1 00:00:08,130 --> 00:00:11,280 Hey guys going on this is Caleb with Devon Lopes dotcom. 2 00:00:11,310 --> 00:00:16,920 And in this video we're going to write a function that's going to save our data for our goal to core 3 00:00:16,920 --> 00:00:21,670 data to our persistent store and we're going to dismiss bact goals. 4 00:00:21,680 --> 00:00:27,060 VC K open your X code project and we're going to go ahead and do this. 5 00:00:27,060 --> 00:00:28,350 Now open up. 6 00:00:28,350 --> 00:00:30,200 Finish goal VC. 7 00:00:30,270 --> 00:00:33,640 And here is where the magic's going to happen. 8 00:00:33,660 --> 00:00:36,480 Right here is create gold button was pressed. 9 00:00:36,480 --> 00:00:40,200 This is where we're going to save all of our things that we've passed. 10 00:00:40,200 --> 00:00:47,820 We've passed in a gold description from Kriegel VC we've passed in a gold type and we've also set a 11 00:00:47,970 --> 00:00:50,810 number of points in our points textfield. 12 00:00:50,880 --> 00:00:52,260 That's really cool. 13 00:00:52,260 --> 00:00:53,790 Now there's one thing we forgot. 14 00:00:53,790 --> 00:01:00,390 Actually we have a back button that we did not yet set up so tap on main story board open up the assistant 15 00:01:00,510 --> 00:01:09,390 editor and make some room and right beneath create Go button was pressed go ahead and drop an IAB action 16 00:01:09,690 --> 00:01:16,170 called back button was pressed and just like before. 17 00:01:16,470 --> 00:01:17,980 Here's what we're going to do. 18 00:01:18,000 --> 00:01:23,840 We're going to type dismiss detail OK and it's going to dismiss back to the previous view controller 19 00:01:23,850 --> 00:01:26,450 just like a UI navigation controller. 20 00:01:26,780 --> 00:01:28,010 OK so sorry. 21 00:01:28,020 --> 00:01:32,300 Let's move on back to what we were going to talk about before I realized that we forgot the back button 22 00:01:32,820 --> 00:01:38,490 and we're actually going to add a function called Save and this is going to utilize core data to pass 23 00:01:38,490 --> 00:01:44,130 in an object into the managed object context and save it in our persistent store. 24 00:01:44,130 --> 00:01:47,750 So go ahead and import core data to begin with. 25 00:01:47,880 --> 00:01:51,580 And we're going to go ahead and write this function now so you know what. 26 00:01:51,630 --> 00:01:55,000 Let me give you some more room here so you can see everything. 27 00:01:55,020 --> 00:01:55,830 There we go. 28 00:01:56,100 --> 00:01:56,420 All right. 29 00:01:56,430 --> 00:02:02,910 So go ahead and type phunk save and that is going to be the name of our function but we need to know 30 00:02:02,910 --> 00:02:05,810 when saving is complete when it's finished when it's not. 31 00:02:05,820 --> 00:02:11,460 Because if it does finish successfully we want to dismiss the view controller if it doesn't we want 32 00:02:11,460 --> 00:02:14,360 to at least print an error to the console for now. 33 00:02:14,460 --> 00:02:18,600 So we're going to go ahead and build a completion handler which is basically a function that we can 34 00:02:18,600 --> 00:02:24,160 pass a value to and whenever we call this function we can get that value wherever we call this function. 35 00:02:24,150 --> 00:02:30,630 So go ahead and type completion and we're going to go ahead and inside of our bracket here we're going 36 00:02:30,630 --> 00:02:31,700 to make a function. 37 00:02:31,800 --> 00:02:32,330 OK. 38 00:02:32,550 --> 00:02:40,320 And it's going to to first take a parameter called Finished of type bool and this function is going 39 00:02:40,320 --> 00:02:44,500 to return an empty function can because we don't care what it returns at the end. 40 00:02:44,610 --> 00:02:49,980 We just need to be able to pass a value here and at the end it's going to return this value to us. 41 00:02:50,070 --> 00:02:50,700 OK. 42 00:02:50,940 --> 00:02:52,720 So that's our completion handler. 43 00:02:52,740 --> 00:02:58,140 And what we're going to do now is we're going to go ahead and set up the managed object context in the 44 00:02:58,170 --> 00:02:59,800 what is core data video. 45 00:02:59,940 --> 00:03:04,770 I told you that you would be interacting the most with the managed object context so we're going to 46 00:03:04,770 --> 00:03:06,320 go ahead and create this now. 47 00:03:06,540 --> 00:03:11,610 But before we do that we need to create an instance of our app delegate because when we create a project 48 00:03:11,640 --> 00:03:17,730 with core data if you scroll down to the bottom you'll see that there is a lot of interesting things 49 00:03:17,730 --> 00:03:19,830 in here from your core data stack. 50 00:03:19,890 --> 00:03:26,820 We have a persistent container we have an a function that lets us save the current context. 51 00:03:27,030 --> 00:03:29,630 Their stuff for core data. 52 00:03:29,630 --> 00:03:35,640 Built right in and it does that for us which is incredibly helpful but we need to go to a to goals VC 53 00:03:36,240 --> 00:03:41,690 and we're going to create a constant that is accessible publicly across all of our value controllers 54 00:03:41,700 --> 00:03:44,070 by writing it outside of the class. 55 00:03:44,160 --> 00:03:54,030 So go ahead and type let app delegate equals UI application shared application or shared delegate that 56 00:03:54,030 --> 00:03:55,180 gets our app delegate. 57 00:03:55,200 --> 00:03:58,420 But we're going to optionally cast it as type app delegate. 58 00:03:58,590 --> 00:03:59,280 OK. 59 00:03:59,520 --> 00:04:00,750 So there's our app delegate. 60 00:04:00,750 --> 00:04:06,990 We now can access that from anywhere and we're going to use that now in our Save function in order to 61 00:04:06,990 --> 00:04:10,170 get our manage object context OK. 62 00:04:10,320 --> 00:04:19,550 So go ahead and type guard let managed context and we're going to set that to be equal to the app delegate. 63 00:04:19,560 --> 00:04:25,470 The one with the lower case a persistent container view context. 64 00:04:25,530 --> 00:04:26,150 OK. 65 00:04:26,340 --> 00:04:31,800 This is how we get our managed object context from the main queue. 66 00:04:31,800 --> 00:04:33,720 It's the one that's associated with the main queue. 67 00:04:33,720 --> 00:04:35,870 It's our main managed object context. 68 00:04:35,870 --> 00:04:36,470 OK. 69 00:04:36,780 --> 00:04:39,960 Now if we can't get that for some reason we're going to just go ahead and call. 70 00:04:39,960 --> 00:04:45,420 Else return because if we can't get this we should not move forward. 71 00:04:45,510 --> 00:04:50,750 Now what we're going to do is we're going to create an instance of goal OK an instance of goal meaning 72 00:04:50,790 --> 00:04:54,780 our goal model our goal entity from core data. 73 00:04:55,060 --> 00:04:59,260 So go back and tickle a finished goal VC and type let goal. 74 00:04:59,700 --> 00:05:05,730 And remember we can just type goal as if it was a swift class super super cool. 75 00:05:05,730 --> 00:05:11,570 And in order to achieve this properly we need to tell the managed object context which model it's going 76 00:05:11,570 --> 00:05:15,320 to be using in order to create the persistent storage coordinator. 77 00:05:15,320 --> 00:05:22,220 So put a print next to it and you'll see we can pass in a context press enter and pass in the managed 78 00:05:22,220 --> 00:05:23,100 context. 79 00:05:23,180 --> 00:05:24,560 Supercool. 80 00:05:24,560 --> 00:05:30,980 So now we have created an instance of goal and we've given it a managed context that it needs to know 81 00:05:31,160 --> 00:05:37,190 so that it knows where it's saving the data so that it can be properly managed very very cool. 82 00:05:37,190 --> 00:05:42,980 Now believe it or not we can use this just like any other swift class we can call goal and now we can 83 00:05:42,980 --> 00:05:45,890 set all four of these properties. 84 00:05:46,070 --> 00:05:51,500 We've already passed in a goal description and initialize that when this view controller is created. 85 00:05:51,500 --> 00:05:52,490 So go ahead and just type. 86 00:05:52,490 --> 00:05:57,530 GOAL GOAL description and set that to be equal to goal description. 87 00:05:57,590 --> 00:05:59,210 The one from this view controller. 88 00:05:59,540 --> 00:06:06,590 Next go ahead and type goal Dago's type and we can also pass the goal type from this view controller. 89 00:06:06,590 --> 00:06:12,560 Next we have goal dot goal completion value. 90 00:06:12,560 --> 00:06:14,950 We can set that to be equal to the textfield right. 91 00:06:14,990 --> 00:06:17,540 Points textfield tells us how many we have. 92 00:06:17,540 --> 00:06:22,960 So we can go ahead and type points textfield dot text and unwrap it right because it's coming from a 93 00:06:23,240 --> 00:06:30,050 textfield which has an optional string but it's giving us an error cannot assign value of type string 94 00:06:30,310 --> 00:06:32,370 to type in 32. 95 00:06:32,390 --> 00:06:36,410 Remember that inside of our goal it's what we need to look at. 96 00:06:36,410 --> 00:06:40,830 Here we're saving goal completion value as an in 32. 97 00:06:40,850 --> 00:06:45,270 So what we're going to actually need to do is cast this as an in 32. 98 00:06:45,410 --> 00:06:51,470 So I'm going to put it in parentheses and at the beginning I'm going to go ahead and type int 32 and 99 00:06:51,470 --> 00:06:54,630 that will cast it as an in 32 value. 100 00:06:54,740 --> 00:07:00,410 So whatever is inside the text field we're saying this is a number and we know it can only be a number 101 00:07:00,410 --> 00:07:02,240 because we have set the number pad. 102 00:07:02,240 --> 00:07:06,540 Now in order to properly forecast this we need to unwrap it at the end so just do that. 103 00:07:06,710 --> 00:07:13,630 But we know for sure that the number value which will be an integer we can cast as an in 32. 104 00:07:13,660 --> 00:07:19,480 Now remember gold type in and of itself is what type. 105 00:07:19,490 --> 00:07:21,030 Can't remember gold type. 106 00:07:21,050 --> 00:07:21,490 OK. 107 00:07:21,740 --> 00:07:28,640 So gold type has an inherent value of string but we need to pull out the raw value to actually access 108 00:07:28,640 --> 00:07:32,510 that as you can tell the raw value of the raw type is string. 109 00:07:32,510 --> 00:07:38,540 So in order to set the goal type we need to set the raw value because Chordata cannot accept gold type 110 00:07:38,590 --> 00:07:40,030 as a as a type. 111 00:07:40,340 --> 00:07:40,930 OK. 112 00:07:41,120 --> 00:07:48,200 So then what we're going to do is we're going to set goal goal progress like so. 113 00:07:48,410 --> 00:07:52,020 Now if you saw go progress is an 32 as well. 114 00:07:52,070 --> 00:07:55,670 When we create our goal we have made zero progress on that goal. 115 00:07:55,670 --> 00:08:01,020 So we should call in 32 and we should give it a value of zero. 116 00:08:01,280 --> 00:08:08,120 OK we're going to set in 32 of 0 as our go progress that's how we're initially starting out is at zero. 117 00:08:08,120 --> 00:08:09,380 Pretty cool. 118 00:08:09,380 --> 00:08:10,720 So this is great. 119 00:08:10,730 --> 00:08:16,730 And we have set this but we have not yet told the managed object context to pass this into persistent 120 00:08:16,730 --> 00:08:18,780 storage we have simply set up a model. 121 00:08:18,950 --> 00:08:25,300 So in order to do that we're going to go ahead and call managed context that's safe. 122 00:08:25,310 --> 00:08:27,500 Now you'll notice it says throws. 123 00:08:27,590 --> 00:08:28,510 Right. 124 00:08:28,670 --> 00:08:35,450 And that is where we're actually going to need to use a do catch block K because we can say do meaning 125 00:08:35,540 --> 00:08:43,310 do this try to save the Manage context and then we can call catch meaning if there's an error. 126 00:08:43,310 --> 00:08:44,600 We're going to catch it. 127 00:08:44,870 --> 00:08:50,150 And in order to to print out the error we're going to use Debug print K and debug. 128 00:08:50,150 --> 00:08:55,700 Print writes the textual representation of the given items most suitable for debugging into the standard 129 00:08:55,700 --> 00:08:56,030 output. 130 00:08:56,030 --> 00:08:57,170 It just helps us out. 131 00:08:57,320 --> 00:09:01,930 So debug print and we're going to say could not save. 132 00:09:02,240 --> 00:09:06,140 And we'll just print out the error that is thrown like so. 133 00:09:06,420 --> 00:09:08,700 Well of course this needs to be a string. 134 00:09:09,080 --> 00:09:13,550 So the error that's thrown is here but we should definitely print out the localized description because 135 00:09:13,550 --> 00:09:17,900 that will give us kind of a plain English version of the error. 136 00:09:17,900 --> 00:09:19,360 So awesome. 137 00:09:19,370 --> 00:09:20,280 This is great. 138 00:09:20,300 --> 00:09:25,850 But in order to actually successfully try this we need to call try OK. 139 00:09:25,970 --> 00:09:32,420 We're going to use do try to save our context if it doesn't work we're going to catch the error and 140 00:09:32,420 --> 00:09:35,250 we're going to print it here so that we know what's going on. 141 00:09:35,480 --> 00:09:40,560 Now this is great and all but we need to be able to tell our completion handler when we're done. 142 00:09:40,580 --> 00:09:46,730 So if saving happens properly we're going to go ahead and call completion and pass it. 143 00:09:46,730 --> 00:09:53,330 True if it doesn't work properly it's going to print out and we're going to call completion false. 144 00:09:53,490 --> 00:09:54,070 OK. 145 00:09:54,470 --> 00:09:55,670 So that's pretty cool. 146 00:09:55,670 --> 00:09:57,070 We're telling it we're good. 147 00:09:57,080 --> 00:10:00,760 We're complete or we're saying we're not complete we didn't finish. 148 00:10:00,980 --> 00:10:04,300 So this is how we're going to save to core data. 149 00:10:04,370 --> 00:10:10,700 K supercool we're using our managed object we're creating a managed object model and we're using it 150 00:10:11,120 --> 00:10:15,140 save in order to commit unsaved changes to the context. 151 00:10:15,140 --> 00:10:16,730 Parents store. 152 00:10:16,730 --> 00:10:20,870 Right which if you look here is the persistent store coordinator. 153 00:10:20,930 --> 00:10:22,370 Very very cool. 154 00:10:22,400 --> 00:10:28,770 So now we need to think about where we're going to save this create Go button was pressed. 155 00:10:28,790 --> 00:10:29,560 Let's do it. 156 00:10:29,690 --> 00:10:36,710 So we're going to call self save and the completion block we're going to set as. 157 00:10:36,710 --> 00:10:38,290 How about complete. 158 00:10:38,900 --> 00:10:42,170 So we can save all of our data is here. 159 00:10:42,350 --> 00:10:49,820 We're going to say if it's complete ok if it's finished we're going to go ahead and dismiss. 160 00:10:50,840 --> 00:10:52,470 And we're going to say true. 161 00:10:52,640 --> 00:10:54,150 And the completion will be nil. 162 00:10:54,170 --> 00:11:00,340 So we're not using our fancy dismissal we're just going to dismiss all the way to the main view controller. 163 00:11:00,350 --> 00:11:02,790 Now there's one thing that I want you to think about here. 164 00:11:02,930 --> 00:11:08,110 What if we have not yet typed anything in points textfield that's going to cause some problems. 165 00:11:08,180 --> 00:11:12,720 So we need to verify that we have actually type something before we can even create this goal. 166 00:11:12,740 --> 00:11:18,260 So go ahead and type if points textfield dot text is not equal to nil. 167 00:11:18,260 --> 00:11:20,470 We're going to call self-deceit safe. 168 00:11:20,480 --> 00:11:21,300 All right. 169 00:11:21,620 --> 00:11:27,340 So pass that in there and let's go see if this works let's try it and if we get an error we'll know 170 00:11:27,380 --> 00:11:29,690 it did not work. 171 00:11:29,690 --> 00:11:30,500 You know what how about this. 172 00:11:30,500 --> 00:11:34,800 If it does work let's just print successfully. 173 00:11:35,100 --> 00:11:36,320 Oops. 174 00:11:36,440 --> 00:11:42,970 Fully saved data so we can just check to see if we're good to go. 175 00:11:43,250 --> 00:11:48,630 And if it properly dismisses a build and run and our simulator will come up here. 176 00:11:48,950 --> 00:11:56,280 Let's go ahead and yeah let's pop open that view controller eat salad twice. 177 00:11:56,420 --> 00:12:04,550 That's a short term goal let's say that this will be done in two salads and create a goal OK successfully 178 00:12:04,550 --> 00:12:10,850 save data and it dismissed but look at this it's still showing our previous view controller that is 179 00:12:10,850 --> 00:12:12,670 not at all what we want. 180 00:12:12,830 --> 00:12:16,970 So we're going to need to fix that but let's do that in the next video. 181 00:12:16,970 --> 00:12:21,920 Then after that we're going to go ahead and write our function to fetch all this data from our core 182 00:12:21,920 --> 00:12:23,340 data data model. 183 00:12:23,390 --> 00:12:24,270 Super duper cool. 184 00:12:24,290 --> 00:12:25,130 Awesome job guys. 185 00:12:25,130 --> 00:12:27,770 We will fix that dismissal in the next video. 186 00:12:27,800 --> 00:12:28,990 Great job with this one. 187 00:12:29,030 --> 00:12:29,570 Acia there.