android_frameworks_base/docs/html/training/keyboard-input/visibility.jd

page.title=Handling Input Method Visibility

trainingnavtop=true

@jd:body

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<h2>This lesson teaches you to</h2>
<ol>
  <li><a href="#ShowOnStart">Show the Input Method When the Activity Starts</a></li>
  <li><a href="#ShowOnDemand">Show the Input Method On Demand</a></li>
  <li><a href="#Respond">Specify How Your UI Should Respond</a></li>
</ol>

</div>
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<p>When input focus moves into or out of an editable text field, Android shows
or hides the input method (such as the on-screen keyboard) as appropriate.
The system also makes decisions about
how your UI and the text field appear above the input method. For example, when the vertical
space on the screen is constrained, the text field might fill all space above the input method.
For most apps, these default behaviors are all that's needed.</p>

<p>In some cases, though, you might want to more directly control
the visibility of the input method and specify how you'd like your layout to appear
when the input method is visible. This lesson explains how to control and respond to
the input method visibility.</p>


<h2 id="ShowOnStart">Show the Input Method When the Activity Starts</h2>

<p>Although Android gives focus to the first text field in your layout
when the activity starts, it does not show the input method. This behavior is appropriate because
entering text might not be the primary task in the activity. However, if entering
text is indeed the primary task (such as in a login screen), then you probably want
the input method to appear by default.</p>

<p>To show the input method when your activity starts, add the <a
href="{@docRoot}guide/topics/manifest/activity-element.html#wsoft">{@code
android:windowSoftInputMode}</a> attribute to the {@code &lt;activity>} element with the
{@code "stateVisible"} value. For example:</p>

<pre>
&lt;application ... >
    &lt;activity
        android:windowSoftInputMode="stateVisible" ... >
        ...
    &lt;/activity>
    ...
&lt;/application>
</pre>

<p class="note"><strong>Note:</strong> If the user's device has an attached hardware keyboard,
the soft input method <em>does not</em> appear.</p>


<h2 id="ShowOnDemand">Show the Input Method On Demand</h2>

<p>If there is a method in your activity's lifecycle where you want to ensure that
the input method is visible, you can use the {@link android.view.inputmethod.InputMethodManager}
to show it.</p>

<p>For example, the following method takes a {@link android.view.View} in which the user should type
something, calls {@link android.view.View#requestFocus requestFocus()} to give it focus, then
{@link android.view.inputmethod.InputMethodManager#showSoftInput showSoftInput()} to open
the input method:</p>

<pre>
public void showSoftKeyboard(View view) {
    if (view.requestFocus()) {
        InputMethodManager imm = (InputMethodManager)
                getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.showSoftInput(view, InputMethodManager.SHOW_IMPLICIT);
    }
}
</pre>

<p class="note"><strong>Note:</strong>
Once the input method is visible, you should not programmatically hide it. The system
hides the input method when the user finishes the task in the text field or the user can hide
it with a system control (such as with the <em>Back</em> button).</p>




<h2 id="Respond">Specify How Your UI Should Respond</h2>

<p>When the input method appears on the screen, it reduces the amount of space available
for your app's UI. The system makes a decision as to how it should adjust the visible portion
of your UI, but it might not get it right. To ensure the best behavior for your app,
you should specify how you'd like the system to display your UI in the remaining space.</p>

<p>To declare your preferred treatment in an activity, use the <a
href="{@docRoot}guide/topics/manifest/activity-element.html#wsoft">{@code
android:windowSoftInputMode}</a> attribute in your manifest's {@code &lt;activity>} element
with one of the "adjust" values.</p>

<p>For example, to ensure that the system resizes your layout to the available space&mdash;which
ensures that all of your layout content is accessible (even though it probably requires
scrolling)&mdash;use {@code "adjustResize"}:</p>

<pre>
&lt;application ... >
    &lt;activity
        android:windowSoftInputMode="adjustResize" ... >
        ...
    &lt;/activity>
    ...
&lt;/application>
</pre>

<p>You can combine the adjustment specification with the <a
href="#ShowOnStart">initial input method visibility</a> specification from above:</p>

<pre>
    &lt;activity
        android:windowSoftInputMode="stateVisible|adjustResize" ... >
        ...
    &lt;/activity>
</pre>


<p>Specifying {@code "adjustResize"} is important if your UI includes controls that the
user might need to access immediately after or while performing text input. For example,
if you use a relative layout to place a button bar at the bottom of the screen, using
{@code "adjustResize"} resizes the layout so the button bar appears above the input method.</p>