1 00:00:00,240 --> 00:00:04,960 So as you can see here these are the lines of code that I actually pasted here. 2 00:00:05,160 --> 00:00:10,770 So here I created a comment and it says deleting a single computer object. 3 00:00:10,770 --> 00:00:16,950 So here I want to actually create an effort in order to delete a single computer object inside the school 4 00:00:17,040 --> 00:00:17,970 database. 5 00:00:17,970 --> 00:00:24,020 So as you can see here the access modifier of the Smurfit is probably the return type of this method 6 00:00:24,030 --> 00:00:24,700 is void. 7 00:00:24,810 --> 00:00:29,020 As you can see here and the name of this method is the computer. 8 00:00:29,210 --> 00:00:29,820 OK. 9 00:00:30,090 --> 00:00:35,940 And here as you can see if it actually accepts an argument of type computer or case of a pass on a computer 10 00:00:36,110 --> 00:00:40,230 or a computer object into this method and it's going to actually delete data computer. 11 00:00:40,350 --> 00:00:40,910 OK. 12 00:00:41,190 --> 00:00:46,560 So here inside the Smurfette Let's see what's going on here in line 161 as you can see. 13 00:00:46,680 --> 00:00:53,400 I created an object of type as Q Like database and the name of this object is database assignment operator. 14 00:00:53,640 --> 00:00:58,350 And here I initialize this object this that gets rightabout database. 15 00:00:58,410 --> 00:01:05,970 So because I want to actually delete an object inside the Kulai database I need to get the right table 16 00:01:05,970 --> 00:01:08,220 database not the readable database. 17 00:01:08,280 --> 00:01:14,040 I want to actually write on the database so I need to actually get the writer of a database. 18 00:01:14,040 --> 00:01:20,460 This is very important and in line one hundred and sixty two as I referred to the name of this object 19 00:01:20,640 --> 00:01:22,310 database that delete. 20 00:01:22,350 --> 00:01:24,320 So I called this method delete. 21 00:01:24,420 --> 00:01:30,030 First of all I need to pass the table table computer and for the second argument I need to specify the 22 00:01:30,030 --> 00:01:31,110 word class. 23 00:01:31,560 --> 00:01:37,260 So at this class specifies how I want to actually delete the specific computer object. 24 00:01:37,260 --> 00:01:39,800 So I'll refer to that column ID. 25 00:01:39,900 --> 00:01:46,320 So I want to delete the computer object that is related to this specific column Id that we have here. 26 00:01:46,530 --> 00:01:52,230 So column ID plus and inside the double quotes is equal to a question mark. 27 00:01:52,470 --> 00:01:56,930 And here is the the argument for this class as you can see here the argument is this line of code here. 28 00:01:56,970 --> 00:01:58,550 New string at. 29 00:01:58,560 --> 00:02:01,040 So we need to provide a string at a. 30 00:02:01,200 --> 00:02:05,960 And here is the object that we have inside this on a stream that the value of. 31 00:02:06,180 --> 00:02:10,350 And he had dismissed it as you can see here that is to say that this string class is going to actually 32 00:02:10,350 --> 00:02:14,420 convert as an integer value into the into the string value. 33 00:02:14,580 --> 00:02:17,120 So history and that value of computer. 34 00:02:17,160 --> 00:02:24,540 So here I referred to the name of this object computer that gets ID so it can actually delete a specific 35 00:02:24,540 --> 00:02:27,870 computer object that is related to a specific column Id. 36 00:02:27,990 --> 00:02:29,550 Ok to the specific ID. 37 00:02:29,580 --> 00:02:34,230 So this is really important after the deletion of this computer object you need to actually close this 38 00:02:34,230 --> 00:02:34,840 database. 39 00:02:34,920 --> 00:02:36,670 So database that close. 40 00:02:37,170 --> 00:02:38,640 So hopefully that makes sense. 41 00:02:38,880 --> 00:02:43,620 And now I'm going to paste in some lines of code here and other fit here and then I'm going to explain 42 00:02:43,620 --> 00:02:45,640 to you what's going on here. 43 00:02:45,660 --> 00:02:49,810 So as you can see here these are the lines of code that I actually pasted here. 44 00:02:50,100 --> 00:02:56,910 And he had I created a comment and it says getting the number of computers inside the New Light database. 45 00:02:57,150 --> 00:03:00,030 So here I have a Meffert and the access modify it. 46 00:03:00,060 --> 00:03:06,180 This method is probably the return type of this method is int integer value and the name of this method 47 00:03:06,210 --> 00:03:08,000 is get computerless count. 48 00:03:08,010 --> 00:03:13,760 So this method is going to return the number of computer objects that we have inside our database. 49 00:03:14,070 --> 00:03:16,880 And as you can see here it's not going to accept any arguments. 50 00:03:16,940 --> 00:03:20,720 OK so let's go inside this method and see what's happening here. 51 00:03:20,730 --> 00:03:27,540 First of all in line 174 I created this string object as you can see here and the name of this object 52 00:03:27,540 --> 00:03:28,590 is computerless. 53 00:03:28,920 --> 00:03:30,180 Count queery. 54 00:03:30,350 --> 00:03:36,420 OK I want to actually get the number of objects that is inside of the table here instead of inside of 55 00:03:36,460 --> 00:03:37,640 that if you liked. 56 00:03:37,890 --> 00:03:41,580 So assignment operator and here is our comment here. 57 00:03:41,610 --> 00:03:45,290 Select and here as you can see we have these symbols here. 58 00:03:45,290 --> 00:03:47,020 Start from. 59 00:03:47,060 --> 00:03:48,680 So select from table. 60 00:03:48,840 --> 00:03:54,540 So if you want to actually select all the computer objects that are inside of our table computer this 61 00:03:54,540 --> 00:03:58,600 is very important and in line 175 as you can see here. 62 00:03:58,620 --> 00:04:04,830 I created an object of type q like database and the name of this object is database so I created this 63 00:04:04,860 --> 00:04:08,590 object in in order to access the database assignment operator. 64 00:04:08,910 --> 00:04:11,630 Does that get like table database. 65 00:04:11,830 --> 00:04:19,120 OK so here again because I want to actually just read the data from the database I could just refer 66 00:04:19,160 --> 00:04:25,650 to the Mefford get readable database and instead of just write up a database I could refer to the get 67 00:04:25,780 --> 00:04:31,740 readable database and it's not necessary to actually revert to the summer if it gets rightabout database. 68 00:04:31,740 --> 00:04:32,510 OK. 69 00:04:32,940 --> 00:04:38,640 And here in line one hundred and seventy six as you can see I have this cursor. 70 00:04:38,640 --> 00:04:41,900 Here is Curson interface assignment operator. 71 00:04:42,120 --> 00:04:44,680 And here I am initializing this interface here. 72 00:04:44,700 --> 00:04:51,540 As you can see so database that raw query as you can see here database you refer to the name of this 73 00:04:51,630 --> 00:04:54,080 object that raw query. 74 00:04:54,270 --> 00:05:02,610 So you want to query all the data all the data inside the ace computers count queries so you want to 75 00:05:02,610 --> 00:05:05,930 actually get all the data from this database. 76 00:05:05,970 --> 00:05:07,490 Select from table computer. 77 00:05:07,490 --> 00:05:09,080 So it's going to give me all the data. 78 00:05:09,480 --> 00:05:14,070 And then as you can see for the second argument which is going to be that world class I assign the value 79 00:05:14,070 --> 00:05:19,140 not because I want to get all the objects the information about all the objects inside the inside the 80 00:05:19,190 --> 00:05:23,750 school like database and at the end I'm just closing the cursor. 81 00:05:23,790 --> 00:05:24,470 OK. 82 00:05:25,020 --> 00:05:33,460 And here as you can see in line 179 here as you can see I am just returning cursor that get count. 83 00:05:33,800 --> 00:05:34,150 OK. 84 00:05:34,230 --> 00:05:40,310 So it's going to give me the number of objects that is inside of our database. 85 00:05:40,320 --> 00:05:43,250 OK For example we have 10 computer objects inside. 86 00:05:43,290 --> 00:05:48,540 Inside our database this method is going to give me a good count and if it is going to give me that 87 00:05:48,540 --> 00:05:51,680 number number 10 to the color of the Smurfette. 88 00:05:51,910 --> 00:05:52,390 OK. 89 00:05:52,440 --> 00:05:54,030 So hopefully that makes sense. 90 00:05:54,030 --> 00:06:00,540 So now let's actually go inside our main activity class here and then here I want to actually make these 91 00:06:00,540 --> 00:06:01,100 buttons. 92 00:06:01,100 --> 00:06:03,990 This bit here at button and this BTA into this button. 93 00:06:04,110 --> 00:06:06,210 A listener to the police of the user. 94 00:06:06,210 --> 00:06:11,020 So I just know who live in PTEN at that said Uncle listener. 95 00:06:11,220 --> 00:06:17,450 And here as an argument I need to pass the context to the context context is main activity that this. 96 00:06:17,490 --> 00:06:22,140 And here again I want to make the spot in between and delete or listen to the clips of the user BTA 97 00:06:22,250 --> 00:06:25,950 and delete that said unclick listener. 98 00:06:26,370 --> 00:06:28,830 Main activity that is. 99 00:06:29,460 --> 00:06:35,000 So now let's actually as you can see here we have an error here and we need this class and it's trying 100 00:06:35,000 --> 00:06:36,690 to implement it. 101 00:06:36,720 --> 00:06:42,190 The view that Uncle Clisson an interface so he here I just need to put this implements keep your keyboard 102 00:06:42,390 --> 00:06:45,440 view that unclick listener. 103 00:06:45,870 --> 00:06:50,110 And then here I need to overwrite the ankle if it inside our main activity class. 104 00:06:50,130 --> 00:06:56,040 So I just need to type in Uncle Dick and now as you can see I am actually writing this method here. 105 00:06:56,040 --> 00:07:02,220 So for the name of this argument just type in your view and then let's switch let's create a switch 106 00:07:02,220 --> 00:07:04,740 statement here streatch view. 107 00:07:04,790 --> 00:07:11,610 So you referred to the name of this argument view that gets ID and then here let's actually open and 108 00:07:11,610 --> 00:07:14,420 close this switch statement by using these curly braces. 109 00:07:14,630 --> 00:07:17,330 And and here I just need to create two case statements. 110 00:07:17,400 --> 00:07:20,670 So case are thought id that BATNA at. 111 00:07:20,730 --> 00:07:26,980 So when a user clicks on these are Add button bitti and add this case statement is going to be executed. 112 00:07:27,240 --> 00:07:30,130 And here at the end I need to put a break statement. 113 00:07:30,180 --> 00:07:31,730 Let's create another case statement. 114 00:07:31,730 --> 00:07:39,810 Here are dots ID that PTEN delete and that I need to put a call in here and then I need to put a break 115 00:07:39,810 --> 00:07:40,930 statement here. 116 00:07:41,160 --> 00:07:46,640 So when the user clicks and these BT and delete this case statement is going to be executed. 117 00:07:46,680 --> 00:07:52,710 So now inside this activity class I want to I try to paste in some lines of code here and then I'm going 118 00:07:52,710 --> 00:07:55,270 to explain to you what's going on here. 119 00:07:55,680 --> 00:08:00,460 So as you can see here these are the lines of code that I actually pasted here. 120 00:08:00,510 --> 00:08:08,150 So in line 21 as you can see I created this list here list and inside the angle brackets I specified 121 00:08:08,150 --> 00:08:11,870 the type of objects that are going to be inside of the list. 122 00:08:11,940 --> 00:08:12,280 OK. 123 00:08:12,300 --> 00:08:16,470 So list computer and the name of this list is all computers. 124 00:08:16,470 --> 00:08:23,820 So if you have an array that are actually that can accept objects that are of type computer and the 125 00:08:23,820 --> 00:08:26,360 name of this array is all computers. 126 00:08:26,370 --> 00:08:27,480 OK. 127 00:08:27,520 --> 00:08:32,880 So I declare this object here inside our main activity class and inline 20 free as you can see. 128 00:08:32,940 --> 00:08:35,640 I created and Aurelius object. 129 00:08:35,670 --> 00:08:41,840 So at least and instead the angle brackets I specified the type of objects that this at least can actually 130 00:08:41,850 --> 00:08:47,390 accept and the type of objects that is on a list can accept is strange as you can see here. 131 00:08:47,820 --> 00:08:54,750 And the name of this object is computerless name an inline 25 actually are created to declare declared 132 00:08:55,020 --> 00:08:56,040 an object of type. 133 00:08:56,040 --> 00:08:59,480 My database handler my escalate handler. 134 00:08:59,640 --> 00:09:02,000 So I just need to change the name to my. 135 00:09:02,150 --> 00:09:03,450 Is Kulai handler. 136 00:09:03,610 --> 00:09:09,120 I am actually declaring this object here because I want to instantiate this object and use that object 137 00:09:09,120 --> 00:09:11,820 that we actually created this class here. 138 00:09:11,850 --> 00:09:17,970 As you can see inside our project in order to use this class for handling database OK because we want 139 00:09:17,970 --> 00:09:23,100 to actually add some data to the database for it we may want to get some data from the database. 140 00:09:23,100 --> 00:09:27,590 We need to actually create an object when I'm this is too late handler class. 141 00:09:28,070 --> 00:09:33,930 And in 9:27 as you can see I actually did declare an object of every adapter. 142 00:09:34,020 --> 00:09:40,470 So if you use this object in order to actually add some other data into our list view OK because we 143 00:09:40,470 --> 00:09:45,180 want to actually add some later on the list is going to actually get the data from the database and 144 00:09:45,180 --> 00:09:48,700 we want to show that it shows shows that are in our list view. 145 00:09:48,750 --> 00:09:50,520 So we need these up this object here. 146 00:09:50,520 --> 00:09:50,780 OK. 147 00:09:50,790 --> 00:09:53,210 Ali it after this is very important. 148 00:09:53,520 --> 00:09:56,760 And now let's go inside this uncreate Smurfit here. 149 00:09:56,790 --> 00:10:01,290 As you can see list I should instantiate these objects that we declared inside our class. 150 00:10:01,290 --> 00:10:06,560 For example these aren't computers these computers name this database handler and this adapter. 151 00:10:06,780 --> 00:10:11,790 So let's go inside these uncreate Meffert and now I'm going to pasting some lines of code here and then 152 00:10:11,820 --> 00:10:14,200 I'm going to explain to you what's going on here.