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App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 131 · 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.True or false: the screen first opens is a timer event. (a) False (b) True
  2. 2.👆 The user taps the button 2 times. What number does the label show now?
    let score = 10;
    button.onTap = function () {
      score = score + 3;
      label.text = score;
    };
  3. 3.👆 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;
    };
  4. 4.True or false: the user presses Save is a tap event. (a) False (b) True
  5. 5.👆 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;
    };
  6. 6.True or false: the user taps Play is a text event. (a) False (b) True
  7. 7.👆 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
  8. 8.👆 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
  9. 9.True or false: the user types a letter is a text event. (a) False (b) True
  10. 10.👆 The user taps the button 4 times. What number does the label show now?
    let score = 1;
    button.onTap = function () {
      score = score + 2;
      label.text = score;
    };
  11. 11.True or false: a 5-minute alarm ends is a load event. (a) False (b) True
  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) Well done, nameBox.text! (c) Riya (d) Well done!
  13. 13.👆 The user taps the button 5 times. What number does the label show now?
    let score = 10;
    button.onTap = function () {
      score = score + 5;
      label.text = score;
    };
  14. 14.👆 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;
    };
  15. 15.👆 The user taps the button 2 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  16. 16.👆 Which of these is an event? (a) a list of names (b) the font size (c) the icon colour (d) the user taps a button
  17. 17.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 7;
    button.onTap = function () {
      lives = lives + 3;
      label.text = lives;
    };
  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.👆 The user taps the button 6 times. What number does the label show now?
    let stars = 6;
    button.onTap = function () {
      stars = stars + 1;
      label.text = stars;
    };
  20. 20.👆 The user taps the button 2 times. What number does the label show now?
    let points = 5;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
  21. 21.👆 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) Hello, nameBox.text! (c) Hello, Zoya! (d) Zoya
  22. 22.👆 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;
    };
  23. 23.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 4;
    button.onTap = function () {
      coins = coins + 1;
      label.text = coins;
    };
  24. 24.👆 The user taps the button 2 times. What number does the label show now?
    let score = 4;
    button.onTap = function () {
      score = score + 5;
      label.text = score;
    };
  25. 25.True or false: a finger hits Like is a tap event. (a) True (b) False
  26. 26.True or false: a countdown hits zero is a timer event. (a) True (b) False
  27. 27.👆 The user taps the button 2 times. What number does the label show now?
    let lives = 5;
    button.onTap = function () {
      lives = lives + 2;
      label.text = lives;
    };
  28. 28.👆 The user taps the button 3 times. What number does the label show now?
    let score = 2;
    button.onTap = function () {
      score = score + 2;
      label.text = score;
    };
  29. 29.True or false: the app starts up is a load event. (a) True (b) False
  30. 30.👆 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) Hello! (b) Hello, nameBox.text! (c) Hello, Arjun! (d) Arjun
  31. 31.👆 What kind of event is this: the search box changes? (a) a text event (b) a timer event (c) a tap event (d) a load event
  32. 32.True or false: a 5-minute alarm ends is a timer event. (a) False (b) True
  33. 33.👆 The user types Riya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Riya (b) Welcome, Riya! (c) Welcome! (d) Welcome, nameBox.text!
  34. 34.👆 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) ON (b) OFF
  35. 35.👆 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!
  36. 36.True or false: the screen first opens is a text event. (a) False (b) True
  37. 37.👆 An event in an app is ___. (a) a kind of list (b) an app store (c) something that happens (d) a colour theme
  38. 38.👆 The user taps the button 2 times. What number does the label show now?
    let coins = 1;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
  39. 39.True or false: the search box changes is a text event. (a) True (b) False
  40. 40.👆 The user taps the button 6 times. What number does the label show now?
    let points = 9;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };

Answer key

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

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