How to detect that the DrawerLayout started opening?

Question

So I have tabs that I want to hide when the Navigation Drawer starts opening. The code I have hides them when it finished opening, but it\'s not what I want

Answer 1

There are 2 possible ways to do that:

1) Use onDrawerSlide(View drawerView, float slideOffset) callback

slideOffset changes from 0 to 1. 1 means it is completely open, 0 - closed.

Once offset changes from 0 to !0 - it means it started opening process. Something like:

mDrawerToggle = new ActionBarDrawerToggle(
        this,                 
        mDrawerLayout,        
        R.drawable.ic_drawer,  
        R.string.drawer_open,  
        R.string.drawer_close  
) {

    @Override
    public void onDrawerSlide(View drawerView, float slideOffset) {
        if (slideOffset == 0
                && getActionBar().getNavigationMode() == ActionBar.NAVIGATION_MODE_STANDARD) {
            // drawer closed
            getActionBar()
                    .setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
            invalidateOptionsMenu();
        } else if (slideOffset != 0
                && getActionBar().getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS) {
            // started opening
            getActionBar()
                    .setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
            invalidateOptionsMenu();
        }
        super.onDrawerSlide(drawerView, slideOffset);
    }
};
mDrawerLayout.setDrawerListener(mDrawerToggle);

2) Use onDrawerStateChanged(int newState) callback

You need to listen to STATE_SETTLING states - this state is reported whenever drawer starts moving (either opens or closes). So once you see this state - check whether drawer is opened now and act accordingly:

mDrawerToggle = new ActionBarDrawerToggle(
        this,                 
        mDrawerLayout,        
        R.drawable.ic_drawer,  
        R.string.drawer_open,  
        R.string.drawer_close  
) {
    @Override
    public void onDrawerStateChanged(int newState) {
        if (newState == DrawerLayout.STATE_SETTLING) {
            if (!isDrawerOpen()) {
                // starts opening
                getActionBar()
                        .setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
            } else {
                // closing drawer
                getActionBar()
                        .setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
            }
            invalidateOptionsMenu();
        }
    }
};
mDrawerLayout.setDrawerListener(mDrawerToggle);