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App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 121 · 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: a countdown hits zero? (a) a tap event (b) a load event (c) a text event (d) a timer event
  2. 2.👆 The user taps the button 3 times. What number does the label show now?
    let score = 8;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  3. 3.👆 What kind of event is this: the app starts up? (a) a load event (b) a text event (c) a tap event (d) a timer event
  4. 4.👆 What kind of event is this: the search box changes? (a) a load event (b) a tap event (c) a text event (d) a timer event
  5. 5.👆 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;
    };
  6. 6.👆 The user taps the button 4 times. What number does the label show now?
    let lives = 0;
    button.onTap = function () {
      lives = lives + 2;
      label.text = lives;
    };
  7. 7.👆 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
  8. 8.👆 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, nameBox.text! (d) Welcome!
  9. 9.👆 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;
    };
  10. 10.True or false: one second passes is a text event. (a) True (b) False
  11. 11.👆 What kind of event is this: a finger hits Like? (a) a text event (b) a load event (c) a tap event (d) a timer event
  12. 12.👆 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) Meera (b) Welcome, Meera! (c) Welcome, nameBox.text! (d) Welcome!
  13. 13.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Welcome, Arjun! (b) Welcome! (c) Welcome, nameBox.text! (d) Arjun
  14. 14.👆 The user taps the button 2 times. What number does the label show now?
    let coins = 0;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
  15. 15.👆 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) OFF (b) ON
  16. 16.👆 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
  17. 17.👆 The user taps the button 6 times. What number does the label show now?
    let coins = 6;
    button.onTap = function () {
      coins = coins + 1;
      label.text = coins;
    };
  18. 18.👆 The user taps the button 4 times. What number does the label show now?
    let stars = 4;
    button.onTap = function () {
      stars = stars + 4;
      label.text = stars;
    };
  19. 19.👆 The user taps the button 2 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  20. 20.👆 The user taps the button 6 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  21. 21.👆 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
  22. 22.👆 The user taps the button 2 times. What number does the label show now?
    let points = 6;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
  23. 23.👆 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! (b) Meera (c) Hello, Meera! (d) Hello, nameBox.text!
  24. 24.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 5;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
  25. 25.👆 What kind of event is this: the user taps Play? (a) a timer event (b) a load event (c) a text event (d) a tap event
  26. 26.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 9;
    button.onTap = function () {
      coins = coins + 1;
      label.text = coins;
    };
  27. 27.👆 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, nameBox.text! (b) Welcome! (c) Aman (d) Welcome, Aman!
  28. 28.👆 An event in an app is ___. (a) a kind of list (b) a colour theme (c) an app store (d) something that happens
  29. 29.👆 The user taps the button 6 times. What number does the label show now?
    let score = 7;
    button.onTap = function () {
      score = score + 2;
      label.text = score;
    };
  30. 30.True or false: the app starts up is a load event. (a) True (b) False
  31. 31.True or false: a countdown hits zero is a timer event. (a) True (b) False
  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 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, Zoya! (b) Zoya (c) Hi! (d) Hi, nameBox.text!
  34. 34.👆 What kind of event is this: the screen first opens? (a) a text event (b) a tap event (c) a timer event (d) a load event
  35. 35.👆 The user taps the button 8 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  36. 36.True or false: the screen first opens is a load event. (a) False (b) True
  37. 37.True or false: a finger hits Like is a tap event. (a) True (b) False
  38. 38.👆 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
  39. 39.👆 What kind of event is this: one second passes? (a) a load event (b) a timer event (c) a tap event (d) a text event
  40. 40.True or false: a 5-minute alarm ends is a tap event. (a) True (b) False

Answer key

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

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