public void openDrawer(@NonNull View drawerView, boolean animate) {
        if (!isDrawerView(drawerView)) {
            throw new IllegalArgumentException("View " + drawerView + " is not a sliding drawer");
        }

        final LayoutParams lp = (LayoutParams) drawerView.getLayoutParams();
        if (mFirstLayout) {
            lp.onScreen = 1.f;
            lp.openState = LayoutParams.FLAG_IS_OPENED;

            updateChildrenImportantForAccessibility(drawerView, true);
        } else if (animate) {
            lp.openState |= LayoutParams.FLAG_IS_OPENING;

            if (checkDrawerViewAbsoluteGravity(drawerView, Gravity.TOP)) {
                mTopDragger.smoothSlideViewTo(drawerView, drawerView.getLeft(), 0);
            } else {
                mBottomDragger.smoothSlideViewTo(drawerView, drawerView.getLeft(),
                        getHeight() - drawerView.getHeight());
            }
        } else {
            moveDrawerToOffset(drawerView, 1.f);
            updateDrawerState(lp.gravity, STATE_IDLE, drawerView);
            drawerView.setVisibility(VISIBLE);
        }
        invalidate();
    }
Open the specified drawer view.

@param drawerView Drawer view to open
@param animate    Whether opening of the drawer should be animated.
app/src/main/java/com/sunnyweather/android/ui/customerUIs/HomeDrawerLayout.java