0 1 00:00:00,720 --> 00:00:08,250 So the first thing is going back. And there's a main differentiation between this navigation button because 1 2 00:00:08,310 --> 00:00:16,800 on Android on the left it is a hardware button and on iOS it tends to be placed in the top left corner. 2 3 00:00:16,800 --> 00:00:22,600 Now these two buttons even though they both essentially navigate back, 3 4 00:00:22,740 --> 00:00:31,310 they actually work quite differently because on Android the nav back button is a time based navigation. 4 5 00:00:31,410 --> 00:00:37,620 So it will take you to the previous screen that you saw. Just like when you're on a website when you 5 6 00:00:37,620 --> 00:00:38,660 click the back button 6 7 00:00:38,670 --> 00:00:41,880 it'll take you to the previous web page, on Android 7 8 00:00:41,880 --> 00:00:50,760 the nav back button takes you to the previous screen historically in time. But on iOS the nav back button 8 9 00:00:51,090 --> 00:00:57,750 is not navigating back in time but it's actually navigating up the hierarchy. 9 10 00:00:57,750 --> 00:01:03,750 So the equivalent would be say if you went from the home page to a particular page then from that page 10 11 00:01:03,750 --> 00:01:07,330 you navigated to another page on the same hierarchy. 11 12 00:01:07,350 --> 00:01:13,440 When you click the back button when you're on this page instead taking you back over here, the back button on 12 13 00:01:13,520 --> 00:01:21,030 iOS would take you up hierarchically i.e. it would take you back to the parent screen or the homescreen 13 14 00:01:21,030 --> 00:01:21,740 in this case. 14 15 00:01:21,750 --> 00:01:27,470 So it's really important to think about how you're going to design your app in terms of its navigation 15 16 00:01:27,600 --> 00:01:32,370 taking into account these differences. Next is navigation. 16 17 00:01:32,370 --> 00:01:38,350 Now we mentioned this briefly about tab bar controllers versus the hamburger menu. 17 18 00:01:38,370 --> 00:01:44,220 Now the hamburger menu is so called because somebody thought that the three lines make it look like 18 19 00:01:44,250 --> 00:01:45,370 a hamburger. 19 20 00:01:45,660 --> 00:01:47,440 Now you may or may not disagree. 20 21 00:01:47,520 --> 00:01:52,320 But essentially one of the most common ways that you'll see navigation occurring in Android apps is 21 22 00:01:52,320 --> 00:01:53,820 through these hamburger menus 22 23 00:01:53,850 --> 00:01:59,460 and when you tap on them, a menu slides out and you can pick and choose which screens you want to go 23 24 00:01:59,460 --> 00:02:00,000 to. 24 25 00:02:00,150 --> 00:02:01,450 And on iOS, 25 26 00:02:01,530 --> 00:02:08,490 traditionally it's been done using a tab bar controller which resides at the bottom and it can only contain 26 27 00:02:08,550 --> 00:02:15,600 a maximum of five items because otherwise it would be hard for the thumb to actually navigate it. 27 28 00:02:15,600 --> 00:02:21,870 Now this brings up a point of contention because a lot of designers really hate this hamburger 28 29 00:02:21,870 --> 00:02:28,980 menu style and with good reason. Because with that button they even though you know that the menu is 29 30 00:02:28,980 --> 00:02:35,520 accessible with just a single tap, as with all things human, when it's out of sight it's out of mind. And 30 31 00:02:35,520 --> 00:02:41,620 users don't tend to think to look into it when they need a certain functionality. 31 32 00:02:41,640 --> 00:02:49,020 And so a lot of designers have gravitated to a slightly different design pattern for Android navigation. 32 33 00:02:49,020 --> 00:02:55,380 And, instead you see a lot of designers implementing something a bit like this where you've got a tab 33 34 00:02:55,410 --> 00:02:59,930 bar by swiping left all right you can navigate between the different screens. 34 35 00:02:59,940 --> 00:03:02,980 An example of that is the Twitter app on Android. 35 36 00:03:03,060 --> 00:03:04,740 So have a look at that 36 37 00:03:04,950 --> 00:03:07,800 if you're interested in implementing this in your app.