Develop Reference

Android Multiple Screen - Using dp for UIs

Okay!
I am developing android application right now, but I want to know how I can fit all the layoutouts to the a multiple device screens.
* I did made multiple screen folders.
res/layout-small/main.xml
res/layout-normal/main.xml
res/layout-large/main.xml
res/layout-xlarge/main.xml
* Here is an example of my code.
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:layout_width="120dp"
android:layout_height="70dp"
android:text="#sting/button1" >
<Button
android:layout_width="120dp"
android:layout_height="70dp"
android:text="#sting/button2" >
<Button
android:layout_width="120dp"
android:layout_height="70dp"
android:text="#sting/button3" >
<Button
android:layout_width="120dp"
android:layout_height="70dp"
android:text="#sting/button3" >
</LinearLayout>
</LinearLayout>
As you can see, I used 120dp for every buttons.
When I ran in the virtual device machine, the screen is fit. (Because I used 480dp width screen in virtual device machine.)
However, when I ran in real cell phone devices (Mine: SamSung Galaxy Note 1(Korean version), my dad's: SamSung Galaxy S2(Korean version), and my mom's: SamSung Galaxy S(Canadian version)), even though I created different screen size of folders, I can see the (width) of the button is go too far from the device's screen layout.
Can anyone tell me how I can fit to all the device screen?
Can I still use dp in this case? (Please give me an example too!)

You need to read up on using LinearLayout and RelativeLayout (and other layouts). You're not using their layout parameters at all. You shouldn't need to specify any specific size (like 120dp) to support multiple screen sizes for your situation.
http://developer.android.com/guide/topics/ui/declaring-layout.html
Here's what you should do:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="4">
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="#sting/button1"
android:layout_weight="1" />
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="#sting/button2"
android:layout_weight="1" />
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="#sting/button3"
android:layout_weight="1" />
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="#sting/button4"
android:layout_weight="1" />
</LinearLayout>

Android Single Layout to FIt All Screen Sizes

I am updating my Android app and realized that I have created a layout for every possible screen size (layout-small, layout-large, etc...) It would be a huge pain to go through every XML file and manually make a small change. I am attempting to create a single XML file to support all screen sizes. After reviewing the Android documentation and other questions on stackoverflow, it seems LinearLayout is the best choice as you can provide a weightSum and layout_weight for each item in the layout. This is not working as expected (see below code and images). I am doing this correctly? Do I have to go back to creating a RelativeLayout for every possible screen size?
My images are an a single drawable folder and my layouts are in a single layout folder.
XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/bg"
android:gravity="center"
android:orientation="vertical"
android:weightSum="100" >
<ImageButton
android:id="#+id/btn1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:src="#drawable/image0"
android:background="#null"
android:layout_weight="30" />
<ImageButton
android:id="#+id/btn2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:src="#drawable/image1"
android:background="#null"
android:layout_weight="30" />
<ImageButton
android:id="#+id/key"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="30"
android:background="#null"
android:src="#drawable/image0_key" />
<TextView
android:id="#+id/tvScore"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="Score: 0"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_weight="10"
android:layout_gravity="left" />
</LinearLayout>
Resulting View (overflow of items and layout not consistent for screen sizes)
Nexus One:
Tablet:
EDIT:
I have added the following drawable-____ folders. It produces the same result.

You might want to consider creating compatibility layout folders. :)

Yes we have a solution for the same by using android's percent layout we can now use app:layout_heightPercent and app:layout_widthPercent to fit all the screens using single layout.
compile 'com.android.support:percent:23.0.0'
Why use LinearLayout weight property now we have simpler solution.
Demo HERE !
GitHub project HERE !
Consider a simple sample
<android.support.percent.PercentRelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/fifty_huntv"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#ff7acfff"
android:text="20% - 50%"
android:textColor="#android:color/white"
app:layout_heightPercent="20%"
app:layout_widthPercent="50%" />
<TextView
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_toRightOf="#id/fifty_huntv"
android:background="#ffff5566"
android:text="80%-50%"
app:layout_heightPercent="80%"
app:layout_widthPercent="50%"
/>
</android.support.percent.PercentRelativeLayout>
Hope it's useful for someone :-)

Use Below layout for arranging your ImageButton and TextView. It works for all screen size Layouts.
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="3" />
<ImageButton
android:id="#+id/imageBtn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#drawable/ic_launcher" />
<ImageButton
android:id="#+id/imageBtn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#drawable/ic_launcher" />
<TextView
android:id="#+id/tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Score: 0" />
</LinearLayout>

Never put an weight sum like hundred ,just try using single digits

DisplayMetric dm =new DisplayMetric();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int h= dm.heightPixels;
int w= dm.widthPixels;
h=h/10; // 10 is for example for 10% of display height
w=((w*20)/100); // 20%of display width
LinearLayout.LayoutParams params= new LinearLayout.LayoutParams(w,h);
YourObject.setLayoutParams(params);
//(YourObject) can be everything such as button , image button, textview,...

There are two issues here, one is to fill the size of the screen and the other is supporting the various resolution sizes of mobiles. Even within xxxhdpi, there are variations as new flagship Samsung Mobiles are drifting to 19.5 x 16.
Linear layout along with weight attributes does give a good coverage but beware of the nested tags and performance. It worked out well for most of the scenarios I have handled.
In addition, as pointed out in other answers, different drawables/resources for the standard sizes helps maintaining similar view in all devices.

As android device screen is bigger, buttons are upper

I put 2 buttons, with wrap_content size, but as device is bigger, buttons are upper, I cannot figure how to fix them, so on all devices to have the same position. Is there a solution not to cover the head of this guy, as example.
Layout.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/background"
tools:context=".BasicScreenActivity" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="102dp"
android:background="#drawable/custom_button1" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/button1"
android:background="#drawable/custom_button2" />
</RelativeLayout>

//try like this below one
#remove the margin top 102dp
#don't use button background image use color with white stroke
#make your button width as match parent and minheight= 100dp as ur need.
#add android:gravity="center" to your parent layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/background"
android:gravity="center"
tools:context=".BasicScreenActivity" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:background="#android:color/holo_green_dark" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/button1"
android:background="#android:color/holo_green_dark" />
</RelativeLayout>

Android is running on multiple devices with different screen resolutions, here is how to support them all: Supporting Multiple Screens
Basically we have following screens resolution:
xlarge screens are at least 960dp x 720dp
large screens are at least 640dp x 480dp
normal screens are at least 470dp x 320dp
small screens are at least 426dp x 320dp
to support them all, in Res folder we have to create folders depending what screens we want to support.
layout-xlarge
layout-large
layout-normal
layout-small
after, copy the your final layout_file.xml to all of them, open it in Graphical mode, and rearrange the buttons to look good on the screen. Depending on the resolution screen android will choose layout which is closer to device resolution . Just test it on different devices, or virtual devices to make sure it looks good.

If you want all of your views to cover the whole screen of the device when the app is launched, you need LinearLayout's weight
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/background"
android:orientation="vertical"
tools:context=".BasicScreenActivity">
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="0 dip" //this is important!
android:layout_weight="5" //<-- add this
android:layout_marginTop="102dp"
android:background="#drawable/custom_button1" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="0 dip" //this is important!
android:layout_weight="5" //<-- add this
android:background="#drawable/custom_button2" />
</LinearLayout>
I usually have the weight total equal to 10 so its easier to compute and visualize the UI

How to make layouts grow and shrink?

I'm playing around with making a random recipe collection app.
Now I came across a problem: at the moment I have designed it with my mobile's resolution in mind. But what if the app is used on a device with larger resolution eg. a tablet.
What I want to achieve is that I want the buttons to grow shrink depending on the resolution. For example: when holding my phone vertically, there are 2 columns of buttons. When holding it horizontally, there still are 2 columns, but the view gets wider. Then there should be 4 columns to fill as much of the white space as possible.
Two pictures to illustrate my thoughts:
vertical
horizontal with 2 more columns
My code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffcc33"
android:orientation="vertical"
android:paddingTop="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp" >
<LinearLayout android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:weightSum="1000" >
<EditText
android:id="#+id/search_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:layout_weight="1000"
android:ems="5"
android:hint="#string/search_hint" />
<Button
android:id="#+id/search_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:text="#string/search_button" />
</LinearLayout>
<ScrollView android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center" >
<RelativeLayout
android:layout_width="225dp"
android:layout_height="wrap_content"
android:layout_below="#+id/search_box"
android:layout_gravity="center"
android:layout_marginTop="15dp" >
<Button
android:id="#+id/btn_lihatoidud"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#android:color/transparent"
android:drawableTop="#drawable/lihatoidud"
android:layout_alignParentTop="true"
android:text="Lihatoidud"
android:textSize="18sp" />
<Button
android:id="#+id/btn_kypsetised"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/btn_lihatoidud"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/kypsetised"
android:text="Küpsetised"
android:textSize="18sp" />
<Button
android:id="#+id/btn_seenetoidud"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/btn_kypsetised"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/seenetoidud"
android:text="Seenetoidud"
android:textSize="18sp" />
<Button
android:id="#+id/btn_juustutoidud"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/btn_seenetoidud"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/juustutoidud"
android:text="Juustutoidud"
android:textSize="18sp" />
<Button
android:id="#+id/btn_lisandid"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/btn_juustutoidud"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/lisandid"
android:text="Lisandid"
android:textSize="18sp" />
<Button
android:id="#+id/btn_supid"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:background="#android:color/transparent"
android:drawableTop="#drawable/supid"
android:text="Supid"
android:textSize="18sp" />
<Button
android:id="#+id/btn_voileivad"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="#+id/btn_supid"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/voileivad"
android:text="Võileivad"
android:textSize="18sp" />
<Button
android:id="#+id/btn_pudrud"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="#+id/btn_voileivad"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/pudrud"
android:text="Pudrud"
android:textSize="18sp" />
<Button
android:id="#+id/btn_joogid"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="#+id/btn_pudrud"
android:layout_marginTop="15dp"
android:background="#android:color/transparent"
android:drawableTop="#drawable/joogid"
android:text="Joogid"
android:textSize="18sp" />
</RelativeLayout>
</LinearLayout>
</ScrollView>
</LinearLayout>

Android has a few mechanisms for dealing with this kind of thing. For most people simply having a different layout for different classes of device will be sufficient. i.e:
res/
layout/
my_layout.xml
layout-land/ # landscape
my_layout.xml
layout-sw600dp # bigger devices
my_layout.xml
layout-sw600dp-land # Big and landscape
Android will automatically pick the right layout on the device your app gets loaded on. See the Developer Guide for details there. Alternatively, you might need to define your own custom view that resizes your grid based on the available size. An example of this is a CellLayout, a class written for the grid of apps in Launcher

I would actually reccomend you use the GridView pattern.
https://developer.android.com/guide/topics/ui/layout/gridview.html
Benfits include
Easily customize able if you need multiple rows/columns
Faster performance because you re-use a lot the same views. Scales much better than scrollview approach
Here example with two column for Phones
Here example with four column for tablets
All changing only the number of columns the grid should show. The best way to do this by what "JRaymond" recommended, by having multiple values resposnes depending on if its a tablet/phone. Example
->values ->attrs_arin_view.xml
->values-land->attrs_arin_view.xml
->values-sw600dp -> attrs_arin_view.xml
inside values ->attrs_arin_view.xml
<resources>
<integer name="number_of_column">2</integer>
</resources>
and then change in the values-land to have number_of_column to 4.
Then in your in your xml you mention the integer once
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<GridView
android:id="#+id/gridView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:horizontalSpacing="8dp"
android:numColumns="#integer/number_of_column"
android:padding="8dp"
tools:listitem="#layout/grid_cell_note"
>
</GridView>
</LinearLayout>

You need to create xml files for different screen sizes
http://developer.android.com/guide/practices/screens_support.html
design your XML files to use references instead of hardcoded strings. You can then assign a reference to layouts, buttons and so on which has a different value depending on screen sizes.
(use android:padding="#dimen/pagepadding" instead of android:padding="16dp" and define the dp in values/dimens.xml like this: <dimen name="pagepadding">16dp</dimen>)
To do that you have to create new folders in your Project like values-sw600dp for devices with 600dp smallest width (like Nexus 7 I believe) or values-sw720dp-land for devices with the smallest width of 720dp (10 inch tablets I believe) in landscape.
Do some reading on the developer page and on the internet for that. It's not too difficult

automatically resize ImageButtons in LinearLayout

Summary: I want a horizontal row of ImageButtons to scale down evenly to fit in the screen size.
I have a row of ImageButtons at the top of the screen. A left-aligned logo ImageButton and then right-aligned ImageButtons for various actions.
Yes, that does sound a lot like a Honeycomb/ICS Action Bar, but the code is targeted for Froyo, so I need to implement the design in 2.2-compatible layouts.
I programmatically detect when I'm on a 7" screen or larger and switch to larger images for the ImageButtons (as the drawable-xlarge directory only works for 10" and up, and drawable-large works for 4" and up).
This works great on a phone or on a 10" tablet. However, on a 7" tablet, the images are too large for the space in portrait mode (the app is locked to portrait mode).
I have tried many different approaches to making the images scale down, as I'd rather not use yet another set of images just for 7" tablets. But the images are not spaced properly, or scale at different levels, or only some of the images appear on the screen. I've used RelativeLayout, LinearLayout, android:weightSum, setting the images as background images, as src images, etc.
EDIT: Another quirk I noticed in my experimentation was that if I set the same layout_weight, the layout worked, forcing each item to have the same width. If I want some items to have different widths--which is necessary in this case, as the first button needs to be substantially wider--then the layout breaks when I set a layout_weight that doesn't match the others. Only one or two of the items appear on screen, the rest presumable being pushed off.
Here's the layout I'm using. This is my best so far--it works great on 10" tablets and phones, and is almost tolerable on 7" tablets. But the logo--which should be the same height as the buttons and about 2.5 times wider--is noticeably taller than the other buttons. Any suggestions on improving the layout?
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/actionBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0"
android:padding="5dip"
android:gravity="center_vertical"
android:orientation="horizontal"
android:background="#drawable/action_bar_bg"
>
<ImageButton
android:id="#+id/logoButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#null"
android:src="#drawable/save_logo_03"
android:padding="2dip"
android:adjustViewBounds="true"
android:scaleType="centerInside"
/>
<View
android:id="#+id/spacer"
android:layout_width="50dip"
android:layout_height="1dip"
android:layout_weight="1"
android:visibility="invisible"
/>
<ImageButton
android:id="#+id/listButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="#drawable/list_button"
android:background="#null"
android:adjustViewBounds="true"
android:padding="2dip"
android:scaleType="centerInside"
/>
<ImageButton
android:id="#+id/mapButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#null"
android:src="#drawable/map_button2"
android:adjustViewBounds="true"
android:padding="2dip"
android:scaleType="centerInside"
/>
<ImageButton
android:id="#+id/ltoButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#null"
android:src="#drawable/lto_button"
android:adjustViewBounds="true"
android:padding="2dip"
android:scaleType="centerInside"
/>
<ImageButton
android:id="#+id/searchButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#null"
android:src="#drawable/search_button"
android:adjustViewBounds="true"
android:padding="2dip"
android:scaleType="centerInside"
/>
</LinearLayout>

Unfortunately, in the end I did have to programmatically change the button sizes depending on the size of the screen.
My final layout looked like this (sanitized):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0"
android:padding="5dip"
android:gravity="center_vertical"
android:orientation="horizontal"
android:background="#drawable/action_bar_bg"
>
<ImageButton
android:id="#+id/logoButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:background="#null"
android:padding="2dip"
android:adjustViewBounds="true"
android:src="#drawable/logo"
android:scaleType="centerInside"
/>
<View
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="1"/>
<ImageButton
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:background="#null"
android:padding="2dip"
android:src="#drawable/button1"
android:scaleType="centerInside"
android:adjustViewBounds="true"
/>
<ImageButton
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:background="#null"
android:padding="2dip"
android:src="#drawable/button2"
android:scaleType="centerInside"
android:adjustViewBounds="true"
/>
<ImageButton
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:background="#null"
android:padding="2dip"
android:src="#drawable/button3"
android:scaleType="centerInside"
android:adjustViewBounds="true"
/>
<ImageButton
android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:background="#null"
android:padding="2dip"
android:src="#drawable/button4"
android:adjustViewBounds="true"
android:scaleType="centerInside"
/>
</LinearLayout>
Notice the empty View that fills up available space, pushing the other buttons over to the right side of the screen.
In the code, I check the screen size. If it seems to be >= 7", then I switch to larger images.
If it seems to be >=7" but < 9", then I programmatically change the size of the images--and that I had to experiment with to come up with just the right number for it to work. If I had more images or they changed, I would have to repeat it. I'm not proud of such an inflexible solution, but I couldn't find anything else that worked.

This is what I've got:
In your specific case, we can say that your app layout and buttons size are under dependecy of:
The mobile device screensize/resolution;
The number of buttons in the
row;
I recommend 2 approaches to you:
Implementing your layout with RelativeLayout and weight tags. Flexible layouts can be made very easy with these ones;
Programatically define your button sizes using DisplayMetrics class, something like the snippet in the end of this post, and use an extra .xml file (say integer.xml) where you can define a constant value for your number of buttons;
In this snippet, dm is a structure that holds your device resolutions.
DisplayMetrics dm = new DisplayMetrics();
context.getWindowManager().getDefaultDisplay().getMetrics(dm);
Hope it helped you! :)