Android Floating activity with dismiss on swipe

Question

The latest Facebook's android app has a very nice floating comment window. There the user can dismiss the window swiping up or down making it really ease to use.

I want to implement a similar behaviour in my app but I don't know how to do it. Any idea or clue about how to do it will be really appreciated.

Screenshots of the Facebook app
(sorry, the Facebook app from where I took the screenshots is in Japanese)

Answer 1

I write some code that match this closing/resizing behaviour, I don't know if it's the way to go but my code is based on Activity class. First thing I do is create an activity and give it Transluscenttheme to get an activity with transparent background.

In my manifest.xml :

<activity
    android:name=".PopupActivity"
    android:label="@string/title_activity_popup"
    <!-- Use Translucent theme to get transparent activity background 
     and NoTitleBar to avoid super old style title bar ;) -->
    android:theme="@android:style/Theme.Translucent.NoTitleBar">
</activity>

Then I create a simple layout file containing a textview (corresponding to Facebook tchatting part) and a view (corresponding to Facebook "Write your msg"/"send smiley" tab)

my layout/activity_popup.xml :

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/base_popup_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="8dp"
    android:background="@android:color/darker_gray"
    android:layout_marginBottom="124dp">

    <TextView
        android:text="@string/hello_world"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:background="@android:color/black"/>

    <View
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:layout_alignParentBottom="true"
        android:background="@android:color/holo_blue_dark"/>

</RelativeLayout>

Finally I handle touch and move event in my PopupActivity class, I use onTouchListener which provide callback in onTouch method.

PopupActivity

public class PopupActivity extends Activity implements View.OnTouchListener{

    private RelativeLayout baseLayout;

    private int previousFingerPosition = 0;
    private int baseLayoutPosition = 0;
    private int defaultViewHeight;

    private boolean isClosing = false;
    private boolean isScrollingUp = false;
    private boolean isScrollingDown = false;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_popup);
        baseLayout = (RelativeLayout) findViewById(R.id.base_popup_layout);
        baseLayout.setOnTouchListener(this);
    }


    public boolean onTouch(View view, MotionEvent event) {

        // Get finger position on screen
        final int Y = (int) event.getRawY();

        // Switch on motion event type
        switch (event.getAction() & MotionEvent.ACTION_MASK) {

            case MotionEvent.ACTION_DOWN:
                // save default base layout height
                defaultViewHeight = baseLayout.getHeight();

                // Init finger and view position
                previousFingerPosition = Y;
                baseLayoutPosition = (int) baseLayout.getY();
                break;

            case MotionEvent.ACTION_UP:
                // If user was doing a scroll up
                if(isScrollingUp){
                    // Reset baselayout position
                    baseLayout.setY(0);
                    // We are not in scrolling up mode anymore
                    isScrollingUp = false;
                }

                // If user was doing a scroll down
                if(isScrollingDown){
                    // Reset baselayout position
                    baseLayout.setY(0);
                    // Reset base layout size
                    baseLayout.getLayoutParams().height = defaultViewHeight;
                    baseLayout.requestLayout();
                    // We are not in scrolling down mode anymore
                    isScrollingDown = false;
                }
                break;
            case MotionEvent.ACTION_MOVE:
                if(!isClosing){
                    int currentYPosition = (int) baseLayout.getY();

                    // If we scroll up
                    if(previousFingerPosition >Y){
                        // First time android rise an event for "up" move
                        if(!isScrollingUp){
                            isScrollingUp = true;
                        }

                    // Has user scroll down before -> view is smaller than it's default size -> resize it instead of change it position
                    if(baseLayout.getHeight()<defaultViewHeight){
                        baseLayout.getLayoutParams().height = baseLayout.getHeight() - (Y - previousFingerPosition);
                        baseLayout.requestLayout();
                    }
                    else {
                        // Has user scroll enough to "auto close" popup ?
                        if ((baseLayoutPosition - currentYPosition) > defaultViewHeight / 4) {
                            closeUpAndDismissDialog(currentYPosition);
                            return true;
                        }

                        //
                    }
                    baseLayout.setY(baseLayout.getY() + (Y - previousFingerPosition));

                }
                // If we scroll down
                else{

                    // First time android rise an event for "down" move
                    if(!isScrollingDown){
                        isScrollingDown = true;
                    }

                    // Has user scroll enough to "auto close" popup ?
                    if (Math.abs(baseLayoutPosition - currentYPosition) > defaultViewHeight / 2)
                    {
                        closeDownAndDismissDialog(currentYPosition);
                        return true;
                    }

                    // Change base layout size and position (must change position because view anchor is top left corner)
                    baseLayout.setY(baseLayout.getY() + (Y - previousFingerPosition));
                    baseLayout.getLayoutParams().height = baseLayout.getHeight() - (Y - previousFingerPosition);
                    baseLayout.requestLayout();
                }

                // Update position
                previousFingerPosition = Y;
            }
            break;
        }
        return true;
    }
}

There are two small methods called when user has scroll enough to close popup (ie animate and finish activity) :

public void closeUpAndDismissDialog(int currentPosition){
    isClosing = true;
    ObjectAnimator positionAnimator = ObjectAnimator.ofFloat(baseLayout, "y", currentPosition, -baseLayout.getHeight());
    positionAnimator.setDuration(300);
    positionAnimator.addListener(new Animator.AnimatorListener()
    {
        . . .
        @Override
        public void onAnimationEnd(Animator animator)
        {
            finish();
        }
        . . .
    });
    positionAnimator.start();
}

public void closeDownAndDismissDialog(int currentPosition){
    isClosing = true;
    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    int screenHeight = size.y;
    ObjectAnimator positionAnimator = ObjectAnimator.ofFloat(baseLayout, "y", currentPosition, screenHeight+baseLayout.getHeight());
    positionAnimator.setDuration(300);
    positionAnimator.addListener(new Animator.AnimatorListener()
     {
        . . .
        @Override
        public void onAnimationEnd(Animator animator)
        {
            finish();
        }
        . . .
    });
    positionAnimator.start();
}

With all this code your should be able to start PopupActivity that globally match Facebook popup behaviour. It's just a draft class and a lot of work remains to do : add animations, work on closing parameters and so on...

Screenshots :