App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 79 · 40 questions

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.

1. 1.👆 The user taps the button 6 times. What number does the label show now?
   let score = 1;
   button.onTap = function () {
     score = score + 1;
     label.text = score;
   };
2. 2.👆 The user taps the button 3 times. What number does the label show now?
   let score = 10;
   button.onTap = function () {
     score = score + 3;
     label.text = score;
   };
3. 3.👆 What kind of event is this: the search box changes? (a) a text event (b) a load event (c) a timer event (d) a tap event
4. 4.True or false: a finger hits Like is a timer event. (a) False (b) True
5. 5.👆 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, Kabir! (b) Well done, nameBox.text! (c) Kabir (d) Well done!
6. 6.👆 The user taps the button 6 times. What number does the label show now?
   let points = 7;
   button.onTap = function () {
     points = points + 1;
     label.text = points;
   };
7. 7.👆 “On tap → do this” links an event to ___. (a) a web address (b) an action (c) a font (d) a charger
8. 8.True or false: the user types a letter is a load event. (a) True (b) False
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 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
11. 11.👆 The user taps the button 5 times. What number does the label show now?
    let points = 3;
    button.onTap = function () {
      points = points + 3;
      label.text = points;
    };
12. 12.👆 An event in an app is ___. (a) an app store (b) a kind of list (c) something that happens (d) a colour theme
13. 13.True or false: a countdown hits zero is a load event. (a) True (b) False
14. 14.👆 What kind of event is this: a countdown hits zero? (a) a load event (b) a tap event (c) a timer event (d) a text event
15. 15.👆 What kind of event is this: a 5-minute alarm ends? (a) a load event (b) a tap event (c) a text event (d) a timer event
16. 16.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 5;
    button.onTap = function () {
      lives = lives + 4;
      label.text = lives;
    };
17. 17.👆 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
18. 18.👆 Code that runs when an event happens is called a ___. (a) headline (b) handler (c) hashtag (d) header
19. 19.👆 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) Arjun (b) Welcome, nameBox.text! (c) Welcome, Arjun! (d) Welcome!
20. 20.👆 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, Aman! (b) Hi, nameBox.text! (c) Aman (d) Hi!
21. 21.👆 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
22. 22.👆 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) Arjun (b) Hello! (c) Hello, nameBox.text! (d) Hello, Arjun!
23. 23.👆 The user types Aman in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    }; (a) Aman (b) Hello, nameBox.text! (c) Hello! (d) Hello, Aman!
24. 24.👆 The user taps the button 5 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
25. 25.👆 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
26. 26.👆 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;
    };
27. 27.True or false: the user taps Play is a tap event. (a) False (b) True
28. 28.👆 Which of these is an event? (a) the font size (b) a list of names (c) the user taps a button (d) the icon colour
29. 29.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
30. 30.True or false: the user presses Save is a tap event. (a) True (b) False
31. 31.👆 What kind of event is this: the user types a letter? (a) a load event (b) a tap event (c) a text event (d) a timer event
32. 32.👆 The user taps the button 5 times. What number does the label show now?
    let stars = 10;
    button.onTap = function () {
      stars = stars + 3;
      label.text = stars;
    };
33. 33.👆 A tap handler runs how many times if the user taps 4 times? (a) 4 (b) 1 (c) 8 (d) 0
34. 34.👆 The user taps the button 2 times. What number does the label show now?
    let score = 4;
    button.onTap = function () {
      score = score + 2;
      label.text = score;
    };
35. 35.👆 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! (d) Welcome, Meera!
36. 36.👆 The user taps the button 2 times. What number does the label show now?
    let stars = 0;
    button.onTap = function () {
      stars = stars + 5;
      label.text = stars;
    };
37. 37.👆 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! (b) Riya (c) Hello, Riya! (d) Hello, nameBox.text!
38. 38.👆 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) ON (b) OFF
39. 39.👆 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
40. 40.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    }; (a) Welcome, Zoya! (b) Welcome! (c) Welcome, nameBox.text! (d) Zoya

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