<resources>
  <declare-styleable name="ArrowRectangleView">
    <attr name="arrow_width" format="dimension" />
    <attr name="arrow_height" format="dimension" />
    <attr name="arrow_offset" format="dimension" />
    <attr name="radius" format="dimension" />
    <attr name="background_color" format="color" />
    <attr name="shadow_color" format="color" />
    <attr name="shadow_thickness" format="dimension" />
  </declare-styleable>
</resources> 

 public class ArrowRectangleView extends ViewGroup {
  ... ...
  public ArrowRectangleView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
        R.styleable.ArrowRectangleView, defStyleAttr, 0);
    for (int i = 0; i < a.getIndexCount(); i++) {
      int attr = a.getIndex(i);
      switch (attr) {
        case R.styleable.ArrowRectangleView_arrow_width:
          mArrowWidth = a.getDimensionPixelSize(attr, mArrowWidth);
          break;
        case R.styleable.ArrowRectangleView_arrow_height:
          mArrowHeight = a.getDimensionPixelSize(attr, mArrowHeight);
          break;
        case R.styleable.ArrowRectangleView_radius:
          mRadius = a.getDimensionPixelSize(attr, mRadius);
          break;
        case R.styleable.ArrowRectangleView_background_color:
          mBackgroundColor = a.getColor(attr, mBackgroundColor);
          break;
        case R.styleable.ArrowRectangleView_arrow_offset:
          mArrowOffset = a.getDimensionPixelSize(attr, mArrowOffset);
          break;
        case R.styleable.ArrowRectangleView_shadow_color:
          mShadowColor = a.getColor(attr, mShadowColor);
          break;
        case R.styleable.ArrowRectangleView_shadow_thickness:
          mShadowThickness = a.getDimensionPixelSize(attr, mShadowThickness);
          break;
      }
    }
    a.recycle();
  } 

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int count = getChildCount();
    int maxWidth = 0;
    // reserve space for the arrow and round corners
    int maxHeight = mArrowHeight + mRadius;
    for (int i = 0; i < count; i++) {
      final View child = getChildAt(i);
      final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
      if (child.getVisibility() != GONE) {
        measureChild(child, widthMeasureSpec, heightMeasureSpec);
        maxWidth = Math.max(maxWidth, child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
        maxHeight = maxHeight + child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
      }
    }

    maxWidth = maxWidth + getPaddingLeft() + getPaddingRight() + mShadowThickness;
    maxHeight = maxHeight + getPaddingTop() + getPaddingBottom() + mShadowThickness;

    setMeasuredDimension(maxWidth, maxHeight);
  } 

   @Override
  public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
    return new MarginLayoutParams(getContext(), attrs);
  } 

   @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int count = getChildCount();
    int topOffset = t + mArrowHeight + mRadius/2;
    int top = 0;
    int bottom = 0;
    for (int i = 0; i < count; i++) {
      final View child = getChildAt(i);
      top = topOffset + i * child.getMeasuredHeight();
      bottom = top + child.getMeasuredHeight();
      child.layout(l, top, r - mRadius/2 - mShadowThickness, bottom);
    }
  } 

 @Override
  protected void dispatchDraw(Canvas canvas) {
    // disable h/w acceleration for blur mask filter
    setLayerType(View.LAYER_TYPE_SOFTWARE, null);

    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setColor(mBackgroundColor);
    paint.setStyle(Paint.Style.FILL);

    // set Xfermode for source and shadow overlap
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OVER));

    // draw round corner rectangle
    paint.setColor(mBackgroundColor);
    canvas.drawRoundRect(new RectF(0, mArrowHeight, getMeasuredWidth() - mShadowThickness, getMeasuredHeight() - mShadowThickness), mRadius, mRadius, paint);

    // draw arrow
    Path path = new Path();
    int startPoint = getMeasuredWidth() - mArrowOffset;
    path.moveTo(startPoint, mArrowHeight);
    path.lineTo(startPoint + mArrowWidth, mArrowHeight);
    path.lineTo(startPoint + mArrowWidth / 2, 0);
    path.close();
    canvas.drawPath(path, paint);

    // draw shadow
    if (mShadowThickness > 0) {
      paint.setMaskFilter(new BlurMaskFilter(mShadowThickness, BlurMaskFilter.Blur.OUTER));
      paint.setColor(mShadowColor);
      canvas.drawRoundRect(new RectF(mShadowThickness, mArrowHeight + mShadowThickness, getMeasuredWidth() - mShadowThickness, getMeasuredHeight() - mShadowThickness), mRadius, mRadius, paint);
    }

    super.dispatchDraw(canvas);
  } 

 <?xml version="1.0" encoding="utf-8"?>
<com.xinxin.arrowrectanglemenu.widget.ArrowRectangleView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:background="@android:color/transparent"
    android:paddingLeft="3dp"
    android:paddingRight="3dp"
    android:splitMotionEvents="false"
    app:arrow_offset="31dp"
    app:arrow_width="16dp"
    app:arrow_height="8dp"
    app:radius="5dp"
    app:background_color="#ffb1df83"
    app:shadow_color="#66000000"
    app:shadow_thickness="5dp">
  <LinearLayout
    android:id="@+id/cmx_toolbar_menu_turn_off"
    android:layout_width="wrap_content"
    android:layout_height="42dp">
    <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="center_vertical"
      android:textSize="16sp"
      android:textColor="#FF393F4A"
      android:paddingLeft="16dp"
      android:paddingRight="32dp"
      android:clickable="false"
      android:text="Menu Item #1"/>
  </LinearLayout>
  <LinearLayout
    android:id="@+id/cmx_toolbar_menu_feedback"
    android:layout_width="wrap_content"
    android:layout_height="42dp">
    <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="center_vertical"
      android:textSize="16sp"
      android:textColor="#FF393F4A"
      android:paddingLeft="16dp"
      android:paddingRight="32dp"
      android:clickable="false"
      android:text="Menu Item #2"/>
  </LinearLayout>
</com.xinxin.arrowrectanglemenu.widget.ArrowRectangleView>