App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 161 · 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.👆 An event in an app is ___. (a) an app store (b) a colour theme (c) something that happens (d) a kind of list
2. 2.👆 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, nameBox.text! (b) Hi! (c) Riya (d) Hi, Riya!
3. 3.👆 The user taps the button 6 times. What number does the label show now?
   let lives = 4;
   button.onTap = function () {
     lives = lives + 4;
     label.text = lives;
   };
4. 4.👆 What kind of event is this: the user presses Save? (a) a text event (b) a load event (c) a timer event (d) a tap event
5. 5.👆 A tap handler runs how many times if the user taps 4 times? (a) 0 (b) 8 (c) 4 (d) 1
6. 6.👆 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;
   };
7. 7.👆 Which of these is an event? (a) the font size (b) the icon colour (c) a list of names (d) the user taps a button
8. 8.True or false: a finger hits Like is a timer event. (a) True (b) False
9. 9.👆 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;
   };
10. 10.👆 What kind of event is this: the user taps Play? (a) a load event (b) a text event (c) a timer event (d) a tap event
11. 11.👆 The user taps the button 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
12. 12.👆 Code that runs when an event happens is called a ___. (a) headline (b) handler (c) hashtag (d) header
13. 13.👆 The user taps the button 5 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
14. 14.True or false: the screen first opens is a load event. (a) False (b) True
15. 15.👆 What kind of event is this: the search box changes? (a) a tap event (b) a text event (c) a load event (d) a timer event
16. 16.👆 The user taps the button 6 times. What number does the label show now?
    let score = 1;
    button.onTap = function () {
      score = score + 2;
      label.text = score;
    };
17. 17.👆 What kind of event is this: a 5-minute alarm ends? (a) a text event (b) a load event (c) a timer event (d) a tap event
18. 18.👆 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) Hello, nameBox.text! (c) Riya (d) Hello, Riya!
19. 19.👆 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
20. 20.👆 The user taps the button 6 times. What number does the label show now?
    let stars = 8;
    button.onTap = function () {
      stars = stars + 1;
      label.text = stars;
    };
21. 21.👆 The user taps the button 3 times. What number does the label show now?
    let stars = 0;
    button.onTap = function () {
      stars = stars + 2;
      label.text = stars;
    };
22. 22.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 5;
    button.onTap = function () {
      coins = coins + 5;
      label.text = coins;
    };
23. 23.👆 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) Aman (b) Hi! (c) Hi, Aman! (d) Hi, nameBox.text!
24. 24.👆 What kind of event is this: one second passes? (a) a text event (b) a tap event (c) a timer event (d) a load event
25. 25.👆 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
26. 26.👆 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) Welcome! (b) Welcome, Meera! (c) Welcome, nameBox.text! (d) Meera
27. 27.True or false: the user presses Save is a tap event. (a) False (b) True
28. 28.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
29. 29.👆 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
30. 30.👆 The user taps the button 6 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
31. 31.True or false: the user types a letter is a tap event. (a) False (b) True
32. 32.True or false: a countdown hits zero is a timer event. (a) False (b) True
33. 33.👆 The user taps the button 3 times. What number does the label show now?
    let lives = 6;
    button.onTap = function () {
      lives = lives + 3;
      label.text = lives;
    };
34. 34.👆 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
35. 35.True or false: the user taps Play is a text event. (a) False (b) True
36. 36.👆 The user types Kabir 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) Kabir (c) Hi! (d) Hi, Kabir!
37. 37.👆 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;
    };
38. 38.👆 The user taps the button 5 times. What number does the label show now?
    let lives = 10;
    button.onTap = function () {
      lives = lives + 1;
      label.text = lives;
    };
39. 39.👆 The user taps the button 4 times. What number does the label show now?
    let score = 10;
    button.onTap = function () {
      score = score + 5;
      label.text = score;
    };
40. 40.True or false: the search box changes is a text event. (a) False (b) True

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