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

App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 107 · 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.👆 What kind of event is this: the user presses Save? (a) a timer event (b) a tap event (c) a load event (d) a text event
  2. 2.True or false: a finger hits Like is a tap event. (a) False (b) True
  3. 3.👆 The user taps the button 5 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
  4. 4.True or false: the screen first opens is a load event. (a) False (b) True
  5. 5.True or false: the user presses Save is a load event. (a) True (b) False
  6. 6.👆 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) Hello! (b) Zoya (c) Hello, Zoya! (d) Hello, nameBox.text!
  7. 7.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    };     (a) Hi, Arjun! (b) Hi, nameBox.text! (c) Hi! (d) Arjun
  8. 8.👆 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;
    };
  9. 9.👆 The user taps the button 4 times. What number does the label show now?
    let lives = 9;
    button.onTap = function () {
      lives = lives + 1;
      label.text = lives;
    };
  10. 10.👆 “On tap → do this” links an event to ___. (a) an action (b) a charger (c) a font (d) a web address
  11. 11.👆 The user taps the button 3 times. What number does the label show now?
    let stars = 0;
    button.onTap = function () {
      stars = stars + 1;
      label.text = stars;
    };
  12. 12.👆 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) OFF (b) ON
  13. 13.👆 The user types Riya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    };     (a) Riya (b) Hi, Riya! (c) Hi, nameBox.text! (d) Hi!
  14. 14.👆 The user types Aman in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Welcome, Aman! (b) Welcome, nameBox.text! (c) Aman (d) Welcome!
  15. 15.👆 The user taps the button 1 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
  16. 16.👆 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;
    };
  17. 17.👆 What kind of event is this: a 5-minute alarm ends? (a) a timer event (b) a tap event (c) a load event (d) a text event
  18. 18.👆 The user taps the button 4 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  19. 19.True or false: a 5-minute alarm ends is a tap event. (a) False (b) True
  20. 20.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 4;
    button.onTap = function () {
      coins = coins + 2;
      label.text = coins;
    };
  21. 21.👆 The user taps the button 4 times. What number does the label show now?
    let stars = 1;
    button.onTap = function () {
      stars = stars + 2;
      label.text = stars;
    };
  22. 22.👆 The user taps the button 2 times. What number does the label show now?
    let coins = 1;
    button.onTap = function () {
      coins = coins + 4;
      label.text = coins;
    };
  23. 23.👆 The user taps the button 5 times. What number does the label show now?
    let score = 0;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  24. 24.👆 A tap handler runs how many times if the user taps 4 times? (a) 8 (b) 0 (c) 1 (d) 4
  25. 25.👆 What kind of event is this: the app starts up? (a) a tap event (b) a text event (c) a load event (d) a timer event
  26. 26.👆 The user taps the button 2 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
  27. 27.👆 The user taps the button 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  28. 28.👆 The user taps the button 4 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  29. 29.👆 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) Zoya (b) Hi, nameBox.text! (c) Hi, Zoya! (d) Hi!
  30. 30.👆 Code that runs when an event happens is called a ___. (a) hashtag (b) handler (c) headline (d) header
  31. 31.👆 The user types Kabir in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Kabir (b) Hello! (c) Hello, Kabir! (d) Hello, nameBox.text!
  32. 32.👆 Which of these is an event? (a) a list of names (b) the font size (c) the user taps a button (d) the icon colour
  33. 33.👆 The user taps the button 3 times. What number does the label show now?
    let stars = 4;
    button.onTap = function () {
      stars = stars + 2;
      label.text = stars;
    };
  34. 34.👆 An event in an app is ___. (a) a colour theme (b) an app store (c) something that happens (d) a kind of list
  35. 35.👆 The user taps the button 3 times. What number does the label show now?
    let points = 9;
    button.onTap = function () {
      points = points + 4;
      label.text = points;
    };
  36. 36.👆 What kind of event is this: one second passes? (a) a load event (b) a text event (c) a tap event (d) a timer event
  37. 37.True or false: one second passes is a tap event. (a) True (b) False
  38. 38.👆 What kind of event is this: the user types a letter? (a) a load event (b) a tap event (c) a timer event (d) a text event
  39. 39.👆 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;
    };
  40. 40.👆 The user taps the button 6 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };

Answer key

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

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