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

App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 49 · 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 taps the button 2 times. What number does the label show now?
    let score = 9;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  2. 2.👆 What kind of event is this: the user presses Save? (a) a text event (b) a timer event (c) a tap event (d) a load event
  3. 3.👆 The user taps the button 5 times. What number does the label show now?
    let points = 2;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
  4. 4.👆 The user taps the button 1 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  5. 5.👆 Code that runs when an event happens is called a ___. (a) header (b) handler (c) headline (d) hashtag
  6. 6.👆 “On tap → do this” links an event to ___. (a) a font (b) a web address (c) a charger (d) an action
  7. 7.👆 The user taps the button 8 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  8. 8.True or false: the search box changes is a text event. (a) False (b) True
  9. 9.👆 The user taps the button 5 times. What number does the label show now?
    let points = 4;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
  10. 10.True or false: the user taps Play is a text event. (a) True (b) False
  11. 11.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Arjun (b) Hello, Arjun! (c) Hello, nameBox.text! (d) Hello!
  12. 12.👆 The user taps the button 2 times. What number does the label show now?
    let points = 6;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
  13. 13.👆 The user taps the button 2 times. What number does the label show now?
    let coins = 10;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
  14. 14.👆 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
  15. 15.👆 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) OFF (b) ON
  16. 16.👆 The user taps the button 3 times. What number does the label show now?
    let lives = 6;
    button.onTap = function () {
      lives = lives + 3;
      label.text = lives;
    };
  17. 17.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  18. 18.True or false: the user presses Save is a tap event. (a) True (b) False
  19. 19.👆 The user taps the button 4 times. What number does the label show now?
    let score = 0;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  20. 20.👆 What kind of event is this: a 5-minute alarm ends? (a) a tap event (b) a timer event (c) a text event (d) a load event
  21. 21.👆 The user taps the button 4 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
  22. 22.True or false: the screen first opens is a load event. (a) False (b) True
  23. 23.👆 The user types Riya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Hello, Riya! (b) Riya (c) Hello! (d) Hello, nameBox.text!
  24. 24.👆 The user taps the button 2 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  25. 25.👆 The user types Aman 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) Aman (c) Hi, Aman! (d) Hi!
  26. 26.👆 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
  27. 27.👆 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;
    };
  28. 28.👆 A tap handler runs how many times if the user taps 4 times? (a) 4 (b) 8 (c) 0 (d) 1
  29. 29.👆 What kind of event is this: the user taps Play? (a) a text event (b) a load event (c) a timer event (d) a tap event
  30. 30.👆 What kind of event is this: the screen first opens? (a) a load event (b) a text event (c) a tap event (d) a timer event
  31. 31.👆 The user types Kabir in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Welcome! (b) Welcome, nameBox.text! (c) Welcome, Kabir! (d) Kabir
  32. 32.👆 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;
    };
  33. 33.👆 Which of these is an event? (a) the icon colour (b) a list of names (c) the font size (d) the user taps a button
  34. 34.👆 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;
    };
  35. 35.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Zoya (b) Welcome, Zoya! (c) Welcome! (d) Welcome, nameBox.text!
  36. 36.👆 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, Kabir! (b) Hi, nameBox.text! (c) Hi! (d) Kabir
  37. 37.👆 The user taps the button 2 times. What number does the label show now?
    let stars = 7;
    button.onTap = function () {
      stars = stars + 4;
      label.text = stars;
    };
  38. 38.👆 An event in an app is ___. (a) an app store (b) something that happens (c) a kind of list (d) a colour theme
  39. 39.True or false: a finger hits Like is a timer event. (a) True (b) False
  40. 40.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 1;
    button.onTap = function () {
      lives = lives + 3;
      label.text = lives;
    };

Answer key

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

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