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

App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 263 · 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 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  2. 2.👆 A tap handler runs how many times if the user taps 4 times? (a) 0 (b) 4 (c) 8 (d) 1
  3. 3.👆 The user types Kabir in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    };     (a) Well done, nameBox.text! (b) Kabir (c) Well done! (d) Well done, Kabir!
  4. 4.True or false: the user taps Play is a tap event. (a) False (b) True
  5. 5.👆 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! (b) Arjun (c) Hi, Arjun! (d) Hi, nameBox.text!
  6. 6.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 6;
    button.onTap = function () {
      coins = coins + 4;
      label.text = coins;
    };
  7. 7.👆 The user taps the button 5 times. What number does the label show now?
    let points = 1;
    button.onTap = function () {
      points = points + 2;
      label.text = points;
    };
  8. 8.👆 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;
    };
  9. 9.True or false: the screen first opens is a load event. (a) False (b) True
  10. 10.👆 The user taps the button 6 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
  11. 11.👆 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) Kabir (c) Hi, nameBox.text! (d) Hi!
  12. 12.👆 The user types Riya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    };     (a) Well done, Riya! (b) Riya (c) Well done, nameBox.text! (d) Well done!
  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) Hi, Riya! (b) Hi, nameBox.text! (c) Riya (d) Hi!
  14. 14.👆 The user taps the button 6 times. What number does the label show now?
    let coins = 8;
    button.onTap = function () {
      coins = coins + 2;
      label.text = coins;
    };
  15. 15.👆 What kind of event is this: the user types a letter? (a) a timer event (b) a load event (c) a tap event (d) a text event
  16. 16.👆 What kind of event is this: a finger hits Like? (a) a timer event (b) a tap event (c) a load event (d) a text event
  17. 17.👆 The user taps the button 2 times. What number does the label show now?
    let coins = 10;
    button.onTap = function () {
      coins = coins + 2;
      label.text = coins;
    };
  18. 18.👆 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) OFF (b) ON
  19. 19.👆 The user types Aman in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    };     (a) Well done! (b) Aman (c) Well done, nameBox.text! (d) Well done, Aman!
  20. 20.👆 What kind of event is this: the user taps Play? (a) a load event (b) a tap event (c) a text event (d) a timer event
  21. 21.👆 The user taps the button 5 times. What number does the label show now?
    let score = 10;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  22. 22.True or false: the screen first opens is a text 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 < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  24. 24.True or false: the user taps Play is a timer event. (a) False (b) True
  25. 25.👆 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;
    };
  26. 26.👆 The user taps the button 6 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  27. 27.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 3;
    button.onTap = function () {
      coins = coins + 1;
      label.text = coins;
    };
  28. 28.👆 What kind of event is this: one second passes? (a) a text event (b) a tap event (c) a load event (d) a timer event
  29. 29.👆 The user taps the button 4 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  30. 30.👆 “On tap → do this” links an event to ___. (a) a font (b) a charger (c) an action (d) a web address
  31. 31.👆 What kind of event is this: a 5-minute alarm ends? (a) a tap event (b) a load event (c) a timer event (d) a text event
  32. 32.👆 What kind of event is this: the search box changes? (a) a tap event (b) a timer event (c) a load event (d) a text event
  33. 33.👆 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;
    };
  34. 34.👆 What kind of event is this: the screen first opens? (a) a load event (b) a tap event (c) a text event (d) a timer event
  35. 35.👆 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;
    };
  36. 36.👆 An event in an app is ___. (a) a kind of list (b) something that happens (c) an app store (d) a colour theme
  37. 37.True or false: a finger hits Like is a timer event. (a) False (b) True
  38. 38.True or false: the search box changes is a text event. (a) False (b) True
  39. 39.👆 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;
    };
  40. 40.👆 The user taps the button 3 times. What number does the label show now?
    let stars = 6;
    button.onTap = function () {
      stars = stars + 1;
      label.text = stars;
    };

Answer key

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

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