docs/html/guide/topics/ui/controls/togglebutton.jd

page.title=Toggle Buttons
page.tags=switch,togglebutton
@jd:body

<div id="qv-wrapper">
<div id="qv">
<h2>In this document</h2>
<ol>
  <li><a href="#HandlingEvents">Responding to Click Events</a>
    <ol>
      <li><a href="#ClickListener">Using an OnCheckedChangeListener</a></li>
    </ol>
  </li>
</ol>
  <h2>Key classes</h2>
  <ol>
    <li>{@link android.widget.ToggleButton}</li>
    <li>{@link android.widget.Switch}</li>
  </ol>
</div>
</div>

<p>A toggle button allows the user to change a setting between two states.</p>

<p>You can add a basic toggle button to your layout with the {@link android.widget.ToggleButton}
object. Android 4.0 (API level 14) introduces another kind of toggle button called a switch that
provides a slider control, which you can add with a {@link android.widget.Switch} object.</p>

<div style="float:left;width:200px">
<img src="{@docRoot}images/ui/togglebutton.png" alt="" />
<p class="img-caption"><em>Toggle buttons</em></p>
</div>

<div style="float:left;width:200px;margin-top:24px">
<img src="{@docRoot}images/ui/switch.png" alt="" />
<p class="img-caption"><em>Switches (in Android 4.0+)</em></p>
</div>

<p style="clear:left">The {@link android.widget.ToggleButton} and {@link android.widget.Switch}
controls are subclasses of {@link android.widget.CompoundButton} and function in the same manner, so
you can implement their behavior the same way.</p>

<h2 id="HandlingEvents">Responding to Click Events</h2>

<p>When the user selects a {@link android.widget.ToggleButton} and {@link android.widget.Switch},
the object receives an on-click event.</p>

<p>To define the click event handler, add the <code><a
href="/reference/android/R.attr.html#onClick">android:onClick</a></code> attribute to the
<code>&lt;ToggleButton&gt;</code> or <code>&lt;Switch&gt;</code> element in your XML
layout. The value for this attribute must be the name of the method you want to call in response
to a click event. The {@link android.app.Activity} hosting the layout must then implement the
corresponding method.</p>

<p>For example, here's a {@link android.widget.ToggleButton} with the <code><a
href="/reference/android/R.attr.html#onClick">android:onClick</a></code> attribute:</p>

<pre>
&lt;ToggleButton 
    android:id="@+id/togglebutton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textOn="Vibrate on"
    android:textOff="Vibrate off"
    android:onClick="onToggleClicked"/>
</pre>

<p>Within the {@link android.app.Activity} that hosts this layout, the following method handles the
click event:</p>

<pre>
public void onToggleClicked(View view) {
    // Is the toggle on?
    boolean on = ((ToggleButton) view).isChecked();
    
    if (on) {
        // Enable vibrate
    } else {
        // Disable vibrate
    }
}
</pre>

<p>The method you declare in the {@link android.R.attr#onClick android:onClick} attribute
must have a signature exactly as shown above. Specifically, the method must:</p>
<ul>
  <li>Be public</li>
  <li>Return void</li>
  <li>Define a {@link android.view.View} as its only parameter (this will be the {@link
android.view.View} that was clicked)</li>
</ul>

<p class="note"><strong>Tip:</strong> If you need to change the state
yourself,
use the {@link android.widget.CompoundButton#setChecked(boolean)} or {@link
android.widget.CompoundButton#toggle()} method to change the state.</p>



<h3 id="ClickListener">Using an OnCheckedChangeListener</h3>

<p>You can also declare a click event handler pragmatically rather than in an XML layout. This
might be necessary if you instantiate the {@link android.widget.ToggleButton} or {@link
android.widget.Switch} at runtime or you need to
declare the click behavior in a {@link android.app.Fragment} subclass.</p>

<p>To declare the event handler programmatically, create an {@link
android.widget.CompoundButton.OnCheckedChangeListener} object and assign it to the button by calling
{@link
android.widget.CompoundButton#setOnCheckedChangeListener}. For example:</p>

<pre>
ToggleButton toggle = (ToggleButton) findViewById(R.id.togglebutton);
toggle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        if (isChecked) {
            // The toggle is enabled
        } else {
            // The toggle is disabled
        }
    }
});
</pre>