App Dev Worksheet: Events

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

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