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/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.widget;
import android.content.Context;
import android.util.AttributeSet;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityNodeInfo;
import android.widget.RemoteViews.RemoteView;
/**
* <p>
* 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
* {@link android.widget.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 {@code android:src} attribute in the
* {@code <ImageButton>} XML element or by the
* {@link #setImageResource(int)} method.</p>
*
* <p>To remove the standard button background image, define your own
* background image or set the background color to be transparent.</p>
* <p>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:</p>
* <pre>
* <?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></pre>
*
* <p>Save the XML file in your project {@code res/drawable/} folder and then
* reference it as a drawable for the source of your ImageButton (in the
* {@code android:src} attribute). Android will automatically change the image
* based on the state of the button and the corresponding images
* defined in the XML.</p>
*
* <p>The order of the {@code <item>} 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 {@code android:state_pressed} and {@code
* android:state_focused} have both evaluated false.</p>
*
* <p>See the <a href="{@docRoot}guide/topics/ui/controls/button.html">Buttons</a>
* guide.</p>
*
* <p><strong>XML attributes</strong></p>
* <p>
* See {@link android.R.styleable#ImageView Button Attributes},
* {@link android.R.styleable#View View Attributes}
* </p>
*/
@RemoteView
public class ImageButton extends ImageView {
public ImageButton(Context context) {
this(context, null);
}
public ImageButton(Context context, AttributeSet attrs) {
this(context, attrs, com.android.internal.R.attr.imageButtonStyle);
}
public ImageButton(Context context, AttributeSet attrs, int defStyleAttr) {
this(context, attrs, defStyleAttr, 0);
}
public ImageButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
setFocusable(true);
}
@Override
protected boolean onSetAlpha(int alpha) {
return false;
}
@Override
public CharSequence getAccessibilityClassName() {
return ImageButton.class.getName();
}
}
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