Add buttons to your app

A button consists of text or an icon, or both, that communicates what action occurs when the user taps it.

You can create a button in your layout in one of three ways, depending on whether you want a button with text, an icon, or both:

  
  <LinearLayout 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"
      android:paddingLeft="16dp"
      android:paddingRight="16dp"
      android:orientation="vertical" >
  
      <Button
          android:id="@+id/supabutton"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="I'm a button" />
  
      <ImageButton
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:contentDescription="A tiny Android icon"
          android:src="@drawable/baseline_android_24"
          app:tint="#ff0000" />
  
      <Button
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:drawableStart="@drawable/baseline_android_24"
          android:drawablePadding="4dp"
          android:drawableTint="#ff0000"
          android:text="I'm a button with an icon" />
  </LinearLayout>

The previous code generates something like this:

An image showing three types of buttons — **Figure 1.** Three styles of buttons.

Respond to click events

When the user taps a button, the Button object receives an on-click event.

To declare the event handler programmatically, create an View.OnClickListener object and assign it to the button by calling setOnClickListener(View.OnClickListener), as in the following example:

Kotlin

findViewById<Button>(R.id.supabutton)
  .setOnClickListener {
      Log.d("BUTTONS", "User tapped the Supabutton")
  }

Java

Button button = (Button) findViewById(R.id.supabutton);
button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
      Log.d("BUTTONS", "User tapped the Supabutton");
    }
});

Style your button

The appearance of your button—the background image and font—varies between devices, because devices by different manufacturers often have different default styles for input controls.

To customize individual buttons with a different background, specify the android:background attribute with a drawable or color resource. Alternatively, you can apply a style for the button, which works in similarly to HTML styles to define multiple style properties such as the background, font, and size. For more information about applying styles, see Styles and themes.

Borderless button

One design that can be useful is a "borderless" button. Borderless buttons resemble basic buttons except that they have no borders or background but still change appearance during different states, such as when tapped.

To create a borderless button, apply the borderlessButtonStyle style to the button, as in the following example:

<Button
  android:id="@+id/supabutton"
  style="?android:attr/borderlessButtonStyle"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="I'm a button" />

Custom background

If you want to truly redefine the appearance of your button, you can specify a custom background. Instead of supplying a simple bitmap or color, however, your background must be a state list resource that changes appearance depending on the button's current state.

You can define the state list in an XML file that defines three images or colors to use for the different button states.

To create a state list drawable for your button background, do the following:

Create three bitmaps for the button background that represent the default, tapped, and focused button states. To ensure that your images fit buttons of various sizes, create the bitmaps as nine-patch bitmaps.
Place the bitmaps into your project's res/drawable/ directory. Name each bitmap to reflect the button state it represents, such as button_default.9.png, button_pressed.9.png, and button_focused.9.png.
Create a new XML file in the res/drawable/ directory. Name it something like button_custom.xml. Insert XML like the following:
```
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/button_pressed"
          android:state_pressed="true" />
    <item android:drawable="@drawable/button_focused"
          android:state_focused="true" />
    <item android:drawable="@drawable/button_default" />
</selector>
```
This defines a single drawable resource that changes its image based on the current state of the button.
- The first <item> defines the bitmap to use when the button is tapped (activated).
- The second <item> defines the bitmap to use when the button is focused, such as when the button is highlighted using the trackball or directional pad.
- The third <item> defines the bitmap to use when the button is in the default state, neither tapped nor focused.
Note: The order of the <item> elements is important. When this drawable is referenced, the <item> elements are traversed in order to determine which one is appropriate for the current button state. Because the default bitmap is last, it is only applied when the conditions android:state_pressed and android:state_focused are evaluated as false.

This XML file represents a single drawable resource. When referenced by a Button for its background, the image displayed changes based on the button's state.

Apply the drawable XML file as the button background:

<Button
    android:id="@+id/button_send"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/button_send"
    android:onClick="sendMessage"
    android:background="@drawable/button_custom"  />

For more information about this XML syntax, including how to define a button that is disabled, hovered, or in another state, read about StateListDrawable.