1 00:00:01,050 --> 00:00:04,610 And now I want to talk about boolean logical operators. 2 00:00:04,930 --> 00:00:10,980 So now let's actually go back inside this content underline minute example because I want to actually 3 00:00:11,010 --> 00:00:14,460 put in lots of components into this screen. 4 00:00:14,460 --> 00:00:15,100 OK. 5 00:00:15,180 --> 00:00:17,840 So as you can see here again is now seen as an error. 6 00:00:18,030 --> 00:00:21,450 So I just need to click on this clear cache here. 7 00:00:21,510 --> 00:00:23,770 Now as you can see the error is gone. 8 00:00:23,790 --> 00:00:31,410 So OK everyone now actually dragging a linearly out horizontal into this linearly out vertical. 9 00:00:31,790 --> 00:00:39,710 OK so now let's actually put in some more components into this are linearly out horizontal OK. 10 00:00:40,020 --> 00:00:43,890 So let's actually dragging our large takes you here. 11 00:00:43,890 --> 00:00:50,910 So just click on this large takes you and then you can actually click on this linearly out horizontal 12 00:00:50,910 --> 00:00:51,210 here. 13 00:00:51,210 --> 00:00:51,950 OK. 14 00:00:52,680 --> 00:00:55,680 So as you can see here now this takes two views here. 15 00:00:55,890 --> 00:00:58,090 So double click on this text view. 16 00:00:58,350 --> 00:01:09,840 And for the text just type in here through and through and for the ID just typing the XTi through and 17 00:01:10,470 --> 00:01:11,180 through. 18 00:01:11,630 --> 00:01:12,230 OK. 19 00:01:12,390 --> 00:01:19,640 And it's actually tracking two more checkboxes into this linearly horizontal. 20 00:01:19,680 --> 00:01:22,460 So as you can see here we've got this checkbox here. 21 00:01:22,800 --> 00:01:28,590 So just click on this checkbox and then click on this linearly out horizontal here. 22 00:01:28,590 --> 00:01:29,510 OK. 23 00:01:29,760 --> 00:01:33,390 So as you can see here now this checkbox is here. 24 00:01:33,630 --> 00:01:38,320 So double click on the checkbox and for the text just type in here yes. 25 00:01:38,820 --> 00:01:45,740 And for the ID just type in it just type in here see it x true and true. 26 00:01:46,230 --> 00:01:47,480 Yes. 27 00:01:48,330 --> 00:01:49,230 OK. 28 00:01:50,190 --> 00:01:58,550 Let's actually rake in another checkbox into this linearly or horizontal. 29 00:01:58,600 --> 00:02:01,780 So just click on this checkbox here and then put it in. 30 00:02:01,780 --> 00:02:05,520 Inside these are linearly and horizontal and then double click. 31 00:02:05,560 --> 00:02:08,260 And this is a checkbox here. 32 00:02:08,500 --> 00:02:10,930 And for the text just type in here no. 33 00:02:11,290 --> 00:02:18,430 And for the ID just type in here see Edge X through and through. 34 00:02:18,700 --> 00:02:19,840 No. 35 00:02:20,740 --> 00:02:21,360 OK. 36 00:02:21,730 --> 00:02:26,230 And then they actually click and these are linearly out horizontal. 37 00:02:26,320 --> 00:02:33,650 And as you can see here we've got our lay out gravity and we've got this gravity attribute OK. 38 00:02:33,790 --> 00:02:40,390 So just click on this gravity attribute and then open this attribute by just clicking on this little 39 00:02:40,390 --> 00:02:45,920 triangle here and then click on this center horizontal here. 40 00:02:45,970 --> 00:02:47,500 OK check this checkbox. 41 00:02:47,500 --> 00:02:54,170 So as you can see here now are components inside this linearly of horizontal is actually positioned 42 00:02:54,190 --> 00:02:57,240 at the center of this linearly of horizontal OK. 43 00:02:57,340 --> 00:02:59,060 So hopefully that makes sense. 44 00:02:59,140 --> 00:03:06,340 And let's actually go back inside this main activity the job of right here and then let's actually create 45 00:03:06,730 --> 00:03:13,010 some more objects from those components as you can see inside this content underline mean that it may 46 00:03:13,030 --> 00:03:18,220 not examine example we need to actually create a text view and two more checkboxes. 47 00:03:18,220 --> 00:03:18,850 OK. 48 00:03:19,180 --> 00:03:24,780 So inside this main activity that over here I can just type in text view. 49 00:03:25,570 --> 00:03:26,340 OK. 50 00:03:26,470 --> 00:03:27,280 XTi. 51 00:03:27,340 --> 00:03:31,140 True and true. 52 00:03:31,660 --> 00:03:37,780 And then I put an assignment operator here and then I need to cast this object to text through this 53 00:03:37,780 --> 00:03:46,010 view find view by id r that ID that T is the true and true. 54 00:03:46,270 --> 00:03:46,940 OK. 55 00:03:47,530 --> 00:03:53,230 So let's actually create a comment here in order to specify that these components are actually related 56 00:03:53,230 --> 00:03:55,860 to this are true and true. 57 00:03:56,040 --> 00:03:56,450 Text. 58 00:03:56,470 --> 00:03:56,890 OK. 59 00:03:56,980 --> 00:03:59,650 So I can just type in True 60 00:04:02,510 --> 00:04:05,620 and true here. 61 00:04:05,720 --> 00:04:06,250 OK. 62 00:04:06,320 --> 00:04:17,360 And now let's actually create two more checkboxes so I can just type in checkbox see X true and true. 63 00:04:17,600 --> 00:04:18,600 Yes. 64 00:04:19,490 --> 00:04:20,070 OK. 65 00:04:20,210 --> 00:04:26,600 And then I put an assignment operator and then I need to actually cast this object to the checkbox object 66 00:04:27,110 --> 00:04:34,500 and then I just need to type in find the way Id are that Id dot see X true and true. 67 00:04:34,550 --> 00:04:35,410 Yes. 68 00:04:35,930 --> 00:04:36,870 OK. 69 00:04:37,430 --> 00:04:43,610 Again I need to create another checkbox object C H x true and true. 70 00:04:43,900 --> 00:04:55,490 No I put an assignment operator here checkbox find view by id r that Id dot see Edge X true and true. 71 00:04:55,880 --> 00:04:56,370 No. 72 00:04:56,470 --> 00:04:57,570 OK. 73 00:04:58,070 --> 00:05:00,250 So hopefully that makes sense. 74 00:05:01,010 --> 00:05:04,100 So now let's actually work on these components. 75 00:05:04,390 --> 00:05:05,080 OK. 76 00:05:05,180 --> 00:05:10,520 So at the bottom here as you can see we can actually create a comment here. 77 00:05:10,520 --> 00:05:13,960 True and true. 78 00:05:14,810 --> 00:05:15,390 OK. 79 00:05:15,590 --> 00:05:16,570 OK everyone. 80 00:05:16,570 --> 00:05:21,550 Now let's actually create a boolean variable here. 81 00:05:21,560 --> 00:05:30,450 So I just need to type in Boolean OK and then the name of my variable is true and true. 82 00:05:30,980 --> 00:05:36,710 OK and then I need to get an assignment operator here and then I want to actually assign a value to 83 00:05:36,710 --> 00:05:37,630 this value. 84 00:05:37,690 --> 00:05:38,160 OK. 85 00:05:38,240 --> 00:05:41,500 So as you can see the data type of a variable is boolean. 86 00:05:41,540 --> 00:05:45,640 So we need to actually assign a value of type Boolean. 87 00:05:45,680 --> 00:05:53,320 So as a result we can only assign either true or false to this true and true valuable. 88 00:05:53,510 --> 00:05:56,420 So I can't just create a boolean expression here. 89 00:05:56,440 --> 00:06:03,220 OK so I just need to put in a pair of round brackets here and then inside Apprentice's can just type 90 00:06:03,220 --> 00:06:03,950 in true. 91 00:06:04,200 --> 00:06:09,680 And so as you can see here I put in two and are symbols here. 92 00:06:09,680 --> 00:06:10,270 OK. 93 00:06:10,490 --> 00:06:12,260 True and true. 94 00:06:14,180 --> 00:06:14,680 OK. 95 00:06:14,780 --> 00:06:18,110 So as you can see here this is actually a boolean expression. 96 00:06:18,110 --> 00:06:18,750 OK. 97 00:06:18,770 --> 00:06:24,250 And the result of this expression is going to be assigned to this a boolean variable. 98 00:06:24,450 --> 00:06:27,680 Ok so now let's actually create an if statement here. 99 00:06:27,680 --> 00:06:33,140 So if and then say the prentices I need to actually specify the condition. 100 00:06:33,260 --> 00:06:36,050 So true and true. 101 00:06:36,320 --> 00:06:43,210 So as you can see here I specified that if the value of this actual and true value above is true. 102 00:06:43,600 --> 00:06:50,420 OK if the result of this expression is true then that true value is going to be assigned to this variable. 103 00:06:50,420 --> 00:06:50,940 OK. 104 00:06:51,050 --> 00:06:54,150 And if the value of this variable is true. 105 00:06:54,290 --> 00:06:57,410 So as you can see here that's the meaning of this statement here. 106 00:06:57,470 --> 00:07:02,440 If the value of this true and true variable is true. 107 00:07:02,900 --> 00:07:07,280 So now I can actually put in my own codes inside of these curly braces. 108 00:07:07,400 --> 00:07:10,460 So C H x true and true. 109 00:07:10,460 --> 00:07:14,020 Yes that said checked. 110 00:07:14,380 --> 00:07:15,570 True. 111 00:07:16,360 --> 00:07:16,570 OK. 112 00:07:16,580 --> 00:07:24,140 And this means that please if the value of this true and true variable is true then we can actually 113 00:07:24,680 --> 00:07:26,470 check this checkbox here. 114 00:07:26,480 --> 00:07:27,580 As you can see it is. 115 00:07:27,680 --> 00:07:28,960 Yes checkbox. 116 00:07:29,190 --> 00:07:31,450 OK and else. 117 00:07:31,450 --> 00:07:39,570 Else if the value of this true and true variable is not true so it is false. 118 00:07:39,800 --> 00:07:40,890 So I can just put it. 119 00:07:40,910 --> 00:07:44,320 I just need to put in an exclamation mark here. 120 00:07:44,330 --> 00:07:46,370 True and true. 121 00:07:46,550 --> 00:07:50,510 And this means if the value of this true and true value bet is false. 122 00:07:50,510 --> 00:07:53,970 So I can just put in another pair of curly braces here. 123 00:07:54,050 --> 00:08:02,930 So as you can see inside these curly braces I can just type in C H x true and true no dot said checked. 124 00:08:02,930 --> 00:08:04,900 So C is true and true. 125 00:08:05,030 --> 00:08:06,620 No that said check it. 126 00:08:06,620 --> 00:08:07,740 True. 127 00:08:08,420 --> 00:08:08,920 OK. 128 00:08:09,020 --> 00:08:10,580 So hopefully that makes sense. 129 00:08:10,580 --> 00:08:12,460 So now let me actually explain again. 130 00:08:12,680 --> 00:08:19,070 First of all we actually created a boolean valuable named true and true and then we assigned a boolean 131 00:08:19,070 --> 00:08:20,760 expression to this idea. 132 00:08:20,860 --> 00:08:24,710 OK and then we actually created an if statement here. 133 00:08:24,800 --> 00:08:32,900 OK so first of all we specify that if the value of these two and two variable is true and that means 134 00:08:32,930 --> 00:08:39,010 if the value of this expression is true then that true value is going to be assigned to this value. 135 00:08:39,050 --> 00:08:39,660 OK. 136 00:08:39,770 --> 00:08:47,150 And if the value of this variable is true then executes this line of code here and LS If the value of 137 00:08:47,150 --> 00:08:51,270 this variable is not true then execute this line of code here. 138 00:08:51,530 --> 00:08:57,760 And if the value of this true and true variable is false it's going to actually check this a no checkbox 139 00:08:57,800 --> 00:08:58,320 here. 140 00:08:58,580 --> 00:08:59,260 OK. 141 00:08:59,450 --> 00:09:03,710 Because we actually specified that is that C is x true and true. 142 00:09:03,710 --> 00:09:05,170 No that said checked. 143 00:09:05,180 --> 00:09:05,690 True. 144 00:09:05,900 --> 00:09:09,730 So it's true it's true value means it's going to actually check this checkbox. 145 00:09:09,740 --> 00:09:16,380 So remember that I told you then that this checkbox is actually checked the value of the 6 X is true. 146 00:09:16,430 --> 00:09:22,670 And when this checkbox is actually is checked of the value of this checkbox is false. 147 00:09:22,790 --> 00:09:23,470 OK. 148 00:09:23,600 --> 00:09:25,340 So hopefully that makes sense. 149 00:09:25,400 --> 00:09:28,060 And let's actually run our project and see what happens. 150 00:09:28,130 --> 00:09:28,620 OK. 151 00:09:28,700 --> 00:09:32,460 Now as you can see our application is actually running on this emulator. 152 00:09:32,630 --> 00:09:38,200 And as you can see here now this checkbox is checked on OK true and true yes. 153 00:09:38,270 --> 00:09:42,690 And this means that the value of this tool and true valuable is true. 154 00:09:42,710 --> 00:09:45,600 So this line of code is actually get executed. 155 00:09:45,920 --> 00:09:46,490 OK. 156 00:09:46,670 --> 00:09:49,490 C S C H x true and true yes. 157 00:09:49,490 --> 00:09:51,590 So this checkbox that checked. 158 00:09:51,590 --> 00:09:52,190 True. 159 00:09:52,550 --> 00:09:53,080 OK. 160 00:09:53,270 --> 00:09:54,650 So hopefully that makes sense.