ICT$372$ Mobile Computing

Tutorial $05$

Topic: Week $5$: OnClickListener: Android Calculator Application

Submission: Five minutes before the end of the tutorial: all files must be uploaded on Moodle.

Exercise $1$: Add functionality to Calculator Application

$1.$ Create a layout like this in Android Studio $($Use the layout that you have created in

Tutorial $1)$

$2.$ Add all the functionalities to the calculator.

$3.$ Create a new project in Android Studio or open your existing project if you have

already created the layout and go to step $12.$Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$4.$ Select Empty Activity template.

$5.$ Name the applications as MyCalculator. Select java as language and press Finish.Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$6.$ After clicking Finish, it takes around ~$2$ minutes to build Activity and files.

$7.$ Let$$s design the UI of activity$\_$main.xml$.$ Go to Res $>$ Layout $>$ activity$\_$main

$8.$ Open activity$\_$main.xml$,$ navigate to code section and remove the existing code.

Add this code

$9.$ Now go back to design section.

$10.$ Drag and drop all the buttons in the layout.

$$ For button $1$ set ID as button$1$

$$ For button $2$ set ID as button$2$

$$ For button $3$ set ID as button$3$ For button $4$ set ID as button$4$ For

button $5$ set ID as button$5$ For button $6$ set ID as button$6$ For button $7$Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

set ID as button$7$ For button $8$ set ID as

button$8$ For button $9$ set ID as button$9$

$$ For button $0$ set ID as button$0$

$$ For button $+$ set ID as buttonadd

$$ For button $-$ set ID as buttonsub

$$ For button x set ID as buttonmul

$$ For button $/$ set ID as buttondiv

$$ For button C set ID as buttonC

$$ For button $.$ set ID as button$10$

$$ For button $=$ set ID as buttoneql

$11.$ Drag and drop a TextView at top and set its ID as textView$\_$result.

$12.$ Now we will add our Java code in our MainActivity.java file.

$13.$ So open you MainActivity.java file from left side of IDE

$($app $->$ java $->$ com.example.mycalculator$->$ MainActivity.java$)$

$14.$ Now declare a button and EditText type of variables in MainActivity. Add the

following code.Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$15.$ Now we will attach our layout buttons with these button variables by using their

IDs. $($ button$0=($Button$)$ findViewById$($R$.$id$.$button$0)$;$)$ Add the following code for

all Buttons and a TextView.

$16.$ Now we will add number for each button click. If user is clicking on button $1$ it

should display $1$ in TextView.

$17.$ Add onClickListener for all the buttons $(0,1,2,3,4,5,6,7,8,9,.)$Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$18.$ Now let$$s start working on addition function. First declare two float values and four

Boolean values.

$19.$ Now add this onClicklistener for buttonAdd at the end.Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$20.$ In the same way add onClicklistener for buttonSub, buttonMul, buttonDivision.Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$21.$ Now we will add code for ButtonEqual. Add the following code at the end.Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition

ICT$372$ Tutorial $04$ Compiled by: Madiha Anjum

$22.$ Now last part is to add functionality to C button. Add the following code at the end.

$23.$ Now run the applications and test all the buttons.

$24.$ This is how output should look like.Information extracted from: Smyth$,$ N$.$ Android Studio $3\mathrm{.}5$ Development Essentials$$ Java Edition