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      1 page.title=Toggle Buttons
      2 page.tags=switch,togglebutton
      3 @jd:body
      4 
      5 <div id="qv-wrapper">
      6 <div id="qv">
      7 <h2>In this document</h2>
      8 <ol>
      9   <li><a href="#HandlingEvents">Responding to Click Events</a>
     10     <ol>
     11       <li><a href="#ClickListener">Using an OnCheckedChangeListener</a></li>
     12     </ol>
     13   </li>
     14 </ol>
     15   <h2>Key classes</h2>
     16   <ol>
     17     <li>{@link android.widget.ToggleButton}</li>
     18     <li>{@link android.widget.Switch}</li>
     19   </ol>
     20 </div>
     21 </div>
     22 
     23 <p>A toggle button allows the user to change a setting between two states.</p>
     24 
     25 <p>You can add a basic toggle button to your layout with the {@link android.widget.ToggleButton}
     26 object. Android 4.0 (API level 14) introduces another kind of toggle button called a switch that
     27 provides a slider control, which you can add with a {@link android.widget.Switch} object.</p>
     28 
     29 <div style="float:left;width:200px">
     30 <img src="{@docRoot}images/ui/togglebutton.png" alt="" />
     31 <p class="img-caption"><em>Toggle buttons</em></p>
     32 </div>
     33 
     34 <div style="float:left;width:200px;margin-top:24px">
     35 <img src="{@docRoot}images/ui/switch.png" alt="" />
     36 <p class="img-caption"><em>Switches (in Android 4.0+)</em></p>
     37 </div>
     38 
     39 <p style="clear:left">The {@link android.widget.ToggleButton} and {@link android.widget.Switch}
     40 controls are subclasses of {@link android.widget.CompoundButton} and function in the same manner, so
     41 you can implement their behavior the same way.</p>
     42 
     43 <h2 id="HandlingEvents">Responding to Click Events</h2>
     44 
     45 <p>When the user selects a {@link android.widget.ToggleButton} and {@link android.widget.Switch},
     46 the object receives an on-click event.</p>
     47 
     48 <p>To define the click event handler, add the <code><a
     49 href="/reference/android/R.attr.html#onClick">android:onClick</a></code> attribute to the
     50 <code>&lt;ToggleButton&gt;</code> or <code>&lt;Switch&gt;</code> element in your XML
     51 layout. The value for this attribute must be the name of the method you want to call in response
     52 to a click event. The {@link android.app.Activity} hosting the layout must then implement the
     53 corresponding method.</p>
     54 
     55 <p>For example, here's a {@link android.widget.ToggleButton} with the <code><a
     56 href="/reference/android/R.attr.html#onClick">android:onClick</a></code> attribute:</p>
     57 
     58 <pre>
     59 &lt;ToggleButton 
     60     android:id="@+id/togglebutton"
     61     android:layout_width="wrap_content"
     62     android:layout_height="wrap_content"
     63     android:textOn="Vibrate on"
     64     android:textOff="Vibrate off"
     65     android:onClick="onToggleClicked"/>
     66 </pre>
     67 
     68 <p>Within the {@link android.app.Activity} that hosts this layout, the following method handles the
     69 click event:</p>
     70 
     71 <pre>
     72 public void onToggleClicked(View view) {
     73     // Is the toggle on?
     74     boolean on = ((ToggleButton) view).isChecked();
     75     
     76     if (on) {
     77         // Enable vibrate
     78     } else {
     79         // Disable vibrate
     80     }
     81 }
     82 </pre>
     83 
     84 <p>The method you declare in the {@link android.R.attr#onClick android:onClick} attribute
     85 must have a signature exactly as shown above. Specifically, the method must:</p>
     86 <ul>
     87   <li>Be public</li>
     88   <li>Return void</li>
     89   <li>Define a {@link android.view.View} as its only parameter (this will be the {@link
     90 android.view.View} that was clicked)</li>
     91 </ul>
     92 
     93 <p class="note"><strong>Tip:</strong> If you need to change the state
     94 yourself,
     95 use the {@link android.widget.CompoundButton#setChecked(boolean)} or {@link
     96 android.widget.CompoundButton#toggle()} method to change the state.</p>
     97 
     98 
     99 
    100 <h3 id="ClickListener">Using an OnCheckedChangeListener</h3>
    101 
    102 <p>You can also declare a click event handler programmatically rather than in an XML layout. This
    103 might be necessary if you instantiate the {@link android.widget.ToggleButton} or {@link
    104 android.widget.Switch} at runtime or you need to
    105 declare the click behavior in a {@link android.app.Fragment} subclass.</p>
    106 
    107 <p>To declare the event handler programmatically, create an {@link
    108 android.widget.CompoundButton.OnCheckedChangeListener} object and assign it to the button by calling
    109 {@link
    110 android.widget.CompoundButton#setOnCheckedChangeListener}. For example:</p>
    111 
    112 <pre>
    113 ToggleButton toggle = (ToggleButton) findViewById(R.id.togglebutton);
    114 toggle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
    115     public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    116         if (isChecked) {
    117             // The toggle is enabled
    118         } else {
    119             // The toggle is disabled
    120         }
    121     }
    122 });
    123 </pre>
    124