1 00:00:00,290 --> 00:00:03,150 So analysis actually putting some more lines of code here. 2 00:00:03,150 --> 00:00:10,000 So now when I actually create some objects from these classes that they actually created in this project. 3 00:00:10,110 --> 00:00:10,880 OK. 4 00:00:10,890 --> 00:00:14,440 So as you can see here these are the new lines of code that they actually pasted here. 5 00:00:14,460 --> 00:00:15,000 OK. 6 00:00:15,000 --> 00:00:21,150 The first object that I actually created is of type desktop computer and the name of this object is 7 00:00:21,150 --> 00:00:22,360 desktop computer. 8 00:00:22,530 --> 00:00:26,070 And here I put an assignment operator new this that computer. 9 00:00:26,070 --> 00:00:31,460 So here I'm going to instantiate this object by putting this new keyboard and here as you can see I 10 00:00:31,460 --> 00:00:37,420 need to actually passing some arguments to the constructor of this class and the name of. 11 00:00:37,440 --> 00:00:39,670 For example this computer is I-Max. 12 00:00:39,930 --> 00:00:46,020 And as you can see the screen is high quality screen physical keyboard and physical mouse. 13 00:00:46,170 --> 00:00:47,220 And this is the power. 14 00:00:47,220 --> 00:00:48,230 This is the super power. 15 00:00:48,240 --> 00:00:49,010 And this is the Ram. 16 00:00:49,170 --> 00:00:49,760 OK. 17 00:00:50,010 --> 00:00:51,850 And we have a laptop computer. 18 00:00:52,050 --> 00:00:55,710 And as you can see instantiating this laptop computer object. 19 00:00:55,710 --> 00:00:56,200 OK. 20 00:00:56,430 --> 00:01:01,980 And here we need to actually passing some values to the constructor of this laptop computer class match 21 00:01:01,980 --> 00:01:05,270 with prope high quality screen physical keyboard. 22 00:01:05,550 --> 00:01:09,880 And as you can see here and this laptop actually has a physical mouse. 23 00:01:10,090 --> 00:01:16,260 And here as you can see inside of this laptop computer inside of the constructor as you can see I actually 24 00:01:16,590 --> 00:01:21,750 specified that the constructor actually accepts a value of type strips 3. 25 00:01:21,960 --> 00:01:27,780 And the name of this argument is mouse and we can actually create an instance variable for this mouse 26 00:01:27,900 --> 00:01:28,670 here. 27 00:01:28,670 --> 00:01:33,660 Private's OK and strange mouse. 28 00:01:33,870 --> 00:01:39,840 And then here I can actually instantiate this mouse here and here inside of this constructor. 29 00:01:39,960 --> 00:01:45,100 I can't just type in this dot mouse assignment operator mouse. 30 00:01:45,180 --> 00:01:51,210 And now let's actually create a getter and the setter for this mouse instance variable. 31 00:01:51,210 --> 00:01:59,250 So inside of this class click here and then click on generates and then click on getter and setter mouse 32 00:02:00,030 --> 00:02:01,660 and then click on finish. 33 00:02:01,950 --> 00:02:09,750 So as you can see here we have a getter and setter for this mouse instance variable and inside of this 34 00:02:09,840 --> 00:02:14,410 and inside of these two string Meffert they can actually putting a person is here. 35 00:02:14,690 --> 00:02:17,700 OK in person yes. 36 00:02:18,240 --> 00:02:23,820 And now after this get touchpad here I can just put in a come up here and that I put into double coats 37 00:02:24,420 --> 00:02:33,120 and I can just typing mouse OK karma gets mouse OK. 38 00:02:33,550 --> 00:02:39,280 So this person as here is for this string value and this person is for this gets mouse he had as you 39 00:02:39,280 --> 00:02:40,120 can see here. 40 00:02:40,390 --> 00:02:45,130 OK this is the method that returns the value of this mouse instance variable. 41 00:02:45,190 --> 00:02:53,020 So I forgot to actually create an instance variable for this mouse here and now let's actually go back 42 00:02:53,020 --> 00:02:58,660 and say this main activity that right fight here as you can see all of this constructed of this laptop 43 00:02:58,660 --> 00:03:03,880 computer as you can see MacBook Pro high quality screen physical keyboard physical mouse. 44 00:03:03,880 --> 00:03:07,270 This is the value of this superpower's 2008 on here. 45 00:03:07,300 --> 00:03:11,730 As you can see this is the value of their RAM. 46 00:03:11,830 --> 00:03:12,700 Fifteen hundred. 47 00:03:12,740 --> 00:03:14,070 OK high quality touchpad. 48 00:03:14,080 --> 00:03:14,650 OK. 49 00:03:14,890 --> 00:03:19,980 And as you can see here smartphone computer and here I am instantiating these objects. 50 00:03:20,110 --> 00:03:25,930 IPhone 6 is retina screen virtual keyboard all US 500 400. 51 00:03:26,070 --> 00:03:26,880 OK. 52 00:03:27,040 --> 00:03:29,270 And we have a tablet computer object. 53 00:03:29,410 --> 00:03:35,860 And here as you can see I am instantiating this object i-Pad as you can see it retina screen virtual 54 00:03:35,860 --> 00:03:39,700 keyboard all us eight hundred seven hundred ten. 55 00:03:39,700 --> 00:03:41,740 So this then is for the screen size. 56 00:03:41,830 --> 00:03:42,940 As you can see here. 57 00:03:43,360 --> 00:03:45,040 So hopefully that makes sense. 58 00:03:45,220 --> 00:03:48,230 And now the circuitry to output these objects to the screen. 59 00:03:48,310 --> 00:03:50,260 So as you can see here I paste. 60 00:03:50,320 --> 00:03:56,050 I actually pasted these lines of code here and now as you can see I referred to the name of this object 61 00:03:56,380 --> 00:03:58,740 DXi desktop computer performance. 62 00:03:58,780 --> 00:04:04,600 That said text performance as you can see plus desktop computer here I referred to the name of this 63 00:04:04,600 --> 00:04:07,830 object this computer data evaluates performance. 64 00:04:07,840 --> 00:04:13,930 So here I am actually calling this method on this object plus a new line character and again takes the 65 00:04:13,930 --> 00:04:21,310 laptop computer performance that takes performance plus laptop computer that evaluates performance plus 66 00:04:21,400 --> 00:04:25,420 a newline character takes the smartphone computer performance. 67 00:04:25,430 --> 00:04:32,680 That's text preferments plus smartphone computer that evaluates performance plus a newline character 68 00:04:33,030 --> 00:04:40,270 takes the tablet computer preferments that's a text preferments Plus a tablet computer that evaluates 69 00:04:40,270 --> 00:04:42,360 performance plus a newline character. 70 00:04:42,460 --> 00:04:45,480 So now let's actually get our project and see what happens. 71 00:04:45,610 --> 00:04:51,700 OK so now as you can see our application is running on the simulator and here as you can see desktop 72 00:04:51,700 --> 00:04:58,930 computer performance is disvalue laptop computer performance is disvalue smartphone computer as you 73 00:04:58,930 --> 00:05:04,700 can see performance this value and tablets computer performance disvalue OK. 74 00:05:04,960 --> 00:05:06,780 So hopefully that makes sense. 75 00:05:06,780 --> 00:05:10,340 And now let's get you to go back inside this main activity that will find here. 76 00:05:10,510 --> 00:05:13,210 And now let's actually put in some other lines of code here. 77 00:05:13,210 --> 00:05:18,460 So here I'm going to actually paste in some lines of code here and then I'm going to explain to you 78 00:05:18,460 --> 00:05:19,550 what's going on here. 79 00:05:19,570 --> 00:05:20,350 OK. 80 00:05:20,680 --> 00:05:27,610 So here as you can see in line for free I created an array of computer objects. 81 00:05:27,640 --> 00:05:31,490 OK I just said that we have an array of computers. 82 00:05:31,630 --> 00:05:32,520 OK but. 83 00:05:32,660 --> 00:05:34,870 And the size of this area is four. 84 00:05:34,870 --> 00:05:40,290 So this means that this area actually exits for a values of type computer object. 85 00:05:40,300 --> 00:05:47,000 OK but in this line of code we didn't actually assign any value to these to this address. 86 00:05:47,020 --> 00:05:47,520 OK. 87 00:05:47,710 --> 00:05:49,100 And 11:44. 88 00:05:49,190 --> 00:05:52,900 I said that computers sup index zero as you can see here. 89 00:05:52,990 --> 00:05:54,040 This is the next zero. 90 00:05:54,280 --> 00:05:55,570 Is this top computer. 91 00:05:55,570 --> 00:06:02,040 So I assigned this object to this computer to the index zero of this Adley computer. 92 00:06:02,290 --> 00:06:02,820 OK. 93 00:06:02,980 --> 00:06:07,240 And here I said computed is sub index one as you can see here. 94 00:06:07,300 --> 00:06:09,460 Assignment operator laptop computer. 95 00:06:09,460 --> 00:06:13,930 So I assigned a laptop computer to the index number of one of these computer. 96 00:06:14,020 --> 00:06:23,200 And here I actually assigned our smartphone computed object on this in this on to this index 0 to the 97 00:06:23,200 --> 00:06:23,570 index. 98 00:06:23,570 --> 00:06:26,150 And number two of these of these computers Aure. 99 00:06:26,200 --> 00:06:26,750 OK. 100 00:06:26,980 --> 00:06:33,550 And here I assigned a tablet computer object to these to the index number three of these are computers 101 00:06:33,580 --> 00:06:34,080 at 8. 102 00:06:34,090 --> 00:06:40,620 So remember that if you have an array of computers OK you have an array of computer objects. 103 00:06:40,630 --> 00:06:41,200 OK. 104 00:06:41,380 --> 00:06:46,780 And because there is actually an is a relationship between these objects and this computer. 105 00:06:46,780 --> 00:06:54,760 For example as you can see this top computer is actually a computer OK laptop computer is a computer 106 00:06:55,090 --> 00:07:01,000 smartphone computer is a computer and tablet computer is actually a smartphone computer. 107 00:07:01,000 --> 00:07:06,820 So because smartphone computer is actually a computer a tablet computer is also a computer. 108 00:07:06,850 --> 00:07:12,310 So that's why we could actually create an array of computers here. 109 00:07:12,400 --> 00:07:14,400 And we said that the size of this area is four. 110 00:07:14,500 --> 00:07:19,570 And here we could we could actually assign these values these objects to indexes of this Aure which 111 00:07:19,570 --> 00:07:21,140 is actually offtake computer. 112 00:07:21,310 --> 00:07:21,840 OK. 113 00:07:21,940 --> 00:07:24,990 So that's the power of polymorphism in Java. 114 00:07:25,150 --> 00:07:32,240 OK so now let's actually create a for loop inside of these are inside of this main activity class here. 115 00:07:32,410 --> 00:07:32,970 OK. 116 00:07:33,340 --> 00:07:35,670 And then I'm going to explain to you what's going on here. 117 00:07:35,920 --> 00:07:37,880 So as you can see here this is my full loop. 118 00:07:37,960 --> 00:07:38,600 OK. 119 00:07:38,830 --> 00:07:39,950 And here this is this. 120 00:07:39,960 --> 00:07:43,750 This is actually an enhanced for loop computer computer. 121 00:07:43,780 --> 00:07:47,930 And here I want to actually iterate over the values that are inside of this array. 122 00:07:47,980 --> 00:07:48,620 OK. 123 00:07:48,760 --> 00:07:53,590 For example this desktop computer laptop computer smartphone computer and tablet computer. 124 00:07:53,590 --> 00:07:59,470 And here as you can see I created an if statement if the value of a computer object as you can see here 125 00:07:59,480 --> 00:08:01,840 this is a variable of type computer. 126 00:08:01,870 --> 00:08:05,840 If this value is actually an instance of this computer. 127 00:08:05,890 --> 00:08:11,140 OK so here we are iterating over the values that are actually inside of these computers. 128 00:08:11,170 --> 00:08:17,560 OK so if this value your computer is actually an instance of this desktop computer then here you are 129 00:08:17,560 --> 00:08:21,060 actually creating an object of type this that computer. 130 00:08:21,130 --> 00:08:27,420 Ok this computer and the name of this object is current desktop computer assignment operator. 131 00:08:27,640 --> 00:08:33,230 And here we are actually casting this object this computer object to our desktop computer. 132 00:08:33,340 --> 00:08:33,910 OK. 133 00:08:34,210 --> 00:08:42,100 So and here in line 54 we said that this computer that said text CONAN This current this that computer 134 00:08:42,130 --> 00:08:43,160 that was strange. 135 00:08:43,360 --> 00:08:43,830 OK. 136 00:08:44,020 --> 00:08:50,820 And we have another if statement if computer is instance of actually laptop computer. 137 00:08:50,860 --> 00:08:51,260 OK. 138 00:08:51,370 --> 00:08:57,750 If this object is actually of type laptop computer here again we created another laptop the computer 139 00:08:57,790 --> 00:09:01,210 object Cullens a laptop computer assignment operator. 140 00:09:01,480 --> 00:09:05,870 And here again we are actually casting this object which is actually a computer. 141 00:09:06,010 --> 00:09:07,230 We are actually downcasting. 142 00:09:07,240 --> 00:09:07,720 OK. 143 00:09:07,870 --> 00:09:13,550 We are done testing means casting an object from our superclass to where sockless. 144 00:09:13,570 --> 00:09:18,190 OK so this computer actually is actually a superclass of this laptop computer. 145 00:09:18,190 --> 00:09:18,590 OK. 146 00:09:18,700 --> 00:09:23,530 So here we could actually cast downcasting object to a laptop computer and then assign that value to 147 00:09:23,530 --> 00:09:25,680 this current laptop computer object. 148 00:09:25,780 --> 00:09:32,200 And here in line 58 as you can see it says the the laptop computer that said text current laptop computer 149 00:09:32,230 --> 00:09:32,730 object. 150 00:09:32,760 --> 00:09:33,900 OK that was strange. 151 00:09:33,910 --> 00:09:37,190 So we are actually calling this to same effect on this object. 152 00:09:37,240 --> 00:09:39,060 And here we have another statement. 153 00:09:39,100 --> 00:09:46,300 If computer is actually an instance of this smartphone computer class as you can see here and here we 154 00:09:46,300 --> 00:09:51,900 actually create an object from the smartphone a computer class assignment operator. 155 00:09:52,030 --> 00:09:58,820 And here we are actually casting this object to our smartphone our computer object as you can see here 156 00:09:59,470 --> 00:10:05,580 and he had said that the smart phone computer that said text current smartphone computer that was three. 157 00:10:05,830 --> 00:10:12,160 And here again we actually created another if statement if computer is actually an instance of these 158 00:10:12,160 --> 00:10:14,530 tablets computer as you can see here. 159 00:10:14,530 --> 00:10:21,110 So here we actually created an object of type tablet computer colorant tablet computer assignment operator. 160 00:10:21,190 --> 00:10:26,230 And here we're actually casting this object this computer object to our tablet computer. 161 00:10:26,230 --> 00:10:32,730 And here we are saying that the tablet computer that a text current tablet computer that is strange. 162 00:10:33,070 --> 00:10:33,770 OK. 163 00:10:34,030 --> 00:10:36,660 So hopefully that makes sense. 164 00:10:36,910 --> 00:10:40,870 And let's actually run our project and see what happens. 165 00:10:40,990 --> 00:10:45,040 So as you can see here our application is running on this emulator. 166 00:10:45,040 --> 00:10:49,130 So there's that computer I imagine high quality screen physical keyboard. 167 00:10:49,330 --> 00:10:56,540 So if you have this rally around this value performance this value and we have a laptop computer might 168 00:10:56,610 --> 00:11:03,370 work for a high quality screen physical keyboard touchpad high quality touchpad mouse physical mouse 169 00:11:03,520 --> 00:11:05,270 performance this value. 170 00:11:05,470 --> 00:11:12,100 And we have our smartphone computer I-pads retina screen virtual keyboard Sebille power lamp screen 171 00:11:12,100 --> 00:11:13,730 size performance. 172 00:11:13,780 --> 00:11:21,890 We have a tablet computer or iPad retina screen virtual keyboard Sibiu power ram screen size performance. 173 00:11:22,270 --> 00:11:23,090 OK. 174 00:11:23,440 --> 00:11:25,130 So hopefully that makes sense. 175 00:11:25,240 --> 00:11:30,460 And if you have any questions please post the discussion in the course and on and then I'll do my best 176 00:11:30,460 --> 00:11:32,440 to answer all of your questions. 177 00:11:32,810 --> 00:11:36,760 And thank you very much for watching and I'll see you in the next tutorial.