
" (double quotation marks), 27
== (equal-to operator), 30, 276
> (greater-than operator), 30, 60
++ (increment operator), 129
< (less-than operator), 30, 60
% (modulo operator), 139
!= (not-equal-to operator), 29
; (semicolon), 24
~ (tilde), 16
* (wildcard character), 46
A
About screen, 113–114
AbsoluteLayout value, 240
ActionListener class, 63–64, 226
action listeners, 46–47, 68, 234
actionPerformed() method, 63, 154–156, 227–228, 234
addActionListener() method, 63
addMouseListener() method, 213
addition operator (+), 12
AlertDialog class, 113–114
alert dialog pop-up, 113–114
Android devices
connecting to computer, 101
Developer mode, 100–101
preparing to run apps, 100
testing apps on, 100–102
Android emulator
BubbleDraw app, 260–261
Hi-Lo guessing game, 94–99
Secret Messages app, 188–189
Android package files (APK), 101–102
Android Studio, 1. See also BubbleDraw app (Android mobile version); Hi-Lo guessing game (Android mobile version); Secret Messages app (Android mobile version)
activity selection, 78–79
Android emulator, 94–99
correcting spelling errors, 275
default project view, 80
Design tab, 80–81
grouping symbols, 277–278
importing classes automatically, 86
installing, 8–9
SDK or API levels, 78
starting projects, 76–80
Target Android Devices window, 78
updating, 176
widgets, 81
animation, 225–229. See also BubbleDraw app (Android mobile version); BubbleDraw app (GUI version)
adding timer, 226
preparing, 227–228
setting timer, 226–227
starting timer, 229
threading, 249
anonymous inner classes, 63, 91, 155, 167, 184, 210
APK (Android package files), 101–102
application program interface (API) levels, 78
apply() method, 119
arguments, 155
arithmetic operators (+, -, *, /), 12
ArrayList data structure, 205–210, 253
assignment operator (=), 13–15, 245, 276
attributes, 26
B
binary search, 40
Boolean expressions, 65
braces ({ }), 23
break statement, 113
Bubble class, 200–205, 255–257
attributes for, 201
defining bubbles, 200–202
methods for, 202–205
modifying, 255–257
BubbleDraw app (Android mobile version)
adding animation variables, 252–253
adding testBubbles() method, 258–259
BubbleView() constructor, 254
custom app launcher icon, 268–270
adding, 268–269
changing app name, 270
creating, 268
displaying, 269–270
drawing with onDraw() method, 257–258
handling OnTouchListener events, 259–260, 264-265
modifying Bubble class, 255–257
running in Android emulator, 260–261
setting up project, 250–252
threading and multitasking, 261–264
touch event handler code, 264–265
combining single-pointer and multitouch events, 271–272
multitouch, 266–267
BubbleDraw app (desktop version)
building frame, 199
creating Bubble class, 200–205
attributes for, 201
defining bubbles, 200–202
methods for, 202–205
creating project files, 198–199
mouse events, 210–217
clicks, 212–214
creating reusable event listener, 211–212
drags, 214–215
wheel events, 215–217
pixelated effect, 219–220
size variable limits, 218
storing bubbles in ArrayList, 205–210
adding constructor, 206–207
adding method, 207–208
testing BubblePanel class, 208–210
BubbleDraw app (GUI version)
adding transparency, 224–225
animation, 225–229
adding timer, 226
preparing, 227–228
setting timer, 226–227
starting timer, 229
building GUI, 232–235
event handlers, 234–235
setting up panel and buttons, 232–233
collision detection, 235–239
hard bounces, 238–239
soft bounces, 236–238
copying project and renaming Java file, 222–223
fixed speed, 244–245
pixelated effect, 245–247
preventing stationary bubbles, 244
random speed and direction, 229–232
sharing app as runnable JAR file, 243
speed control slider, 240–243
customizing, 241
event handler, 242–243
BubbleDraw class, 199
BubbleListener class, 212–214, 227
Bubble() method, 202–204
BubblePanel class, 199, 201, 203, 206–209, 214–215
BubbleView class, 251–255
BubbleView() constructor, 254
Button component, 82, 84, 87, 180
buttons
adding, 82
adding event listeners, 62–64, 91–94
Clear button, 232–235
Click me! button, 46–47
Encode/Decode button, 152, 154–156, 159–164, 167, 179–180, 182–186
floating action button (fab), 84–85, 190–193
Guess! button, 54–55, 62–63, 66–69, 82, 93, 99
Move Up ^ button, 172–173, 196
OK button, 114
Pause/Start button, 232–235
showing and hiding, 73–74
C
Caesar cipher, 125–126
Canvas class, 256
chained assignment, 245
charAt() method, 130–132
char data type, 132
checkGuess() method, 58–59, 65, 68–69, 73, 88–89, 106, 116, 120
child classes, 49
anonymous inner classes, 63, 91, 155, 167, 184, 210
extending, 49
importing, 25
public, 23
superclasses, 48
Clear button, 232–235
Click me! button, 46–47
code recommenders, 59, 274–275
collision detection, 235–239
hard bounces, 238–239
soft bounces, 236–238
Color Chooser dialog (in Eclipse), 160, 165
Color class, 201, 203, 224, 255–256
command line apps, running without Eclipse, 141–144
opening command line window, 142–144
workspace folders, 141–142
comparison operators
not equal to (!=), 29
compiler directives, 91
concatenation operator (+), 12–13, 27, 30, 130–131
conditional expressions, 30
conditions, 28
confirm dialogs, 163
content panes, 52
D
data structures, 205
debugging, 28
case sensitivity, 274
code completion, 278
commenting out, 28
grouping symbols, 276–278
spelling errors, 274–276
statement completion, 278
syntax coloring, 273
USB debugging, 100–102, 188, 267
decrement operator (--), 130
defaultCloseOperation property, 51–52
Dimension class, 64–65
dismiss() method, 114
dot notation, 26
double quotation marks ("), 27
double variable type (double-precision floating point), 14
do-while loops, 33–35
draw() method, 204–205, 247, 256
drawOval() method, 250, 256–257
drawRect() method, 204
E
Eclipse, 1. See also BubbleDraw app (GUI version); Hi-Lo guessing game (GUI version); Secret Messages app (GUI version)
automatic indentation clean-up, 35
content assist and code recommenders, 59, 274–275
correcting spelling errors, 274–275
creating classes, 21–23
creating new Java project, 20–21
customizing appearance of, 7–8
grouping symbols, 277
installing, 3–4
perspectives, 21
saving code, 25
setting up
default workspace storage location, 4–5
installing WindowBuilder Editor, 6–7
modifying to run with Java 9, 5
setting up GUI projects, 48–49
themes, 7
WindowBuilder Editor, 50
Design tab, 50
installing, 6–7
Palette pane, 52–54
Properties pane, 51–52
Source tab, 56
workspace folders, 4–5, 141–142
/edit command, 16
editor action, 103
EditText component, 82, 84, 87, 102, 107, 178, 185
else-if statements, 138–139
else statements, 31
encapsulation, 201
Encode/Decode button, 152, 154–156, 159–164, 167, 179–180, 182–186
encode() method, 151–155, 182–185
equalsIgnoreCase() method, 34
equal-to operator (==), 30, 276
escape character sequence ( ), 107, 178
event listeners, 62, 117. See also mouse events; touch events
creating reusable, 211–212
for ENTER key, 103–104
exception handlers, 70–72
exceptions, 70
/exit command, 16
expressions, evaluating in JShell, 12–13
extending classes, 49
F
fab (floating action button) icon, 84–85, 190–193
fillOval() method, 204–205
finally block, 71–72
findViewById() method, 87
floating action button (fab) icon, 84–85, 190–193
floating-point numbers, 14
FlowLayout value, 240
focus, 69
Font Chooser dialog (in Eclipse), 159
for loops, 129–134
G
game loops (do-while loops), 33–35
getHeight() method, 236–238
getInt() method, 120
getMenuInflator() method, 111
getPointerCount() method, 266, 271
getProgress() method, 186
getSource() method, 235
getStringExtra() method, 194
getText() method, 59, 155, 185
getUnitsToScroll() method, 216
getValue() method, 167–168, 243
getWidth() method, 236–238
Graphics class, 204
greater-than operator (>), 30, 60
grouping symbols, 276–278
Guess! button, 54–55, 62–63, 66–69, 82, 93, 99
H
"Hello, Java!" test code, 9
/help command, 16
HiLo class, 21–23
Hi-Lo guessing game (Android mobile version)
adding method to begin new game, 90–91
adding method to check player’s guess, 88–89
building GUI layout, 80–83
changing guessing range, 114–117
adding variable, 115
dialog to allow user to select range, 116–117
modifying behavior of app to use variable, 115–116
changing number of tries, 122–123
event listeners, 91–94
options menu, 109–114
adding items to XML file, 110–111
alert dialog pop-up for About screen, 113–114
displaying, 111–112
responding to user selections, 112–113
ratio of wins to losses, 123
running in Android emulator, 94–99
running on real Android device, 100–102
setting up project, 76–80
storing game stats, 120–122
storing user preferences, 118–120
Toast messages, 106
UX improvements, 102–105
aligning text field, 104
centering input in text field, 103
event listener for ENTER key, 103–104
visual improvements, 107
wiring up, 83–88
Hi-Lo guessing game (command line version)
completed code for, 37–38
counting tries, 40–41
creating HiLo class, 21–23
creating new Java project, 20–21
generating random numbers, 23–25
getting keyboard input, 25–27
increasing range of numbers, 40
loops, 28–35
if statements, 30–32
play again feature, 33–35
making program print output, 27–28
overview of, 19–20
planning basic version of, 20
prompting for user input, 26
testing, 36–37
thank-you for playing, 36–37
Hi-Lo guessing game (GUI version)
adding method to check player’s guess, 58
converting strings to numbers, 60–61
getting text from text field, 59–60
designing GUI, 50–58
aligning elements, 54–55
customizing components, 52–54
setting properties, 51–52
wiring up, 55–58
event listeners, 62–64
handling bad input, 69–72
new game (picking new random number), 61–62
play again feature, 66–67, 73–74
setting up GUI window, 64–65
setting up project, 48–49
showing and hiding Play Again button, 73–74
showing number of tries, 73
testing, 66
UX improvements, 67–70
automatically removing old guesses, 68–69
pressing ENTER to guess, 68
/history command, 16
I
image editors, 268
/imports command, 16
increment operator (++), 129
indexes, 129
inflate() method, 111
inheritance, 48
input dialogs, 163
Integer class, 60
int variable type (integer), 13
isSpace() method, 135
<item> tag, 111
iteration, 128
J
JAR (Java archive) files, 169–171, 243
Java, 1
as first programming language, xx
modifying Eclipse to run with Java 9, 5
as object-oriented programming language, 21
printing output in, 15
testing setup using JShell, 9–17
Java archive (JAR) files, 169–171, 243
Java Development Kit (JDK), 2–3, 10
Java Perspective (in Eclipse), 21
Java Runtime Environment (JRE) software, 1–2, 141
Java Virtual Machine (JVM) software, 1–2, 141
JButton component, 46, 52, 54, 63, 74, 151, 232
JCheckBox component, 52
JDK (Java Development Kit), 2–3, 10
JFrame class, 44, 48–49, 199, 223
JLabel component, 52–54, 57, 61, 74, 151, 240
JOptionPane component, 164
JPanel component, 46, 198–199, 207–208, 232, 240
JRE (Java Runtime Environment) software, 1–2, 141
JScrollPane component, 173–174
JShell, 9
commands, 16–17
creating GUIs in, 44–47
declaring Java variables in, 13–15
evaluating Java expressions in, 12–13
“Hello, Java!” test code, 9
opening code in, 16
printing output, 15
running, 9–11
from command line, 10–11
confirming installed version of JDK, 10
from shortcut, 11–12
saving code created in, 16
starting new code snippets, 17
testing Java setup, 9–17
JShell Edit Pad, 46–47
JSlider component, 164–167
JTextArea component, 150–152
scroll bars for, 173–174
wrapping text, 162
JTextField component, 52–53, 56–57, 59–60, 68–69, 151–152
JVM (Java Virtual Machine) software, 1–2, 141
K
key/value pairs, 118
L
labels
alignment, 53
font, 53
naming for coding, 56
length() method, 129–131
less-than operator (<), 30, 60
lineWrap property, 162
/list command, 16
logarithms, 123
log() method, 123
do-while loops, 33–35
for loops, 129–134
nested, 38
while loops, 28–30
M
MadLibs class, 41
MadLibs game
Android mobile version, 107
command line version, 41
GUI version, 74
main() method
BubbleDraw app
desktop version, 210
GUI version, 222–223
Hi-Lo guessing game
command line version, 22–23, 25, 29, 35
Secret Messages app
command line version, 127–128, 135–136
majorTickSpacing property, 165, 241
makeText() method, 106
manifest file, 193
Math class, 23
math expressions, 12
MenuInflator class, 111
<menu> tag, 110–111
message dialogs, 163–164
displaying available methods with content assist, 68–69
method signature, 207
minorTickSpacing property, 165, 241
modulo operator (%), 139
MouseAdapter class, 212
mouseClicked() method, 212
mouseDragged() method, 214–215
MouseEvent class, 212–213
mouse events, 210–217
clicks, 212–214
creating reusable event listener, 211–212
drags, 214–215
wheel events, 215–217
mouseMoved() method, 214
mousePressed() method, 212–214
mouseReleased() method, 212
MouseWheelEvent class, 215–216
mouseWheelMoved() method, 216, 218
Move Up ^ button, 172–173, 196
N
(escape character sequence), 107, 178
nested loops, 38
newGame() method, 61–62, 64, 66–67, 90, 113–115, 120
New Java Class dialog (in Eclipse), 22–23, 49, 148
New Java Project dialog (in Eclipse), 20–21
nextInt() method, 25, 27–28, 203–204, 224, 231
not-equal-to operator (!=), 29
numeric variables, 13–14
O
object-oriented programming, 21, 198
objects, 21
OK button, 114
OnClickListener event handler class, 91–92, 184
onClick() method, 93, 114, 184–185, 191
onCreate() method, 87, 90–91, 115, 120, 182, 191
onCreateOptionsMenu() method, 111
online resources, xxi–xxii
onOptionsItemSelected() method, 112, 116, 118–119, 121
onProgressChanged() method, 188
OnSeekBarChangeListener event handler, 187–188
onStartTrackingTouch() method, 188
onStopTrackingTouch() method, 188
OnTouchListener interface, 251–252, 259–260
onTouch() method, 259–260, 264–265, 271
/open command, 16
operators
arithmetic (+, -, *, /), 12
assignment (=), 13–15, 245, 276
comparison
not equal to (!=), 29
concatenation, 12–13, 27, 30, 130–131
decrement (--), 130
increment (++), 129
modulo (%), 139
options menu, adding in Android, 109–114
adding items to XML file, 110–111
alert dialog pop-up for About screen, 113–114
displaying, 111–112
responding to user selections, 112–113
P
package declarations, 85–86
Paint class, 253
paintComponent() method, 207
parameters, 153
parent classes (superclasses), 48
parsing, 60
Pause/Start button, 232–235
persistent information, storing, 118–121
pixelated effect, 219–220, 245–247
pointers, 266
postDelayed() method, 263
private modifier, 57
procedural programming, 198
public modifier, 58
R
Random class, 203
range settings dialog, 116–117
refactoring, 223
RelativeLayout value, 255
repaint() method, 209, 213, 215, 228, 234
requestFocus() method, 164
/reset command, 16
return statement, 113
run() method, 262
Runnable interface, 262
S
/save command, 16
scrolling
different operating systems and, 216–217
mouse wheel events, 215–217
scroll bars, 173–174
SDK (software development kit) levels, 78
Secret Messages app (Android mobile version)
connecting Encode button to encode() method, 182–185
customizing fab icon, 190–193
designing GUI, 177–181
Move Up ^ button, 196
receiving secret messages from other apps, 193–195
running in Android emulator, 188–189
running on real Android device, 188–190
SeekBar component, 187–188, 196
setting up project, 176–177
testing, 185–187
wiring up, 182–188
Secret Messages app (command line version)
adding loops to, 144–145
Caesar cipher, 125–126
character values, 132–133
closing all input/output resources, 135–136
custom key values, 137–138
encoding digits, 138–141
encoding only letters, 133–135
full version of, 140–141
languages other than English, 135
reversing and encoding, 145
setting up project, 126–131
asking user for input, 128
creating project in Eclipse, 127
message reverser, 128–131
strings, 128–131
try-catch blocks, 145
Secret Messages app (GUI version)
building main() method, 156–157
creating encode() method, 151–154
designing GUI, 148–151
event handling, 154–156
full source code, 157–159
handling bad input, 156, 162–164
improving GUI, 159–169
line and word wrap, 161–162
Move Up ^ button, 172–173
numeric slider
adding, 164–166
code cracking with, 166, 168–169
moving when value in text field changes, 174
scroll bars, 173–174
setting up project, 148
sharing as runnable JAR file, 169–171
wiring up, 148–151
SecretMessagesGUI class, 152
SeekBar component, 179–180, 187–188, 196
Select Deployment Target dialog (in Android Studio), 98, 198
semicolon (;), 24
setBackground() method, 207
setButton() method, 114
setColor() method, 204
setItems() method, 117
setOnClickListener() method, 183–184, 191
setOnSeekBarChangeListener() method, 187
setOnTouchListener() method, 265
setSize() method, 64
setText() method, 61, 107, 156, 167
shared preferences, 118–121
showMessageDialog() method, 163
show() method, 106
sliders
numeric
adding, 164–166
code cracking with, 166, 168–169
moving when value in text field changes, 174
speed control, 240–243
customizing, 241
event handler, 242–243
smart completion, 278
Snackbar pop-up messages, 191
software development kit (SDK) levels, 78
spelling errors, 274–276
src (source code) folder, 22, 48, 127, 141, 148
start() method, 229
stateChanged() method, 166–167, 242
statement completion, 278
stop() method, 229
storeRange() method, 119
strings, 12
String variable type, 14–15, 33
stubs, 22
superclasses (parent classes), 48
super() method, 253
switch statement, 113
syntax coloring, 273
System class, 26
System.in object, 25
System.out object, 26
T
temporary variables, 12
Terminal, 142
testBubbles() method, 208–210, 213, 258–259, 265
Text class, 88
text fields
adding, 82
aligning, 104
centering input in, 103
declaring at top level of class, 56–57
getting text from, 59
sizing, 83
TextView component, 81–82, 84, 87, 104, 107, 114–116, 177
Thread class, 262
threads, 253
tilde (~), 16
Timer class, 225–227
title property, 51
Toast messages, 106
touch events, 251–252, 259–260, 264–267, 271–272
transparency, 224–225
try-catch statements, 71–72, 145, 156, 162–163
U
undo, 55
Unicode, 132
update() method, 228, 237–238, 255
USB debugging in Android, 100–101
user experience (UX), 67
V
variables
declaring and initializing, 26
declaring at top level of class, 56–58
declaring in JShell, 13–15
temporary, 12
/vars command, 16
void modifier, 58
W
what-you-see-is-what-you-get (WYSIWYG) interfaces, 50
while loops, 28–30
wildcard character (*), 46
WindowBuilder Editor (in Eclipse), 50–52
Design tab, 50
installing, 6–7
Palette pane, 52–54
Properties pane, 51–52
Source tab, 56
windows
close operation, 51–52
content panes, 52
creating, 44–45
sizing, 64
titles, 51
wrapStyleWord property, 162
WYSIWYG (what-you-see-is-what-you-get) interfaces, 50