1

00:00:00,260 --> 00:00:03,640

And now let's actually delete this line of code here.



2

00:00:03,990 --> 00:00:10,200

And now let's actually create a listener for the spot in and send data on the server.



3

00:00:10,200 --> 00:00:15,840

So just step in here PTEN send data to a server that sits on click listener.



4

00:00:15,980 --> 00:00:17,230

OK new.



5

00:00:17,400 --> 00:00:23,300

And then here just hold the shift key on your keyboard and then press on the little Vicci on your keyboard.



6

00:00:23,600 --> 00:00:30,240

And now as you can see here the autocomplete feature of the Android studio is helping us to choose this



7

00:00:30,240 --> 00:00:31,540

option unclick listener.



8

00:00:31,660 --> 00:00:36,680

And now as you can see here inside the curly braces you can see this value dot dot dot.



9

00:00:36,840 --> 00:00:40,670

So choose this value and that person entered key on your keyboard.



10

00:00:40,980 --> 00:00:46,440

And now as you can see here these lines of code here are automatically put here by the Android studio.



11

00:00:46,650 --> 00:00:53,620

So here we have actually an anonymous in a class that actually implements this unclick listener interface.



12

00:00:53,730 --> 00:00:58,830

And because that anonymous in a class is actually implementing this unclick listener interface that



13

00:00:58,830 --> 00:01:03,610

class must provide an implementation for this Smurfit uncle.



14

00:01:03,810 --> 00:01:10,680

So now we are actually inside an anonymous inner class so here for example I can actually just typing



15

00:01:11,040 --> 00:01:15,520

database reference dot child.



16

00:01:15,630 --> 00:01:17,640

So now I can specify the child.



17

00:01:17,910 --> 00:01:22,580

And now I can actually just get the value of this as it takes it.



18

00:01:22,590 --> 00:01:23,390

EDT keep.



19

00:01:23,490 --> 00:01:25,590

So here we are going to specify the key.



20

00:01:25,620 --> 00:01:26,060

Right.



21

00:01:26,160 --> 00:01:31,470

So EDT key dot get text dot to a string.



22

00:01:31,800 --> 00:01:32,260

Right.



23

00:01:32,490 --> 00:01:40,430

And now I can say Dot said while you and here for the value you can put the value of these text it is



24

00:01:40,440 --> 00:01:41,190

de-value right.



25

00:01:41,190 --> 00:01:45,980

So EDT value that get tix to string.



26

00:01:46,290 --> 00:01:49,570

And then I can put a semicolon at the end of my statement.



27

00:01:49,890 --> 00:01:53,610

So as you can see here again let me actually just explain again.



28

00:01:53,880 --> 00:01:59,250

Actually we have this database reference that is referring to this instance as you can see here to this



29

00:01:59,260 --> 00:02:00,530

database instance.



30

00:02:00,780 --> 00:02:02,880

Now let me actually did it this value here.



31

00:02:04,440 --> 00:02:09,930

So here we have actually our reference database reference that is referring to this instance inside



32

00:02:09,960 --> 00:02:10,750

our database.



33

00:02:10,770 --> 00:02:11,340

Right.



34

00:02:11,760 --> 00:02:14,760

And now we say that tight.



35

00:02:14,880 --> 00:02:22,530

So here we want to actually create a child for this instance and the tide value is going to be key that



36

00:02:22,660 --> 00:02:24,260

takes that to history.



37

00:02:24,780 --> 00:02:30,360

And then we are going to actually call this method and that tight set value.



38

00:02:30,450 --> 00:02:36,080

So then we can actually specify the values the value that takes that to history.



39

00:02:36,450 --> 00:02:40,510

So now let's run our project and see what happens.



40

00:02:42,020 --> 00:02:44,130

Now let me actually open the web browser.



41

00:02:44,140 --> 00:02:46,890

Now let me show you the emulator here.



42

00:02:47,000 --> 00:02:58,770

So here let me specify the key so that you can be for example up more by name and the value can be phone.



43

00:02:59,480 --> 00:03:02,260

IPhone 7 right.



44

00:03:02,270 --> 00:03:06,070

And here let's actually click on this button send data to a server.



45

00:03:06,530 --> 00:03:11,730

And now here inside this database you can see that we have actually a child.



46

00:03:12,110 --> 00:03:17,790

And the key is mobility lane and the value is iPhone 7 right.



47

00:03:18,110 --> 00:03:20,520

So hopefully that makes sense.



48

00:03:20,520 --> 00:03:23,570

And now I want to show you something really important.



49

00:03:23,660 --> 00:03:32,030

So let's go back to what Android studio and here I can actually create are random actually unique ID



50

00:03:32,540 --> 00:03:34,220

for my keys.



51

00:03:34,220 --> 00:03:34,820

Right.



52

00:03:34,820 --> 00:03:37,530

So as you can see this is the key and this is the value.



53

00:03:37,610 --> 00:03:46,100

I can actually create a random ID for my keys so that there will be different keys for different values.



54

00:03:46,100 --> 00:03:48,250

So let me actually show you that here.



55

00:03:48,260 --> 00:03:54,720

So in order to create a random ID here first of all we need to actually create a variable of types think



56

00:03:54,980 --> 00:03:55,300

so.



57

00:03:55,340 --> 00:03:58,140

So it is unclear if I have actually just they've been.



58

00:03:58,490 --> 00:04:06,830

And the name of this variable can be for example unique ID and then I put an assignment operator here



59

00:04:08,120 --> 00:04:11,060

and then I'll refer to that to this database reference.



60

00:04:11,060 --> 00:04:16,370

So remember this database reference here actually holds the reference as you can see here.



61

00:04:16,670 --> 00:04:21,850

This database reference holds the reference to this database instance as you can see here.



62

00:04:21,860 --> 00:04:22,710

Right.



63

00:04:22,820 --> 00:04:28,160

So now here I am referring to this database reference dot dot.



64

00:04:28,400 --> 00:04:31,940

And here I can see push right push.



65

00:04:32,030 --> 00:04:38,270

When I actually call this push method and this reference is going to actually create our Random unique



66

00:04:38,360 --> 00:04:45,710

ID inside its database reference and it's going to be as a key that unique ID is going to be as a key



67

00:04:46,000 --> 00:04:46,800

right.



68

00:04:46,820 --> 00:04:57,210

And here in order to assign that unique ID to this variable unique ID here and say Dot get key right.



69

00:04:57,260 --> 00:05:00,520

And then I need to put a semicolon at the end of my statement.



70

00:05:00,750 --> 00:05:07,280

And now let's see how we can actually create a child with that unique ID.



71

00:05:07,310 --> 00:05:08,960

So in order to do that.



72

00:05:08,960 --> 00:05:20,870

So now let me actually just make this area disappeared and now I can say just database reference dot



73

00:05:21,830 --> 00:05:23,820

and here I can specify the child.



74

00:05:23,840 --> 00:05:29,930

So remember when I say database reference this database reference here is actually holding the reference



75

00:05:30,230 --> 00:05:31,390

to this instance.



76

00:05:31,430 --> 00:05:37,060

So I need to create children for this instance and then I can actually provide values for this instance.



77

00:05:37,070 --> 00:05:37,850

Right.



78

00:05:37,880 --> 00:05:45,380

So first of all I need to specify the child so the database reference that child and the child is going



79

00:05:45,380 --> 00:05:48,260

to be this unique ID write the child.



80

00:05:48,410 --> 00:05:49,020

Right.



81

00:05:49,070 --> 00:05:54,820

So you can say unique ID dot set value.



82

00:05:55,280 --> 00:05:59,760

And then here I can specify the value so the value can be a string value.



83

00:05:59,760 --> 00:06:09,160

And here I can say that this is of value and then I can put a semi-colon at the end of my statement.



84

00:06:09,200 --> 00:06:13,640

So now let's run our project and see what happens.



85

00:06:13,640 --> 00:06:16,140

So now as you can see here our press is actually running.



86

00:06:16,250 --> 00:06:22,700

So let me show you with the attitude of a browser and this is my emulator and here as you can see for



87

00:06:22,700 --> 00:06:25,980

the key I put this more by name an iPhone 7.



88

00:06:26,210 --> 00:06:26,910

Right.



89

00:06:26,930 --> 00:06:37,670

I can actually create other values so for the key which has actually just a computer name and for the



90

00:06:37,670 --> 00:06:46,550

value I can say match with pro MacBook Pro and here let's actually click on this send data to server



91

00:06:47,800 --> 00:06:53,590

and now it's going to actually create a new value here for me which is this one computer named Mike



92

00:06:53,750 --> 00:06:57,170

Rowe and it also created this value for me here.



93

00:06:57,410 --> 00:06:59,090

As you can see look at this key here.



94

00:06:59,150 --> 00:07:04,760

This key is actually a unique ID that is created by the firebase for me right.



95

00:07:04,760 --> 00:07:10,570

This key is not going to be similar to any other keys that are going to be created by the fireplace.



96

00:07:10,580 --> 00:07:12,590

So this is completely unique.



97

00:07:13,010 --> 00:07:16,140

And now we have actually a value right.



98

00:07:16,340 --> 00:07:21,870

So you can actually make all this key actually as a category.



99

00:07:21,980 --> 00:07:23,650

So lets see how we can do that.



100

00:07:23,870 --> 00:07:30,350

Let's actually go back to our Android studio and now let's create another actually another unique ID



101

00:07:30,620 --> 00:07:33,590

so we can say database reference.



102

00:07:34,040 --> 00:07:46,290

And here I can say that push and here I can say that child write database reference that push that child.



103

00:07:46,350 --> 00:07:52,360

So here let's actually specify the child so the child could be for example a child.



104

00:07:53,580 --> 00:07:56,560

And here are each and specify another child.



105

00:07:56,670 --> 00:08:02,570

So here this child is actually going to be the child of that unique ID.



106

00:08:02,580 --> 00:08:02,900

Right.



107

00:08:02,910 --> 00:08:04,320

I can specify another child.



108

00:08:04,330 --> 00:08:11,790

So let's actually just set a value to this child and he'll say set value.



109

00:08:12,270 --> 00:08:17,440

And then I put two double quotes here and and I can say what do you let's actually put a semicolon here



110

00:08:17,850 --> 00:08:22,380

and now let's actually run our project and see what happens.



111

00:08:24,980 --> 00:08:29,810

Now let me actually open my browser and this is my emulator.



112

00:08:30,020 --> 00:08:32,060

So let's actually click on this button again here.



113

00:08:32,060 --> 00:08:40,010

Send data to server and again as you can see here it actually created this unique idea here with disvalue.



114

00:08:40,030 --> 00:08:47,230

So again because this is actually a unique ID different keys can be here can be put here with different



115

00:08:47,230 --> 00:08:47,990

names right.



116

00:08:48,160 --> 00:08:52,850

But at different times with the same name can not be put here.



117

00:08:53,170 --> 00:08:59,270

So as you can see we have this key here and here we have this child which has this value.



118

00:08:59,440 --> 00:09:03,750

So this key is actually playing the role of a category.



119

00:09:03,850 --> 00:09:07,220

And inside this category we have this child and value.



120

00:09:07,420 --> 00:09:16,720

So let's see how we can actually access the values of these are actually keys the values of these instances.



121

00:09:16,750 --> 00:09:17,330

Right.



122

00:09:17,560 --> 00:09:20,830

So for now we have these children and we have these values.



123

00:09:20,890 --> 00:09:24,450

So how we can actually get these values from the database.



124

00:09:24,760 --> 00:09:27,240

And now let's actually go back to our Java code.



125

00:09:27,250 --> 00:09:35,800

Let's go back to our Android studio and now after the ending prentices of this listener for this PTEN



126

00:09:36,010 --> 00:09:41,920

send data to a server here I'm going and going to actually create a listener for this button Betty and



127

00:09:41,920 --> 00:09:43,480

get data from server.



128

00:09:43,690 --> 00:09:48,090

So as you can see here if I show you the emulator we have this button gets data from server.



129

00:09:48,220 --> 00:09:50,980

So let's actually create a listener for this spot.



130

00:09:51,010 --> 00:09:58,430

So here I can say BATNA get data from server that set unclick listener.



131

00:09:58,510 --> 00:10:00,260

And here I put the new keyboard.



132

00:10:00,550 --> 00:10:05,490

And then here I hold the shift key on my keyboard and then personally there Vicci on your keyboard.



133

00:10:05,710 --> 00:10:10,990

And now as you can see here the auto complete feature of Android studio is helping me to choose this



134

00:10:10,990 --> 00:10:11,400

option.



135

00:10:11,410 --> 00:10:16,670

Uncle Glassner and then choose it and then press on Enter key on your keyboard.



136

00:10:17,050 --> 00:10:23,050

And now as you can see here the autocomplete feature on Android stood You helped me to actually just



137

00:10:23,290 --> 00:10:29,290

put these lines of code here and now as you can see and as you know we have actually anonymous in a



138

00:10:29,290 --> 00:10:36,730

class that is implementing these unclick listener interface and it is actually providing a implement



139

00:10:36,850 --> 00:10:39,090

an implementation for this unclick method.



140

00:10:39,400 --> 00:10:45,580

So inside this enclave nymphet we need to put the codes in order to get the values that we have inside



141

00:10:45,580 --> 00:10:46,530

the database.



142

00:10:46,540 --> 00:10:49,180

So let's see how we can do that.



143

00:10:49,180 --> 00:10:52,660

So first of all we need to pro-white our listener.



144

00:10:52,660 --> 00:10:58,780

So now let me show you the web browser first of all we need to provide a listener for these children



145

00:10:58,810 --> 00:11:03,040

or for instance you can pro-white actually.



146

00:11:03,520 --> 00:11:06,060

Actually it is called value Lessner right.



147

00:11:06,070 --> 00:11:11,270

You can pro-white a value listener for each of these instances right.



148

00:11:11,320 --> 00:11:17,200

For example for this instance we can provide a listener for this one for this one or for any others.



149

00:11:17,200 --> 00:11:19,540

So let's go back to our Android studio.



150

00:11:19,930 --> 00:11:26,210

And now first of all for example I want to get the value of this keep right.



151

00:11:26,290 --> 00:11:27,750

I want to get the value of this key.



152

00:11:27,760 --> 00:11:29,580

So let's go back to our Android studio.



153

00:11:29,680 --> 00:11:34,450

So here I need to actually get our reference to this key.



154

00:11:34,660 --> 00:11:40,720

So if I click on this key here as you can see this actually you are right here is changed.



155

00:11:40,840 --> 00:11:41,650

Right.



156

00:11:41,650 --> 00:11:43,190

So it is called.



157

00:11:43,420 --> 00:11:45,600

Now we have actually a different you all.



158

00:11:45,820 --> 00:11:49,740

So first of all we need to access this key we need to get this key.



159

00:11:49,960 --> 00:11:55,140

So let me ask you to click on this one here and I going to show me the whole database here.



160

00:11:55,370 --> 00:12:00,530

So now I'm going to pro-white a listener are valueless in their 40s key.



161

00:12:00,740 --> 00:12:01,340

Right.



162

00:12:01,340 --> 00:12:09,350

So let's go back to what Android studio and now we need to actually get our defense to our firebase



163

00:12:09,500 --> 00:12:10,340

database.



164

00:12:10,340 --> 00:12:16,100

So if I scroll to the top here as you can see in line number two in eight we actually created just a



165

00:12:16,100 --> 00:12:22,490

variable which is after firebase database that holds the instance of the database that we are going



166

00:12:22,490 --> 00:12:23,910

to want to get right.



167

00:12:23,960 --> 00:12:32,180

So let's scroll down here and now I can here just say firebase database dot.



168

00:12:32,540 --> 00:12:36,070

And here I can get the difference right.



169

00:12:36,140 --> 00:12:37,430

Good defense.



170

00:12:37,460 --> 00:12:38,770

So here I want to get that there.



171

00:12:38,900 --> 00:12:40,300

Get the reference right.



172

00:12:40,580 --> 00:12:47,060

So I want to actually change the reference because let's say go to the just google crowd here to our



173

00:12:47,060 --> 00:12:48,600

Web browser as you can see.



174

00:12:48,620 --> 00:12:50,150

You want to get.



175

00:12:50,210 --> 00:12:52,040

Let's let's see the whole database.



176

00:12:52,200 --> 00:12:54,980

You want to get the value of this key right.



177

00:12:54,980 --> 00:12:55,900

That's the goal here.



178

00:12:55,910 --> 00:12:56,620

Right.



179

00:12:56,660 --> 00:13:00,230

So now all you need to have are reference to this key.



180

00:13:00,380 --> 00:13:02,700

So how we can do that in order to do that.



181

00:13:02,750 --> 00:13:07,270

First of all we need to actually refer to our firebase database instance.



182

00:13:07,430 --> 00:13:12,500

If I scroll to the top here as you can see inside this uncreate it in line number twenty eight we have



183

00:13:12,520 --> 00:13:15,660

actually an instance of type firebase database.



184

00:13:15,660 --> 00:13:16,460

Right.



185

00:13:16,790 --> 00:13:21,230

And now we want to actually change the reference to this key.



186

00:13:21,620 --> 00:13:24,320

This key here right because I want to get this value.



187

00:13:24,470 --> 00:13:30,960

So here I can say firebase database but get reference as you can see here.



188

00:13:31,100 --> 00:13:37,610

So we have free Moffats get reference with actually an argument of types 3 and a get to without arguments



189

00:13:37,700 --> 00:13:39,780

and gets a reference from Dorel.



190

00:13:39,890 --> 00:13:45,780

Let's choose this one get reference here that accepts one argument of types 3 and.



191

00:13:46,150 --> 00:13:48,750

And now I need to specify the argument.



192

00:13:48,750 --> 00:13:49,370

Right.



193

00:13:49,370 --> 00:13:52,800

So the argument is these key right.



194

00:13:52,820 --> 00:13:56,750

As you can see here because you want to get the reference to Diski here.



195

00:13:56,750 --> 00:14:04,640

So just highlight this key here and right click on it and then just click on copy and let's go back



196

00:14:04,700 --> 00:14:09,330

to our Android studio and instead of double quotes put this value.



197

00:14:09,860 --> 00:14:20,190

And now I can call this Mefford dot at add value event listeners so we need to actually provide a listener



198

00:14:20,700 --> 00:14:27,770

for this key so that when the data is changed this class here is going to be notified.



199

00:14:27,930 --> 00:14:33,650

So add value event listeners just press an interviewee on your keyboard as you can see here add value



200

00:14:33,650 --> 00:14:35,100

into listener.



201

00:14:35,100 --> 00:14:41,310

Now let me ask you to create a new line here so that you can see the value better thought Id value event



202

00:14:41,340 --> 00:14:43,400

listener and inside Apprentice's.



203

00:14:43,410 --> 00:14:49,590

I can't say new and then hold the shift key on your keyboard and then press and delay their key on your



204

00:14:49,590 --> 00:14:50,950

keyboard.



205

00:14:51,360 --> 00:14:57,360

And now just select this option here a value event listener and then press an Enter key on your keyboard.



206

00:14:57,630 --> 00:15:02,790

And now as you can see here these lines of code are actually automatically put here and now as you can



207

00:15:02,790 --> 00:15:06,810

see here we have an error and it says X expediter expect that a semicolon.



208

00:15:06,960 --> 00:15:12,030

So just put a semi-colon at the end of this prentices and now the error is gone.



209

00:15:12,030 --> 00:15:17,110

So if you have two Misfit's here the first one is on the path change.



210

00:15:17,250 --> 00:15:23,530

So this method is going to be called vended data is actually changed and it is going to be called another



211

00:15:23,530 --> 00:15:23,850

time.



212

00:15:23,850 --> 00:15:28,220

For example when this actually Meffert is going to be called.



213

00:15:28,350 --> 00:15:29,170

Right.



214

00:15:29,190 --> 00:15:33,250

So when I actually click on the spot button PTEN get data from server.



215

00:15:33,380 --> 00:15:34,560

This method is going to be called.



216

00:15:34,750 --> 00:15:40,340

And also the data here is changed this method is also going to be called on data change.



217

00:15:40,650 --> 00:15:46,340

So inside the curly braces of this agency you get this data and we have another MFL which is on canceled.



218

00:15:46,410 --> 00:15:50,430

And this is called When that data is actually canceled.



219

00:15:50,430 --> 00:15:55,520

So for example we want to get the data on the entire internet connection is actually gone.



220

00:15:55,620 --> 00:15:57,740

So in that case we can't actually get that data.



221

00:15:57,870 --> 00:16:00,650

And in that case this method is going to be called.



222

00:16:00,840 --> 00:16:09,060

So inside this on day to change I can just say just create a string variable in order to hold the value



223

00:16:09,060 --> 00:16:11,140

of this key stream.



224

00:16:11,250 --> 00:16:17,900

And here I can say value assignment operator and here as you can see we have this argument.



225

00:16:17,940 --> 00:16:20,200

So this argument holds this value.



226

00:16:20,310 --> 00:16:24,320

The value is key because we actually provided a listener for this key.



227

00:16:24,330 --> 00:16:25,220

Right.



228

00:16:25,230 --> 00:16:34,050

So here I can say something about you assignment operator date snapshot data snapshot that get value



229

00:16:34,890 --> 00:16:36,930

and then put a semicolon at the end of your statement.



230

00:16:36,930 --> 00:16:42,260

And here we have an error and it says incompatible types required Java that line.



231

00:16:42,270 --> 00:16:45,790

That's strange but it is found in Java that Langat object.



232

00:16:45,800 --> 00:16:51,720

So let's go inside Apprentice's in order to specify specify that this value is actually a string value.



233

00:16:51,720 --> 00:16:55,700

We can say three in which capital S that class.



234

00:16:56,040 --> 00:16:57,600

And now the error is gone.



235

00:16:57,600 --> 00:16:59,980

And here I can set this value to my take.



236

00:17:00,020 --> 00:17:05,410

It takes you so it takes the value that text value.



237

00:17:05,430 --> 00:17:08,250

Now let's run our project and see what happens.



238

00:17:08,250 --> 00:17:11,580

So now let me actually to just open the web browser.



239

00:17:11,640 --> 00:17:14,930

And now let me actually just open the emulator here.



240

00:17:17,140 --> 00:17:24,480

Now the emulator is here and now let's click on this get data from server and now as you can see here



241

00:17:24,690 --> 00:17:26,610

we successfully got this value.



242

00:17:26,610 --> 00:17:29,350

This is of value right.



243

00:17:29,370 --> 00:17:33,910

As you can see here disvalue is here for Diski.



244

00:17:34,050 --> 00:17:35,430

So hopefully that makes sense.



245

00:17:35,430 --> 00:17:38,970

And let's actually get the other values here for the other keys.