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

App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 275 · 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 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
  2. 2.👆 What kind of event is this: a 5-minute alarm ends? (a) a tap event (b) a timer event (c) a load event (d) a text event
  3. 3.👆 The user taps the button 5 times. What number does the label show now?
    let points = 0;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
  4. 4.True or false: the user presses Save is a timer event. (a) True (b) False
  5. 5.👆 The user taps the button 2 times. What number does the label show now?
    let lives = 4;
    button.onTap = function () {
      lives = lives + 1;
      label.text = lives;
    };
  6. 6.👆 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) Welcome, Riya! (b) Welcome, nameBox.text! (c) Welcome! (d) Riya
  7. 7.True or false: the search box changes is a timer event. (a) False (b) True
  8. 8.True or false: the screen first opens is a load event. (a) True (b) False
  9. 9.👆 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;
    };
  10. 10.👆 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
  11. 11.👆 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
  12. 12.👆 The user taps the button 3 times. What number does the label show now?
    let score = 9;
    button.onTap = function () {
      score = score + 3;
      label.text = score;
    };
  13. 13.👆 What kind of event is this: one second passes? (a) a load event (b) a tap event (c) a timer event (d) a text event
  14. 14.True or false: a 5-minute alarm ends is a tap event. (a) True (b) False
  15. 15.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 2;
    button.onTap = function () {
      lives = lives + 1;
      label.text = lives;
    };
  16. 16.👆 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) OFF (b) ON
  17. 17.👆 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) Riya (b) Hi, Riya! (c) Hi! (d) Hi, nameBox.text!
  18. 18.👆 What kind of event is this: a countdown hits zero? (a) a text event (b) a tap event (c) a load event (d) a timer event
  19. 19.👆 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;
    };
  20. 20.👆 A tap handler runs how many times if the user taps 4 times? (a) 1 (b) 0 (c) 4 (d) 8
  21. 21.True or false: a 5-minute alarm ends is a text event. (a) True (b) False
  22. 22.👆 The user taps the button 4 times. What number does the label show now?
    let points = 0;
    button.onTap = function () {
      points = points + 3;
      label.text = points;
    };
  23. 23.👆 Code that runs when an event happens is called a ___. (a) header (b) headline (c) handler (d) hashtag
  24. 24.👆 “On tap → do this” links an event to ___. (a) a web address (b) an action (c) a charger (d) a font
  25. 25.👆 What kind of event is this: the screen first opens? (a) a timer event (b) a tap event (c) a text event (d) a load event
  26. 26.👆 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) OFF (b) ON
  27. 27.👆 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! (b) Welcome, nameBox.text! (c) Arjun (d) Welcome, Arjun!
  28. 28.👆 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
  29. 29.👆 What kind of event is this: the search box changes? (a) a timer event (b) a text event (c) a load event (d) a tap event
  30. 30.👆 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
  31. 31.👆 The user taps the button 6 times. What number does the label show now?
    let coins = 7;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
  32. 32.👆 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;
    };
  33. 33.👆 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
  34. 34.👆 The user taps the button 5 times. What number does the label show now?
    let lives = 7;
    button.onTap = function () {
      lives = lives + 4;
      label.text = lives;
    };
  35. 35.👆 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) Zoya (b) Hi, nameBox.text! (c) Hi! (d) Hi, Zoya!
  36. 36.True or false: the app starts up is a load event. (a) False (b) True
  37. 37.👆 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
  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.👆 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 types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    };     (a) Zoya (b) Well done, Zoya! (c) Well done, nameBox.text! (d) Well done!

Answer key

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

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