Before I begin coding, I'm going to answer this question. I really still know about only two view groups, LinearLayouts and RelativeLayouts. Now the key word right here was that these two have to take up equal space. Using layout weight is a really easy way to do this. Okay, let's go ahead and look at the code. All right, I'm not working in Java anymore, so I'm going to go ahead and go over to activity_main.xml. And here's my XML file. So I'm going to start by putting all of this code to another LinearLayout. And this is the parent LinearLayout for my two mini LinearLayouts. And I'm going to move these two lines up here, because they need to be attached to the root view, add a closing brace. Okay, Android Studio automatically made a closing tag for me right here. So, I'm going to go ahead and cut this closing tag, scroll down to the bottom, and paste it. Okay, now I got a red squiggly line, and if I look at the error, I can see that it says I need to have layout_height and layout_width defined. Whoops! All right, let's do that. So because this is the root view, I'll go ahead and make this match_parent. Okay, so I have one LinearLayout surrounding a child LinearLayout right now. And if I go to the Preview, it looks pretty much the same. Okay, so what I'm going to do, is I'm going to copy everything in the Team A LinearLayout, and right below Team A, I am going to paste it. And this is going to be my Team B LinearLayout. So, now things are beginning to look a little bit disorganized. So I am going to do a Cmd+A, or a select all, and then I am going to use the keyboard shortcut Cmd+Option+L to format my code. On Windows, that's Ctrl+Alt+L, that looks a little bit better. Now, I just want to make sure that you understand what's going on here. Scrolling to the top, I have a root LinearLayout here. It starts here, and if I scroll all the way to the bottom, it ends here. Inside of that root LinearLayout, I'm going to scroll up again. I've got one child layout here, which starts here. I'll scroll down slowly. And it ends here. This is for TeamA. And I have another child LinearLayout, which starts here. Scroll down slowly, ends here for TeamB. All right, now I noticed some red up at the top, so I'm going to scroll up again and see what the error says. Wrong orientation, no orientation specified, and default is horizontal. Yet this layout has multiple children, where at least one has width match_parent. Hm, well I do want it to be horizontal, but let's go ahead and specify the orientation. Again, this is not technically needed, because the default is horizontal, but it's good to be explicit. Okay, and it was saying something about children covering each other up. I'm going to click on Preview. Hm, And this doesn't seem to have really changed very much, even though I went to all the trouble of copying and pasting another LinearLayout. This might have had to do with the error that I just looked at. It was saying that it's a horizontal layout. So it's trying to lay these two LinearLayouts next to each other, but that the LinearLayout has a layout_width of match_parent which fills up the screen. So basically my first LinearLayout is filling up the screen, and then the other LinearLayout is getting placed next to it somewhere off screen. So let's think about what we actually want to have happen at this point. We want to have the two layouts taking up equal space and next to each other. So this when we're going to need to bring in layout_weights. I'm going to take the first LinearLayout and give it a layout_weight of 1. I'm also going to set its width to 0. Okay, so we can see already that we do in fact have two LinearLayouts, they're just not really being displayed properly. But this is a bit better. So I have to put a layout_weight also on my second LinearLayout, this one right here. So I'm going to scroll down. Here's my second LinearLayout. I'm going to do exactly the same thing. I'm going to say that it has a layout_weight of 1 as well, so now they have equivalent layout_weights. And then I'm going to set the width to 0. Okay, and the reason that I set the width of both of them to 0, is basically, that if both of these sides aren't taking up any width. Then, it's going to take all the extra space, which is the entire screen, and divide it up, giving half to one and half to the other, because they both have the same layout weight. If that's at all confusing, I've linked to a few videos in the instructor notes that talk about layout_weight. Okay, but this is looking pretty good, except it says Team A. I'm going to scroll down to change that here, change this to Team B. Now you might have noticed that there is also an error here, and that error occurs because, well, we have a duplicate ID. Remember, I just copied and pasted the code. So, we basically have two things that are trying to have the same id of team_a_score. So, I'm actually going to change this to team_b_score. Okay, this is looking pretty good. It's a little hard to see. I'll zoom in. But, it says Team B here. And I got all the correct buttons, and all the correct text views. So I'm going to try to run this on my phone. Okay, and this looks pretty good. Now if I press the Team A buttons, it's updating so that's great. If I press the Team B buttons, well, it's also updating. That's special. But remember, we just wanted to get the XML right. We didn't really care about the Java. But now that we got the XML working, why not fix the Java?