Develop Reference

How to give Round corners and blurred background to a linear layout?

I am trying to add a linear layout with rounded corners and blurred background in my app. So far ive managed to give the layout rounded corners but i cant figure out how to give it a blurred background.Ive tried setting an alpha attribute in the xml file but it dosent work.
Heres what i want to achieve:
The Drawable resource file:
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#fff"/>
<stroke android:width="0.5dp" android:color="#B1BCBE" />
<corners android:radius="160dp"/>
<padding android:left="0dp" android:top="0dp" android:right="0dp" android:bottom="0dp" />
</shape>
The Xml code of the layout:
<LinearLayout
android:id="#+id/team_lay"
android:layout_width="match_parent"
android:layout_height="95dp"
android:layout_marginTop="40dp"
android:background="#drawable/layout_bg"
android:orientation="horizontal">
</LinearLayout>
What i have achieved so far:
How can i achieve the desired results?
TIA..!!!

You can achieve it by create a blur background as a xml file and then set background of your container view to it.
Try my example:
blur_background.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape
android:shape="rectangle">
<solid android:color="#4CAF50" />
</shape>
</item>
<item>
<shape
android:shape="rectangle">
<solid android:color="#AA000000" />
</shape>
</item>
</layer-list>
And your container layout:
<LinearLayout
android:id="#+id/team_lay"
android:layout_width="match_parent"
android:layout_height="95dp"
android:layout_marginTop="40dp"
android:background="#drawable/blur_background"
android:orientation="horizontal">
</LinearLayout>
Hope it help. ^^

So i fount the solution myself. I changed the transparency of the solid color in the drawable resouce file(as mentioned here https://stackoverflow.com/a/41865518/8175719 ) and it worked.

how to design layout button to be half one color, half other

I need to design button for android app to be rectangle, and to be half one color, half other. In XML of course.
I have tried this:
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<padding
android:left="7dp"
android:top="15dp"
android:right="7dp"
android:bottom="15dp" />
<gradient
android:startColor="#a241cb"
android:endColor="#a241cb"
android:type="linear"
android:angle="90"/>
<stroke>
android:width="1dip"
android:color="#a241cb" />
<corners android:radius="0dp" />
</shape>
Any help is appreciated

Using a 9 patch like this (save it in your drawable folder as bw_bg.9.png):
You can get a result like this:
Example layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#f00f"
>
<Button
android:layout_width="120dp"
android:layout_height="60dp"
android:layout_centerInParent="true"
android:background="#drawable/bw_bg"
/>
</RelativeLayout>
Don't mind the size (it's running on a Froyo 2.8 inch screen).
Also don't mind the notification (it's from another running app).

Try this:
frist create background.xml in drwable folder
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient android:startColor="#4A225E"
android:endColor="#4C4064"
android:centerColor="#B4AFC5"/>
</shape>
and then set button backgrond its work for me

you can achieve this by using gradients as background. use this
create a new XML file under res/drawable folder and name it as button_bg.xml.
button_bg.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient
android:startColor="#D5DDE0"
android:centerColor="#e7e7e8"
android:endColor="#CFCFCF"
android:angle="270" />
</shape>
now use it for your Button like this:
android:background="#drawable/button_bg"
Hope it helps. :)

How to change the shapes of the corners of textview, button, edit text by applying themes dynamically?

This is my code. I have never seen any changes in my application. I have created this in resources/drawable. How should I apply themes in a style dynamically for all components by changing text color, fonts, shapes etc.
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval" android:padding="20dp">
<solid android:color="#FFA500"/>
<corners android:bottomRightRadius="50dp" android:bottomLeftRadius="50dp"
android:topLeftRadius="50dp" android:topRightRadius="50dp"/>
<stroke android:color="#FFA500" android:dashWidth="50dp" />
</shape>

Create an shape.xml in drawable
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
android:shape="rectangle">
<gradient
android:startColor="#99CCFF"
android:endColor="#99CCFF"
android:angle="45"/>
<padding android:left="6dp"
android:top="6dp"
android:right="6dp"
android:bottom="6dp" />
<corners android:radius="30dp" />
</shape>
Now for your Button code add android:background as shown below.
<Button
android:id="#+id/bt"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/shape"/> // shape is name of xml file created

Your code above works absolutely fine. Maybe the problem is with the way you declared the background: are you doing it in XML file or dynamically by Java code?

Show only left and right borders of a rectangle [duplicate]

I have a TextView and I'd like to add a black border along its top and bottom borders. I tried adding android:drawableTop and android:drawableBottom to the TextView, but that only caused the entire view to become black.
<TextView
android:background="#android:color/green"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:drawableTop="#android:color/black"
android:drawableBottom="#android:color/black"
android:text="la la la" />
Is there a way to easily add a top and bottom border to a View (in particular, a TextView) in Android?

In android 2.2 you could do the following.
Create an xml drawable such as /res/drawable/textlines.xml and assign this as a TextView's background property.
<TextView
android:text="My text with lines above and below"
android:background="#drawable/textlines"
/>
/res/drawable/textlines.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape
android:shape="rectangle">
<stroke android:width="1dp" android:color="#FF000000" />
<solid android:color="#FFDDDDDD" />
</shape>
</item>
<item android:top="1dp" android:bottom="1dp">
<shape
android:shape="rectangle">
<stroke android:width="1dp" android:color="#FFDDDDDD" />
<solid android:color="#00000000" />
</shape>
</item>
</layer-list>
The down side to this is that you have to specify an opaque background colour, as transparencies won't work. (At least i thought they did but i was mistaken). In the above example you can see that the solid colour of the first shape #FFdddddd is copied in the 2nd shapes stroke colour.

I've used a trick so that the border is displayed outside the container. With this trick only a line is drawn so the background will be shown of the underlying view.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:bottom="1dp"
android:left="-2dp"
android:right="-2dp"
android:top="-2dp">
<shape android:shape="rectangle" >
<stroke
android:width="1dp"
android:color="#FF000000" />
<solid android:color="#00FFFFFF" />
<padding android:left="10dp"
android:right="10dp"
android:top="10dp"
android:bottom="10dp" />
</shape>
</item>
</layer-list>

To add a 1dp white border at the bottom only and to have a transparent background you can use the following which is simpler than most answers here.
For the TextView or other view add:
android:background="#drawable/borderbottom"
And in the drawable directory add the following XML, called borderbottom.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:top="-2dp" android:left="-2dp" android:right="-2dp">
<shape android:shape="rectangle">
<stroke android:width="1dp" android:color="#ffffffff" />
<solid android:color="#00000000" />
</shape>
</item>
</layer-list>
If you want a border at the top, change the android:top="-2dp" to android:bottom="-2dp"
The colour does not need to be white and the background does not need to be transparent either.
The solid element may not be required. This will depend on your design (thanks V. Kalyuzhnyu).
Basically, this XML will create a border using the rectangle shape, but then pushes the top, right and left sides beyond the render area for the shape. This leaves just the bottom border visible.

Option 1: Shape Drawable
This is the simplest option if you want a border around a layout or view in which you can set the background. Create an XML file in the drawable folder that looks something like this:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<solid android:color="#8fff93" />
<stroke
android:width="1px"
android:color="#000" />
</shape>
You can remove the solid if you don't want a fill. The set background="#drawable/your_shape_drawable" on your layout/view.
Option 2: Background View
Here's a little trick I've used in a RelativeLayout. Basically you have a black square under the view you want to give a border, and then give that view some padding (not margin!) so the black square shows through at the edges.
Obviously this only works properly if the view doesn't have any transparent areas. If it does I would recommend you write a custom BorderView which only draws the border - it should only be a few dozen lines of code.
<View
android:id="#+id/border"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/image"
android:layout_alignLeft="#+id/image"
android:layout_alignRight="#+id/image"
android:layout_alignTop="#+id/main_image"
android:background="#000" />
<ImageView
android:id="#+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_...
android:padding="1px"
android:src="#drawable/..." />
If you're wondering, it does work with adjustViewBounds=true. However, it doesn't work if you want to have a background in an entire RelativeLayout, because there is a bug that stops you filling a RelativeLayout with a View. In that case I'd recommend the Shape drawable.
Option 3: 9-patch
A final option is to use a 9-patch drawable like this one:
You can use it on any view where you can set android:background="#drawable/...". And yes it does need to be 6x6 - I tried 5x5 and it didn't work.
The disadvantage of this method is you can't change the colours very easily, but if you want fancy borders (e.g. only a border at the top and bottom, as in this question) then you may not be able to do them with the Shape drawable, which isn't very powerful.
Option 4: Extra views
I forgot to mention this really simple option if you only want borders above and below your view. You can put your view in a vertical LinearLayout (if it isn't already) and then add empty Views above and below it like this:
<View android:background="#000" android:layout_width="match_parent" android:layout_height="1px"/>

The currently accepted answer doesn't work. It creates thin vertical borders on the left and right sides of the view as a result of anti-aliasing.
This version works perfectly. It also allows you to set the border widths independently, and you can also add borders on the left / right sides if you want. The only drawback is that it does NOT support transparency.
Create an xml drawable named /res/drawable/top_bottom_borders.xml with the code below and assign it as a TextView's background property.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="rectangle">
<solid android:color="#DDDD00" /> <!-- border color -->
</shape>
</item>
<item
android:bottom="1dp"
android:top="1dp"> <!-- adjust borders width here -->
<shape android:shape="rectangle">
<solid android:color="#FFFFFF" /> <!-- background color -->
</shape>
</item>
</layer-list>
Tested on Android KitKat through Marshmallow

So I wanted to do something slightly different: a border on the bottom ONLY, to simulate a ListView divider. I modified Piet Delport's answer and got this:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape
android:shape="rectangle">
<solid android:color="#color/background_trans_light" />
</shape>
</item>
<!-- this mess is what we have to do to get a bottom border only. -->
<item android:top="-2dp"
android:left="-2dp"
android:right="-2dp"
android:bottom="1px">
<shape
android:shape="rectangle">
<stroke android:width="1dp" android:color="#color/background_trans_mid" />
<solid android:color="#null" />
</shape>
</item>
</layer-list>
Note using px instead of dp to get exactly 1 pixel divider (some phone DPIs will make a 1dp line disappear).

Add file to res/drawable
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:left="-2dp" android:right="-2dp">
<shape android:shape="rectangle">
<stroke
android:width="1dp"
android:color="#000000" />
</shape>
</item>
</layer-list>
Add link on this file to background property

Just as #Nic Hubbard said, there is a very easy way to add a border line.
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="#000000" >
</View>
You can change the height and background color to whatever you want.

You can also wrap the view in a FrameLayout, then set the frame's background color and padding to what you want; however, the textview, by default has a 'transparent' background, so you'd need to change the textview's background color too.

My answers is based on #Emile version but I use transparent color instead of solid.
This example will draw a 2dp bottom border.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape android:shape="rectangle" >
<stroke android:width="2dp"
android:color="#50C0E9" />
<solid android:color="#android:color/transparent" />
</shape>
</item>
<item android:bottom="2dp" >
<shape android:shape="rectangle" >
<stroke android:width="2dp"
android:color="#color/bgcolor" />
<solid android:color="#android:color/transparent" />
</shape>
</item>
</layer-list>
#color/bgcolor is the color of the background on wich you draw your view with border.
If you want to change the position of the border change the offset with one of:
android:bottom="2dp"
android:top="2dp"
android:right="2dp"
android:left="2dp"
or combine them to have 2 or more borders:
android:bottom="2dp" android:top="2dp"

You can do this by this code snippet -
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!--Minus (-) how much dp you gave in the stroke width from left right-->
<item android:left="-10dp" android:right="-10dp">
<shape
android:shape="rectangle">
<stroke android:width="10dp" android:color="#android:color/holo_red_dark" />
<!--This is the main background -->
<solid android:color="#FFDDDDDD" />
</shape>
</item>
</layer-list>
Preview -

Why not just create a 1dp high view with a background color? Then it can be easily placed where you want.

To change this:
<TextView
android:text="My text"
android:background="#drawable/top_bottom_border"/>
I prefer this approach in "drawable/top_bottom_border.xml":
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape>
<gradient
android:angle="270"
android:startColor="#000"
android:centerColor="#android:color/transparent"
android:centerX="0.01" />
</shape>
</item>
<item>
<shape>
<gradient
android:angle="90"
android:startColor="#000"
android:centerColor="#android:color/transparent"
android:centerX="0.01" />
</shape>
</item>
</layer-list>
This only makes the borders, not a rectangle that will appear if your background has a color.

Simplest way to add borders to inset the borders using InsetDrawable,following will show top border only :
<?xml version="1.0" encoding="utf-8"?>
<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:insetBottom="-2dp"
android:insetLeft="-2dp"
android:insetRight="-2dp">
<shape android:shape="rectangle">
<solid android:color="#color/light_gray" />
<stroke
android:width=".5dp"
android:color="#color/dark_gray" />
</shape>
</inset>

Just to add my solution to the list..
I wanted a semi transparent bottom border that extends past the original shape (So the semi-transparent border was outside the parent rectangle).
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape android:shape="rectangle" >
<solid android:color="#33000000" /> <!-- Border colour -->
</shape>
</item>
<item android:bottom="2dp" >
<shape android:shape="rectangle" >
<solid android:color="#164586" />
</shape>
</item>
</layer-list>
Which gives me;

First make a xml file with contents shown below and name it border.xml and place it inside the layout folder inside the res directory
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<stroke android:width="1dp" android:color="#0000" />
<padding android:left="0dp" android:top="1dp" android:right="0dp"
android:bottom="1dp" />
</shape>
After that inside the code use
TextView tv = (TextView)findElementById(R.id.yourTextView);
tv.setBackgroundResource(R.layout.border);
This will make a black line on top and bottom of the TextView.

Simply add Views at the top and bottom of the View
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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">
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#color/your_color"
app:layout_constraintBottom_toTopOf="#+id/textView"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintStart_toStartOf="#+id/textView" />
<TextView
android:id="#+id/textView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:gravity="center"
android:text="Testing"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#color/your_color"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintStart_toStartOf="#+id/textView"
app:layout_constraintTop_toBottomOf="#+id/textView" />
</android.support.constraint.ConstraintLayout>

Write down below code
<View
android:layout_width="wrap_content"
android:layout_height="2dip"
android:layout_below="#+id/topics_text"
android:layout_marginTop="7dp"
android:layout_margin="10dp"
android:background="#ffffff" />

Try wrapping the image with a linearlayout, and set it's background to the border color you want around the text. Then set the padding on the textview to be the thickness you want for your border.

You can also use a 9-path to do your job. Create it so that colored pixel do not multiply in height but only the transparent pixel.

Based on accepted answer of Pi Delport and Emile, I made it a little simpler
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item> <!--divider TOP and BOTTOM-->
<shape android:shape="rectangle">
<stroke
android:width="1dp"
android:color="#color/divider" />
</shape>
</item>
<!--background surface-->
<item
android:top="1dp"
android:bottom="1dp">
<shape android:shape="rectangle">
<solid android:color="#color/background" />
</shape>
</item>

// Just simply add border around the image view or view
<ImageView
android:id="#+id/imageView2"
android:layout_width="90dp"
android:layout_height="70dp"
android:layout_centerVertical="true"
android:layout_marginRight="10dp"
android:layout_toLeftOf="#+id/imageView1"
android:background="#android:color/white"
android:padding="5dip" />
// After that dynamically put color into your view or image view object
objView.setBackgroundColor(Color.GREEN);
//VinodJ/Abhishek

<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#color/light_grey1" />
<stroke
android:width="1dip"
android:color="#color/light_grey1" />
<corners
android:bottomLeftRadius="0dp"
android:bottomRightRadius="0dp"
android:topLeftRadius="5dp"
android:topRightRadius="5dp" />
</shape>

<TextView
android:id="#+id/textView3"
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="#72cdf4"
android:text=" aa" />
Just Add this TextView below the text where you want to add the border

Just to enforce #phreakhead ´s and user1051892 ´s answers, <item android:bottom|android:left|android:right|android:top> if negative, must to be greater than <stroke android:width>. If not, item´s painting will be mixed with stroke´s painting and you may think these values are not working.

Is there an easy way to add a border to the top and bottom of an Android View?

I have a TextView and I'd like to add a black border along its top and bottom borders. I tried adding android:drawableTop and android:drawableBottom to the TextView, but that only caused the entire view to become black.
<TextView
android:background="#android:color/green"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:drawableTop="#android:color/black"
android:drawableBottom="#android:color/black"
android:text="la la la" />
Is there a way to easily add a top and bottom border to a View (in particular, a TextView) in Android?

In android 2.2 you could do the following.
Create an xml drawable such as /res/drawable/textlines.xml and assign this as a TextView's background property.
<TextView
android:text="My text with lines above and below"
android:background="#drawable/textlines"
/>
/res/drawable/textlines.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape
android:shape="rectangle">
<stroke android:width="1dp" android:color="#FF000000" />
<solid android:color="#FFDDDDDD" />
</shape>
</item>
<item android:top="1dp" android:bottom="1dp">
<shape
android:shape="rectangle">
<stroke android:width="1dp" android:color="#FFDDDDDD" />
<solid android:color="#00000000" />
</shape>
</item>
</layer-list>
The down side to this is that you have to specify an opaque background colour, as transparencies won't work. (At least i thought they did but i was mistaken). In the above example you can see that the solid colour of the first shape #FFdddddd is copied in the 2nd shapes stroke colour.

I've used a trick so that the border is displayed outside the container. With this trick only a line is drawn so the background will be shown of the underlying view.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:bottom="1dp"
android:left="-2dp"
android:right="-2dp"
android:top="-2dp">
<shape android:shape="rectangle" >
<stroke
android:width="1dp"
android:color="#FF000000" />
<solid android:color="#00FFFFFF" />
<padding android:left="10dp"
android:right="10dp"
android:top="10dp"
android:bottom="10dp" />
</shape>
</item>
</layer-list>

To add a 1dp white border at the bottom only and to have a transparent background you can use the following which is simpler than most answers here.
For the TextView or other view add:
android:background="#drawable/borderbottom"
And in the drawable directory add the following XML, called borderbottom.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:top="-2dp" android:left="-2dp" android:right="-2dp">
<shape android:shape="rectangle">
<stroke android:width="1dp" android:color="#ffffffff" />
<solid android:color="#00000000" />
</shape>
</item>
</layer-list>
If you want a border at the top, change the android:top="-2dp" to android:bottom="-2dp"
The colour does not need to be white and the background does not need to be transparent either.
The solid element may not be required. This will depend on your design (thanks V. Kalyuzhnyu).
Basically, this XML will create a border using the rectangle shape, but then pushes the top, right and left sides beyond the render area for the shape. This leaves just the bottom border visible.

Option 1: Shape Drawable
This is the simplest option if you want a border around a layout or view in which you can set the background. Create an XML file in the drawable folder that looks something like this:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<solid android:color="#8fff93" />
<stroke
android:width="1px"
android:color="#000" />
</shape>
You can remove the solid if you don't want a fill. The set background="#drawable/your_shape_drawable" on your layout/view.
Option 2: Background View
Here's a little trick I've used in a RelativeLayout. Basically you have a black square under the view you want to give a border, and then give that view some padding (not margin!) so the black square shows through at the edges.
Obviously this only works properly if the view doesn't have any transparent areas. If it does I would recommend you write a custom BorderView which only draws the border - it should only be a few dozen lines of code.
<View
android:id="#+id/border"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/image"
android:layout_alignLeft="#+id/image"
android:layout_alignRight="#+id/image"
android:layout_alignTop="#+id/main_image"
android:background="#000" />
<ImageView
android:id="#+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_...
android:padding="1px"
android:src="#drawable/..." />
If you're wondering, it does work with adjustViewBounds=true. However, it doesn't work if you want to have a background in an entire RelativeLayout, because there is a bug that stops you filling a RelativeLayout with a View. In that case I'd recommend the Shape drawable.
Option 3: 9-patch
A final option is to use a 9-patch drawable like this one:
You can use it on any view where you can set android:background="#drawable/...". And yes it does need to be 6x6 - I tried 5x5 and it didn't work.
The disadvantage of this method is you can't change the colours very easily, but if you want fancy borders (e.g. only a border at the top and bottom, as in this question) then you may not be able to do them with the Shape drawable, which isn't very powerful.
Option 4: Extra views
I forgot to mention this really simple option if you only want borders above and below your view. You can put your view in a vertical LinearLayout (if it isn't already) and then add empty Views above and below it like this:
<View android:background="#000" android:layout_width="match_parent" android:layout_height="1px"/>

The currently accepted answer doesn't work. It creates thin vertical borders on the left and right sides of the view as a result of anti-aliasing.
This version works perfectly. It also allows you to set the border widths independently, and you can also add borders on the left / right sides if you want. The only drawback is that it does NOT support transparency.
Create an xml drawable named /res/drawable/top_bottom_borders.xml with the code below and assign it as a TextView's background property.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="rectangle">
<solid android:color="#DDDD00" /> <!-- border color -->
</shape>
</item>
<item
android:bottom="1dp"
android:top="1dp"> <!-- adjust borders width here -->
<shape android:shape="rectangle">
<solid android:color="#FFFFFF" /> <!-- background color -->
</shape>
</item>
</layer-list>
Tested on Android KitKat through Marshmallow

So I wanted to do something slightly different: a border on the bottom ONLY, to simulate a ListView divider. I modified Piet Delport's answer and got this:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape
android:shape="rectangle">
<solid android:color="#color/background_trans_light" />
</shape>
</item>
<!-- this mess is what we have to do to get a bottom border only. -->
<item android:top="-2dp"
android:left="-2dp"
android:right="-2dp"
android:bottom="1px">
<shape
android:shape="rectangle">
<stroke android:width="1dp" android:color="#color/background_trans_mid" />
<solid android:color="#null" />
</shape>
</item>
</layer-list>
Note using px instead of dp to get exactly 1 pixel divider (some phone DPIs will make a 1dp line disappear).

Add file to res/drawable
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:left="-2dp" android:right="-2dp">
<shape android:shape="rectangle">
<stroke
android:width="1dp"
android:color="#000000" />
</shape>
</item>
</layer-list>
Add link on this file to background property

Just as #Nic Hubbard said, there is a very easy way to add a border line.
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="#000000" >
</View>
You can change the height and background color to whatever you want.

You can also wrap the view in a FrameLayout, then set the frame's background color and padding to what you want; however, the textview, by default has a 'transparent' background, so you'd need to change the textview's background color too.

My answers is based on #Emile version but I use transparent color instead of solid.
This example will draw a 2dp bottom border.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape android:shape="rectangle" >
<stroke android:width="2dp"
android:color="#50C0E9" />
<solid android:color="#android:color/transparent" />
</shape>
</item>
<item android:bottom="2dp" >
<shape android:shape="rectangle" >
<stroke android:width="2dp"
android:color="#color/bgcolor" />
<solid android:color="#android:color/transparent" />
</shape>
</item>
</layer-list>
#color/bgcolor is the color of the background on wich you draw your view with border.
If you want to change the position of the border change the offset with one of:
android:bottom="2dp"
android:top="2dp"
android:right="2dp"
android:left="2dp"
or combine them to have 2 or more borders:
android:bottom="2dp" android:top="2dp"

You can do this by this code snippet -
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!--Minus (-) how much dp you gave in the stroke width from left right-->
<item android:left="-10dp" android:right="-10dp">
<shape
android:shape="rectangle">
<stroke android:width="10dp" android:color="#android:color/holo_red_dark" />
<!--This is the main background -->
<solid android:color="#FFDDDDDD" />
</shape>
</item>
</layer-list>
Preview -

Why not just create a 1dp high view with a background color? Then it can be easily placed where you want.

To change this:
<TextView
android:text="My text"
android:background="#drawable/top_bottom_border"/>
I prefer this approach in "drawable/top_bottom_border.xml":
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape>
<gradient
android:angle="270"
android:startColor="#000"
android:centerColor="#android:color/transparent"
android:centerX="0.01" />
</shape>
</item>
<item>
<shape>
<gradient
android:angle="90"
android:startColor="#000"
android:centerColor="#android:color/transparent"
android:centerX="0.01" />
</shape>
</item>
</layer-list>
This only makes the borders, not a rectangle that will appear if your background has a color.

Simplest way to add borders to inset the borders using InsetDrawable,following will show top border only :
<?xml version="1.0" encoding="utf-8"?>
<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:insetBottom="-2dp"
android:insetLeft="-2dp"
android:insetRight="-2dp">
<shape android:shape="rectangle">
<solid android:color="#color/light_gray" />
<stroke
android:width=".5dp"
android:color="#color/dark_gray" />
</shape>
</inset>

Just to add my solution to the list..
I wanted a semi transparent bottom border that extends past the original shape (So the semi-transparent border was outside the parent rectangle).
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape android:shape="rectangle" >
<solid android:color="#33000000" /> <!-- Border colour -->
</shape>
</item>
<item android:bottom="2dp" >
<shape android:shape="rectangle" >
<solid android:color="#164586" />
</shape>
</item>
</layer-list>
Which gives me;

First make a xml file with contents shown below and name it border.xml and place it inside the layout folder inside the res directory
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<stroke android:width="1dp" android:color="#0000" />
<padding android:left="0dp" android:top="1dp" android:right="0dp"
android:bottom="1dp" />
</shape>
After that inside the code use
TextView tv = (TextView)findElementById(R.id.yourTextView);
tv.setBackgroundResource(R.layout.border);
This will make a black line on top and bottom of the TextView.

Simply add Views at the top and bottom of the View
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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">
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#color/your_color"
app:layout_constraintBottom_toTopOf="#+id/textView"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintStart_toStartOf="#+id/textView" />
<TextView
android:id="#+id/textView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:gravity="center"
android:text="Testing"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#color/your_color"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintStart_toStartOf="#+id/textView"
app:layout_constraintTop_toBottomOf="#+id/textView" />
</android.support.constraint.ConstraintLayout>

Write down below code
<View
android:layout_width="wrap_content"
android:layout_height="2dip"
android:layout_below="#+id/topics_text"
android:layout_marginTop="7dp"
android:layout_margin="10dp"
android:background="#ffffff" />

Try wrapping the image with a linearlayout, and set it's background to the border color you want around the text. Then set the padding on the textview to be the thickness you want for your border.

You can also use a 9-path to do your job. Create it so that colored pixel do not multiply in height but only the transparent pixel.

Based on accepted answer of Pi Delport and Emile, I made it a little simpler
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item> <!--divider TOP and BOTTOM-->
<shape android:shape="rectangle">
<stroke
android:width="1dp"
android:color="#color/divider" />
</shape>
</item>
<!--background surface-->
<item
android:top="1dp"
android:bottom="1dp">
<shape android:shape="rectangle">
<solid android:color="#color/background" />
</shape>
</item>

// Just simply add border around the image view or view
<ImageView
android:id="#+id/imageView2"
android:layout_width="90dp"
android:layout_height="70dp"
android:layout_centerVertical="true"
android:layout_marginRight="10dp"
android:layout_toLeftOf="#+id/imageView1"
android:background="#android:color/white"
android:padding="5dip" />
// After that dynamically put color into your view or image view object
objView.setBackgroundColor(Color.GREEN);
//VinodJ/Abhishek

<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#color/light_grey1" />
<stroke
android:width="1dip"
android:color="#color/light_grey1" />
<corners
android:bottomLeftRadius="0dp"
android:bottomRightRadius="0dp"
android:topLeftRadius="5dp"
android:topRightRadius="5dp" />
</shape>

<TextView
android:id="#+id/textView3"
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="#72cdf4"
android:text=" aa" />
Just Add this TextView below the text where you want to add the border

Just to enforce #phreakhead ´s and user1051892 ´s answers, <item android:bottom|android:left|android:right|android:top> if negative, must to be greater than <stroke android:width>. If not, item´s painting will be mixed with stroke´s painting and you may think these values are not working.