1 00:00:00,850 --> 00:00:04,830 So here as you can see our application is running on the emulator. 2 00:00:05,210 --> 00:00:10,580 So now let's actually assign a value for this and Bill amount for example one hundred. 3 00:00:10,930 --> 00:00:19,210 And now as you can see the tip is $25 and the total is 125 because here we specified that the percent 4 00:00:19,330 --> 00:00:20,740 is going to be 25 percent. 5 00:00:20,830 --> 00:00:25,420 So I can actually change this value to another value for example 10 percent. 6 00:00:25,880 --> 00:00:31,930 And as you can see here these values are changing the tip is now $10 and the total value that the user 7 00:00:31,930 --> 00:00:35,480 should pay is actually $110 right. 8 00:00:35,500 --> 00:00:37,340 So hopefully this makes sense. 9 00:00:37,400 --> 00:00:42,160 And now let's actually vote on our savings calculator here. 10 00:00:42,190 --> 00:00:50,410 So now let's go back to our jobs file here and now as you can see I actually created these valuables 11 00:00:50,410 --> 00:00:54,480 here inside our main activity class for example in line 24/7. 12 00:00:54,490 --> 00:00:58,130 We have this valuable which is of type double total salary. 13 00:00:58,270 --> 00:01:04,050 So this total salary is going to be the salary here that the user assigned is what you hear right. 14 00:01:04,090 --> 00:01:08,430 And here we have these savings percent as you can see here. 15 00:01:08,710 --> 00:01:14,170 So these savings percent variable which is of type double is going to actually hold the value of this 16 00:01:14,170 --> 00:01:14,900 percent. 17 00:01:15,100 --> 00:01:20,710 So when the user actually sits on the search bar it is going to actually change the value of this percent 18 00:01:21,070 --> 00:01:23,340 and then we can actually save that value. 19 00:01:23,350 --> 00:01:27,770 We can hold that value here inside this savings percent variable. 20 00:01:28,150 --> 00:01:34,330 And according to these savings percent and according to the salary that the user enters here we can 21 00:01:34,330 --> 00:01:39,590 actually calculate the value or the money that the user is actually saving. 22 00:01:39,700 --> 00:01:39,940 OK. 23 00:01:39,940 --> 00:01:41,830 Or the use that one to save. 24 00:01:41,890 --> 00:01:42,770 Right. 25 00:01:42,820 --> 00:01:45,460 So this is going to be our savings calculator. 26 00:01:45,460 --> 00:01:51,390 So we have this total salary savings present and we have to take suffuse for this first. 27 00:01:51,430 --> 00:01:56,210 The first one is for this save a person here this person here. 28 00:01:56,410 --> 00:01:58,570 And the second one is takes the money saved. 29 00:01:58,810 --> 00:02:02,720 And the second one is for this actually takes few here as you can see. 30 00:02:02,980 --> 00:02:10,180 So now first of all let's go inside this uncreate method here and after these lines of code here as 31 00:02:10,180 --> 00:02:17,950 you can see we have two handlers for actually this takes edited out and we have another handler for 32 00:02:17,950 --> 00:02:19,320 this sequel person. 33 00:02:19,480 --> 00:02:23,490 So we need two more handlers inside this uncreate Mefford. 34 00:02:23,680 --> 00:02:29,050 So now I'm going to pace seen some lines of code here and then I'm going to explain to you what's going 35 00:02:29,050 --> 00:02:30,430 on here. 36 00:02:30,460 --> 00:02:35,050 So as you can see here these are lines of code that I pasted here. 37 00:02:35,080 --> 00:02:41,920 First of all I created this line of code here as you can see I created an object of type a text. 38 00:02:42,310 --> 00:02:49,390 And this time the name of my editor is actually his salary so he had to actually create an object for 39 00:02:49,470 --> 00:02:54,690 this as he takes here as you can see here it is salary so assignment operator. 40 00:02:54,940 --> 00:03:03,100 And here I am actually testing this object to an edit text object find view by ID or that ID that it 41 00:03:03,140 --> 00:03:03,830 salary. 42 00:03:03,880 --> 00:03:04,990 Right. 43 00:03:05,080 --> 00:03:07,880 And here in line 66 it salary. 44 00:03:07,900 --> 00:03:13,750 So here I actually referred to the name of this edited edit text object it itself essentially that takes 45 00:03:13,780 --> 00:03:14,900 change listener. 46 00:03:15,100 --> 00:03:20,680 So here I want to actually make this less this it takes actually a listener. 47 00:03:20,800 --> 00:03:21,300 OK. 48 00:03:21,400 --> 00:03:29,460 To what happens inside these edits for example when the users at or actually move some values from this 49 00:03:29,470 --> 00:03:30,120 editor. 50 00:03:30,310 --> 00:03:35,560 You want to actually know what's going on here we want these it takes to be aware of what's happening 51 00:03:35,560 --> 00:03:36,970 inside these text. 52 00:03:37,240 --> 00:03:40,070 So that's why they actually put this line of code here. 53 00:03:40,240 --> 00:03:43,170 It is clearly that add text change to listener. 54 00:03:43,390 --> 00:03:46,040 And here as you can see I actually put this value here. 55 00:03:46,060 --> 00:03:47,670 It is decidedly changed. 56 00:03:47,720 --> 00:03:54,540 KC's watcher so this is going to be the name of our handler which we haven't actually put this. 57 00:03:54,760 --> 00:03:58,120 We haven't actually defined it is handler here. 58 00:03:58,190 --> 00:04:05,950 Yet inside our class and here in line 68 as you can see I actually created an object of type search 59 00:04:05,950 --> 00:04:13,210 bar and the name of my object is search bar save percent assignment operator. 60 00:04:13,630 --> 00:04:21,190 And then here I am actually testing this object to a simple object find view by ID or that ID that seach 61 00:04:21,200 --> 00:04:23,820 part save percent as you can see here. 62 00:04:23,980 --> 00:04:26,060 So here let me disappear. 63 00:04:26,070 --> 00:04:30,700 This virtual keyboard here as you can see we have this part here right. 64 00:04:30,700 --> 00:04:36,430 So here I created an object of type each part and then I referred to the ID of these people here. 65 00:04:36,790 --> 00:04:44,910 So in 1969 here I refer to the name of our object seek birthday present that said unsichtbare chain 66 00:04:44,960 --> 00:04:46,030 to the center. 67 00:04:46,030 --> 00:04:47,740 So again I want to be aware. 68 00:04:47,770 --> 00:04:54,370 I want to actually know what the what is going to be the value of this Sebarenzi use that actually seeks 69 00:04:54,430 --> 00:04:55,940 on the part here. 70 00:04:56,050 --> 00:04:56,670 Right. 71 00:04:56,710 --> 00:05:02,930 So that's why I actually put this line of code here such Percy percent that set on six part change the 72 00:05:02,940 --> 00:05:03,430 center. 73 00:05:03,650 --> 00:05:10,330 And that I actually put this value here in this name so bar savings percent change listener. 74 00:05:10,520 --> 00:05:13,200 So this is going to be again the name of our handler. 75 00:05:13,460 --> 00:05:17,720 So first of all let's actually create this handler and then we're going to go ahead and create this 76 00:05:17,720 --> 00:05:18,810 handler here. 77 00:05:19,130 --> 00:05:26,300 So now as you can see let's actually scroll down here and after. 78 00:05:26,540 --> 00:05:31,940 And as you can see here inside this class inside is main activity class and before the end in calibers 79 00:05:32,030 --> 00:05:37,090 of this main activity class here as you can see we're going to actually put our own code here. 80 00:05:37,370 --> 00:05:47,750 So now let me create a comment savings person savings calculator logic OK. 81 00:05:47,970 --> 00:05:53,160 So here I got a pasting sometimes some lines of code here and then I'm going to explain to you what's 82 00:05:53,160 --> 00:05:54,650 going on here. 83 00:05:55,140 --> 00:06:01,620 So as you can see here these are the lines of code that I pasted here and now I'm going to actually 84 00:06:01,620 --> 00:06:03,900 explain to you what's going on here. 85 00:06:03,930 --> 00:06:05,220 Exactly. 86 00:06:05,220 --> 00:06:10,980 First of all as you can see we have this private access modifier and we have to find out which which 87 00:06:10,980 --> 00:06:17,610 means that this is actually a constant and the data type of a handler is actually the text Wotcher and 88 00:06:17,610 --> 00:06:25,350 the name of our handler is EDT salary changed text bocher the same name that you specify here inside 89 00:06:25,350 --> 00:06:26,940 this uncreate method. 90 00:06:26,940 --> 00:06:30,550 Here as you can see it is Elodie changed text watcher. 91 00:06:30,870 --> 00:06:32,870 So let's go back to our handler here. 92 00:06:33,000 --> 00:06:36,810 So assignment operator new text watcher. 93 00:06:37,040 --> 00:06:43,560 OK so now it's going to actually create an anonymous inner class and that anonymous class is going to 94 00:06:43,560 --> 00:06:52,820 actually implement these text watcher interface and then it is going to actually implement these methods. 95 00:06:52,830 --> 00:06:57,860 These are abstract methods that are inside these texts which are in interface. 96 00:06:57,870 --> 00:07:03,270 So now if we actually hold the comments on my keyboard or the if you are using a Windows machine you 97 00:07:03,270 --> 00:07:05,520 need to hold the control key on your keyboard. 98 00:07:05,820 --> 00:07:12,010 And then I just click on the states which are here as you can see this is actually an interface right. 99 00:07:12,090 --> 00:07:18,680 And here we have some methods inside this interface as you can see here before text changed on text 100 00:07:18,690 --> 00:07:21,630 change and after the text changed. 101 00:07:21,630 --> 00:07:22,560 Right. 102 00:07:22,560 --> 00:07:26,570 So these are the facts that are inside this text which are inside the interface. 103 00:07:26,820 --> 00:07:29,590 So let's go back to our main activity file here. 104 00:07:29,850 --> 00:07:34,000 So now these are them if it's before the exchange so we don't need that for here. 105 00:07:34,290 --> 00:07:36,620 And here is our Meffert on takes changed. 106 00:07:36,630 --> 00:07:42,330 We use this method here and we also don't use this after taste change year aftertaste change Meffert 107 00:07:42,360 --> 00:07:43,410 you're right. 108 00:07:43,560 --> 00:07:50,370 So now let's go inside this text change method and here as you can see I have this try catch block here. 109 00:07:50,730 --> 00:07:52,100 And here's try. 110 00:07:52,320 --> 00:07:54,980 So let's go inside the curly braces of destroy black. 111 00:07:55,170 --> 00:08:01,210 And here are you referred to the name of this variable that I created inside this main activity class. 112 00:08:01,230 --> 00:08:06,240 So let's go back to our class here as you can see I actually created this variable here. 113 00:08:06,240 --> 00:08:07,550 This variable is of type double. 114 00:08:07,560 --> 00:08:11,300 And then I assigned this value zero point zero to the value of it. 115 00:08:11,400 --> 00:08:16,130 So now here are you referring to the name of that variable assignment operator. 116 00:08:16,380 --> 00:08:21,710 And then you refer to the name of this double class that parse double. 117 00:08:21,720 --> 00:08:27,570 So I actually called this parse double method on this double class so this is actually this method is 118 00:08:27,780 --> 00:08:29,090 actually a static method. 119 00:08:29,100 --> 00:08:29,880 Right. 120 00:08:30,000 --> 00:08:34,820 And this method actually accepts an argument of pipe string. 121 00:08:35,100 --> 00:08:41,790 So then it's going to actually convert that string value to a integer value or double value as you can 122 00:08:41,790 --> 00:08:42,690 see here. 123 00:08:42,690 --> 00:08:49,170 Double the pulse double if you wanted to use Integer instead of double we needed to actually call integer 124 00:08:49,230 --> 00:08:50,490 that parse integer. 125 00:08:50,520 --> 00:08:55,980 Right but here it's going to actually convert this string value to a double value. 126 00:08:56,070 --> 00:09:01,150 And here in say the apprentices as you can see here refers to the name of this argument that we receive 127 00:09:01,200 --> 00:09:05,640 from this text change method so s that is 3. 128 00:09:05,640 --> 00:09:09,000 So as you can see here this argument is of type chart sequence right. 129 00:09:09,030 --> 00:09:12,070 So we need to convert that value to a string value. 130 00:09:12,300 --> 00:09:19,080 And as I told you before this value is actually the value that we actually assign to these Eadie text. 131 00:09:19,080 --> 00:09:19,350 Right. 132 00:09:19,350 --> 00:09:22,310 For example number two number three or other values. 133 00:09:22,500 --> 00:09:25,440 This is going to be this is which is off the chart sequence. 134 00:09:25,440 --> 00:09:28,590 And here we are actually converting that by twisting value. 135 00:09:28,830 --> 00:09:34,290 And here by using these parts double Methody are converting that string value to a double value. 136 00:09:34,290 --> 00:09:38,290 And then we can assign that double value to this total salary. 137 00:09:38,540 --> 00:09:44,040 And here as you can see we have this catch plug here and this church is going to actually catch the 138 00:09:44,040 --> 00:09:48,530 errors that are actually number format exception as you can see here. 139 00:09:48,750 --> 00:09:53,930 So for example the user might assign a value that is actually not a not a numeric value. 140 00:09:53,930 --> 00:09:54,630 Right. 141 00:09:54,690 --> 00:09:57,910 So in that case it's going to actually execute this Cheche plug. 142 00:09:58,350 --> 00:10:03,570 It's going to execute this check catch plug and then it's going to assign this number point zero. 143 00:10:03,600 --> 00:10:07,130 This number is zero point zero to this total salary. 144 00:10:07,290 --> 00:10:08,180 Right. 145 00:10:08,220 --> 00:10:13,580 So in that case in that specific case it's not going to actually crash. 146 00:10:13,620 --> 00:10:14,220 OK. 147 00:10:14,220 --> 00:10:18,150 We are catching this error here so hopefully that makes sense.