← Events: on tap, do this lesson New set →

App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 212 · 40 questions
TalentJR

Developer's tip (When this, do that): Event → handler → action: “on tap, do this”. The handler runs once for every tap. Counter: start + taps × step. A limit stops it growing; on = !on flips ON / OFF.

NameDateTime takenScore ___ / 40
  1. 1.👆 The user types Meera in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Hello, Meera! (b) Hello! (c) Hello, nameBox.text! (d) Meera
  2. 2.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  3. 3.👆 The user taps the button 2 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  4. 4.👆 Which of these is an event? (a) the user taps a button (b) the font size (c) the icon colour (d) a list of names
  5. 5.True or false: the screen first opens is a tap event. (a) False (b) True
  6. 6.👆 The user taps the button 7 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    };     (a) ON (b) OFF
  7. 7.👆 What kind of event is this: the app starts up? (a) a text event (b) a timer event (c) a tap event (d) a load event
  8. 8.👆 What kind of event is this: the user presses Save? (a) a text event (b) a timer event (c) a load event (d) a tap event
  9. 9.👆 “On tap → do this” links an event to ___. (a) a font (b) a web address (c) a charger (d) an action
  10. 10.👆 What kind of event is this: a 5-minute alarm ends? (a) a text event (b) a timer event (c) a tap event (d) a load event
  11. 11.👆 The user taps the button 2 times. What number does the label show now?
    let coins = 6;
    button.onTap = function () {
      coins = coins + 2;
      label.text = coins;
    };
  12. 12.👆 An event in an app is ___. (a) a colour theme (b) an app store (c) something that happens (d) a kind of list
  13. 13.👆 The user taps the button 3 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    };     (a) ON (b) OFF
  14. 14.👆 What kind of event is this: the user types a letter? (a) a tap event (b) a timer event (c) a load event (d) a text event
  15. 15.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Zoya (b) Hello, Zoya! (c) Hello, nameBox.text! (d) Hello!
  16. 16.👆 The user taps the button 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  17. 17.👆 The user types Meera in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Welcome, nameBox.text! (b) Welcome, Meera! (c) Welcome! (d) Meera
  18. 18.True or false: the user presses Save is a tap event. (a) False (b) True
  19. 19.👆 The user types Kabir in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    };     (a) Hi, nameBox.text! (b) Hi, Kabir! (c) Kabir (d) Hi!
  20. 20.👆 A tap handler runs how many times if the user taps 4 times? (a) 8 (b) 1 (c) 4 (d) 0
  21. 21.True or false: a finger hits Like is a text event. (a) True (b) False
  22. 22.True or false: a 5-minute alarm ends is a timer event. (a) True (b) False
  23. 23.👆 The user taps the button 1 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  24. 24.👆 What kind of event is this: the screen first opens? (a) a load event (b) a tap event (c) a timer event (d) a text event
  25. 25.👆 The user taps the button 6 times. What number does the label show now?
    let score = 3;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  26. 26.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  27. 27.👆 The user taps the button 2 times. What number does the label show now?
    let lives = 1;
    button.onTap = function () {
      lives = lives + 1;
      label.text = lives;
    };
  28. 28.👆 Code that runs when an event happens is called a ___. (a) headline (b) header (c) handler (d) hashtag
  29. 29.True or false: the app starts up is a load event. (a) False (b) True
  30. 30.👆 What kind of event is this: the search box changes? (a) a text event (b) a timer event (c) a load event (d) a tap event
  31. 31.👆 The user taps the button 5 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  32. 32.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    };     (a) Hi, nameBox.text! (b) Zoya (c) Hi! (d) Hi, Zoya!
  33. 33.👆 The user taps the button 4 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  34. 34.👆 The user taps the button 4 times. What number does the label show now?
    let points = 5;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
  35. 35.👆 The user taps the button 3 times. What number does the label show now?
    let score = 3;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  36. 36.👆 What kind of event is this: a finger hits Like? (a) a text event (b) a timer event (c) a tap event (d) a load event
  37. 37.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  38. 38.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 10;
    button.onTap = function () {
      lives = lives + 2;
      label.text = lives;
    };
  39. 39.👆 The user taps the button 5 times. What number does the label show now?
    let coins = 2;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
  40. 40.True or false: the search box changes is a tap event. (a) False (b) True

Answer key

  1. Hello, Meera!
  2. 5
  3. 2
  4. the user taps a button
  5. False
  6. ON
  7. a load event
  8. a tap event
  9. an action
  10. a timer event
  11. 10
  12. something that happens
  13. ON
  14. a text event
  15. Hello, Zoya!
  16. 3
  17. Welcome, Meera!
  18. True
  19. Hi, Kabir!
  20. 4
  21. False
  22. True
  23. 1
  24. a load event
  25. 9
  26. 3
  27. 3
  28. handler
  29. True
  30. a text event
  31. 3
  32. Hi, Zoya!
  33. 4
  34. 25
  35. 6
  36. a tap event
  37. 4
  38. 22
  39. 17
  40. False

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students