How to detect that the DrawerLayout started openin

问题:

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.

mDrawerToggle = new ActionBarDrawerToggle(
        this,                 
        mDrawerLayout,        
        R.drawable.ic_drawer,  
        R.string.drawer_open,  
        R.string.drawer_close  
) {
    @Override
    public void onDrawerClosed(View view) {
        invalidateOptionsMenu(); 
        setActionBarMode(ActionBar.NAVIGATION_MODE_TABS);
    }

    @Override
    public void onDrawerOpened(View drawerView) {
        invalidateOptionsMenu(); 
        setActionBarMode(ActionBar.NAVIGATION_MODE_STANDARD);
    }

};
mDrawerLayout.setDrawerListener(mDrawerToggle);

Here's what I tried:

• Setting an onClickListener to mDrawerLayout. onClick never gets called
• Setting an onTouchListener to mDrawerLayout. onTouch never gets called
• Researched ActionBarDrawerToggle and DrawerLayout classes. Could not find anything like onDrawerStartedOpening.

回答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);

回答2:

Currently accepted answer by Pavel Dudka is already deprecated. Please use mDrawerLayout.addDrawerListener() method instead to set a listener.

mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerLayout.addDrawerListener(new DrawerLayout.DrawerListener() {

        @Override
        public void onDrawerSlide(View drawerView, float slideOffset) {
            //Called when a drawer's position changes.
        }

        @Override
        public void onDrawerOpened(View drawerView) {
            //Called when a drawer has settled in a completely open state.
            //The drawer is interactive at this point.
            // If you have 2 drawers (left and right) you can distinguish 
            // them by using id of the drawerView. int id = drawerView.getId(); 
            // id will be your layout's id: for example R.id.left_drawer            
        }

        @Override
        public void onDrawerClosed(View drawerView) {
            // Called when a drawer has settled in a completely closed state.
        }

        @Override
        public void onDrawerStateChanged(int newState) {
            // Called when the drawer motion state changes. The new state will be one of STATE_IDLE, STATE_DRAGGING or STATE_SETTLING.
        }
    });

Works perfectly. Cheers!

回答3:

try to override a method of DrawerLayout.DrawerListener

@Override
public void onDrawerStateChanged(int newState) {
    if( newState == DrawerLayout.STATE_DRAGGING && isDrawerOpen() == false ) {
        // this where Drawer start opening
    }
}

回答4:

drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close){
      @Override
      public void onDrawerOpened(View drawerView) {
           super.onDrawerOpened(drawerView);
           app.sendScreenView("Menu");
      }
};
drawer.setDrawerListener(toggle);
toggle.syncState();

It's the best way.

回答5:

fookwood answer did not work for me but slight modification in the if statment did the trick)

ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, navigationDrawerLayout, topToolbar,
                R.string.open_drawer, R.string.close_drawer) {
            @Override public void onDrawerStateChanged(int newState) {
                if (newState == DrawerLayout.STATE_SETTLING && !navigationDrawerLayout.isDrawerOpen(navigationDrawerView)) {
                    // this where Drawer start opening
}

回答6:

Up-to-date solution:

As others have suggested, the current answer is outdated and it's advised to use mDrawerLayout.addDrawerListener(). A working solution would then be:

mDrawerLayout.addDrawerListener(new DrawerLayout.SimpleDrawerListener() {
        @Override
        public void onDrawerStateChanged(int newState) {
            if (newState == DrawerLayout.STATE_SETTLING && !mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
                // Drawer started opening
            }
        }
    });

Naturally, replace GravityCompat.START with whatever identifies your drawer (layout ID or its gravity ~ location).

Also, if you want to detect when the drawer starts closing, you can simply do:

mDrawerLayout.addDrawerListener(new DrawerLayout.SimpleDrawerListener() {
        @Override
        public void onDrawerStateChanged(int newState) {
            if (newState == DrawerLayout.STATE_SETTLING) {
                if (!mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
                    // Drawer started opening
                } else {
                    // Drawer started closing
                }
            }
        }
    });

回答7:

For Kotlin

var toggle = object : ActionBarDrawerToggle(this,
                drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close) {

            override fun onDrawerOpened(drawerView: View) {
                super.onDrawerOpened(drawerView)
            }
        }