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App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 273 · 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: a 5-minute alarm ends is a text event. (a) True (b) False
  2. 2.True or false: a finger hits Like is a load event. (a) True (b) False
  3. 3.👆 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
  4. 4.👆 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, nameBox.text! (c) Welcome, Meera! (d) Welcome!
  5. 5.👆 The user taps the button 5 times. What number does the label show now?
    let stars = 5;
    button.onTap = function () {
      stars = stars + 1;
      label.text = stars;
    };
  6. 6.👆 The user taps the button 6 times. What number does the label show now?
    let points = 7;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
  7. 7.👆 What kind of event is this: a finger hits Like? (a) a tap event (b) a text event (c) a timer event (d) a load event
  8. 8.👆 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
  9. 9.👆 A tap handler runs how many times if the user taps 4 times? (a) 8 (b) 0 (c) 4 (d) 1
  10. 10.👆 The user taps the button 3 times. What number does the label show now?
    let stars = 1;
    button.onTap = function () {
      stars = stars + 3;
      label.text = stars;
    };
  11. 11.👆 The user taps the button 5 times. What number does the label show now?
    let stars = 4;
    button.onTap = function () {
      stars = stars + 2;
      label.text = stars;
    };
  12. 12.👆 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;
    };
  13. 13.👆 An event in an app is ___. (a) something that happens (b) a colour theme (c) an app store (d) a kind of list
  14. 14.👆 The user taps the button 4 times. What number does the label show now?
    let stars = 2;
    button.onTap = function () {
      stars = stars + 5;
      label.text = stars;
    };
  15. 15.👆 The user taps the button 8 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  16. 16.👆 The user taps the button 4 times. What number does the label show now?
    let stars = 7;
    button.onTap = function () {
      stars = stars + 1;
      label.text = stars;
    };
  17. 17.👆 What kind of event is this: the screen first opens? (a) a timer event (b) a load event (c) a tap event (d) a text event
  18. 18.True or false: the user types a letter is a text event. (a) True (b) False
  19. 19.👆 The user taps the button 6 times. What number does the label show now?
    let stars = 6;
    button.onTap = function () {
      stars = stars + 5;
      label.text = stars;
    };
  20. 20.True or false: a 5-minute alarm ends is a load event. (a) False (b) True
  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) ON (b) OFF
  22. 22.👆 The user taps the button 4 times. What number does the label show now?
    let points = 0;
    button.onTap = function () {
      points = points + 2;
      label.text = points;
    };
  23. 23.True or false: the user taps Play is a timer event. (a) False (b) True
  24. 24.👆 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, nameBox.text! (b) Hello! (c) Hello, Riya! (d) Riya
  25. 25.👆 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;
    };
  26. 26.👆 The user taps the button 4 times. What number does the label show now?
    let points = 10;
    button.onTap = function () {
      points = points + 4;
      label.text = points;
    };
  27. 27.True or false: a countdown hits zero is a tap event. (a) False (b) True
  28. 28.👆 Which of these is an event? (a) the icon colour (b) the user taps a button (c) a list of names (d) the font size
  29. 29.👆 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
  30. 30.👆 The user taps the button 4 times. What number does the label show now?
    let lives = 10;
    button.onTap = function () {
      lives = lives + 5;
      label.text = lives;
    };
  31. 31.👆 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, Aman! (b) Well done, nameBox.text! (c) Well done! (d) Aman
  32. 32.👆 What kind of event is this: the user taps Play? (a) a load event (b) a text event (c) a tap event (d) a timer event
  33. 33.👆 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;
    };
  34. 34.True or false: a finger hits Like is a tap event. (a) False (b) True
  35. 35.👆 The user taps the button 4 times. What number does the label show now?
    let lives = 1;
    button.onTap = function () {
      lives = lives + 3;
      label.text = lives;
    };
  36. 36.True or false: the user types a letter is a load event. (a) False (b) True
  37. 37.👆 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! (b) Zoya (c) Hi, nameBox.text! (d) Hi, Zoya!
  38. 38.👆 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! (c) Arjun (d) Hi, nameBox.text!
  39. 39.True or false: the user taps Play is a load event. (a) True (b) False
  40. 40.True or false: the user taps Play is a tap event. (a) False (b) True

Answer key

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

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