[android] How to change the color of a button?

I'm new to android programming. How do I change the color of a button?

<Button
    android:id="@+id/btn"
    android:layout_width="55dp"
    android:layout_height="50dp"
    android:layout_gravity="center"
    android:text="Button Text"
    android:paddingBottom="20dp"/>

Here is my code, to make different colors on button, and Linear, Constraint and Scroll Layout

First, you need to make a custom_button.xml on your drawable

1. Go to res
2. Expand it, right click on drawable
3. New -> Drawable Resource File
4. File Name : custom_button, Click OK

Custom_Button.xml Code

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:drawable="@color/red"/> <!-- pressed -->
    <item android:state_focused="true" android:drawable="@color/blue"/> <!-- focused -->
    <item android:drawable="@color/black"/> <!-- default -->
</selector>

Second, go to res

1. Expand values
2. Double click on colors.xml
3. Copy the code below

Colors.xml Code

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>

    <color name="black">#000</color>
    <color name="violet">#9400D3</color>
    <color name="indigo">#4B0082</color>
    <color name="blue">#0000FF</color>
    <color name="green">#00FF00</color>
    <color name="yellow">#FFFF00</color>
    <color name="orange">#FF7F00</color>
    <color name="red">#FF0000</color>
</resources>

Screenshots below

XML Coding Design Preview

You can change the value in the XML like this:

<Button
    android:background="#FFFFFF"
     ../>

Here, you can add any other color, from the resources or hex.

Similarly, you can also change these values form the code like this:

demoButton.setBackgroundColor(Color.WHITE);

Another easy way is to make a drawable, customize the corners and shape according to your preference and set the background color and stroke of the drawable. For eg.

button_background.xml

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <stroke android:width="2dp" android:color="#ff207d94" />
    <corners android:radius="5dp" />
    <solid android:color="#FFFFFF" />
</shape>

And then set this shape as the background of your button.

<Button
    android:background="@drawable/button_background.xml"
     ../>

Hope this helps, good luck!

If you are trying to set the background as some other resource file in your drawable folder, say, a custom-button.xml, then try this:

button_name.setBackgroundResource(R.drawable.custom_button_file_name);

eg. Say, you have a custom-button.xml file. Then,

button_name.setBackgroundResource(R.drawable.custom_button);

Will set the button background as the custom-button.xml file.

The RIGHT way...

The following methods actually work.

if you wish - using a theme
By default a buttons color is android:colorAccent. So, if you create a style like this...

<style name="Button.White" parent="ThemeOverlay.AppCompat">
    <item name="colorAccent">@android:color/white</item>
</style>

You can use it like this...

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:theme="@style/Button.White"
    />

alternatively - using a tint
You can simply add android:backgroundTint for API Level 21 and higher, or app:backgroundTint for API Level 7 and higher.

For more information, see this blog.

The problem with the accepted answer...

If you replace the background with a color you will loose the effect of the button, and the color will be applied to the entire area of the button. It will not respect the padding, shadow, and corner radius.

For the text color add:

android:textColor="<hex color>"

For the background color add:

android:background="<hex color>"

From API 21 you can use:

android:backgroundTint="<hex color>"
android:backgroundTintMode="<mode>"

Note: If you're going to work with android/java you really should learn how to google ;)
How to customize different buttons in Android

Through Programming:

btn.setBackgroundColor(getResources().getColor(R.color.colorOffWhite));

and your colors.xml must contain...

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <color name="colorOffWhite">#80ffffff</color>
</resources>

To change the color of button programmatically

Here it is :

Button b1;
//colorAccent is the resource made in the color.xml file , you can change it.
b1.setBackgroundResource(R.color.colorAccent);