1 00:00:08,120 --> 00:00:13,490 Hey everybody this is Caleb with Dev soapstar calm and in this fantastic video we're going to write 2 00:00:13,490 --> 00:00:17,930 a function to remove objects from our core data persistent store. 3 00:00:17,930 --> 00:00:19,180 We're going to remove them forever. 4 00:00:19,210 --> 00:00:20,290 Going to get rid of them. 5 00:00:20,600 --> 00:00:25,340 And we're also going to add the ability to delete them from our table view cell. 6 00:00:25,340 --> 00:00:27,540 We're going to be able to swipe tap delete. 7 00:00:27,560 --> 00:00:32,360 And we're going to be able to remove it and obliterate it forever as well as reload our table view and 8 00:00:32,360 --> 00:00:34,640 show all of the changes right away. 9 00:00:34,640 --> 00:00:35,570 It's so cool. 10 00:00:35,570 --> 00:00:41,360 So let's begin by pulling open that X code project and going into goals. 11 00:00:41,360 --> 00:00:48,620 VC OK now we're going to go down to our extension and we're going to write a function to remove objects 12 00:00:48,620 --> 00:00:50,850 from a managed context. 13 00:00:50,850 --> 00:00:51,380 OK. 14 00:00:51,650 --> 00:00:59,420 Now to do this go ahead and type phunk remove let's do remove goal K and we're going to remove a goal 15 00:00:59,420 --> 00:01:01,100 at a certain index path right. 16 00:01:01,100 --> 00:01:07,280 We want to pull it out from our array of managed objects so we're going to go ahead and say an index 17 00:01:07,670 --> 00:01:14,300 path and we're going to pass an internal parameter here of index path which is a type index path lots 18 00:01:14,300 --> 00:01:15,380 of index path there. 19 00:01:15,710 --> 00:01:19,080 And we're going to go ahead and use that to remove our object. 20 00:01:19,160 --> 00:01:19,790 OK. 21 00:01:20,120 --> 00:01:23,790 Now we need to get another managed context here. 22 00:01:23,930 --> 00:01:26,740 So we're going to create a reference to the managed context. 23 00:01:26,930 --> 00:01:28,210 So let's do that by typing. 24 00:01:28,230 --> 00:01:35,180 Guard let managed context equals app delegate that persistent container view context. 25 00:01:35,390 --> 00:01:39,050 And if we don't have that we're going to just return just like below. 26 00:01:39,050 --> 00:01:43,150 We need just the reference to our managed context inside this function. 27 00:01:43,160 --> 00:01:47,750 Next what we're going to do is we're going to call managed context delete. 28 00:01:47,860 --> 00:01:48,470 OK. 29 00:01:48,890 --> 00:01:51,460 Now we need to delete a certain object. 30 00:01:51,470 --> 00:01:59,180 And as you know this array of goals is of type goal which if you go to the declaration of goal let's 31 00:01:59,180 --> 00:02:00,080 go find it. 32 00:02:00,080 --> 00:02:04,190 We can see that it inherits from an S. managed object from core data. 33 00:02:04,190 --> 00:02:10,820 So if we go back down we need to get a certain N-S managed object and to do that we're going to go into 34 00:02:10,820 --> 00:02:15,640 the goals array and we're going to pull out the item at the index path dot row. 35 00:02:15,710 --> 00:02:16,520 We ask. 36 00:02:16,610 --> 00:02:17,120 OK. 37 00:02:17,360 --> 00:02:20,360 We're going to call this from our table view. 38 00:02:20,360 --> 00:02:25,460 When we tap on a certain cell we're going to pass the index view of that cell which is going to correspond 39 00:02:25,460 --> 00:02:29,450 exactly with the goal from the goals array because that's how the data is shown in the table view. 40 00:02:29,450 --> 00:02:30,040 Right. 41 00:02:30,350 --> 00:02:33,030 And then we're going to call managed context not delete. 42 00:02:33,080 --> 00:02:37,160 That's a function that's going to delete the goal at that and X path. 43 00:02:37,270 --> 00:02:37,910 OK. 44 00:02:38,150 --> 00:02:41,720 Now that is not enough though to actually delete what we need. 45 00:02:41,720 --> 00:02:44,830 We need to call managed contexts save. 46 00:02:44,930 --> 00:02:50,520 Do you remember in set when we saved the function save we needed to settle this data. 47 00:02:50,540 --> 00:02:55,580 But then in order for it to actually pass in we need to call save on the managed context. 48 00:02:55,580 --> 00:03:00,710 We're going to do the same thing in remove We need to tell it we need to tell the manager contex that 49 00:03:00,710 --> 00:03:01,940 it needs to update itself. 50 00:03:01,940 --> 00:03:10,000 So we're going to use a do and catch block in order to do this like you may have been expecting and 51 00:03:10,030 --> 00:03:14,080 all we're going to do is just say Try managed context save. 52 00:03:14,480 --> 00:03:18,160 You probably noticed that said you probably noticed that it said throws. 53 00:03:18,200 --> 00:03:21,380 And so we're going to go ahead and debug print. 54 00:03:21,710 --> 00:03:26,460 And we're going to say could not remove because that's what we're doing here. 55 00:03:26,810 --> 00:03:33,110 And we're going to take the error from the dot save function and we're going to call error that localize 56 00:03:33,110 --> 00:03:33,720 description. 57 00:03:33,750 --> 00:03:36,760 That'll give us a little bit more information if there's a problem. 58 00:03:36,800 --> 00:03:43,730 So let's say that we do successfully remove an object we're going to go ahead and just print successfully 59 00:03:44,470 --> 00:03:45,390 removed. 60 00:03:45,550 --> 00:03:50,330 Gul All right it looks good. 61 00:03:50,330 --> 00:03:55,700 So you know what guys this is all we need to do to remove something we need to find the item at the 62 00:03:55,700 --> 00:03:57,690 certain index path we want to remove. 63 00:03:57,740 --> 00:04:02,480 We're going to remove it from our managed context and we're going to save that managed context to update 64 00:04:02,480 --> 00:04:03,410 everything. 65 00:04:03,500 --> 00:04:05,280 That's all we've got to do to remove a goal. 66 00:04:05,300 --> 00:04:06,770 It's that easy. 67 00:04:06,800 --> 00:04:12,250 Next we need to enable our table view to be able to swipe and edit cells. 68 00:04:12,320 --> 00:04:16,380 So there are a couple of different table view delegate methods we need to call. 69 00:04:16,520 --> 00:04:20,330 We need to set a property called can edit row an index path. 70 00:04:20,330 --> 00:04:24,160 So go ahead and call that can edit row at index path. 71 00:04:24,200 --> 00:04:29,780 Believe it or not all we need to do to enable editing is call or is return true. 72 00:04:30,170 --> 00:04:31,480 Now we can edit our table view. 73 00:04:31,490 --> 00:04:32,960 It's that easy. 74 00:04:32,960 --> 00:04:36,640 Next what we're gonna do is we're going to go ahead and set the editing style. 75 00:04:36,770 --> 00:04:43,700 So we're going to go ahead and call editing style Foro an index path and we're going to return a table 76 00:04:43,700 --> 00:04:45,790 view editing style. 77 00:04:46,010 --> 00:04:50,620 And if you push if you put a period you can see there are a few different things. 78 00:04:50,810 --> 00:04:54,310 There is insert delete and there is none. 79 00:04:54,320 --> 00:04:58,500 Now insert is going to add a plus a green circle and closing with a little plus sign. 80 00:04:58,580 --> 00:05:00,740 Delete makes a red circle with a dash. 81 00:05:00,740 --> 00:05:04,910 We don't want either of those to show up on our cells because we have kind of a custom configuration 82 00:05:04,910 --> 00:05:05,410 here. 83 00:05:05,600 --> 00:05:07,280 So we're going to just press none. 84 00:05:07,370 --> 00:05:09,300 That way it doesn't show up anything special. 85 00:05:09,470 --> 00:05:13,220 And so we can actually get rid of the table view cell editing style thing. 86 00:05:13,340 --> 00:05:16,200 So our Eddings style has been saved. 87 00:05:16,220 --> 00:05:20,680 Now we need to actually create the editing actions so we can edit it. 88 00:05:20,690 --> 00:05:27,280 Now let's create the actions so let's go ahead and type edit actions forro at index path. 89 00:05:27,380 --> 00:05:28,410 Very very cool. 90 00:05:28,430 --> 00:05:30,470 So we're going to create two actions. 91 00:05:30,470 --> 00:05:36,780 One is going to delete and one is going to add progress in this video we're only focusing on deleting. 92 00:05:36,800 --> 00:05:39,830 So let's go ahead and create our delete action. 93 00:05:39,830 --> 00:05:41,390 Go ahead and type let delete. 94 00:05:41,390 --> 00:05:44,000 Action equals UI. 95 00:05:44,000 --> 00:05:47,270 Table View row action. 96 00:05:47,300 --> 00:05:49,010 Whoops row action. 97 00:05:49,040 --> 00:05:54,620 And what we're going to do is put a parentheses there so that we can instantiate it properly first with 98 00:05:54,620 --> 00:05:56,850 a style then with a title and last. 99 00:05:56,850 --> 00:06:00,550 There's a handler at the end where we actually set what the action does. 100 00:06:00,560 --> 00:06:07,400 So we're going to set the style to be destructive because destructive is what you use when data is going 101 00:06:07,400 --> 00:06:08,630 to be destroyed. 102 00:06:08,690 --> 00:06:11,440 The title is going to say delete. 103 00:06:11,930 --> 00:06:14,800 OK we're going to use all caps just so it looks extra cool. 104 00:06:14,870 --> 00:06:17,990 Deleting should be a very final thing. 105 00:06:18,320 --> 00:06:20,680 And press enter on the handler. 106 00:06:20,840 --> 00:06:21,800 And I want you to notice. 107 00:06:21,830 --> 00:06:26,930 It's going to be returning a table view row action and an index path to us. 108 00:06:27,020 --> 00:06:27,650 OK. 109 00:06:27,650 --> 00:06:29,470 We're going to need the index path. 110 00:06:29,470 --> 00:06:31,910 We won't need the row action but we still need to give it a name. 111 00:06:31,910 --> 00:06:38,910 So go ahead and call RHO action WIPs action and the index path just type index path. 112 00:06:38,930 --> 00:06:43,190 So this is where we're going to actually do the stuff when we push the delete button. 113 00:06:43,190 --> 00:06:51,380 So in order to actually remove something we need to call self remove goal that function we just wrote 114 00:06:51,790 --> 00:06:54,500 Where are we going to get the index path from here. 115 00:06:54,500 --> 00:06:56,940 It's returned to us super easy. 116 00:06:56,960 --> 00:07:01,540 So go ahead and type index path and we have now remove that goal and saved it. 117 00:07:01,790 --> 00:07:08,090 Next what we need to do is we need to fetch all the data from our core data model because we've just 118 00:07:08,090 --> 00:07:08,780 removed it. 119 00:07:08,780 --> 00:07:12,320 It's changed now we need to fetch it all and we need to update our table view. 120 00:07:12,320 --> 00:07:15,530 So go ahead and call self fetch. 121 00:07:15,650 --> 00:07:19,070 But you know what we don't want to go through all of this completion junk again. 122 00:07:19,070 --> 00:07:23,210 So let's go ahead and let's find where we called it earlier here. 123 00:07:23,480 --> 00:07:27,890 And we're going to actually put this into its own function so we can call it from anywhere in this in 124 00:07:27,890 --> 00:07:28,520 this class. 125 00:07:28,520 --> 00:07:34,010 So cut this and below we're going to call phunk fetch. 126 00:07:34,130 --> 00:07:45,440 Fetch core data objects and pass that in there so we can now call fecche core data objects and that 127 00:07:45,440 --> 00:07:49,340 will do the same thing that we need to as when we want to call it here. 128 00:07:49,340 --> 00:07:55,670 So instead of calling the function from our extension we can call fecche core data objects and it does 129 00:07:55,670 --> 00:07:56,630 the same exact thing. 130 00:07:56,630 --> 00:07:59,680 We don't have to call on this big block of code. 131 00:07:59,690 --> 00:08:01,380 This one here we don't have to call it twice. 132 00:08:01,400 --> 00:08:05,030 We can just call it once with that function or we can call the same name twice. 133 00:08:05,030 --> 00:08:06,220 We can write less code. 134 00:08:06,320 --> 00:08:12,680 So now that we fetched all of the objects all the data is updated we can go ahead and call table view 135 00:08:13,310 --> 00:08:16,400 delete rows at index path. 136 00:08:16,490 --> 00:08:21,390 And what this is going to do is it's going to remove a certain row that we have deleted and then animate 137 00:08:21,440 --> 00:08:23,180 closing it's really cool. 138 00:08:23,180 --> 00:08:26,450 So it's asking for an array of index path. 139 00:08:26,630 --> 00:08:30,750 So we're going to give it that an array of index path from the returned index path. 140 00:08:30,890 --> 00:08:32,740 We're going to go ahead and give it an animation. 141 00:08:32,750 --> 00:08:33,340 And you know what. 142 00:08:33,350 --> 00:08:38,150 There are quite a few of them but we're just going to use Automattic K that's just a nice little fade 143 00:08:38,150 --> 00:08:42,280 up it pulls all the ones below it up and kind of animates it down. 144 00:08:42,280 --> 00:08:43,640 It's very cool. 145 00:08:43,640 --> 00:08:48,330 So that is our delete action that's what we want to happen when we push delete. 146 00:08:48,330 --> 00:08:54,420 But we have not yet returned it to our table view yet we just have created it. 147 00:08:54,480 --> 00:08:58,830 But first before we do that we need to set a background color because you can set the color of these 148 00:08:58,830 --> 00:09:00,660 buttons to be whatever you want. 149 00:09:00,690 --> 00:09:08,790 But I found that it's easy if you just type delete action whoops delete action background color and 150 00:09:08,790 --> 00:09:13,350 we're just going to use a color literal so tap on the color little double click it and we're going to 151 00:09:13,350 --> 00:09:15,330 set it to be a nice red color. 152 00:09:15,330 --> 00:09:17,080 Let's go ahead and let's do. 153 00:09:17,120 --> 00:09:17,790 Ooh yeah. 154 00:09:17,920 --> 00:09:19,080 You know that's nice. 155 00:09:19,080 --> 00:09:20,130 So select mirror Shino. 156 00:09:20,130 --> 00:09:21,790 That just means red I think. 157 00:09:22,110 --> 00:09:28,660 And now that we have set the background color we can properly return our delete action. 158 00:09:28,820 --> 00:09:32,820 OK but if I do that watch what happens it yells at me it's expecting an array. 159 00:09:32,820 --> 00:09:37,200 So even though there's only one we need to put it inside of an array we're going to add a second one 160 00:09:37,200 --> 00:09:38,350 later so it's OK. 161 00:09:38,640 --> 00:09:42,360 So go ahead and build and run this well for now I'm just building it. 162 00:09:42,570 --> 00:09:44,470 But now build and run. 163 00:09:44,490 --> 00:09:50,280 And let's go check it out in our applet see if we can properly delete an item from Chordata calling 164 00:09:50,280 --> 00:09:56,010 move goal removing the item at the index path fetching all of the objects after the data is changed 165 00:09:56,040 --> 00:09:57,640 and reloading the rows. 166 00:09:57,660 --> 00:10:01,470 So if we swipe we should be able to see our delete button. 167 00:10:01,470 --> 00:10:02,690 Very cool. 168 00:10:02,760 --> 00:10:04,410 Let's try to delete this one if I press it. 169 00:10:04,410 --> 00:10:06,100 Watch what happens. 170 00:10:06,300 --> 00:10:10,980 It deletes and I don't know if you saw that but it said successfully fetch data successfully removed 171 00:10:10,980 --> 00:10:12,360 goals successfully fetched data. 172 00:10:12,360 --> 00:10:13,780 So this is the initial loading. 173 00:10:14,070 --> 00:10:19,450 That's when I removed the goal then it fetched the new data and deleted the row it showed the animation. 174 00:10:19,470 --> 00:10:24,030 Now you don't only have to swipe and press the button you can actually swipe all the way through and 175 00:10:24,030 --> 00:10:24,660 it will delete it. 176 00:10:24,660 --> 00:10:30,240 It's so cool that's just kind of an added thing that's in there for us so we can now successfully remove 177 00:10:30,240 --> 00:10:35,990 any goals that we want and show our table view when it's done because remember we have conditional code. 178 00:10:36,000 --> 00:10:42,900 If it's less then or if it's less than 1 if it's 0 it's going to hide our table view just like that. 179 00:10:43,050 --> 00:10:44,490 Super super cool guys. 180 00:10:44,490 --> 00:10:45,670 This is amazing. 181 00:10:45,690 --> 00:10:51,500 The only thing that we need to do next is to add a new action here for adding progress. 182 00:10:51,690 --> 00:10:58,200 And at the very end when we meet our progress goal we need to set a UI view to fade in saying goal complete 183 00:10:58,620 --> 00:11:03,180 We're going to do that in the next video and we will call this app finished amazing work. 184 00:11:03,180 --> 00:11:06,210 Let's move on to that last video and let's get it started.