android_frameworks_base/docs/html/training/wearables/ui/cards.jd

page.title=Creating Cards

@jd:body

<div id="tb-wrapper">
<div id="tb">
<h2>This lesson teaches you to</h2>
<ol>
  <li><a href="#card-fragment">Create a Card Fragment</a></li>
  <li><a href="#card-layout">Add a Card to Your Layout</a></li>
</ol>
<h2>You should also read</h2>
<ul>
  <li><a href="{@docRoot}design/wear/index.html">Android Wear Design Principles</a></li>
</ul>
</div>
</div>


<p>Cards present information to users with a consistent look and feel across different apps.
This lesson shows you how to create cards in your Android Wear apps.</p>

<p>The Wearable UI Library provides implementations of cards specifically designed for wearable
devices. This library contains the
<a href="{@docRoot}reference/android/support/wearable/view/CardFrame.html"><code>CardFrame</code></a>
class, which wraps views inside a card-styled frame with a white background, rounded corners, and a
light-drop shadow. A
<a href="{@docRoot}reference/android/support/wearable/view/CardFrame.html"><code>CardFrame</code></a>
instance can only contain one direct child, usually a layout manager, to which
you can add other views to customize the content inside the card.</p>

<p>You can add cards to your app in two ways:</p>

<ul>
  <li>Use or extend the
  <a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
  class.</li>
  <li>Add a card inside a
  <a href="{@docRoot}reference/android/support/wearable/view/CardScrollView.html"><code>CardScrollView</code></a>
  instance in your layout.</li>
</ul>

<p class="note"><strong>Note:</strong> This lesson shows you how to add cards to Android Wear
activities. Android notifications on wearable devices are also displayed as cards. For more
information, see <a href="{@docRoot}training/wearables/notifications/index.html">Adding Wearable
Features to Notifications</a>.</p>


<h2 id="card-fragment">Create a Card Fragment</h2>

<p>The
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
class provides a default card layout with a title, a description, and an icon. Use this approach to
add cards to your app if the default card layout shown in figure 1 meets your needs.</p>

<img src="{@docRoot}wear/images/05_uilib.png" width="500" height="245" alt=""/>
<p class="img-caption"><strong>Figure 1.</strong> The default
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
layout.</p>

<p>To add a
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
instance to your app:</p>

<ol>
<li>In your layout, assign an ID to the element that contains the card</li>
<li>Create a
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
instance in your activity</li>
<li>Use the fragment manager to add the
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
instance to its container</li>
</ol>

<p>The following sample code shows the code for the screen display shown in figure 1:</p>

<pre>
&lt;android.support.wearable.view.BoxInsetLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:background="@drawable/robot_background"
android:layout_height="match_parent"
android:layout_width="match_parent">

    &lt;FrameLayout
        <strong>android:id="@+id/frame_layout"</strong>
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_box="bottom">

    &lt;/FrameLayout>
&lt;/android.support.wearable.view.BoxInsetLayout>
</pre>

<p>The following code adds the
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
instance to the activity in figure 1:</p>

<pre>
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_wear_activity2);

    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    CardFragment cardFragment = CardFragment.create(getString(R.string.cftitle),
                                                    getString(R.string.cfdesc),
                                                    R.drawable.p);
    fragmentTransaction.add(R.id.frame_layout, cardFragment);
    fragmentTransaction.commit();
}
</pre>

<p>To create a card with a custom layout using the
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html"><code>CardFragment</code></a>
class, extend the class and override its
<a href="{@docRoot}reference/android/support/wearable/view/CardFragment.html#onCreateContentView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)"><code>onCreateContentView</code></a>
method.</p>


<h2 id="card-layout">Add a CardFrame to Your Layout</h2>

<p>You can also add a card directly to your layout definition, as shown in figure 2. Use this
approach when you want to define a custom layout for the card inside a layout definition file.</p>

<img src="{@docRoot}wear/images/04_uilib.png" width="500" height="248" alt=""/>
<p class="img-caption"><strong>Figure 2.</strong> Adding a
<a href="{@docRoot}reference/android/support/wearable/view/CardFrame.html"><code>CardFrame</code></a>
to your layout.</p>

<p>The following layout code sample demonstrates a vertical linear layout with two elements. You
can create more complex layouts to fit the needs of your app.</p>

<pre>
&lt;android.support.wearable.view.BoxInsetLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:background="@drawable/robot_background"
android:layout_height="match_parent"
android:layout_width="match_parent">

    &lt;<strong>android.support.wearable.view.CardScrollView</strong>
        android:id="@+id/card_scroll_view"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        app:layout_box="bottom">

        &lt;<strong>android.support.wearable.view.CardFrame</strong>
            android:layout_height="wrap_content"
            android:layout_width="fill_parent">

            &lt;LinearLayout
                android:layout_height="wrap_content"
                android:layout_width="match_parent"
                android:orientation="vertical"
                android:paddingLeft="5dp">
                &lt;TextView
                    android:fontFamily="sans-serif-light"
                    android:layout_height="wrap_content"
                    android:layout_width="match_parent"
                    android:text="@string/custom_card"
                    android:textColor="@color/black"
                    android:textSize="20sp"/>
                &lt;TextView
                    android:fontFamily="sans-serif-light"
                    android:layout_height="wrap_content"
                    android:layout_width="match_parent"
                    android:text="@string/description"
                    android:textColor="@color/black"
                    android:textSize="14sp"/>
            &lt;/LinearLayout>
        &lt;/android.support.wearable.view.CardFrame>
    &lt;/android.support.wearable.view.CardScrollView>
&lt;/android.support.wearable.view.BoxInsetLayout>
</pre>

<p>The
<a href="{@docRoot}reference/android/support/wearable/view/CardScrollView.html><code>&lt;CardScrollView&gt;</code></a>
element in the example layout above lets you assign gravity to
the card when its content is smaller than the container. This example aligns the card to the
bottom of the screen:</p>

<pre>
&#64;Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_wear_activity2);

    CardScrollView cardScrollView =
        (CardScrollView) findViewById(R.id.card_scroll_view);
    cardScrollView.setCardGravity(Gravity.BOTTOM);
}
</pre>

<p>The
<a href="{@docRoot}reference/android/support/wearable/view/CardScrollView.html"><code>&lt;CardScrollView&gt;</code></a>
element detects the shape of the screen and displays the card differently
on round and square devices, using wider side margins on round screens. However,
placing the
<a href="{@docRoot}reference/android/supprot/wearable/view/CardScrollView.html"><code>&lt;CardScrollView&gt;</code></a>
element inside a
<a href="{@docRoot}reference/android/support/wearable/view/BoxInsetLayout.html"><code>&lt;BoxInsetLayout&gt;</code></a>
and using the <code>layout_box="bottom"</code> attribute is useful to align the card to the bottom
of round screens without cropping its content.</p>