UNIT 4

Question 1

components that make up a flutter application

Answer 1

widgets

Question 2

when part of user interface u are describing does not depend on anything other than configuration

Answer 2

stateless

Question 3

data within the widget that can change during its lifetime

Answer 3

state

Question 4

widget’s value needs to be updated by typing into textfield

Answer 4

stateful widget

Question 5

every widget build method which receives a BuildContext and returns a single Flutter Widget

Answer 5

widget build function

Question 6

display string to the screen

Answer 6

text widget

Question 7

• flutter comes with built-in set of icons

Icon(
Icons.cake,
color: Colors.red,
size: 200,
)

Answer 7

icon widget

Question 8

display image on flutter

Answer 8

image widget

Question 9

put image in project file folder and edit in pubspec.yam

Image.asset(‘ ‘)

Answer 9

embedded images

Question 10

image fetched from internet via HTTP

Answer 10

Network Image
Image.network(‘URL’)

Question 11

flutter layout engine will shrink image in a container but not grow in it

Answer 11

BoxFit

Question 12

image is stretched in both height and width exactly; distort image

Answer 12

fill

Question 13

shrink or grow until space is filled but image is cropped

Answer 13

cover

Question 14

make height fit exactly; add extrea width space

Answer 14

fitHeight

Question 15

make width fit exactly; clip height or add extra space

Answer 15

fitWidth

Question 16

shrink both height and width to fit; add space on both

Answer 16

contain

fit: BoxtFit.contain

Question 17

textfield syntax

Answer 17

TextField(
OnChanged: (String val) => searchTerm = val

Question 18

event handler that fires after every keystroke

Answer 18

onChanged

Question 19

receives what the user types

Answer 19

String

Question 20

appears above on TextField

Answer 20

labelText

Question 21

Light ghost inside TextField

Answer 21

hintText

Question 22

Error message that appears below, usually red

Answer 22

errorText

Question 23

Text in the TextField to the left of the stuff the user types in

Answer 23

prefixText

Question 24

Same as prefixText but to the far right

Answer 24

suffixTexT

Question 25

Draws an icon to the left of the entire TextField

Answer 25

icon

Question 26

Draws one inside the TextField to the left

Answer 26

prefixIcon

Question 27

Same as prefixIcon but to the far right

Answer 27

suffixIcon

Question 28

make it true to make password box

Answer 28

obscureText property

Question 29

forbids characters from being entered

Answer 29

BlackListinngInputTextFormatter

Question 30

allows onlu these characters to be entered

Answer 30

WhiteListinngInputTextFormatter

Question 31

can’t type more than x characters

Answer 31

LengthListinngInputTextFormatter

Question 32

select one, others are not selected

Answer 32

Radio Button

Question 33

• handy affordance when user picks a numeric value within upper and lower limit
• min 0.0
• max 1.0

Answer 33

slider

Slider(
label: value.toString(),
min: 0, max: 100
divisions: 100
value: _value,
onChanged: (double val) => _value = val
)

Question 34

great for picking one of small number of things

Answer 34

dropdown

DropdownMenuItem<SearchType>
( child: Text('Image'),
value: SearchType.image</SearchType>

Question 35

only purpose is to wrap all of its inputs thereby grouping them and their data

Answer 35

key

Question 36

• BOOL
• true means it will run as many field changes
• false means it will run manually

Answer 36

autovalidate

Question 37

three key currentState property

Answer 37

1. save()
2. validate()
3. reset()

Question 38

save all fields inside the form by calling onSaved

Answer 38

saved()

Question 39

run each field’s validator function

Answer 39

validate()

Question 40

reset each field inside the form back to initialValue

Answer 40

reset()

Question 41

entire purpose is to save, reset, validate event handlers to an inner widget

Answer 41

FormField Widget

Question 42

wrap FormField widget around each input widget

Answer 42

builder

Question 43

Form has a key which has a currentState which has a saved() method

Answer 43

onSaved
key.currentState.save();

Question 44

if autovalidate is true, flutter will validate immediately as user make changes

Answer 44

validate
key.currentState.validate();