1 00:00:00,240 --> 00:00:06,020 Hire everyone in this theater you are really going to go ahead and create another Android application. 2 00:00:06,030 --> 00:00:12,220 So just click on this starts a new Android studio your project here and for the application name just 3 00:00:12,220 --> 00:00:14,610 type in here app 28. 4 00:00:15,000 --> 00:00:24,480 And then we can Next choose a 16 Android 4.1 Jelly Bean for a minimum STK next and here choose Blancher 5 00:00:24,480 --> 00:00:26,070 activity next. 6 00:00:26,280 --> 00:00:27,960 And then we can finish. 7 00:00:28,190 --> 00:00:28,710 OK. 8 00:00:28,800 --> 00:00:32,140 Now let's actually select this hello world takes you here. 9 00:00:32,280 --> 00:00:37,380 And then press on delete key on your keyboard and then double click on the rest folder here. 10 00:00:37,410 --> 00:00:43,390 Lay out activity underline minute example and here choose this fluting action but in here. 11 00:00:43,410 --> 00:00:45,550 And then press on delete key on your keyboard. 12 00:00:45,590 --> 00:00:50,330 OK so now let's actually go back and say this content underlined minute example. 13 00:00:50,580 --> 00:00:55,100 And here we want to actually design the user interface of our application. 14 00:00:55,230 --> 00:01:01,990 So first of all this actually track linearly and vertical at the center of this relatively out here. 15 00:01:02,100 --> 00:01:02,700 OK. 16 00:01:02,970 --> 00:01:10,350 And now actually drag up a vertical scroll view into this linearly athletico. 17 00:01:10,350 --> 00:01:14,620 So just put it at the center of this linearly or vertical. 18 00:01:14,910 --> 00:01:20,580 And now let's actually write another linearly or 12 circle into this scroll view here. 19 00:01:21,000 --> 00:01:27,900 And now let's actually drag our own components into this linearly held vertical here. 20 00:01:27,930 --> 00:01:34,860 So now let's actually track our large takes you into These are linearly out to a circle here. 21 00:01:34,950 --> 00:01:35,420 OK. 22 00:01:35,580 --> 00:01:37,260 And double click on it. 23 00:01:37,260 --> 00:01:39,820 And here is just typing in desktop computer. 24 00:01:39,840 --> 00:01:42,880 OK and person Enter key on your keyboard. 25 00:01:43,200 --> 00:01:48,870 So now let's actually drag and other large takes you into this linearly outerwear cycle here. 26 00:01:49,050 --> 00:01:55,470 Double click on it and then delete the text of the stakes view and for the ID just type in here to the 27 00:01:55,920 --> 00:02:03,240 desktop computer and then a person Enter key on your keyboard. 28 00:02:03,560 --> 00:02:09,440 And now let's actually write another large takes you into this linearly out vertical here. 29 00:02:09,660 --> 00:02:16,170 Double click on it delete the text of this text view and for the ID just step in here to the desktop 30 00:02:17,310 --> 00:02:20,690 computer performance. 31 00:02:21,700 --> 00:02:22,250 OK. 32 00:02:22,380 --> 00:02:25,180 And then our press on Enter key on your keyboard. 33 00:02:25,230 --> 00:02:32,230 OK so now let's actually drag and other large takes you into These are linearly elsewhere equal here. 34 00:02:32,340 --> 00:02:33,330 Double click on it. 35 00:02:33,450 --> 00:02:43,350 And for the text just typing here a laptop computer and then press Enter key on your keyboard then drag 36 00:02:43,410 --> 00:02:47,020 and other large takes you into this linearly out vertical here. 37 00:02:47,070 --> 00:02:47,710 OK. 38 00:02:47,730 --> 00:02:53,730 Double click on it delete the text of this text will and for the ID just type in here TXI the laptop 39 00:02:55,020 --> 00:02:57,160 computer. 40 00:02:57,210 --> 00:02:57,840 OK. 41 00:02:58,050 --> 00:03:02,960 Now let's get you to the right and other large stakes into this linearly ultra vertical here. 42 00:03:03,000 --> 00:03:04,300 Double click on it. 43 00:03:04,360 --> 00:03:05,800 It's the text of the state's view. 44 00:03:05,810 --> 00:03:17,610 And for the OED to step in here takes the laptop computer performance and then press enter key on your 45 00:03:17,610 --> 00:03:18,780 keyboard. 46 00:03:18,780 --> 00:03:24,390 So now let's actually track another large text view into this linearly outworks equal here. 47 00:03:24,390 --> 00:03:25,260 Double click on it. 48 00:03:25,290 --> 00:03:36,720 And for the text just typing here smartphone computer and then person enter key on your keyboard and 49 00:03:36,780 --> 00:03:42,490 nounless actually do like and other large takes you into these linearly and vertical here double click 50 00:03:42,490 --> 00:03:44,760 on it delete the text of this text. 51 00:03:44,800 --> 00:03:54,640 And for the idea that they can hear the smartphone computer and then let's actually write another large 52 00:03:54,720 --> 00:03:57,590 stakes into this linearly vertical here. 53 00:03:57,820 --> 00:04:05,290 Double click on it delete the text of this text view and for the ID just type in here thinks the smartphone 54 00:04:08,530 --> 00:04:09,250 computer 55 00:04:11,680 --> 00:04:17,730 performance OK and then person enter key on your keyboard. 56 00:04:17,770 --> 00:04:18,620 OK. 57 00:04:19,000 --> 00:04:25,540 And now let's actually do like another large takes into this linearly out vertical here. 58 00:04:25,540 --> 00:04:34,900 Double click on it and for the text just type in here tablet computer and then press and in key on your 59 00:04:34,900 --> 00:04:35,640 keyboard. 60 00:04:35,920 --> 00:04:41,760 And now let's actually do like another large takes you into this linearly or two vertical here. 61 00:04:41,770 --> 00:04:47,380 Double click on it and delete the takes of this takes few and for the idea just they've been here takes 62 00:04:47,380 --> 00:04:54,540 the tablet computer and then person enter key on your keyboard. 63 00:04:54,550 --> 00:05:00,900 So now let's actually try again other large stakes into this linearly vertical here and double click 64 00:05:00,900 --> 00:05:10,990 on it delete the text of this text view and for the ID just type in here TXI the tablet computer performance 65 00:05:12,760 --> 00:05:15,180 and then press sun Enter key on your keyboard. 66 00:05:15,190 --> 00:05:15,690 OK. 67 00:05:15,790 --> 00:05:20,110 So now the design of our user interface is actually finished. 68 00:05:20,140 --> 00:05:25,020 So now let's actually go back inside this main activity that Jobo file here and then actually did it. 69 00:05:25,030 --> 00:05:27,990 These lines of code that are actually related to the Options menu. 70 00:05:28,330 --> 00:05:32,920 And now let's actually deal is this a floating action button here as you can see these lines of code 71 00:05:32,920 --> 00:05:35,980 that directly related to the floating action button. 72 00:05:36,250 --> 00:05:43,690 And now this actually create some double classes here and there first class that I want to actually 73 00:05:43,690 --> 00:05:46,680 create is actually a computer class. 74 00:05:46,690 --> 00:05:50,570 So just click on File New and then click on Java class. 75 00:05:50,590 --> 00:05:51,190 OK. 76 00:05:51,400 --> 00:05:56,650 And for the class name just type in your computer and then click on OK. 77 00:05:57,250 --> 00:06:02,980 And the second class that I want to actually create is actually a desktop computer class. 78 00:06:03,010 --> 00:06:09,910 So a new Java class and for the class then just typing here our desktop 79 00:06:12,250 --> 00:06:15,430 computer is but you don't. 80 00:06:15,450 --> 00:06:18,900 There must be no space between your class names. 81 00:06:18,910 --> 00:06:19,350 OK. 82 00:06:19,420 --> 00:06:21,210 Desktop computer. 83 00:06:22,180 --> 00:06:23,820 And then click on OK. 84 00:06:25,090 --> 00:06:31,420 And here let's actually create another java class here five new and for the Java class here as you can 85 00:06:31,420 --> 00:06:41,710 see click on Java class and for the name of the class just type in his laptop computer and then click 86 00:06:41,710 --> 00:06:48,130 on OK let's actually create another java class 5 new Java class. 87 00:06:48,130 --> 00:06:56,550 And here is actually create a smartphone or computer class smart phone computer. 88 00:06:57,260 --> 00:06:58,150 OK. 89 00:06:58,670 --> 00:07:07,800 And now find new Java class tablets computer tablet computer. 90 00:07:08,350 --> 00:07:11,140 And then click on OK here OK. 91 00:07:11,650 --> 00:07:14,410 So now let's go back and say it is a computer. 92 00:07:14,410 --> 00:07:20,590 The java file here as you can see if you have a computer class here but are actually computer is actually 93 00:07:20,590 --> 00:07:22,040 an abstract concept. 94 00:07:22,060 --> 00:07:26,440 OK if you want to I asks you that please give me a computer. 95 00:07:26,530 --> 00:07:27,230 You may ask. 96 00:07:27,310 --> 00:07:29,800 You may actually ask me that or what computer. 97 00:07:29,800 --> 00:07:31,370 What kind of computer do you want. 98 00:07:31,480 --> 00:07:37,940 Do you want a desktop computer or a laptop computer or a smartphone computer or a tablet computer. 99 00:07:38,170 --> 00:07:42,060 So a computer is actually an abstract class. 100 00:07:42,160 --> 00:07:42,660 OK. 101 00:07:42,700 --> 00:07:43,820 So public. 102 00:07:44,170 --> 00:07:44,630 OK. 103 00:07:44,800 --> 00:07:47,580 Abstract class computer. 104 00:07:47,650 --> 00:07:48,130 OK. 105 00:07:48,220 --> 00:07:52,570 Because a computer by itself is actually an abstract concept. 106 00:07:52,570 --> 00:07:56,820 We need to actually declare this cause this class as an abstract class. 107 00:07:56,860 --> 00:08:03,640 Ok so are abstract classes are actually a little bit different from the other classes that are actually 108 00:08:03,640 --> 00:08:05,720 called concrete classes. 109 00:08:06,160 --> 00:08:11,420 And you cannot actually create an object from an abstract class. 110 00:08:11,630 --> 00:08:18,430 OK so now let's actually put in some lines of code here and then I'll explain to you what's going on 111 00:08:18,430 --> 00:08:18,730 here. 112 00:08:18,780 --> 00:08:23,320 OK so first of all I want to actually create some instance variables. 113 00:08:23,320 --> 00:08:23,850 OK. 114 00:08:24,160 --> 00:08:30,310 So here as you can see I actually declared some instance variables and as you can see in line 10. 115 00:08:30,320 --> 00:08:37,480 I actually declare this instance variable the access modifier of this instance variable is private and 116 00:08:37,480 --> 00:08:39,870 this instance variable is actually final. 117 00:08:39,910 --> 00:08:43,030 And this means that this instance variable is constant. 118 00:08:43,090 --> 00:08:50,350 And once we assign a value to this instance variable we cannot change that value leader. 119 00:08:50,410 --> 00:08:50,990 OK. 120 00:08:51,370 --> 00:08:57,170 And the type of this instance value about is strange and the name of this instance variable is name. 121 00:08:57,250 --> 00:08:59,770 OK so every computer has a name. 122 00:08:59,830 --> 00:09:00,500 OK. 123 00:09:00,790 --> 00:09:08,590 And here in line 11 as you can see we have another instance variable private its final string screen. 124 00:09:08,870 --> 00:09:09,430 OK. 125 00:09:09,550 --> 00:09:17,820 Every computer has a screen and inline 12 as you can see private fine on screen keyboard and every computer 126 00:09:17,820 --> 00:09:18,720 has a keyboard. 127 00:09:18,750 --> 00:09:19,400 OK. 128 00:09:19,710 --> 00:09:24,450 So now let's actually create a constructor inside of this class here. 129 00:09:24,570 --> 00:09:29,080 So as you can see here this is our constructor that actually pasted here. 130 00:09:29,160 --> 00:09:29,810 OK. 131 00:09:30,090 --> 00:09:33,440 And the access modifier of this constructor is public. 132 00:09:33,570 --> 00:09:36,950 The name of the constructor must be the same as the name of the class. 133 00:09:36,990 --> 00:09:41,830 OK Computer and here this constructor actually to accept some arguments. 134 00:09:41,850 --> 00:09:42,350 OK. 135 00:09:42,540 --> 00:09:47,850 The first argument that this constructor accepts is actually of types 3 and name. 136 00:09:48,010 --> 00:09:54,960 OK the second argument is again of types think screen and the first argument is again of type String 137 00:09:55,080 --> 00:09:55,580 keyboard. 138 00:09:55,650 --> 00:09:56,200 OK. 139 00:09:56,370 --> 00:10:03,330 And here inside of these a constructor as you can see instantiating my instance variables that I actually 140 00:10:03,330 --> 00:10:05,320 created inside of this computer class. 141 00:10:05,330 --> 00:10:05,720 OK.