Creating Cards

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.

The Wearable UI Library provides implementations of cards specifically designed for wearable devices. This library contains the CardFrame class, which wraps views inside a card-styled frame with a white background, rounded corners, and a light-drop shadow. CardFrame can only contain one direct child, usually a layout manager, to which you can add other views to customize the content inside the card.

You can add cards to your app in two ways:

• Use or extend the CardFragment class.
• Add a card inside a CardScrollView in your layout.

Note: 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 Adding Wearable Features to Notifications.

Create a Card Fragment

The CardFragment 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.

Figure 1. The default CardFragment layout.

To add a CardFragment to your app:

1. In your layout, assign an ID to the element that contains the card
2. Create a CardFragment instance in your activity
3. Use the fragment manager to add the CardFragment instance to its container

The following sample code shows the code for the screen display shown in Figure 1:

<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">

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

    </FrameLayout>
</android.support.wearable.view.BoxInsetLayout>

The following code adds the CardFragment instance to the activity in Figure 1:

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();
}

To create a card with a custom layout using CardFragment, extend this class and override its onCreateContentView method.

Add a CardFrame to Your Layout

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.

Figure 2. Adding a CardFrame to your layout.

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.

<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">

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

        <android.support.wearable.view.CardFrame
            android:layout_height="wrap_content"
            android:layout_width="fill_parent">

            <LinearLayout
                android:layout_height="wrap_content"
                android:layout_width="match_parent"
                android:orientation="vertical"
                android:paddingLeft="5dp">
                <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"/>
                <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"/>
            </LinearLayout>
        </android.support.wearable.view.CardFrame>
    </android.support.wearable.view.CardScrollView>
</android.support.wearable.view.BoxInsetLayout>

The CardScrollView 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:

@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);
}

CardScrollView 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 CardScrollView element inside a BoxInsetLayout and using the layout_box="bottom" attribute is useful to align the card to the bottom of round screens without cropping its content.