tooltipの作成方法について

package com.example.kanemoto.samplecoachmarks;

import android.app.Activity;
import android.content.Context;
import android.databinding.DataBindingUtil;
import android.databinding.ViewDataBinding;
import android.graphics.Color;
import android.graphics.Rect;
import android.hardware.camera2.CameraManager;
import android.support.annotation.ColorRes;
import android.support.annotation.IntDef;
import android.support.v4.content.ContextCompat;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.Window;
import android.view.animation.Animation;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.example.kanemoto.samplecoachmarks.databinding.WidgetCoachTooltipBinding;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.ArrayList;
import java.util.List;

import kotlin.jvm.functions.Function0;
import kotlin.jvm.functions.Function1;

class CoachMark {
private static final int ROOT_TOP = 1;
private static final int ROOT_BOTTOM = 2;
private static final int ROOT_CENTER = 3;

private static final int TARGET_TOP = 4;
private static final int TARGET_BOTTOM = 5;
private static final int TARGET_TOP_LEFT = 6;
private static final int TARGET_BOTTOM_LEFT = 7;
private static final int TARGET_TOP_RIGHT = 8;
private static final int TARGET_BOTTOM_RIGHT = 9;
private static final int TARGET_FILL_IN = 10;
private static final int TARGET_LEFT = 11;
private static final int TARGET_RIGHT = 12;

private static final int POINTER_RIGHT = 1;
private static final int POINTER_MIDDLE = 2;
private static final int POINTER_LEFT = 3;
private static final int POINTER_GONE = 4;

public static final double CIRCLE_ADDITIONAL_RADIUS_RATIO = 1.5D;

@IntDef({ROOT_TOP, ROOT_CENTER, ROOT_BOTTOM, TARGET_TOP, TARGET_BOTTOM,
        TARGET_TOP_LEFT, TARGET_BOTTOM_LEFT, TARGET_TOP_RIGHT, TARGET_BOTTOM_RIGHT,
        TARGET_FILL_IN, TARGET_LEFT, TARGET_RIGHT})
@Retention(RetentionPolicy.SOURCE)
public @interface TooltipAlignment {
}

@IntDef({POINTER_RIGHT, POINTER_MIDDLE, POINTER_LEFT, POINTER_GONE})
@Retention(RetentionPolicy.SOURCE)
public @interface PointerTooltipAlignment {
}

private final int animDuration;
private final Activity activity;
private final FrameLayout container;
private int tooltipAlignment;
private int tooltipPointerAlignment;
private final int overlayPadding;
private final int tooltipMargin;
private final int backgroundColorResource;
private final int radius;
private final boolean dismissible;
private final boolean isCircleMark;
private boolean isShow;
private final float backgroundAlpha;
private CoachMarkOverlay coachMarkOverlay;
private final View targetView;
private View.OnClickListener targetOnClick;
private final Function0 onDismissListener;
private final Function0 onAfterDismissListener;
private final Animation tooltipShowAnimation;
private final Animation tooltipDismissAnimation;
private final WidgetCoachTooltipBinding tooltipBinding;
private final List<View> tooltipChild;

CoachMark(Builder builder) {
    this.activity = builder.activity;
    this.container = new FrameLayout(this.activity);
    this.backgroundColorResource = builder.backgroundColor;
    this.isCircleMark = builder.isCircleMark;
    this.targetView = builder.target;
    this.overlayPadding = ViewUtils.dpToPx(this.activity, builder.markerPadding);
    this.dismissible = builder.dismissible;
    this.tooltipAlignment = builder.tooltipAlignment;
    this.tooltipPointerAlignment = builder.pointerTooltipAlignment;
    this.tooltipMargin = ViewUtils.dpToPx(this.activity, builder.tooltipMargin);
    this.onDismissListener = builder.onDismissListener;
    this.onAfterDismissListener = builder.onAfterDismissListener;
    this.tooltipShowAnimation = builder.tooltipShowAnimation;
    this.tooltipDismissAnimation = builder.tooltipDismissAnimation;
    this.radius = builder.radius;
    this.backgroundAlpha = builder.backgroundAlpha;
    this.tooltipChild = builder.tooltipChilds;

    LayoutInflater layoutInflater = LayoutInflater.from(activity);
    tooltipBinding = DataBindingUtil.inflate(layoutInflater, R.layout.widget_coach_tooltip, container, false);

    View tooltipView = tooltipBinding.getRoot();
    tooltipView.setBackgroundColor(builder.tooltipBackgroundColor);

    Window window = activity.getWindow();
    if (window != null) {
        ViewGroup decorView = (ViewGroup) window.getDecorView();
        FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(
                FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT);
        container.setBackgroundColor(Color.TRANSPARENT);

        decorView.addView(container, layoutParams);
        coachMarkOverlay = new CoachMarkOverlay(activity);
        coachMarkOverlay.setBackgroundResource(backgroundColorResource);
        coachMarkOverlay.setAlpha(backgroundAlpha);
        container.addView(coachMarkOverlay, layoutParams);
        container.addView(tooltipView);
    }

    animDuration = container.getResources().getInteger(android.R.integer.config_longAnimTime);
    container.setClickable(true);
    container.setVisibility(View.GONE);
    container.setAlpha(0.0f);

    addTarget();
}

private void setTooltipAlignment(@TooltipAlignment int tooltipAlignment,
                                 @PointerTooltipAlignment int pointerTooltipAlignment) {
    this.tooltipAlignment = tooltipAlignment;
    this.tooltipPointerAlignment = pointerTooltipAlignment;
    tooltipBinding.getRoot().getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
        @Override
        public boolean onPreDraw() {
            relocationTooltip(targetView, CoachMark.this.tooltipAlignment);
            pointerTooltipAlignment(targetView, CoachMark.this.tooltipPointerAlignment);
            tooltipBinding.getRoot().getViewTreeObserver().removeOnPreDrawListener(this);
            return false;
        }
    });
}

private void addTarget() {
    if (targetView == null) {
        throw new IllegalArgumentException("");
    } else {
        targetView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
            @Override
            public boolean onPreDraw() {
                addRoundRect(targetView);
                setTooltipAlignment(tooltipAlignment, tooltipPointerAlignment)
                targetView.getViewTreeObserver().removeOnPreDrawListener(this);
                return false;
            }
        });
    }
}

private void addRoundRect(View view) {
    Rect rect = new Rect();
    view.getGlobalVisibleRect(rect);
    int radius = this.radius;

    int x = rect.left;
    int y = rect.top;
    int width = rect.width();
    int height = rect.height();
    addTargetClick(rect, view);
    coachMarkOverlay.setBackgroundResource(backgroundColorResource)
    coachMarkOverlay.alpha = backgroundAlpha
    coachMarkOverlay.addRect(x, y, width, height, radius, overlayPadding, isCircleMark)
    coachMarkOverlay.postInvalidate()
}