1 00:00:05,480 --> 00:00:11,660 Say what's up everyone at soap's dot com and this is a special lesson OK. 2 00:00:11,910 --> 00:00:14,370 This is a lesson that is just for you. 3 00:00:14,370 --> 00:00:19,040 After thousands of students have encountered a problem and I'm going to show you how to debug it. 4 00:00:19,050 --> 00:00:21,600 It's a very common thing to have happen. 5 00:00:21,650 --> 00:00:23,200 It's a let's make it happen. 6 00:00:23,220 --> 00:00:30,780 So if you remember from a while back one of the first lessons OK in this league or in this first welcome 7 00:00:30,780 --> 00:00:36,600 be see if I right click here on the out on the document outline we've got a background image and a swoosh. 8 00:00:36,600 --> 00:00:39,140 Remember how we actually made those IAB outlets. 9 00:00:39,150 --> 00:00:44,610 So if I go over here into my welcome b c we've got those two ibl you remember right in your code it's 10 00:00:44,610 --> 00:00:45,300 right there. 11 00:00:45,450 --> 00:00:45,740 OK. 12 00:00:45,750 --> 00:00:50,330 And if I run the app it should run just fine let's make sure there's no crashes or problems. 13 00:00:50,340 --> 00:00:51,080 OK. 14 00:00:53,410 --> 00:00:54,260 And it works just fine. 15 00:00:54,310 --> 00:00:59,200 So this is the most common problem that new developers have. 16 00:00:59,200 --> 00:01:04,180 And the most common thing that I answer for new developers are people who are learning and this is what 17 00:01:04,180 --> 00:01:04,690 happens. 18 00:01:04,690 --> 00:01:09,790 They're like OK I don't need these outlets anymore so they're like oh I don't need to call these anymore. 19 00:01:09,790 --> 00:01:10,540 This is great. 20 00:01:10,810 --> 00:01:15,550 And so they delete this and they go on their happy way and maybe they code for 15 more minutes and then. 21 00:01:15,580 --> 00:01:16,720 OK great. 22 00:01:17,050 --> 00:01:18,340 Let's go ahead and run the app. 23 00:01:18,340 --> 00:01:19,470 Blah blah blah. 24 00:01:19,660 --> 00:01:23,200 Run the app OK to do. 25 00:01:23,770 --> 00:01:26,880 Let's look at all the code I wrote the last 15 minutes it's great. 26 00:01:26,960 --> 00:01:29,440 And then it crashes. 27 00:01:29,530 --> 00:01:34,230 Say it and they get this big huge error here. 28 00:01:34,250 --> 00:01:35,380 Let's close the left. 29 00:01:35,400 --> 00:01:36,260 I don't need that. 30 00:01:36,430 --> 00:01:36,630 OK. 31 00:01:36,640 --> 00:01:38,200 I just I can't open down here. 32 00:01:38,200 --> 00:01:38,770 OK. 33 00:01:38,880 --> 00:01:42,640 The right side open and they see all those crazy stuff and it's so confusing. 34 00:01:42,640 --> 00:01:44,020 And yeah it is a little confusing. 35 00:01:44,020 --> 00:01:47,280 Come on Apple really can't you just say what the problem really is. 36 00:01:47,290 --> 00:01:52,510 But this is the biggest problem that people see. 37 00:01:52,810 --> 00:01:53,210 OK. 38 00:01:53,300 --> 00:01:57,740 Set value for undefined key and they freak out because they're brand new to programming. 39 00:01:57,740 --> 00:01:59,140 They're learning all this new stuff. 40 00:01:59,140 --> 00:02:01,440 In fact I'm going to save this somewhere. 41 00:02:04,190 --> 00:02:04,810 Save that. 42 00:02:04,940 --> 00:02:05,330 OK. 43 00:02:05,450 --> 00:02:07,610 So you're going see this problem all the time. 44 00:02:07,610 --> 00:02:10,200 If you did what we just did which was delete Iby out that's OK. 45 00:02:10,310 --> 00:02:13,590 So the problem was what happened was you you deleted some code. 46 00:02:13,760 --> 00:02:17,250 If you remember back over here in the welcome to b c we deleted some code. 47 00:02:17,390 --> 00:02:18,040 OK which is great. 48 00:02:18,040 --> 00:02:19,280 We don't need it anymore. 49 00:02:19,280 --> 00:02:23,830 The problem is remember Interface Builder makes connections to the code. 50 00:02:23,830 --> 00:02:30,250 So if we go to our main store board ok and see this welcome b c if we are right click it. 51 00:02:30,350 --> 00:02:32,630 Notice how there's a yellow warning sign on these here. 52 00:02:32,710 --> 00:02:36,260 OK it's like hey where's the background image and where's the swoosh. 53 00:02:36,350 --> 00:02:39,770 It's supposed to be there in the code because you told me it was supposed to be there. 54 00:02:40,220 --> 00:02:44,780 Well it's not there so the app crashed so all you have to do whenever you encounter this problem that 55 00:02:44,780 --> 00:02:46,590 set value for undefined key. 56 00:02:46,670 --> 00:02:50,900 OK and most ninety nine point nine percent of times a new developer when they see that err it's because 57 00:02:50,900 --> 00:02:56,690 they did this they deleted an IP outlet and they forgot to delete the references so you go into your 58 00:02:57,260 --> 00:03:01,150 interface builder you select the view controller that the problems happening on or where you deleted 59 00:03:01,250 --> 00:03:07,300 the IBL lets you right click the icon and just click the x's on the warning signs. 60 00:03:07,380 --> 00:03:09,020 Boom you deleted the references. 61 00:03:09,120 --> 00:03:15,520 OK so the interface builder is no longer looking for those functions or outlets to be in your code. 62 00:03:15,680 --> 00:03:16,490 OK. 63 00:03:16,490 --> 00:03:18,430 And now it works just fine. 64 00:03:18,530 --> 00:03:19,070 OK. 65 00:03:19,280 --> 00:03:24,080 So this is a very special lessoned refer back to when you have this problem ok because you are going 66 00:03:24,080 --> 00:03:27,230 to probably encounter it many times as you as you go and delete things. 67 00:03:27,230 --> 00:03:27,670 OK. 68 00:03:27,980 --> 00:03:29,110 So that's it for now. 69 00:03:29,390 --> 00:03:29,780 OK. 70 00:03:29,870 --> 00:03:33,010 We're going to move on before we cleaned up our Cobi did not need those I.V. outlets. 71 00:03:33,050 --> 00:03:34,070 And so that's it. 72 00:03:34,070 --> 00:03:38,920 Mark Price a soap's dot com doing some debugging.