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Android APIs
public class

ImageButton

extends ImageView
java.lang.Object
   ↳ android.view.View
     ↳ android.widget.ImageView
       ↳ android.widget.ImageButton
Known Direct Subclasses

Class Overview

Displays a button with an image (instead of text) that can be pressed or clicked by the user. By default, an ImageButton looks like a regular Button, with the standard button background that changes color during different button states. The image on the surface of the button is defined either by the android:src attribute in the XML element or by the setImageResource(int) method.

To remove the standard button background image, define your own background image or set the background color to be transparent.

To indicate the different button states (focused, selected, etc.), you can define a different image for each state. E.g., a blue image by default, an orange one for when focused, and a yellow one for when pressed. An easy way to do this is with an XML drawable "selector." For example:

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

Save the XML file in your project res/drawable/ folder and then reference it as a drawable for the source of your ImageButton (in the android:src attribute). Android will automatically change the image based on the state of the button and the corresponding images defined in the XML.

The order of the elements is important because they are evaluated in order. This is why the "normal" button image comes last, because it will only be applied after android:state_pressed and android:state_focused have both evaluated false.

See the Form Stuff tutorial.

XML attributes

See Button Attributes, View Attributes

Summary

[Expand]
Inherited XML Attributes
From class android.widget.ImageView
From class android.view.View
[Expand]
Inherited Constants
From class android.view.View
[Expand]
Inherited Fields
From class android.view.View
Public Constructors
ImageButton(Context context)
ImageButton(Context context, AttributeSet attrs)
ImageButton(Context context, AttributeSet attrs, int defStyle)
Public Methods
void onInitializeAccessibilityEvent(AccessibilityEvent event)
Initializes an AccessibilityEvent with information about this View which is the event source.
void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)
Initializes an AccessibilityNodeInfo with information about this view.
Protected Methods
boolean onSetAlpha(int alpha)
Invoked if there is a Transform that involves alpha.
[Expand]
Inherited Methods
From class android.widget.ImageView
From class android.view.View
From class java.lang.Object
From interface android.graphics.drawable.Drawable.Callback
From interface android.view.KeyEvent.Callback
From interface android.view.accessibility.AccessibilityEventSource

Public Constructors

public ImageButton (Context context)

Since: API Level 1

public ImageButton (Context context, AttributeSet attrs)

Since: API Level 1

public ImageButton (Context context, AttributeSet attrs, int defStyle)

Since: API Level 1

Public Methods

public void onInitializeAccessibilityEvent (AccessibilityEvent event)

Since: API Level 14

Initializes an AccessibilityEvent with information about this View which is the event source. In other words, the source of an accessibility event is the view whose state change triggered firing the event.

Example: Setting the password property of an event in addition to properties set by the super implementation: 

 public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
     super.onInitializeAccessibilityEvent(event);
     event.setPassword(true);
 }

If an View.AccessibilityDelegate has been specified via calling setAccessibilityDelegate(AccessibilityDelegate) its onInitializeAccessibilityEvent(View, AccessibilityEvent) is responsible for handling this call.

Note: Always call the super implementation before adding information to the event, in case the default implementation has basic information to add.

Parameters
event The event to initialize.

public void onInitializeAccessibilityNodeInfo (AccessibilityNodeInfo info)

Since: API Level 14

Initializes an AccessibilityNodeInfo with information about this view. The base implementation sets:

Subclasses should override this method, call the super implementation, and set additional attributes.

If an View.AccessibilityDelegate has been specified via calling setAccessibilityDelegate(AccessibilityDelegate) its onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfo) is responsible for handling this call.

Parameters
info The instance to initialize.

Protected Methods

protected boolean onSetAlpha (int alpha)

Since: API Level 1

Invoked if there is a Transform that involves alpha. Subclass that can draw themselves with the specified alpha should return true, and then respect that alpha when their onDraw() is called. If this returns false then the view may be redirected to draw into an offscreen buffer to fulfill the request, which will look fine, but may be slower than if the subclass handles it internally. The default implementation returns false.

Parameters
alpha The alpha (0..255) to apply to the view's drawing
Returns
  • true if the view can draw with the specified alpha.