Added in API level 1

Button


open class Button : TextView
kotlin.Any
   ↳ android.view.View
   ↳ android.widget.TextView
   ↳ android.widget.Button

A user interface element the user can tap or click to perform an action.

To display a button in an activity, add a button to the activity's layout XML file:

<Button
      android:id="@+id/button_id"
      android:layout_height="wrap_content"
      android:layout_width="wrap_content"
      android:text="@string/self_destruct" />

To specify an action when the button is pressed, set a click listener on the button object in the corresponding activity code:

public class MyActivity extends Activity {
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
 
          setContentView(R.layout.content_layout_id);
 
          final Button button = findViewById(R.id.button_id);
          button.setOnClickListener(new View.OnClickListener() {
              public void onClick(View v) {
                  // Code here executes on main thread after user presses button
              }
          });
      }
  }

The above snippet creates an instance of android.view.View.OnClickListener and wires the listener to the button using setOnClickListener(View.OnClickListener). As a result, the system executes the code you write in onClick(View) after the user presses the button.

The system executes the code in onClick on the main thread. This means your onClick code must execute quickly to avoid delaying your app's response to further user actions. See Keeping Your App Responsive for more details.

Every button is styled using the system's default button background, which is often different from one version of the platform to another. If you are not satisfied with the default button style, you can customize it. For more details and code samples, see the Styling Your Button guide.

For all XML style attributes available on Button see Button Attributes, TextView Attributes, View Attributes. See the Styles and Themes guide to learn how to implement and organize overrides to style-related attributes.

Summary

Inherited XML attributes
Inherited constants
Public constructors
Button(context: Context!)

Simple constructor to use when creating a button from code.

Button(context: Context!, attrs: AttributeSet!)

LayoutInflater calls this constructor when inflating a Button from XML.

Button(context: Context!, attrs: AttributeSet!, defStyleAttr: Int)

This constructor allows a Button subclass to use its own class-specific base style from a theme attribute when inflating.

Button(context: Context!, attrs: AttributeSet!, defStyleAttr: Int, defStyleRes: Int)

This constructor allows a Button subclass to use its own class-specific base style from either a theme attribute or style resource when inflating.

Public methods
open CharSequence!

open PointerIcon!
onResolvePointerIcon(event: MotionEvent!, pointerIndex: Int)

Inherited functions
Inherited properties

Public constructors

Button

Added in API level 1
Button(context: Context!)

Simple constructor to use when creating a button from code.

Parameters
context Context!: The Context the Button is running in, through which it can access the current theme, resources, etc.

Button

Added in API level 1
Button(
    context: Context!,
    attrs: AttributeSet!)

LayoutInflater calls this constructor when inflating a Button from XML. The attributes defined by the current theme's android:buttonStyle override base view attributes. You typically do not call this constructor to create your own button instance in code. However, you must override this constructor when creating custom views.

Parameters
context Context!: The Context the view is running in, through which it can access the current theme, resources, etc.
attrs AttributeSet!: The attributes of the XML Button tag being used to inflate the view.

Button

Added in API level 1
Button(
    context: Context!,
    attrs: AttributeSet!,
    defStyleAttr: Int)

This constructor allows a Button subclass to use its own class-specific base style from a theme attribute when inflating. The attributes defined by the current theme's defStyleAttr override base view attributes.

For Button's base view attributes see Button Attributes, TextView Attributes, View Attributes.

Parameters
context Context!: The Context the Button is running in, through which it can access the current theme, resources, etc.
attrs AttributeSet!: The attributes of the XML Button tag that is inflating the view.
defStyleAttr Int: The resource identifier of an attribute in the current theme whose value is the the resource id of a style. The specified style’s attribute values serve as default values for the button. Set this parameter to 0 to avoid use of default values.

Button

Added in API level 21
Button(
    context: Context!,
    attrs: AttributeSet!,
    defStyleAttr: Int,
    defStyleRes: Int)

This constructor allows a Button subclass to use its own class-specific base style from either a theme attribute or style resource when inflating. To see how the final value of a particular attribute is resolved based on your inputs to this constructor, see android.view.View#View(Context, AttributeSet, int, int).

Parameters
context Context!: The Context the Button is running in, through which it can access the current theme, resources, etc.
attrs AttributeSet!: The attributes of the XML Button tag that is inflating the view.
defStyleAttr Int: The resource identifier of an attribute in the current theme whose value is the the resource id of a style. The specified style’s attribute values serve as default values for the button. Set this parameter to 0 to avoid use of default values.
defStyleRes Int: The identifier of a style resource that supplies default values for the button, used only if defStyleAttr is 0 or cannot be found in the theme. Set this parameter to 0 to avoid use of default values.

Public methods

getAccessibilityClassName

Added in API level 23
open fun getAccessibilityClassName(): CharSequence!

onResolvePointerIcon

Added in API level 24
open fun onResolvePointerIcon(
    event: MotionEvent!,
    pointerIndex: Int
): PointerIcon!
Parameters
event MotionEvent!: The MotionEvent that requires a pointer icon to be resolved for one of pointers.
pointerIndex Int: The index of the pointer in event for which to retrieve the PointerIcon. This will be between 0 and MotionEvent#getPointerCount().
Return
PointerIcon! the pointer icon to use for specified pointer, or null if a pointer icon is not specified and the default icon should be used.