| 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><ToggleButton></code> or <code><Switch></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> |
| <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> |