A simple FloatActionMenu implementation using design support FloatActionButton

fab_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<net.andersonribeiro.customviews.FloatActionMenu xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/floating_action_menu"
    style="@style/AppTheme.FloatActionMenu"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <View
        android:tag="background"
        style="@style/AppTheme.FloatActionMenu.Background"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

    <TextView
        android:id="@+id/label_action4"
        style="@style/AppTheme.FloatActionMenu.Label.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toLeftOf="@+id/fab_action4"
        android:layout_alignTop="@+id/fab_action4"
        android:text="New Collection"/>
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_action4"
        style="@style/AppTheme.FloatActionMenu.FloatActionButton.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/fab_action3"
        android:layout_alignLeft="@+id/fab_action1" />

    <TextView
        android:id="@+id/label_action3"
        style="@style/AppTheme.FloatActionMenu.Label.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toLeftOf="@+id/fab_action3"
        android:layout_alignTop="@+id/fab_action3"
        android:text="Invite People"/>
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_action3"
        style="@style/AppTheme.FloatActionMenu.FloatActionButton.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/fab_action2"
        android:layout_alignLeft="@+id/fab_action1" />

    <TextView
        android:id="@+id/label_action2"
        style="@style/AppTheme.FloatActionMenu.Label.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toLeftOf="@+id/fab_action2"
        android:layout_alignTop="@+id/fab_action2"
        android:text="Create Team"/>
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_action2"
        style="@style/AppTheme.FloatActionMenu.FloatActionButton.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/fab_action1"
        android:layout_alignLeft="@+id/fab_action1" />

    <TextView
        android:id="@+id/label_action1"
        style="@style/AppTheme.FloatActionMenu.Label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toLeftOf="@+id/fab_action1"
        android:layout_alignTop="@+id/fab_action1"
        android:text="Create Post"/>
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_action1"
        style="@style/AppTheme.FloatActionMenu.FloatActionButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        />
</net.andersonribeiro.customviews.FloatActionMenu>

FloatActionMenu.java

package net.andersonribeiro.customviews;

import android.animation.Animator;
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.support.design.widget.FloatingActionButton;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewAnimationUtils;
import android.view.animation.OvershootInterpolator;
import android.widget.RelativeLayout;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class FloatActionMenu extends RelativeLayout {
    private static final int CIRCULAR_ANIMATION_DURATION = 450;
    private static final int ANIMATION_DURATION = 150;
    private static final int LAST_ANIMATION_DELAY = 120;

    private OnClickListener onOptionMenuClickListener;
    private OnClickListener onOptionMenuClickListenerWrapper = new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (onOptionMenuClickListener != null) {
                    hide(true);
                    onOptionMenuClickListener.onClick(v);
                }
            }
        };

    private View viewBackground;
    private List<TextView> labels = new ArrayList<>();
    private FloatingActionButton fabMenu;
    private List<FloatingActionButton> buttons = new ArrayList<>();

    private boolean shown;

    public FloatActionMenu(Context context) {
        super(context);
    }

    public FloatActionMenu(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public FloatActionMenu(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public FloatActionMenu(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();

        viewBackground = findViewWithTag("background");

        int count = getChildCount();
        for(int i=0; i < count; ++i) {
            View child = getChildAt(i);
            if (child instanceof TextView) {
                labels.add((TextView)child);
            } else if (child instanceof FloatingActionButton) {
                buttons.add((FloatingActionButton)child);
            } else if (viewBackground != child) {
                throw new RuntimeException("No supported view type");
            }
        }

        fabMenu = (FloatingActionButton) buttons.get(buttons.size() - 1);
        buttons.remove(fabMenu);

        viewBackground.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                hide(true);
            }
        });

        for (View button : buttons) {
            button.setOnClickListener(onOptionMenuClickListenerWrapper);
        }

        fabMenu.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (shown) {
                    onOptionMenuClickListenerWrapper.onClick(v);
                }
                else {
                    show(true);
                }

            }
        });

        shown = false;

        viewBackground.setVisibility(INVISIBLE);
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
            viewBackground.setAlpha(0);
        }

        hideAfterInflate(labels);
        hideAfterInflate(buttons);
    }

    public void show(boolean animate) {

        if (!shown) {
            shown = true;

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                int centerX = fabMenu.getLeft() + (fabMenu.getMeasuredWidth() / 2);
                int centerY = fabMenu.getTop() + (fabMenu.getMeasuredHeight() / 2);
                int startRadius = 0;
                int endRadius = (int) Math.hypot(centerX, centerY);

                Animator animator = ViewAnimationUtils
                        .createCircularReveal(viewBackground, centerX, centerY, startRadius, endRadius)
                        .setDuration(animate ? CIRCULAR_ANIMATION_DURATION : 0);
                animator.addListener(createAnimationListener(viewBackground, false));
                animator.start();
            }
            else {
                viewBackground.animate()
                        .alpha(1f)
                        .setDuration(animate ? ANIMATION_DURATION : 0)
                        .setListener(createAnimationListener(viewBackground, false))
                        .start();
            }

            Collections.reverse(buttons);
            bubbleViews(animate, buttons);
            Collections.reverse(buttons);

            Collections.reverse(labels);
            bubbleViews(animate, labels);
            Collections.reverse(labels);
        }
    }

    public void hide(boolean animate) {
        if (shown) {
            shown = false;

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                int centerX = fabMenu.getLeft() + (fabMenu.getMeasuredWidth() / 2);
                int centerY = fabMenu.getTop() + (fabMenu.getMeasuredHeight() / 2);
                int startRadius = (int) Math.hypot(centerX, centerY);
                int endRadius = 0;

                Animator animator = ViewAnimationUtils
                        .createCircularReveal(viewBackground, centerX, centerY, startRadius, endRadius)
                        .setDuration(animate ? CIRCULAR_ANIMATION_DURATION / 2 : 0);
                animator.addListener(createAnimationListener(viewBackground, true));
                animator.start();
            }
            else {
                viewBackground.animate()
                        .alpha(0)
                        .setDuration(animate ? ANIMATION_DURATION : 0)
                        .setListener(createAnimationListener(viewBackground, true))
                        .start();
            }

            hideViews(animate, buttons);
            hideViews(animate, labels);
        }
    }

    public void setOnOptionMenuClickListener(OnClickListener onOptionMenuClickListener) {
        this.onOptionMenuClickListener = onOptionMenuClickListener;
    }

    public boolean isShown() {
        return shown;
    }

    private static <T extends View> void bubbleViews(boolean animate, List<T> views) {
        int length = views.size() - 1;
        int index = 0;
        for (View view : views) {
            view.animate()
                    .alpha(1f)
                    .scaleX(1f)
                    .scaleY(1f)
                    .setDuration(animate ? ANIMATION_DURATION : 0)
                    .setStartDelay(animate ? ((LAST_ANIMATION_DELAY / length) * index) : 0)
                    .setListener(createAnimationListener(view, false))
                    .setInterpolator(new OvershootInterpolator())
                    .start();
            index++;
        }
    }

    private static <T extends View> void hideViews(boolean animate, List<T> views) {
        int length = views.size() - 1;
        int index = 0;
        for (final View view : views) {
            view.animate()
                    .alpha(0)
                    .scaleX(0)
                    .scaleY(0)
                    .setDuration(animate ? ANIMATION_DURATION : 0)
                    .setStartDelay(animate ? ((LAST_ANIMATION_DELAY / length) * index) : 0)
                    .setListener(createAnimationListener(view, true))
                    .start();
            index++;
        }
    }

    private static <T extends View> void hideAfterInflate(List<T> views) {
        for (View view : views) {
            view.setVisibility(INVISIBLE);
            view.setAlpha(0);
            view.setScaleX(0);
            view.setScaleY(0);
        }
    }

    private static Animator.AnimatorListener createAnimationListener(final View view, final boolean hide) {
        return new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {
                view.setVisibility(VISIBLE);
            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (hide) {
                    view.setVisibility(INVISIBLE);
                }
            }

            @Override
            public void onAnimationCancel(Animator animation) {

            }

            @Override
            public void onAnimationRepeat(Animator animation) {

            }
        };
    }
}