1

00:00:00,300 --> 00:00:07,880

So here first of all let's actually a create a variable which is of types three in here inside our class.



2

00:00:07,890 --> 00:00:12,100

So first let's specify the access modifier which is actually private.



3

00:00:12,360 --> 00:00:18,330

And now I need to specify the Data Type of my variable which is string and the name of my variable is



4

00:00:18,380 --> 00:00:23,980

all it takes the received data semicolon.



5

00:00:24,300 --> 00:00:25,540

Right.



6

00:00:25,680 --> 00:00:32,670

Now as you can see if this variable is going to actually hold the all the value of our Takes view which



7

00:00:32,670 --> 00:00:34,660

is this one takes the received data.



8

00:00:34,890 --> 00:00:39,340

So now let's actually scroll down here and let's go inside this and later change my faith.



9

00:00:39,570 --> 00:00:44,880

Now I'm going to paste some lines of code here and then I'm going to explain to you what's going on



10

00:00:44,880 --> 00:00:45,230

here.



11

00:00:45,240 --> 00:00:46,170

Exactly.



12

00:00:46,170 --> 00:00:47,680

So as you can see here.



13

00:00:47,850 --> 00:00:52,540

So as you can see here these are the lines of code that I pasted here.



14

00:00:52,550 --> 00:00:54,800

Inside this on data change method.



15

00:00:55,110 --> 00:00:57,180

So first of all we have a for loop.



16

00:00:57,180 --> 00:00:57,790

Right.



17

00:00:58,110 --> 00:01:04,570

And here you are actually iterating over the values of this state snapshot.



18

00:01:04,570 --> 00:01:08,430

You're either reading over the children of this data or snapshot.



19

00:01:08,430 --> 00:01:16,160

So first as you can see we are calling this add value event listener and this database reference.



20

00:01:16,230 --> 00:01:20,520

So let's scroll to the top here and let's see this valuable database reference.



21

00:01:20,640 --> 00:01:26,610

What is the value of this reference as you can see we are referring to the database reference right



22

00:01:26,610 --> 00:01:28,160

database that gets reference.



23

00:01:28,170 --> 00:01:32,540

So this means that we're are actually referring to let me try to show you the web browser.



24

00:01:32,670 --> 00:01:38,710

We are actually to this instance to this node right when we call database that gets reference is going



25

00:01:38,770 --> 00:01:40,990

to actually give me this note.



26

00:01:41,250 --> 00:01:45,700

So now we provided some children for this note.



27

00:01:45,750 --> 00:01:50,700

As you can see here this one is the highlight of this note and this one as you can see is actually the



28

00:01:50,820 --> 00:01:52,130

height of this note.



29

00:01:52,140 --> 00:01:53,920

This one is the height of this note.



30

00:01:53,940 --> 00:01:57,590

And this one is also the child of this note.



31

00:01:57,600 --> 00:02:00,090

So here we are referring to this note.



32

00:02:00,150 --> 00:02:00,650

Right.



33

00:02:00,780 --> 00:02:04,680

And you are assigning that reference to this database reference variable.



34

00:02:04,950 --> 00:02:06,400

So let me scroll down here.



35

00:02:06,830 --> 00:02:12,830

And here I am actually are either 18 or at the children of this reference data or snapshot.



36

00:02:12,900 --> 00:02:19,560

So when I say database reference that value even listener I am actually creating a listener for this



37

00:02:19,620 --> 00:02:20,220

note.



38

00:02:20,310 --> 00:02:27,820

So what ever whatever happens to the children of this note or two did to this not directly.



39

00:02:27,990 --> 00:02:29,330

Are going to be notified.



40

00:02:29,520 --> 00:02:35,850

Right this update or change if it is going to be called what happens to this node or to the children



41

00:02:35,850 --> 00:02:36,730

of this note.



42

00:02:36,960 --> 00:02:37,740

Right.



43

00:02:38,010 --> 00:02:42,030

And now let's get into insights on that or change it.



44

00:02:42,270 --> 00:02:47,410

But we are we want to as you can see we have children right.



45

00:02:47,490 --> 00:02:55,440

This note has children and we actually created this for loop in order to either aid over the children



46

00:02:55,500 --> 00:02:56,630

of that node.



47

00:02:56,910 --> 00:03:01,630

So I say 48 hours snapshot data snapshot Boxer object.



48

00:03:01,650 --> 00:03:07,780

So as you can see here we have actually a valuable right data snapshot box that object.



49

00:03:07,800 --> 00:03:15,360

So as you can see because we are receiving the data up from the server as the value of type data snapshot



50

00:03:15,820 --> 00:03:19,540

we are actually creating a valuable type data status snapshot which.



51

00:03:19,550 --> 00:03:21,320

Its name is box that object.



52

00:03:21,750 --> 00:03:28,530

And we want to iterate over the children of this data or snapshot that we actually receive from the



53

00:03:28,530 --> 00:03:29,780

Smurfette right.



54

00:03:29,880 --> 00:03:31,730

We receive data as a data snapshot.



55

00:03:31,740 --> 00:03:32,260

Right.



56

00:03:32,460 --> 00:03:37,850

So this data snapshot actually holds this note right.



57

00:03:37,890 --> 00:03:44,550

This data snapshot here holds this node and I am actually getting the children of this note.



58

00:03:44,670 --> 00:03:48,780

So in this way we can actually access the children of this note and we can actually either take over



59

00:03:48,780 --> 00:03:56,040

these notes over these children and we can actually access the objects or box that objects as you can



60

00:03:56,040 --> 00:03:56,880

see here.



61

00:03:56,880 --> 00:04:02,980

So each of these IDs actually has Buxar object as you can see here.



62

00:04:03,000 --> 00:04:12,090

So as you can see this for loop here is going to be executed for each boxer object that we have inside



63

00:04:12,180 --> 00:04:14,330

our server.



64

00:04:14,430 --> 00:04:20,990

So as you can see for example this for loop here is going to be executed for each child.



65

00:04:21,000 --> 00:04:23,860

So let me show you the web browser as you can see this is the child.



66

00:04:23,880 --> 00:04:26,420

Right this is one of these tights.



67

00:04:26,430 --> 00:04:27,560

This is an adult child.



68

00:04:27,570 --> 00:04:30,650

This is another child and this is another child.



69

00:04:30,660 --> 00:04:37,350

So for the first time that this is going to be executed the value of this box that object is going to



70

00:04:37,350 --> 00:04:42,840

actually hold this box that object variable is going to actually hold this child.



71

00:04:42,950 --> 00:04:43,280

Right.



72

00:04:43,290 --> 00:04:44,320

This one.



73

00:04:44,820 --> 00:04:50,580

And now let's actually to go inside the curly braces of this for a loop and let's see what's going on



74

00:04:50,580 --> 00:04:51,430

here.



75

00:04:51,450 --> 00:04:54,950

First of all you're actually getting the boxer object.



76

00:04:55,020 --> 00:04:58,470

So you are getting the boxer object from this child.



77

00:04:58,470 --> 00:04:59,060

Right.



78

00:04:59,070 --> 00:05:02,750

So this actually holds this box that object.



79

00:05:02,750 --> 00:05:03,960

Let me show you this again.



80

00:05:04,100 --> 00:05:12,210

This I.D. here actually holds this box object which its name is a it's punch power it's one hundred



81

00:05:12,230 --> 00:05:14,370

and each and it's punch.



82

00:05:14,370 --> 00:05:16,160

Speed is 200.



83

00:05:16,160 --> 00:05:20,240

So now in line number 72 I am getting the box object.



84

00:05:20,240 --> 00:05:26,800

So Boxer Boxer assignment operator and here I am referring to the sparks that object from this fall.



85

00:05:26,830 --> 00:05:32,480

As you can see here inside the apprentice's all told you that this is going to be executed for each



86

00:05:32,570 --> 00:05:36,740

child that we have here inside our server.



87

00:05:36,740 --> 00:05:37,270

Right.



88

00:05:37,310 --> 00:05:40,130

That we have for this note.



89

00:05:40,130 --> 00:05:45,240

So for the first time that this fall here is going to be executed the first child is this one.



90

00:05:45,740 --> 00:05:52,070

And in this way we can actually get the box objects or box it up take that good value boxer that class.



91

00:05:52,070 --> 00:05:53,680

So here are we.



92

00:05:53,730 --> 00:05:56,810

I should change the spots that object child.



93

00:05:57,140 --> 00:06:02,650

Let's actually change this one also to child and in this way it makes more sense.



94

00:06:02,660 --> 00:06:07,370

So here you can see that we're actually either over the children of the state or a snapshot which is



95

00:06:07,370 --> 00:06:08,180

this one.



96

00:06:08,300 --> 00:06:12,360

This is the latest snapshot right because it holds the reference to this note.



97

00:06:12,500 --> 00:06:17,990

So first we are actually getting the box set up to act like creating a variable of type Boxer and its



98

00:06:17,990 --> 00:06:20,200

name is Buxar assignment operator.



99

00:06:20,270 --> 00:06:22,410

And here I am referring to this child.



100

00:06:22,790 --> 00:06:23,290

Right.



101

00:06:23,310 --> 00:06:25,660

That gets value boxes that class.



102

00:06:25,670 --> 00:06:28,730

So this idea here is actually the height of this note.



103

00:06:28,730 --> 00:06:29,290

Right.



104

00:06:29,570 --> 00:06:34,820

And when I say child so I am referring to this ID that gets value.



105

00:06:34,850 --> 00:06:37,850

The value is actually the sparks that object.



106

00:06:38,060 --> 00:06:38,530

Right.



107

00:06:38,540 --> 00:06:41,000

Box it and its type is box at that class.



108

00:06:41,000 --> 00:06:43,210

So we must specify the type.



109

00:06:43,220 --> 00:06:46,170

So inside the prentices I just say boxes that class.



110

00:06:46,610 --> 00:06:49,910

And here we have an if statement.



111

00:06:50,120 --> 00:06:52,820

And here I am saying that if all the received data.



112

00:06:52,820 --> 00:06:57,640

So here I am referring to is sitting valuable that we created here in line number 28.



113

00:06:57,710 --> 00:07:04,430

So so here I am saying that if the value of this variable is actually null then instead of printing



114

00:07:04,510 --> 00:07:10,820

a null instead of actually displaying the value not to the user just that display an empty value swipe



115

00:07:10,940 --> 00:07:11,810

instead of double quotes.



116

00:07:11,800 --> 00:07:15,380

Or just put a space right on MTV.



117

00:07:15,530 --> 00:07:16,750

So all takes the risk.



118

00:07:16,860 --> 00:07:24,140

If the assignment operator an empty string value right and now after this if statements look at these



119

00:07:24,140 --> 00:07:28,530

lines of code here I am saying that TXI received data.



120

00:07:28,550 --> 00:07:34,150

So here I am referring to this text view that that we actually declare here inside our class and to



121

00:07:34,160 --> 00:07:35,090

be initialized.



122

00:07:35,210 --> 00:07:37,980

This takes you here inside our uncreate Smurfette.



123

00:07:38,030 --> 00:07:44,180

So here I am saying that TXU received data that said text old to receive data.



124

00:07:44,210 --> 00:07:49,530

So first I want to actually print the old value of party activity data.



125

00:07:49,530 --> 00:07:57,470

I want to actually display this value first plus And then I am referring to the sponsored object that



126

00:07:58,120 --> 00:08:00,590

gets box surname right.



127

00:08:00,590 --> 00:08:03,800

Buxar that get Buxar name first.



128

00:08:03,820 --> 00:08:10,250

I want to display this value plus an inside double quotes we have a dash plus.



129

00:08:10,520 --> 00:08:19,730

And then I want to print this value box that gets punch power plus dash plus boxer that get punch speed



130

00:08:20,350 --> 00:08:21,210

plus.



131

00:08:21,260 --> 00:08:23,830

And here we have this backward slash.



132

00:08:23,850 --> 00:08:30,640

And so this is going to actually create a new life character after printing the values of our boxer



133

00:08:30,680 --> 00:08:32,020

objects.



134

00:08:32,030 --> 00:08:40,220

And finally as you can see here we are actually assigning the value of RTX the received data here that



135

00:08:40,340 --> 00:08:43,850

takes that whispering to are all ATX to receive data.



136

00:08:44,180 --> 00:08:51,590

So in this way this variable here is going to actually hold the old values of RTX to receive data as



137

00:08:51,590 --> 00:08:52,640

a string value.



138

00:08:53,060 --> 00:08:56,290

And we can actually display all of those values to the user.



139

00:08:56,360 --> 00:09:00,380

So now let me actually run our project and then it will make more sense.



140

00:09:00,380 --> 00:09:06,380

So now as you can see here our application is actually running on this emulator and now you can see



141

00:09:06,380 --> 00:09:09,040

that we received the data from the server.



142

00:09:09,170 --> 00:09:13,710

So the first Buxar is name the name of the first Buxar is a.



143

00:09:14,120 --> 00:09:16,950

And the punch power is 100.



144

00:09:16,970 --> 00:09:20,410

And the punch spit is to hunt that so you can see these values here.



145

00:09:20,420 --> 00:09:26,750

The second box is B 10 20 C 490 and D 4900.



146

00:09:26,750 --> 00:09:31,700

So these are the Buxar objects that we are receiving from the server.



147

00:09:31,850 --> 00:09:41,210

So let's actually create some more Puckster optics so here I can say a b c d e 20 free 12.



148

00:09:42,050 --> 00:09:58,100

And here as you can see we have again these values a 100 dash 20 write the 10 20 C 490 and the 14:19.



149

00:09:58,280 --> 00:10:07,010

So when ever I actually click on the spot in the all the values of our text you are going to be also



150

00:10:07,010 --> 00:10:08,090

displayed.



151

00:10:08,090 --> 00:10:08,470

Right.



152

00:10:08,600 --> 00:10:11,580

And then we have also the new value which is this one.



153

00:10:11,690 --> 00:10:15,320

And if it is a scroll down here you can see this here.



154

00:10:15,860 --> 00:10:21,360

And as you can see it because you actually created a scroll you can actually scroll here.



155

00:10:21,530 --> 00:10:24,200

So let's actually create some more values here.



156

00:10:24,650 --> 00:10:32,310

So here I can say for example a B C D E F and the box a power punch power is for example 90 depan speed



157

00:10:32,360 --> 00:10:33,630

is 2000.



158

00:10:33,950 --> 00:10:40,960

And if I can send data to several here and again you can see that these values are again displayed.



159

00:10:40,980 --> 00:10:46,070

They have a B C D E and F right.



160

00:10:46,130 --> 00:10:48,700

So these values are the old values of art.



161

00:10:48,710 --> 00:10:57,080

It takes a view and we have also the value of the newest object that we actually sent to the server.



162

00:10:57,080 --> 00:10:57,960

So that's why.



163

00:10:57,980 --> 00:11:04,070

Let me introduce you to the Android studio that's actually created this valuable all the exclusive data



164

00:11:04,070 --> 00:11:08,330

in order to hold the the old value of RTX the receive data.



165

00:11:08,330 --> 00:11:17,070

So if I actually create for example someone objects G and if I click on this button for example it may



166

00:11:17,070 --> 00:11:25,100

create some objects which send that observer they send data to a server.



167

00:11:25,150 --> 00:11:29,040

And now as you can see we have all these objects here.



168

00:11:29,050 --> 00:11:29,660

Right.



169

00:11:29,860 --> 00:11:35,620

And we have these objects A B C D E F G H k.



170

00:11:35,740 --> 00:11:43,480

You can see that I actually put these values here and we have also the old values that are actually



171

00:11:43,480 --> 00:11:44,520

printed here.



172

00:11:44,680 --> 00:11:45,280

Right.



173

00:11:45,280 --> 00:11:51,220

So here in this tutorial I wanted to show you that how you can actually either aid over the children



174

00:11:51,340 --> 00:11:52,480

of your note.



175

00:11:52,750 --> 00:11:54,660

So let me show you the web browser.



176

00:11:54,760 --> 00:11:58,480

So here as you can see let me scroll to the top as he has it is our notes right.



177

00:11:58,660 --> 00:12:03,640

And we are referring to this note not a specific child in the previous tutorials.



178

00:12:03,640 --> 00:12:11,020

I actually told you about up just referring to one specific child in order to get the values of that



179

00:12:11,020 --> 00:12:12,100

specific child.



180

00:12:12,250 --> 00:12:18,880

But in this the story or I am showing you obey in order to iterate over the children of your note and



181

00:12:18,880 --> 00:12:25,510

get the values of all these notes right and get the values of all these children.



182

00:12:25,510 --> 00:12:28,450

So now let me show you another important point.



183

00:12:28,480 --> 00:12:30,240

So now let me show you the emulator.



184

00:12:30,370 --> 00:12:35,800

And as you can see here you can see these values here and you can see that the older values are actually



185

00:12:36,130 --> 00:12:38,340

displayed here multiple times.



186

00:12:38,370 --> 00:12:41,400

Maybe you don't want this to happen right.



187

00:12:41,480 --> 00:12:50,170

And here in order to solve this problem before this for loop here I can just refer to the name of this



188

00:12:50,170 --> 00:12:54,610

valuable old Teac the received data assignment operator.



189

00:12:54,790 --> 00:12:58,870

And then I can assign an empty string value to this variable.



190

00:12:59,230 --> 00:13:01,350

So let's run our project.



191

00:13:01,690 --> 00:13:04,510

And now here I'm going to actually explain to you what's going on here.



192

00:13:04,510 --> 00:13:11,380

Exactly let's actually see our application here and now it can actually display these values here that



193

00:13:11,380 --> 00:13:15,410

are going to be received from the server.



194

00:13:15,730 --> 00:13:26,010

So now you can see that we have only this a here b c d e f g h k and we have these are all other values.



195

00:13:26,080 --> 00:13:28,230

Let's actually open our web browser.



196

00:13:28,240 --> 00:13:31,300

Let me create another box and object.



197

00:13:31,300 --> 00:13:37,680

So here for example I can say Buxar a box or a.



198

00:13:37,870 --> 00:13:40,220

And the punch power is for example 5000.



199

00:13:40,240 --> 00:13:42,120

And the punch speed is 5000.



200

00:13:42,130 --> 00:13:42,780

Right.



201

00:13:42,820 --> 00:13:45,490

Let's actually click on the spot and send data server.



202

00:13:45,910 --> 00:13:49,110

And here as you can see we have this object right.



203

00:13:49,240 --> 00:13:55,510

But you can see that the previous values the old values are not printed are not actually displayed here



204

00:13:55,540 --> 00:13:56,160

again.



205

00:13:56,320 --> 00:13:57,140

Right.



206

00:13:57,220 --> 00:14:03,850

So you can see that we have also we have just this value and if we actually print P for example it may



207

00:14:03,850 --> 00:14:05,090

actually disappear.



208

00:14:05,080 --> 00:14:08,120

This virtual keyboard for example box.



209

00:14:08,470 --> 00:14:10,730

And if I click on the spot and send data at the server.



210

00:14:10,750 --> 00:14:13,080

Now you can see this box here.



211

00:14:13,410 --> 00:14:14,040

Right.



212

00:14:14,050 --> 00:14:18,430

Let me actually change this to boxers see if I click on this button.



213

00:14:18,430 --> 00:14:21,030

Now we have only the sponsors see why.



214

00:14:21,040 --> 00:14:22,720

Let me show you the Android studio.



215

00:14:22,900 --> 00:14:29,650

So for example you know that is an update or change if it is going to be called when ever the user changes



216

00:14:30,080 --> 00:14:32,290

the date of an event that they are inside.



217

00:14:32,290 --> 00:14:33,980

Our server is after the change.



218

00:14:34,090 --> 00:14:39,500

So now you can see that first of all we are actually assigning the value zero to this all takes the



219

00:14:39,520 --> 00:14:42,220

received data and we have this for loop here.



220

00:14:42,220 --> 00:14:47,680

So this follow up here is going to be executed for each child that we have inside our notes.



221

00:14:47,680 --> 00:14:52,510

So now let me show you the web browser so you can see that we have this note and these are the children



222

00:14:52,540 --> 00:14:53,270

of this note.



223

00:14:53,320 --> 00:14:53,680

Right.



224

00:14:53,680 --> 00:14:55,570

We have multiple children.



225

00:14:55,570 --> 00:15:01,990

We have lots of children here and now or you can see that we are getting the box that object from these



226

00:15:01,990 --> 00:15:03,810

children as you can see here for example.



227

00:15:03,810 --> 00:15:06,810

This is the first child and this is the box of object.



228

00:15:06,880 --> 00:15:07,700

Right.



229

00:15:07,720 --> 00:15:10,730

And here you are actually creating this if statement.



230

00:15:10,930 --> 00:15:18,020

So I told you about this if statement here and you're actually getting the value of that Buxar right.



231

00:15:18,040 --> 00:15:20,770

For example box name a 100 200.



232

00:15:20,770 --> 00:15:23,640

So now let me show you the emulator.



233

00:15:23,650 --> 00:15:25,210

So this these are the values.



234

00:15:25,420 --> 00:15:27,820

These are the values of 100 200.



235

00:15:27,970 --> 00:15:33,830

And here in this line of code you are assigning the value of these Teac still receive data to this all



236

00:15:33,910 --> 00:15:35,310

the receive data body.



237

00:15:35,340 --> 00:15:43,090

And so in this way after this follow up finishes executing these lines of code we have all these values



238

00:15:43,090 --> 00:15:43,750

here.



239

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Right.



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So in this way you can see that we have these values and if we actually create another box that object



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for example box of the then in that way again it's going to actually send this data to the server and



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we can actually get.



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Again it's going to execute this for loop and it's going to actually display these values here.



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But you can see that when this data change if it here is going to be executed first it's going to actually



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empty the value of this valuable all text receive data and then it's going to actually execute this



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for a loop.



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And that's why you can see that these values are here and these values are not repeated.



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We can only see this here once B C and all the all the other values.



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So hopefully that makes sense and I think that's enough for this theater.



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So if you have any questions about the concepts that are hard to you in this tutorial please post the



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discussion in the course and then I'll do my best to answer all of your questions.



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Thank you very much for watching and I'll see you in the next year.



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Tanyard.