Android create a "flat button"

Add dependency to build.gradle

dependencies {
    compile 'com.android.support:appcompat-v7:25.0.0'
}

Then in your layout XML file, add a style attribute to the Button

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Button"
    style="@style/Widget.AppCompat.Button.Borderless"/>

You can change the color when the button is pressed by defining a custom style

<style name="FlatButtonStyle" parent="Theme.AppCompat.Dark">
    <item name="colorControlHighlight">@color/transparent</item>
</style>

and applying this style in layout XML

android:theme="@style/FlatButtonStyle"

You can use the style="?android:attr/borderlessButtonStyle on your Button as follows:

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextGoesHere"
style="?android:attr/borderlessButtonStyle"
/>

BorderlessButtonStyle

Style for buttons without an explicit border, often used in groups.

Also you can use those Flat Buttons