The Google Glass Explorer Edition SDK is deprecated. This documentation is no longer being maintained. If you're interested in developing Glass solutions for enterprise clients, visit the Google Glass Enterprise Edition developer documentation.

Slider

You can use sliders to show a loading, progress, or navigation bar on the bottom of the screen. Sliders are global UX components and should be treated with care when implementing them in your Glassware.


Scroller Slider

Scroller sliders are used to indicate the position of a card as you swipe through multiple cards. You can create the same type of effect using Slider.Scroller.

  1. Use Slider.from() to create a Slider that uses a View to display the slider.
  2. Create the Slider.Scroller using startScroller() and set the max and initial positions.

Here's a simple implementation that animates a scroller to the next position when the user taps:

public final class SliderActivity extends Activity {

    private static final int MAX_SLIDER_VALUE = 5;
    private static final long ANIMATION_DURATION_MILLIS = 5000;

    private CardScrollView mCardScroller;
    private Slider mSlider;

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        // Create the cards for the view
        mCardScroller = new CardScrollView(this);
        mCardScroller.setAdapter(new CardAdapter(createCards()));

        // Set the view for the Slider
        mSlider = Slider.from(mCardScroller);

        mCardScroller.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                processSliderRequest(position+1);
            }
        });

        setContentView(mCardScroller);
    }

    private void processSliderRequest(position) {
        Slider.Scroller scroller = mSlider.startScroller(MAX_SLIDER_VALUE, 0);

        // Animate the slider to the next position. The slider
        // automatically hides after the duration has elapsed
        ObjectAnimator.ofFloat(scroller, "position", 0, position)
            .setDuration(ANIMATION_DURATION_MILLIS)
            .start();
    }
}

Grace Period Slider

Grace period sliders work in activities where it is useful for a user to see a notification, but user interaction is not required. You can add this animation by using Slider.GracePeriod.

  1. Use Slider.from() to create a Slider that uses a View to display the slider.
  2. Create a GracePeriod.Listener and implement the onGracePeriodEnd() and onGracePeriodCancel() to handle those events.
  3. Create a Slider.GracePeriod and start the animation by passing in the GracePeriod.Listener to the startGracePeriod() method.
  4. Override the activity's onBackPressed() to handle the swipe down gesture.
  5. If the user swipes down, call cancel() on the Slider.GracePeriod to dismiss the slider.

In the following example, the grace period scroller is intiated with a listener that plays a success sound when the period ends and a dismissed sound if the grace period slider is cancelled:

public final class SliderActivity extends Activity {

    ...
    private Slider.GracePeriod mGracePeriod;

    private final GracePeriod.Listener mGracePeriodListener =
        new GracePeriod.Listener() {

        @Override
        public void onGracePeriodEnd() {
            // Play a SUCCESS sound to indicate the end of the grace period.
            AudioManager am = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
            am.playSoundEffect(Sounds.SUCCESS);
            mGracePeriod = null;
        }

        @Override
        public void onGracePeriodCancel() {
            // Play a DIMISS sound to indicate the cancellation of the grace period.
            AudioManager am = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
            am.playSoundEffect(Sounds.DISMISSED);
            mGracePeriod = null;
        }
    };

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        // Create the cards for the view
        mCardScroller = new CardScrollView(this);
        mCardScroller.setAdapter(new CardAdapter(createCards()));

        // Set the view for the Slider
        mSlider = Slider.from(mCardScroller);

        mCardScroller.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                mGracePeriod = mSlider.startGracePeriod(mGracePeriodListener);
            }
        });

        setContentView(mCardScroller);
    }

    @Override
    public void onBackPressed() {
        // If the Grace Period is running,
        // cancel it instead of finishing the Activity.
        if (mGracePeriod != null) {
            mGracePeriod.cancel();
        } else {
            super.onBackPressed();
        }
    }
}

Determinate Slider

Determinate sliders are mainly used to show progress where you can calculate when a task finishes. You can add this animation by using Slider.Determinate.

  1. Use Slider.from() to create a Slider that uses a View to display the slider.
  2. Create the Slider.Determinate using startScroller() and set the max and initial positions.
  3. When the animation finishes, call the hide() method on the Slider.Determinate to hide the slider.

Here's a simple implementation that animates the scroller to a set position when the user taps:

public final class SliderActivity extends Activity {

    ...
    private Slider.Determinate mDeterminate;

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        // Create the cards for the view
        mCardScroller = new CardScrollView(this);
        mCardScroller.setAdapter(new CardAdapter(createCards()));

        // Set the view for the Slider
        mSlider = Slider.from(mCardScroller);

        mCardScroller.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                   int position, long id) {
                mDeterminate = mSlider.startDeterminate(MAX_SLIDER_VALUE, 0);
                ObjectAnimator animator = ObjectAnimator.ofFloat(mDeterminate,
                    "position", 0, MAX_SLIDER_VALUE);

                // Hide the slider when the animation stops.
                animator.addListener(new AnimatorListenerAdapter() {
                    @Override
                    public void onAnimationEnd(Animator animation) {
                        mDeterminate.hide();
                    }
                });

                // Start an animation showing the different positions of the slider.
                animator.setDuration(ANIMATION_DURATION_MILLIS).start();
            }
        });

        setContentView(mCardScroller);
    }
}

Indeterminate Slider

Indeterminate sliders can be used for loading screens where it is difficult to calculate when the task finishes. You can add this animation by using Slider.Indeterminate.

  1. Use Slider.from() to create a Slider that uses a View to display the slider.
  2. Start the animation with the Slider.startIndeterminate() method.
  3. When you are ready to stop the animation, call the hide() method on the Slider.Indeterminate.

Here's a simple implementation that creates the indeterminate scroller when the user taps the card and hides it when the user taps again:

public final class SliderActivity extends Activity {

    ...
    private Slider.Indeterminate mIndeterminate;

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        // Create the cards for the view
        mCardScroller = new CardScrollView(this);
        mCardScroller.setAdapter(new CardAdapter(createCards()));

        // Set the view for the Slider
        mSlider = Slider.from(mCardScroller);

        mCardScroller.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                   int position, long id) {
                // Toggle between showing/hiding the indeterminate slider.
                if (mIndeterminate != null) {
                    mIndeterminate.hide();
                    mIndeterminate = null;
                } else {
                    mIndeterminate = mSlider.startIndeterminate();
                }
        });

        setContentView(mCardScroller);
    }
}