Index

• @ (at-sign), 151

• \ (backslash character), 93

• $ (dollar sign), 126

• => (fat arrow) notation, 127

• ∞ (infinity symbol), 315

• + (plus sign), 94

• / (slash), 275
• // (slashes), 77, 120

A

• abs method, 228
• abstract class, 138
• abstract method, 138
• access modifiers, 161
• Account class, 228
• adding
  • imports, 325
  • itemCount, 325
  • padding, 171–173
  • parameters, 148–151
  • virtual devices, 46–50
  • visual tweaks, 88–89
  • widgets, 91–93
• ahead-of-time (AOT) compiler, 22
• alignment parameter, 177
• Android
  • Android Studio IDE, 30
  • emulators, 31
• Android devices
  • preparing to test on, 54–56
  • running apps on, 52–53
  • testing on, 59
• Android runtime (ART), 12
• Android Studio
  • about, 59
  • configuring, 35–36
  • installing, 43–44
  • installing Flutter plugin, 44–46
  • launching, 44
  • main window, 60–63
  • Project tool window, 61–62
  • starting up, 59–60
  • using, 59–63
• Android Studio IDE, 30, 33
• Android Virtual Devices (AVD)
  • about, 41, 47, 48
  • emulators vs., 47
• angle brackets, 152
• animation
  • about, 297
  • bouncing, 308–310
  • color, 310–312
  • curves, 312–314
  • dragging widgets, 314–319
  • moving along straight lines, 303–307
  • preparing for, 297–303
  • size, 310–312
• Animation class, 300
• AnimationController , 301, 306
• annotation, override, 151–152
• anonymous functions, 153–156
• AOT (ahead-of-time) compiler, 22
• Apache Cordova, 19
• API (application programming interface)
  • about, 12
  • Dart programming language, 14–15, 123
  • Flutter, 14–15
  • public, 293–294
• app bar, controlling Back button of, 266–267
• application programming interface (API)
  • about, 12
  • Dart programming language, 14–15, 123
  • Flutter, 14–15
  • public, 293–294
• application programs, 12
• Application widget, 26
• apps
  • development of, 25–28
  • enhancing, 146–162
  • mobile development of
    • about, 29–30, 43
    • adding virtual devices, 46–50
    • devices, 52–59
    • installing Android Studio, 43–44
    • installing Android Studio’s Flutter plugin, 44–46
    • installing Flutter, 50–52
    • launching Android Studio, 44
    • running sample programs from book, 63–66
    • setting up computer for, 332
    • steps for, 32–42
    • tools for, 30–32
    • using Android Studio, 59–63
  • running, 36–42
  • running on Android devices, 52–53
  • testing on physical devices, 53–59
• ART (Android runtime), 12
• asking questions, 329
• assets, declaring, 325–326
• assignment statement, 115
• async keyword (Dart), 264–266, 295
• at-sign (@), 151
• automaticallyImplyLeading parameter, 266
• AVD (Android Virtual Devices)
  • about, 41, 47, 48
  • emulators vs., 47
• AVD Manager, opening, 48–50
• avoiding mistakes, 323–326
• await keyword (Dart), 264–266, 295

B

• Back button
  • about, 255
  • controlling, 266–267
• Background widget, 26
• backslash character (\), 93
• Bell, Alexander Graham, 69

• ’bite-size’ programs, 209

• bitLength property, 227
• Black Screen app, 23–24
• blank spaces, 38, 94
• block comments, 120–121
• blue circle
  • methods for widgets, 135–138
  • pressing, 132–146
  • stateful widgets, 134–135
  • stateless widgets, 134–135
• bool type, 122
• border parameter, 178
• borderRadius parameter, 178
• bouncing around, animation and, 308–310
• bounded constraint, 194–195
• box widget, 23
• break statement, 282–283
• breaking connections, 55–56
• build method, 129–130, 135–136, 137, 139, 151–152, 202
• buildColumn method, 170

• _buildDropdownButtonRow method, 244
• _buildExpandedBox method, 198

• building
  • dropdown buttons, 239–245
  • enums, 233
  • function declarations, 124–130
  • functions, 106–112
  • list items one-by-one, 285–287
  • lists, 276–290
  • maps, 245
  • named routes, 272–276
  • parameter lists, 169–170
  • pieces of code, 167–169
  • radio buttons, 230–239
  • radio groups, 233–235
  • scaffolds, 86–87
  • stacks, 255
• buildPositionedWidget method, 304, 318
• buildRoundedBox method, 191

• _buildRowOfThree method, 186, 191

• built-in types (Dart), 121–123
• Burd, Barry (author), 6
• Button widget, 26
• buttons
  • floating action
    • methods for widgets, 135–138
    • pressing, 132–146
    • stateful widgets, 134–135
    • stateless widgets, 134–135
  • icons on, 254–255

C

• The C Programming Language (Kernighan and Ritchie), 69

• Cake icon, 308
• callbacks, in Flutter framework, 141–142
• capitalization, 323
• captioned boxes, 183–184
• career, advancing your, 327–330
• cascade operator, 307
• case sensitivity, in Dart programming language, 70
• Center widget, 83–85, 302
• centering text, 94–100

• _changeText function, 140–141, 144–145, 154

• changing orientation for devices, 175
• charging cables, 55
• Cheat Sheet (website), 6
• checking connections, 55–56
• children parameter, 303
• classes
  • about, 79–83
  • abstract, 138
  • Account, 228
  • Animation, 300
  • Color, 171
  • Curves, 310
  • DateTime, 123
  • DetailPage, 280
  • DropdownMenuItem, 242
  • Flex, 199
  • Flexible, 199
  • GestureDetector, 316, 317
  • Hello World program, 79–83
  • Icons, 151
  • Image, 103
  • int, 113, 121, 227, 228
  • _MyHomePage, 202
  • _MyHomePageState, 162, 224, 260, 307
  • Navigator, 275
  • StatefulWidget, 307
  • StatelessWidget, 80, 151–152
  • Widget, 124
• closed project, 59
• code
  • about, 14–15
  • creating pieces of, 167–169
  • critiquing your own, 328
  • getting reviews of your, 328
  • indenting, 326
  • native, 17
• code decoration, 121
• code listing
  • accessing online data, 290–292
  • adding widgets, 91–92
  • aligning text, 99
  • animation along straight lines, 304
  • basic navigation, 252–253
  • captioned boxes, 183–184
  • centering text, 84, 96
  • changing animation size/color, 310–311
  • changing animation velocity, 308–309
  • checking device orientation, 199–200
  • columns, 181–182
  • copying iPhone apps, 90
  • creating functions, 106
  • creating list items one-by-one, 285–286
  • creating lists, 277–278
  • creating named routes, 273–275
  • curves, 312–313
  • debugging, 193
  • displaying images, 103
  • dragging widgets, 315
  • dropdown buttons, 240–242
  • enhancing apps, 146–147
  • expanding widgets, 187–188, 189–190, 192
  • function declarations, 124–125
  • Hello World program, 70, 105
  • JSON code, 293–294
  • for layout, 164–166
  • margin, 178–179, 179–180
  • master-detail interface, 251–252
  • nesting widgets, 185
  • padding, 178–179, 179–180
  • passing data back to sources, 261–262
  • passing data from sources to destinations, 256–257
  • passing data in both directions, 268–269
  • preparing for animation, 298–299
  • pressing floating action buttons, 132–133
  • radio buttons, 231–232
  • responding to a button press, 215–216
  • rows, 181–182
  • slider app, 217–218
  • specifying relative size, 197–198
  • for statement, 289
  • Switch app, 208–209
  • using functions, 106
  • using scaffolds, 86, 88
  • widgets, 26
• collection for, 289–290
• color
  • animation and, 310–312
  • layouts and, 170–171
• Color class, 171
• color property, 177, 312
• Column widget, 91, 173–175, 182, 281
• columns
  • ListView widgets inside, 281
  • nesting, 181–183
• command line interfaces, 50
• comments, 120–121
• compatibility, 16, 213–214
• compiler, 23–24
• compiling, 21
• composition hierarchy, 81
• compressed archive files, 35
• computers
  • Macs
    • command line in, 51
    • compressed archive files in, 35
    • creating iPhone apps in, 34–35
    • filename extensions on, 34
    • installing Android Studio, 43
    • launching Android Studio, 44
  • setting up for mobile app development, 332
  • Windows
    • command line in, 51
    • compressed archive files in, 35
    • filename extensions in, 34
    • installing Android Studio, 43
    • launching Android Studio, 44
• conditional expression, 213
• conditional operator, 213
• configuring Android Studio, 35–36
• connections, breaking/checking, 55–56
• const keyword (Dart), 211–213
• ConstraintsLogger widget, 196
• constructor call, 73
• constructors, parameters for, 75–76
• Container widget, 176–181
• context parameter, 203
• control. see control element
• control element
  • about, 203
  • creating dropdown buttons, 239–245
  • creating radio buttons, 230–239
  • feedback, 214–217
  • slider app, 217–220
  • Switch, 208–214
  • text fields, 220–230
• controlling Back button, 266–267
• Cordova (Apache), 19

• _counter variable, 156–157

• createState method, 136, 139
• creating
  • dropdown buttons, 239–245
  • enums, 233
  • function declarations, 124–130
  • functions, 106–112
  • list items one-by-one, 285–287
  • lists, 276–290
  • maps, 245
  • named routes, 272–276
  • parameter lists, 169–170
  • pieces of code, 167–169
  • radio buttons, 230–239
  • radio groups, 233–235
  • scaffolds, 86–87
  • stacks, 255
• Cross Reference icon, 6
• crossAxisAlignment property, 173–174, 177, 182
• cross-platform development, Flutter for, 15–17
• cross-platform framework, 19
• Cupertino widgets, 90, 256
• curly braces, 83, 129
• CurvedAnimation object, 309
• curves
  • animation and, 312–314
  • defined, 308
• Curves class, 310

D

• Dalvik bytecode instructions, 24
• Dart programming language
  • about, 11
  • application programming interface (API), 14–15, 123
  • async keyword, 264–266, 295
  • await keyword, 264–266, 295
  • built-in types, 121–123
  • case sensitivity in, 70, 323
  • const keyword, 211–213
  • Dartfmt tool, 111
  • declarations, 112–113
  • enum feature, 89
  • expressions, 114–117
  • Extension keyword, 248–250
  • highlight function, 117–119
  • import declarations, 123–124
  • int.parse method, 230
  • library (website), 124
  • literals, 114–117
  • programming in, 112–124
  • for statement, 288–290
  • statements, 112–113
  • strings, 93–94
  • switch statement, 282–283
  • top-level variables, 259
  • types, non-built-in, 123
  • typing feature, 113–114
  • var keyword, 119–121
  • variables, 114–117
• dartdoc program, 120–121
• Dartfmt tool, 111
• data
  • fetching from Internet, 290–296
  • passing back to sources, 261–267
  • passing from sources to destinations, 256–261
  • passing in both directions, 267–272
• data cables, 55
• DateTime class, 123
• dating app, 337–345
• declarations
  • about, 80
  • Dart programming language, 112–113
• declaring
  • assets, 325–326
  • dependencies, 325–326
  • variable names, 224
• decoration parameter, 177–178
• density-independent pixel (dp), 172
• dependencies, declaring, 325–326
• desktop, 13
• destination page, 255
• destinations, passing data from sources to, 256–261
• DetailPage class, 280
• developers, 10
• development computer, 31
• devices
  • about, 31, 52
  • Android
    • preparing to test on, 54–56
    • running apps on, 52–53
    • testing on, 59
  • changing orientation, 175
  • iPhones
    • Android Studio IDE, 30
    • preparing to test on, 57–58
    • simulators, 31
    • testing on, 59
  • physical
    • about, 31
    • preparing to test on Android, 54–56
    • preparing to test on iPhone, 57–58
    • testing apps on, 53–59
    • testing on Android, 59
    • testing on iPhone, 59
  • running apps on Android, 52–53
  • size of, 199–203
  • testing apps on physical devices, 53–59
  • virtual
    • about, 31
    • adding, 46–50
• directories, 33
• displaying
  • images, 100–104
  • user choice, 235–236
  • widgets, 194–195
• displayNicely function, 249–250
• dispose method, 223
• dispose method (Flutter), 230
• distanceFromLeft, 318
• distanceFromRight, 318
• distanceFromTop, 318
• divisions parameter, 219
• DO statement, 288
• doc comments, 120–121
• documentation, 82–83
• dollar sign ($), 126
• dot notation, 227–229
• double, 113–114
• double quotation marks, 93
• double type, 121
• downloading software, 31
• dp (density-independent pixel), 172
• dragging widgets, 314–319
• dropdown buttons, creating, 239–245
• DropdownMenuItem class, 242

E

• EdgeInsets object, 172
• Editor area (Android Studio), 62
• emulators
  • about, 31, 47
  • Android Virtual Devices (AVD) vs., 47
• encapsulation, 162
• end-of-line comments, 120–121
• endsWith method, 228
• enhancing apps, 146–162
• enum feature (Dart), 89
• enums, creating, 233
• escape sequence, 212
• event driven programming, 142
• event handler, 140
• events
  • defined, 140
  • Flutter framework, 140–141
• Expanded widget, 186–199, 281, 325
• expressions
  • about, 289
  • Dart programming language, 114–117
• Extension keyword (Dart), 248–250

F

• fat arrow (=>) notation, 127
• feedback, 214–217
• fetching data from Internet, 290–296
• field, 156
• filename extensions, 34
• files
  • pubspec.yaml, 325–326
  • uncompressing, 35
  • unzipping, 35
  • .yaml, 295
• finite state machine diagram, 270, 272
• FlatButton widget, 244
• Flex class, 199
• flex factor, 198
• flex property, 175, 199
• Flexible class, 199
• floating action buttons
  • methods for widgets, 135–138
  • pressing, 132–146
  • stateful widgets, 134–135
  • stateless widgets, 134–135
• Flutter. see also specific topics
  • about, 9–10, 331
  • application programming interface (API), 14–15
  • framework
    • about, 17, 139–140
    • callbacks, 141–142
    • code outline, 142–144
    • cross-platform, 19
    • events, 140–141
  • history of, 18–20
  • installing, 50–52
  • library (website), 124
  • uses for, 15–28
• Flutter Doctor, 50
• Flutter Inspector, 94
• Flutter SDK path, 33
• folders, 33
• for statement (Dart), 288–290
• FORTRAN, 114, 288
• fragmentation, 17
• framework (Flutter)
  • about, 17, 139–140
  • callbacks, 141–142
  • code outline, 142–144
  • cross-platform, 19
  • events, 140–141
• function call, 108
• function declarations
  • about, 107–108
  • creating, 124–130
  • typing names in, 127–128
• functions
  • anonymous, 153–156
  • _changeText, 140–141, 144–145, 154
  • creating, 106–112
  • displayNicely, 249–250
  • get, 295
  • _getNewInfo, 144
  • _getNewText, 141, 145
  • getSuffix, 283
  • _handlerFunction, 143
  • highlight, 109, 112–113, 116, 117–119, 126–127, 130
  • _incrementCounter, 158–159, 323–324
  • main, 127, 128, 139, 228
  • print, 113
  • setState, 143–145, 153, 154, 155, 306, 317, 324
  • sqrt, 314
  • _updateAgeSwitch, 210–211, 216
  • _updateGenderRadio, 234
  • _updateResults, 216
  • using, 106–112
  • VoidCallback, 155, 210–211

G

• _genderRadioValue, 236

• generating
  • dropdown buttons, 239–245
  • enums, 233
  • function declarations, 124–130
  • functions, 106–112
  • list items one-by-one, 285–287
  • lists, 276–290
  • maps, 245
  • named routes, 272–276
  • parameter lists, 169–170
  • pieces of code, 167–169
  • radio buttons, 230–239
  • radio groups, 233–235
  • scaffolds, 86–87
  • stacks, 255
• generic, 152
• GestureDetector class, 316, 317
• get function, 295
• getAnimation method, 305–306, 307, 316

• _getNewInfo function, 144
• _getNewText function, 141, 145

• getSuffix function, 283
• goToDetailPage method, 254, 280
• graphical user interface (GUI), 50, 139

H

• _handlerFunction function, 143

• hardware, 10–15
• Hardware Accelerated Execution Manager (HAXM), 53
• header, 108
• height parameter, 169, 176
• Hello World program
  • about, 69, 72–74, 332
  • classes, 79–83
  • constructor parameters, 75–76
  • indentation, 77–78
  • objects, 79–83
  • punctuation, 76–77
  • styling, 83–104
  • widgets, 79–83
• highlight function, 109, 112–113, 116, 117–119, 126–127, 130
• hint parameter, 243
• history, of Flutter, 18–20
• home directory, 33
• home parameter, 275
• Homebrew, 57
• hot reload, 25, 85
• hot restart, 24, 85
• hybrid app development, 18

I

• ICANN (Internet Corporation for Assigned Names and Numbers), 40
• Icon instance, 151
• icons
  • on buttons, 254–255
  • Cake, 308
  • explained, 5–6
• Icons class, 151
• IDE (integrated development environment), 30
• if statement, 200–201, 213–214, 244
• if-null operator, 239
• Image class, 103
• images, displaying, 100–104
• import declarations, in Dart programming language, 123–124
• import statements, 160–161
• imports, adding, 325

• _incrementCounter function, 158–159, 323–324

• indentation, 77–78, 326
• index, 92, 245, 324
• infinity symbol (∞), 315
• inheritance hierarchy, 81
• initialRoute parameter, 276
• initState method, 223, 224–225, 230
• installing
  • Android Studio, 43–44
  • Android Studio’s Flutter plugin, 44–46
  • Flutter, 50–52
  • software, 32–34
• instance, 79
• instance variable, 156
• int class, 113, 121, 227, 228
• integrated development environment (IDE), 30
• Intel Hardware Accelerated Execution Manager (HAXM), 53
• Intel Virtualization Technology (VT), 53
• Internet, fetching data from, 290–296
• Internet Corporation for Assigned Names and Numbers (ICANN), 40
• Internet resources
  • Android Studio IDE, 31
  • Cheat Sheet, 6
  • Color class documentation, 171
  • curve values, 309
  • Dart library, 124
  • example Flutter apps, 30
  • Flutter API reference documentation, 15
  • Flutter library, 124
  • Flutter SDK, 31
  • Homebrew, 57
  • images in Icons class, 151
  • Material Design, 73
  • Material Design’s elevation property, 89
  • The Movie Database, 293
  • @override annotations, 152
  • swatches, 149
  • for this book, 31, 63
  • Virtual Studio Code (VS Code), 33
• interpolating strings, 125–126
• int.parse method (Dart), 230
• int.tryParse method, 230
• iPhones
  • Android Studio IDE, 30
  • preparing to test on, 57–58
  • simulators, 31
  • testing on, 59
• isEmpty property, 227
• isEven property, 227

• _isFavorite, 259, 260, 263–264

• isNegative property, 227
• itemBuilder parameter, 279–280
• itemCount parameter, 279, 325

J

• Java, 25
• JavaScript Object Notation (JSON), 293–294, 296
• JIT (just-in-time) compiler, 22
• JSON code, 293–294
• just-in-time (JIT) compiler, 22

K

• kernel, 12
• Kernighan, Brian (author)
  • The C Programming Language, 69
• Kotlin, 25

L

• label parameter, 169, 220
• landscape mode, 175
• Last-In-First-Out (LIFO) rule, 255
• launching
  • Android Studio, 44
  • AVD Manager, 48–50
• layout
  • about, 163–164
  • adding padding, 171–173
  • color, 170–171
  • Column widget, 173–175
  • Container widget, 176–181
  • creating parameter lists, 169–170
  • creating pieces of code, 167–169
  • device size, 199–203
  • examples of, 164–166
  • Expanded widget, 186–199
  • nesting levels, 183–186
  • nesting rows/columns, 181–183
  • SizedBox widget, 175
• leading parameter, 266
• learning, importance of, 329
• left property, 302
• length property, 227
• library. see application programming interface (API)
• LIFO (Last-In-First-Out) rule, 255
• List type, 122, 287
• listing, code
  • accessing online data, 290–292
  • adding widgets, 91–92
  • aligning text, 99
  • animation along straight lines, 304
  • basic navigation, 252–253
  • captioned boxes, 183–184
  • centering text, 84, 96
  • changing animation size/color, 310–311
  • changing animation velocity, 308–309
  • checking device orientation, 199–200
  • columns, 181–182
  • copying iPhone apps, 90
  • creating functions, 106
  • creating list items one-by-one, 285–286
  • creating lists, 277–278
  • creating named routes, 273–275
  • curves, 312–313
  • debugging, 193
  • displaying images, 103
  • dragging widgets, 315
  • dropdown buttons, 240–242
  • enhancing apps, 146–147
  • expanding widgets, 187–188, 189–190, 192
  • function declarations, 124–125
  • Hello World program, 70, 105
  • JSON code, 293–294
  • for layout, 164–166
  • margin, 178–179, 179–180
  • master-detail interface, 251–252
  • nesting widgets, 185
  • padding, 178–179, 179–180
  • passing data back to sources, 261–262
  • passing data from sources to destinations, 256–257
  • passing data in both directions, 268–269
  • preparing for animation, 298–299
  • pressing floating action buttons, 132–133
  • radio buttons, 231–232
  • responding to a button press, 215–216
  • rows, 181–182
  • slider app, 217–218
  • specifying relative size, 197–198
  • for statement, 289
  • Switch app, 208–209
  • using functions, 106
  • using scaffolds, 86, 88
  • widgets, 26
• lists
  • about, 247–248
  • creating, 276–290
  • creating items one-by-one, 285–287
  • ListView widget, 100, 279–284, 285–287, 289, 325
  • master-detail interface, 251–252
  • parameterized
    • about, 152
    • creating, 169–170
• ListTile widget, 287
• ListView widget, 100, 279–284, 285–287, 289, 325
• literals, in Dart programming language, 114–117
• loose constraint, 196

M

• macOS, filename extensions in, 34
• Macs
  • command line in, 51
  • compressed archive files in, 35
  • creating iPhone apps in, 34–35
  • filename extensions on, 34
  • installing Android Studio, 43
  • launching Android Studio, 44
• main axis, 98
• main function, 127, 128, 139, 228
• main window (Android Studio), 60–63
• mainAxisAlignment property, 173, 177, 182–183
• Map type, 122, 245
• maps, creating, 245
• margin, 181
• margin parameter, 178–181
• master-detail interface, 251–252
• Material Design
  • about, 73, 88, 89–90
  • elevation property, 89
  • widgets, 256
• Material widget, 78, 81, 85, 87, 89, 179
• MaterialApp widget, 78
• max parameter, 219
• members, 228
• methods
  • abs, 228
  • abstract, 138
  • build, 129–130, 135–136, 137, 139, 151–152, 202
  • buildColumn, 170
  • _buildDropdownButtonRow, 244
  • _buildExpandedBox, 198
  • buildPositionedWidget, 304, 318
  • buildRoundedBox, 191
  • _buildRowOfThree, 186, 191
  • createState, 136, 139
  • dispose, 223, 230
  • endsWith, 228
  • getAnimation, 305–306, 307, 316
  • goToDetailPage, 254, 280
  • initState, 223, 224–225, 230
  • int.parse, 230
  • int.tryParse, 230
  • onHorizontalDragUpdate, 316
  • onPanUpdate, 316
  • onScaleUpdate, 316
  • onSecondaryTapDown, 316
  • parse, 227
  • pushedNamed, 275
  • replaceAll(), 235
  • shorten, 238–239
  • split, 228
  • toRadixString, 228
  • toString, 235, 236
  • toUpperCase, 228
  • trim, 228
  • updateOverview, 296
  • for widgets, 135–138
• min parameter, 219
• mistakes, avoiding, 323–326
• mixin, 301
• mobile app development
  • about, 29–30, 43
  • adding virtual devices, 46–50
  • devices, 52–59
  • installing Android Studio, 43–44
  • installing Android Studio’s Flutter plugin, 44–46
  • installing Flutter, 50–52
  • launching Android Studio, 44
  • running sample programs from book, 63–66
  • setting up computer for, 332
  • steps for, 32–42
  • tools for, 30–32
  • using Android Studio, 59–63

• The Movie Database, 293

• _MyHomePage class, 202
• _MyHomePageState class, 162, 224, 260, 307

N

• named constructor, 103
• named parameter, 76
• names
  • typing in function declarations, 127–128
  • underscores and, 160–161
• naming parameters, 128–129
• native code, 17
• navigation
  • about, 247–248
  • basic, 252–253
  • creating named routes, 272–276
  • destination page, 255
  • Extension keyword, 248–250
  • fetching data from Internet, 290–296
  • master-detail interface, 251–252
  • passing data back to sources, 261–267
  • passing data from sources to destinations, 256–261
  • passing data in both directions, 267–272
  • scrolling, 284
  • source page, 255
• navigation bar (Android Studio), 61
• Navigator class, 275
• nesting
  • levels of, 183–186
  • rows/columns, 181–183
• null-aware operator, 238
• num type, 121

O

• Objective-C language, 25
• object-oriented programming, 227
• objects
  • about, 79–83
  • CurvedAnimation, 309
  • EdgeInsets, 172
  • properties of, 97
  • State, 223
• obtaining software, 32–34
• On The Web icon, 6
• onChanged event handler, 216, 220, 222, 243
• onHorizontalDragUpdate method, 316
• onPanUpdate method, 316
• onPressed event handler, 216
• onScaleUpdate method, 316
• onSecondaryTapDown method, 316
• onWillPop parameter, 267
• open project, 59
• opening
  • Android Studio, 44
  • AVD Manager, 48–50
• operating system (OS) software, 11
• orientation, changing for devices, 175
• orientation property, 202
• OS (operating system) software, 11
• OS user interface, 13
• overflow, 187
• override annotation, 151–152

P

• package, 40
• Packages view (Android Studio), 62
• padding
  • about, 180
  • adding, 171–173
• padding parameter, 178–181
• Padding widget, 26, 171–173
• parameterized list
  • about, 152
  • creating, 169–170
• parameters
  • about, 108–112
  • adding, 148–151
  • alignment, 177
  • automaticallyImplyLeading, 266
  • border, 178
  • borderRadius, 178
  • children, 303
  • for constructors, 75–76
  • context, 203
  • decoration, 177–178
  • divisions, 219
  • height, 169, 176
  • hint, 243
  • home, 275
  • initialRoute, 276
  • itemBuilder, 279–280
  • itemCount, 279, 325
  • label, 169, 220
  • leading, 266
  • margin, 178–181
  • max, 219
  • min, 219
  • named, 76
  • naming, 128–129
  • onWillPop, 267
  • padding, 178–181
  • positional, 76
  • theme, 148
  • title, 148
  • value, 220, 243
  • vertical, 172
  • width, 176
• parentheses, 323–324
• parse method, 227
• passes constraints, 194
• passing
  • data back to sources, 261–267
  • data from sources to destinations, 256–261
  • data in both directions, 267–272
• physical devices
  • about, 31
  • preparing to test on Android, 54–56
  • preparing to test on iPhone, 57–58
  • testing apps on, 53–59
  • testing on Android, 59
  • testing on iPhone, 59
• Pixel C tablet, 202
• platform, 16
• plug-ins, 19
• plus sign (+), 94
• polling, 142
• popping, off stacks, 255–256
• portrait mode, 175
• positional parameter, 76
• Positioned widget, 302, 304, 314, 317
• practice, importance of, 327
• preparing, for animation, 297–303
• pressing floating action buttons, 132–146
• print function, 113
• programmer, 10
• programming languages
  • Dart
    • about, 11, 112–124
    • application programming interface (API), 14–15, 123
    • async keyword, 264–266, 295
    • await keyword, 264–266, 295
    • built-in types, 121–123
    • case sensitivity in, 70, 323
    • const keyword, 211–213
    • Dartfmt tool, 111
    • declarations, 112–113
    • enum feature, 89
    • expressions, 114–117
    • Extension keyword, 248–250
    • highlight function, 117–119
    • import declarations, 123–124
    • int.parse method, 230
    • library (website), 124
    • literals, 114–117
    • programming in, 112–124
    • for statement, 288–290
    • statements, 112–113
    • strings, 93–94
    • switch statement, 282–283
    • top-level variables, 259
    • types, non-built-in, 123
    • typing feature, 113–114
    • var keyword, 119–121
    • variables, 114–117
  • defined, 11
• programs
  • application, 12
  • dartdoc, 120–121
  • defined, 10
  • Hello World
    • about, 69, 72–74, 332
    • classes, 79–83
    • constructor parameters, 75–76
    • indentation, 77–78
    • objects, 79–83
    • punctuation, 76–77
    • styling, 83–104
    • widgets, 79–83
• Project tool button (Android Studio), 62
• Project tool window (Android Studio), 61–62
• Project view (Android Studio), 61
• properties
  • bitLength, 227
  • color, 177, 312
  • crossAxisAlignment, 173–174, 177, 182
  • flex, 175, 199
  • isEmpty, 227
  • isEven, 227
  • isNegative, 227
  • left, 302
  • length, 227
  • mainAxisAlignment, 173, 177, 182–183
  • in object-oriented programming, 227
  • of objects, 97
  • orientation, 202
  • right, 302
  • size, 311
  • text, 227
  • values of, 97
• public API, 293–294
• pubspec.yaml file, 325–326
• punctuation characters, 38, 76–77
• pushedNamed method, 275
• pushing, to stacks, 255–256

Q

• questions, asking, 329
• quick-and-easy development cycle, Flutter for, 17–25
• quotation marks, 93, 94

R

• radio buttons, creating, 230–239
• radio groups, building, 233–235
• RaisedButton widget, 215, 244, 254, 255
• React Native, 20
• real devices. see physical devices
• Remember icon, 5
• replaceAll() method, 235
• researching technology, 328
• Reset button, 244
• resources, Internet
  • Android Studio IDE, 31
  • Cheat Sheet, 6
  • Color class documentation, 171
  • curve values, 309
  • Dart library, 124
  • example Flutter apps, 30
  • Flutter API reference documentation, 15
  • Flutter library, 124
  • Flutter SDK, 31
  • Homebrew, 57
  • images in Icons class, 151
  • Material Design, 73
  • Material Design’s elevation property, 89
  • The Movie Database, 293
  • @override annotations, 152
  • swatches, 149
  • for this book, 31, 63
  • Virtual Studio Code (VS Code), 33
• return statement, 110, 112, 283
• return value, 108–112
• right property, 302
• Ritchie, Dennis (author), 288
  • The C Programming Language, 69
• routes
  • creating named, 272–276
  • defined, 256
• rows, nesting, 181–183
• Run icon, 85
• Run tool window (Android Studio), 62
• Runes type, 122
• running
  • apps, 36–42
  • apps on Android devices, 52–53
  • sample programs from book, 63–66
• runtime, 12

S

• SafeArea widget, 181
• Scaffold widget, 87
• scaffolds, creating, 86–87
• scrolling, 284
• SDK (Software Development Kit), 30
• SEARCH ON WIDGETS IN FIRST 100 PAGES
• sending URLs to servers, 295
• servers, sending URLs to, 295
• Set type, 122
• setState function, 143–145, 153, 154, 155, 306, 317, 324
• setup, computer for mobile app development, 332
• shorten method, 238–239
• showing
  • images, 100–104
  • user choice, 235–236
  • widgets, 194–195
• simulator, 31
• single quotation marks, 93
• SingleChildScrollView, 284
• size
  • animation and, 310–312
  • of devices, 199–203
• size property, 311
• SizedBox widget, 175
• slash character (/), 275
• slashes (//), 77, 120
• sleep, importance of, 330
• slider app, 217–220
• software
  • about, 10–15
  • compatibility and, 16
  • downloading, 31
  • installing, 32–34
  • obtaining, 32–34
  • operating system (OS), 11
• Software Development Kit (SDK), 30
• source code, 10
• source page, 255
• sources
  • passing data back to, 261–267
  • passing data to destinations from, 256–261
• split method, 228
• sqrt function, 314
• square brackets, 296
• Stack, 302, 303
• stacks, 255–256
• Stanley’s Swell Shaving Cream/Superior Shaving Cream, 131–132
• starting
  • Android Studio, 44, 59–60
  • AVD Manager, 48–50
• state, 134
• State object, 223
• stateful widgets, 134–135
• StatefulWidget class, 307
• stateless widgets, 134–135
• StatelessWidget class, 80, 151–152
• statements
  • for, 288–290
  • about, 289
  • assignment, 115
  • break, 282–283
  • Dart programming language, 112–113
  • defined, 116
  • DO, 288
  • if, 200–201, 213–214, 244
  • import, 160–161
  • return, 110, 112, 283
  • switch, 282–283
• static members, 229
• static variables, 260
• status bar (Android Studio), 63
• straight lines, animation along, 303–307
• String instance, 114, 122, 228
• strings
  • Dart programming language, 93–94
  • interpolating, 125–126
• styling, in Hello World program, 83–104
• swatch, 149
• Swift language, 25
• Switch control, 208–214
• switch statement (Dart), 282–283
• Symbol type, 122
• system image, 47

T

• target devices, 31
• Technical Stuff icon, 6
• technology, researching, 328
• ternary operator, 214
• testing apps on physical devices, 53–59
• text, centering, 94–100
• text fields, 220–230
• text property, 227
• Text widget, 26, 75, 81, 83, 84–87, 91, 223, 280
• TextEditingController instance, 227
• theme parameter, 148
• ticker, 301
• tight constraint, 196
• Tip icon, 5
• title parameter, 148
• toolbar (Android Studio), 61
• tools
  • Dartfmt, 111
  • for mobile app development, 30–32
• tooltip string, 151
• top-level declaration, 159
• top-level names, 162
• top-level variables (Dart), 259
• toRadixString method, 228
• toString method, 235, 236
• Touge, Alice (historian), 20
• toUpperCase method, 228
• trailing comma, 76–77, 111
• trim method, 228
• triple quotation marks, 94
• type safe, 114
• typing
  • in Dart programming language, 113–114
  • names in function declarations, 127–128

U

• unbounded constraint, 194
• uncompressing files, 35
• underscores
  • about, 38
  • names and, 160–161
• unzipping files, 35

• _updateAgeSwitch function, 210–211, 216
• _updateGenderRadio function, 234

• updateOverview method, 296

• _updateResults function, 216

• uppercase letters, 38
• URLs, sending to servers, 295
• USB cables, 55
• user group meetings, 328–329
• user interaction
  • about, 203
  • creating dropdown buttons, 239–245
  • creating radio buttons, 230–239
  • feedback, 214–217
  • slider app, 217–220
  • Switch, 208–214
  • text fields, 220–230
• users
  • defined, 10
  • displaying user choice, 235–236

V

• value indicator, 220
• value parameter, 220, 243
• values, of properties, 97
• var keyword, 119–121
• variable declarations, 115
• variable names, declaring, 224
• variables
  • Dart programming language, 114–117
  • limiting access to, 324
  • static, 260
• vertical parameter, 172
• virtual devices
  • about, 31
  • adding, 46–50
• Virtual Studio Code (VS Code), 33
• Virtualization Technology (VT), 53
• Visibility widget, 259
• visual tweaks, adding, 88–89
• VoidCallback function, 155, 210–211
• VT (Virtualization Technology), 53

W

• Warning icon, 5
• websites
  • Android Studio IDE, 31
  • Cheat Sheet, 6
  • Color class documentation, 171
  • curve values, 309
  • Dart library, 124
  • example Flutter apps, 30
  • Flutter API reference documentation, 15
  • Flutter library, 124
  • Flutter SDK, 31
  • Homebrew, 57
  • images in Icons class, 151
  • Material Design, 73
  • Material Design’s elevation property, 89
  • The Movie Database, 293
  • @override annotations, 152
  • swatches, 149
  • for this book, 31, 63
  • Virtual Studio Code (VS Code), 33
• Widget classes, 124

• <Widget>, 152–153

• widgets
  • about, 26, 79–83
  • adding, 91–93
  • Application, 26
  • Background, 26
  • box, 23
  • Button, 26
  • Center, 83–85, 302
  • Column, 91, 173–175, 182, 281
  • ConstraintsLogger, 196
  • Container, 176–181
  • Cupertino, 90, 256
  • displaying, 194–195
  • dragging, 314–319
  • Expanded, 186–199, 281, 325
  • FlatButton, 244
  • Hello World program, 79–83
  • layout of, 163–164
  • ListTile, 287
  • ListView, 100, 279–284, 285–287, 289, 325
  • Material, 78, 81, 85, 87, 89, 179
  • Material Design, 256
  • MaterialApp, 78
  • methods for, 135–138
  • Padding, 26, 171–173
  • Positioned, 302, 304, 314, 317
  • RaisedButton, 215, 244, 254, 255
  • SafeArea, 181
  • Scaffold, 87
  • SizedBox, 175
  • stateful, 134–135
  • stateless, 134–135
  • Text, 26, 75, 81, 83, 84–87, 91, 223, 280
  • Visibility, 259
• width parameter, 176
• Windows
  • command line in, 51
  • compressed archive files in, 35
  • filename extensions in, 34
  • installing Android Studio, 43
  • launching Android Studio, 44

• “within-ness,” 81–82

• working directory, 51

X

• Xamarin, 20

Y

• .yaml file, 295

Z

• zip files, 35