1 00:00:00,600 --> 00:00:06,310 OK everyone now inside this main activity class I want to actually create some objects. 2 00:00:06,330 --> 00:00:07,000 OK. 3 00:00:07,260 --> 00:00:14,820 So first of all let me actually specify the access modifier of my object to private and then I want 4 00:00:14,820 --> 00:00:17,550 these objects to be static. 5 00:00:17,820 --> 00:00:22,050 And this means that this object is actually a class object. 6 00:00:22,050 --> 00:00:22,510 OK. 7 00:00:22,650 --> 00:00:29,170 So we can actually do the first with the name of this object by using the class dot notation. 8 00:00:29,220 --> 00:00:32,670 OK the name of this class that the name of that object. 9 00:00:32,670 --> 00:00:33,330 OK. 10 00:00:33,750 --> 00:00:39,900 So you can actually delete this static keyboard here if you want to but are here I just wanted to show 11 00:00:39,900 --> 00:00:43,730 you that you can actually create static objects too. 12 00:00:43,860 --> 00:00:44,440 OK. 13 00:00:44,850 --> 00:00:45,880 So fine. 14 00:00:46,080 --> 00:00:49,340 And this finally means that this object is actually a constant. 15 00:00:49,650 --> 00:00:50,180 OK. 16 00:00:50,460 --> 00:00:53,390 And when we say that an object is actually a constant. 17 00:00:53,520 --> 00:01:01,920 This means that the reference that we have to that object is going to be a constant throughout the entire 18 00:01:01,920 --> 00:01:02,820 application. 19 00:01:02,850 --> 00:01:09,430 That reference is only referring to that object inside the memory and not any other objects. 20 00:01:09,460 --> 00:01:12,930 OK so fine on secure random. 21 00:01:13,270 --> 00:01:13,730 OK. 22 00:01:13,860 --> 00:01:15,310 Secure random. 23 00:01:15,510 --> 00:01:18,700 And the name of our object is secure. 24 00:01:19,050 --> 00:01:24,160 Random numbers. 25 00:01:24,300 --> 00:01:25,190 OK. 26 00:01:25,260 --> 00:01:29,780 Assignment operator new secure. 27 00:01:30,030 --> 00:01:30,790 Random. 28 00:01:31,110 --> 00:01:31,760 OK. 29 00:01:32,070 --> 00:01:39,360 So as you can see here I created an object from this secure random class and then I assigned this name 30 00:01:39,390 --> 00:01:45,570 to this object to secure random numbers and then I actually instantiated this object by using this new 31 00:01:45,590 --> 00:01:46,450 keyword here. 32 00:01:46,470 --> 00:01:47,060 OK. 33 00:01:47,430 --> 00:01:54,600 So when you instantiate an object this means that you're are actually creating a reference to that object 34 00:01:54,630 --> 00:01:55,590 inside the memory. 35 00:01:55,650 --> 00:02:03,090 OK so we have now our reference to the address of that object inside the memory. 36 00:02:03,090 --> 00:02:03,770 OK. 37 00:02:04,260 --> 00:02:08,030 So now I want to talk about a concept called in arms. 38 00:02:08,280 --> 00:02:13,890 OK so let's actually create on an income and then I actually are talking about in Java OK. 39 00:02:13,890 --> 00:02:21,910 So first let me specify the access modifier private's and income. 40 00:02:22,490 --> 00:02:22,820 OK. 41 00:02:22,830 --> 00:02:28,930 As you can see in some key vote we'll keep access modifier on keyboard. 42 00:02:29,100 --> 00:02:33,020 And then again I need to actually give a name to my name. 43 00:02:33,030 --> 00:02:42,740 So just type in hero status with the capital S status and then I need to actually open my by actually 44 00:02:42,750 --> 00:02:51,650 using an opening curly brace and then I need to close that in and by using our closing curly brace OK. 45 00:02:51,780 --> 00:02:58,290 So inside this you know I can actually put in some values so remember that you can in order to actually 46 00:02:58,290 --> 00:03:03,670 give values to an arm and the leaders of all of your values must be chapiter OK. 47 00:03:04,110 --> 00:03:06,400 This is actually a convention in Java. 48 00:03:06,750 --> 00:03:14,710 So for the first value just type in here not started yet. 49 00:03:15,230 --> 00:03:16,830 OK come on. 50 00:03:17,640 --> 00:03:19,710 And the second value is proceed 51 00:03:22,530 --> 00:03:23,050 OK. 52 00:03:23,140 --> 00:03:31,860 Comma on a first value is 1 and or fourth value is lost. 53 00:03:33,400 --> 00:03:37,600 OK so here as you can see we have an income. 54 00:03:37,780 --> 00:03:38,270 OK. 55 00:03:38,470 --> 00:03:41,820 And we gave a name to this in you know status. 56 00:03:41,940 --> 00:03:42,840 OK. 57 00:03:42,970 --> 00:03:45,220 The access modified of this is private. 58 00:03:45,250 --> 00:03:53,920 So it is of value is actually this is actually visible only to this class and no other classes can use 59 00:03:54,400 --> 00:03:55,110 this in. 60 00:03:55,210 --> 00:04:00,030 OK because we actually defined this as private. 61 00:04:00,340 --> 00:04:09,730 OK so in arms actually introduces a new type ok like in teacher for example when you create an integer 62 00:04:09,730 --> 00:04:15,850 variable like this the type of this variable is int integer. 63 00:04:15,920 --> 00:04:18,750 OK so it is just like this. 64 00:04:18,790 --> 00:04:19,310 OK. 65 00:04:19,540 --> 00:04:28,560 We have an income OK here aren't the type of our in is status OK it is just like your right here. 66 00:04:28,660 --> 00:04:29,240 OK. 67 00:04:29,320 --> 00:04:34,760 And the type of our variable is status defined or own type. 68 00:04:34,780 --> 00:04:41,800 Remember when you declare it when you declare an income you are actually defining your own type in that 69 00:04:42,010 --> 00:04:42,800 project. 70 00:04:43,000 --> 00:04:46,370 OK so this status is actually our own type. 71 00:04:46,510 --> 00:04:53,540 And these are the values actually the only values that we actually specified for this. 72 00:04:53,560 --> 00:04:58,020 You know OK this type can only accept these values. 73 00:04:58,060 --> 00:04:59,440 Not started yet. 74 00:04:59,650 --> 00:05:00,930 I made a mistake here. 75 00:05:01,030 --> 00:05:02,110 Not started yet. 76 00:05:02,140 --> 00:05:02,670 OK. 77 00:05:02,920 --> 00:05:09,730 So this arm this can only have this can only actually accept these values. 78 00:05:09,730 --> 00:05:11,120 Not started yet. 79 00:05:11,230 --> 00:05:13,750 Proceed one last. 80 00:05:13,960 --> 00:05:14,520 OK. 81 00:05:14,770 --> 00:05:19,150 And you may wonder what the type of these values. 82 00:05:19,170 --> 00:05:22,530 Ok the type of these values is actually integer. 83 00:05:22,810 --> 00:05:23,150 OK. 84 00:05:23,170 --> 00:05:28,940 Because assigning integer numbers to this type is a little confusing. 85 00:05:29,260 --> 00:05:38,010 I decided to actually assign some values that is human readable and a human can understand those values 86 00:05:38,340 --> 00:05:41,190 but actually those values are integer values. 87 00:05:41,190 --> 00:05:41,600 OK. 88 00:05:41,700 --> 00:05:46,010 So for example this in on here is actually 0. 89 00:05:46,120 --> 00:05:48,620 This value is actually 0. 90 00:05:48,630 --> 00:05:51,090 OK this value is 1. 91 00:05:51,090 --> 00:05:52,980 This value is 2. 92 00:05:53,190 --> 00:05:54,970 And this value is free. 93 00:05:55,220 --> 00:05:55,840 OK. 94 00:05:56,040 --> 00:06:02,220 So this in on here defines a set of named integer constants. 95 00:06:02,220 --> 00:06:04,400 So remember these are constants. 96 00:06:04,490 --> 00:06:09,170 OK we cannot change these values later in our code. 97 00:06:09,180 --> 00:06:14,100 These are constants and these are integer constants OK and start. 98 00:06:14,100 --> 00:06:18,660 And these are not actually starts with the value 0 by default. 99 00:06:18,660 --> 00:06:23,870 OK so this value is 0 1 2 3. 100 00:06:24,240 --> 00:06:25,620 OK. 101 00:06:25,710 --> 00:06:29,390 And these values are actually incremented by 1 automatically. 102 00:06:29,400 --> 00:06:32,900 If I actually put another value here for example something like this. 103 00:06:32,900 --> 00:06:36,920 This value is actually number fourth. 104 00:06:37,080 --> 00:06:37,980 OK. 105 00:06:38,400 --> 00:06:41,230 It is actually incremented by one automatically. 106 00:06:41,310 --> 00:06:45,010 So hopefully that makes sense and I'll talk more about it. 107 00:06:45,120 --> 00:06:51,620 So don't worry if there's if this doesn't make any sense to you let's actually go ahead and continue 108 00:06:51,650 --> 00:06:56,500 building our application and it will make sense to you at the end of this tutorial OK. 109 00:06:56,970 --> 00:07:03,440 So let's actually create some constants inside this class and remember we are actually creating this 110 00:07:04,170 --> 00:07:06,860 objects and this in an inside the class. 111 00:07:06,930 --> 00:07:07,370 OK. 112 00:07:07,410 --> 00:07:09,350 And not inside this creates method. 113 00:07:09,360 --> 00:07:15,780 So make sure that you actually create these values inside this class and here let's actually create 114 00:07:15,780 --> 00:07:17,290 some constants. 115 00:07:17,340 --> 00:07:24,080 So first of all I want to specify the access modifier of my constant so private. 116 00:07:24,970 --> 00:07:25,660 OK. 117 00:07:25,830 --> 00:07:27,280 Static. 118 00:07:28,100 --> 00:07:28,730 OK. 119 00:07:28,820 --> 00:07:32,380 Final int. 120 00:07:33,280 --> 00:07:33,900 OK. 121 00:07:34,200 --> 00:07:39,360 So as you can see here the access modifier of my constant is private. 122 00:07:39,410 --> 00:07:41,400 My constant is actually static. 123 00:07:41,570 --> 00:07:42,080 OK. 124 00:07:42,270 --> 00:07:47,490 You can actually delete this static key word here but I wanted to show you that you can actually create 125 00:07:47,490 --> 00:07:57,960 constants that are actually static and static means that we can refer to this actually valuable to this 126 00:07:57,960 --> 00:08:05,760 constant by actually referring to the name of this class without creating any objects from this class 127 00:08:05,850 --> 00:08:11,930 by referring to the name of this class that the name of this constant we can access the value of this 128 00:08:11,930 --> 00:08:12,450 constant. 129 00:08:12,450 --> 00:08:12,970 OK. 130 00:08:13,140 --> 00:08:15,230 So that's the rule for. 131 00:08:15,230 --> 00:08:18,350 Are you actually using a static variable or objects. 132 00:08:18,410 --> 00:08:19,130 OK. 133 00:08:19,440 --> 00:08:21,780 So hopefully that makes sense. 134 00:08:22,020 --> 00:08:28,350 And then now I want to actually give a name to my constant And remember when you create a constant the 135 00:08:28,350 --> 00:08:32,720 letters of the name of that constant should be capitalized. 136 00:08:32,760 --> 00:08:33,550 OK. 137 00:08:33,570 --> 00:08:37,120 The name of a constant is Tiger. 138 00:08:38,430 --> 00:08:41,080 Underline class. 139 00:08:42,180 --> 00:08:42,920 OK. 140 00:08:43,120 --> 00:08:47,310 And I want to assign a value to my variable for example number two. 141 00:08:47,960 --> 00:08:48,710 OK. 142 00:08:49,020 --> 00:08:55,250 So let's actually create another cons another constant private's static final. 143 00:08:56,000 --> 00:08:56,360 OK. 144 00:08:56,400 --> 00:09:01,810 Int the name of my variable this time is three. 145 00:09:02,730 --> 00:09:06,010 And then I assign the value free to my variable. 146 00:09:06,030 --> 00:09:09,670 Actually it is a constant OK a special type of variable. 147 00:09:09,690 --> 00:09:13,740 Ok constants are a special type of variable. 148 00:09:13,860 --> 00:09:18,410 Once we assign a value to those variables we cannot change that value. 149 00:09:18,510 --> 00:09:22,240 We cannot change that value of later in our code. 150 00:09:22,260 --> 00:09:35,670 Ok so private static final INT and this time the name of my variable is 7 with a capital. 151 00:09:35,670 --> 00:09:37,350 See here as you can see. 152 00:09:37,440 --> 00:09:50,310 And then I assign the value of 7 to my variable to my constant here private static final INT and at 153 00:09:50,340 --> 00:09:54,450 this time the name of my variable is the Levan. 154 00:09:55,070 --> 00:09:55,460 OK. 155 00:09:55,470 --> 00:09:59,600 And then I assigned a value 11 to this constant.