App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 255 · 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.👆 What kind of event is this: the user taps Play? (a) a timer event (b) a tap event (c) a text event (d) a load event
2. 2.True or false: one second passes is a timer event. (a) False (b) True
3. 3.True or false: the screen first opens is a tap event. (a) False (b) True
4. 4.👆 The user taps the button 4 times. What number does the label show now?
   let likes = 0;
   button.onTap = function () {
     if (likes < 3) {
       likes = likes + 1;
     }
     label.text = likes;
   };
5. 5.👆 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) Hi, Riya! (b) Hi, nameBox.text! (c) Riya (d) Hi!
6. 6.👆 A tap handler runs how many times if the user taps 4 times? (a) 4 (b) 1 (c) 8 (d) 0
7. 7.True or false: a 5-minute alarm ends is a timer event. (a) True (b) False
8. 8.👆 What kind of event is this: the user presses Save? (a) a text event (b) a tap event (c) a load event (d) a timer event
9. 9.👆 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!
10. 10.👆 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
11. 11.👆 The user taps the button 1 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
12. 12.👆 What kind of event is this: the user types a letter? (a) a load event (b) a tap event (c) a timer event (d) a text event
13. 13.👆 An event in an app is ___. (a) an app store (b) a colour theme (c) a kind of list (d) something that happens
14. 14.👆 The user taps the button 3 times. What number does the label show now?
    let points = 10;
    button.onTap = function () {
      points = points + 4;
      label.text = points;
    };
15. 15.👆 Code that runs when an event happens is called a ___. (a) header (b) handler (c) hashtag (d) headline
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.👆 “On tap → do this” links an event to ___. (a) a charger (b) a web address (c) an action (d) a font
18. 18.👆 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) ON (b) OFF
19. 19.👆 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! (b) Zoya (c) Welcome, Zoya! (d) Welcome, nameBox.text!
20. 20.👆 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
21. 21.👆 The user taps the button 3 times. What number does the label show now?
    let points = 7;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
22. 22.👆 The user taps the button 8 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
23. 23.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 7;
    button.onTap = function () {
      lives = lives + 3;
      label.text = lives;
    };
24. 24.👆 The user taps the button 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
25. 25.True or false: the user presses Save is a tap event. (a) False (b) True
26. 26.👆 What kind of event is this: a countdown hits zero? (a) a timer event (b) a text event (c) a load event (d) a tap event
27. 27.👆 The user types Meera in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    }; (a) Meera (b) Well done, nameBox.text! (c) Well done! (d) Well done, Meera!
28. 28.True or false: the user presses Save is a text event. (a) True (b) False
29. 29.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 4;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
30. 30.👆 The user taps the button 6 times. What number does the label show now?
    let score = 3;
    button.onTap = function () {
      score = score + 5;
      label.text = score;
    };
31. 31.👆 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
32. 32.👆 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, nameBox.text! (b) Arjun (c) Welcome, Arjun! (d) Welcome!
33. 33.👆 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, nameBox.text! (b) Well done, Aman! (c) Well done! (d) Aman
34. 34.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    }; (a) Arjun (b) Well done! (c) Well done, nameBox.text! (d) Well done, Arjun!
35. 35.👆 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;
    };
36. 36.👆 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
37. 37.👆 What kind of event is this: the search box changes? (a) a load event (b) a tap event (c) a timer event (d) a text event
38. 38.👆 The user taps the button 6 times. What number does the label show now?
    let points = 6;
    button.onTap = function () {
      points = points + 2;
      label.text = points;
    };
39. 39.👆 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, nameBox.text! (b) Riya (c) Welcome! (d) Welcome, Riya!
40. 40.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 1;
    button.onTap = function () {
      coins = coins + 2;
      label.text = coins;
    };

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