How to Code a Navigation Drawer for an Android App

Note that when showing the navigation list items from a menu resource, we could use a ListView instead. But, by configuring the navigation drawer with a menu resource, we get the material design styling on the navigation drawer for free! If you used a ListView, you would have to maintain the list and also style it to meet the recommended material design specs for the navigation drawer. 

3. Initialization of Components

Next, we are going to initialize instances of our DrawerLayout and ActionBarDrawerToggle. Initialization is going to happen inside onCreate() in MainActivity.kt.

import android.content.res.Configuration
import android.os.Bundle
import android.support.v4.widget.DrawerLayout
import android.support.v7.app.ActionBarDrawerToggle
import android.support.v7.app.AppCompatActivity
import android.support.v7.widget.Toolbar
import android.view.MenuItem

class MainActivity : AppCompatActivity() {

    private lateinit var drawer: DrawerLayout
    private lateinit var toggle: ActionBarDrawerToggle

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val toolbar: Toolbar = findViewById(R.id.toolbar_main)
        setSupportActionBar(toolbar)

        drawer = findViewById(R.id.drawer_layout)

        toggle = ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close)
        drawer.addDrawerListener(toggle)
        supportActionBar?.setDisplayHomeAsUpEnabled(true)
        supportActionBar?.setHomeButtonEnabled(true)
    }

    // ... 
}

The ActionBarDrawerToggle sets up the app icon located on the left of the action bar or toolbar to open and close the navigation drawer. To be able to create an instance of ActionBarDrawerToggle, we have to provide the following parameters: 

• a parent context—for example, in an Activity you use this, while in a Fragment you call getActivity()
• an instance of the DrawerLayout widget to link to the activity’s ActionBar
• the icon to place on top of the app icon to indicate that there is a toggle
• the string resources for the open and close operations respectively (for accessibility)

We invoked the method addDrawerListener() on a DrawerLayout so as to connect an ActionBarDrawerToggle with a DrawerLayout. 

Note that we also enable the app icon via setHomeButtonEnabled() and enable it for “up” navigation via setDisplayHomeAsUpEnabled(). 

We then forward the onPostCreate(), onConfigurationChanged(), and onOptionsItemSelected() activity callback methods on to the toggle:

class MainActivity : AppCompatActivity() {

    // ... 

    override fun onPostCreate(savedInstanceState: Bundle?) {
        super.onPostCreate(savedInstanceState)
        toggle.syncState()
    }

    override fun onConfigurationChanged(newConfig: Configuration?) {
        super.onConfigurationChanged(newConfig)
        toggle.onConfigurationChanged(newConfig)
    }

    override fun onOptionsItemSelected(item: MenuItem?): Boolean {
        if (toggle.onOptionsItemSelected(item)) {
            return true
        }
        return super.onOptionsItemSelected(item)
    }
}

Here is what the syncState() does, according to the official documentation: 

Synchronizes the state of the drawer indicator/affordance with the linked DrawerLayout… This should be called from your Activity‘s onPostCreate method to synchronize after the DrawerLayout’s instance state has been restored, and any other time when the state may have diverged in such a way that the ActionBarDrawerToggle was not notified. (For example, if you stop forwarding appropriate drawer events for a period of time.)

4. Testing the App

At this point, we can run the app!

As you can see, launching the app will show the “hamburger” navigation drawer icon in the action bar. Try tapping this app icon to open the drawer. Also, clicking on the navigation drawer items won’t do anything—we’re going to handle that part in the next section. 

5. Handling Click Events

Now, let’s see how to handle click events for each of the items in the navigation drawer. Note that clicking on any item is supposed to take you to a new Activity or Fragment—that’s why it’s called a navigation drawer!

First, your activity needs to implement the NavigationView.OnNavigationItemSelectedListener. 

class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
    // ... 
}

By implementing this contract or interface, we must now override the only method: onNavigationItemSelected(). 

class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
    
    // ... 

    override fun onNavigationItemSelected(item: MenuItem): Boolean {

        when (item.itemId) {
            R.id.nav_item_one -> Toast.makeText(this, "Clicked item one", Toast.LENGTH_SHORT).show()
            R.id.nav_item_two -> Toast.makeText(this, "Clicked item two", Toast.LENGTH_SHORT).show()
            R.id.nav_item_three -> Toast.makeText(this, "Clicked item three", Toast.LENGTH_SHORT).show()
            R.id.nav_item_four -> Toast.makeText(this, "Clicked item four", Toast.LENGTH_SHORT).show()
        }
        return true
    }
}

This method is invoked when an item in the navigation menu is selected. We used the when expression to perform different actions based on the menu item that was clicked—the menu item ids serve as constants for the when expression. 

Next, we have to initialize our NavigationView and set this listener inside onCreate() of our activity. 

class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
    // ...
    override fun onCreate(savedInstanceState: Bundle?) {
        // ... 
        val navigationView: NavigationView = findViewById(R.id.nav_view)
        navigationView.setNavigationItemSelectedListener(this)
        // ... 
    }
// ... 

Run the project again!

When you click on some items, a toast message is displayed—just what we expected. But remember that clicking on an item should take the user to a new Activity or Fragment (we ignored this here for brevity’s sake). 

You will notice that when you click on an item, the drawer still remains. It would be better if it closed automatically anytime an item was clicked. Let’s see how to do that. 

override fun onNavigationItemSelected(item: MenuItem): Boolean {

    when (item.itemId) {
        R.id.nav_item_one -> Toast.makeText(this, "Clicked item one", Toast.LENGTH_SHORT).show()
        R.id.nav_item_two -> Toast.makeText(this, "Clicked item two", Toast.LENGTH_SHORT).show()
        R.id.nav_item_three -> Toast.makeText(this, "Clicked item three", Toast.LENGTH_SHORT).show()
        R.id.nav_item_four -> Toast.makeText(this, "Clicked item four", Toast.LENGTH_SHORT).show()
    }
    drawer.closeDrawer(GravityCompat.START)
    return true
}

To close the drawer after a link has been clicked, simply invoke closeDrawer() on an instance of DrawerLayout and pass GravityCompat.START to the method. 

Run the project one more time and see the result! 

6. Handling the Back Button Being Pressed

When the drawer is open, it would be a better user experience not to close the home activity if the Back button is pressed. This is the way popular apps like Google’s Inbox app work. 

So, when the drawer is open and the Back button is pressed, only close the drawer instead of the current home activity. Then, if the user presses the Back button again, the home activity should be closed. 

Here’s how we can achieve this: 

override fun onBackPressed() {
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START)
    } else {
        super.onBackPressed()
    }
}

Run the project again and test it out! 

7. Bonus: Using Android Studio Templates

Now that you have learnt about the APIs involved to create a navigation drawer, I’ll show you a shortcut that will make it faster next time. You can simply use a template instead of coding a navigation drawer Activity from scratch. 

Android Studio provides code templates that follow the Android design and development best practices. These existing code templates (available in Java and Kotlin) can help you quickly kick-start your project. One such template can be used to create a navigation drawer activity. 

I’ll show you how to use this handy feature in Android Studio. 

For a new project, fire up Android Studio. 

Enter the application name and click the Next button. 

You can leave the defaults as they are in the Target Android Devices dialog. Click the Next button again. 

In the Add an Activity to Mobile dialog, scroll down and select Navigation Drawer Activity. Click the Next button after that. 

In the last dialog, you can rename the Activity name, layout name or title if you want. Finally, click the Finish button to accept all configurations. 

Android Studio has now helped us to create a project with a navigation drawer activity. Really cool!

You are strongly advised to explore the code generated. 

You can use templates for an already existing Android Studio project too. Simply go to File > New > Activity > Navigation Drawer Activity.  

The templates that come included with Android Studio are good for simple layouts and making basic apps, but if you want to kick-start your app even further, you might consider some of the app templates available from Envato Market. 

They’re a huge time saver for experienced developers, helping them to cut through the slog of creating an app from scratch and focus their talents instead on the unique and customised parts of creating a new app.

Conclusion

In this tutorial, you learned how to create a navigation drawer in Android using the DrawerLayout and NavigationView API from scratch. We also explored how to easily and quickly use the Android Studio templates to create a navigation drawer. 

I highly recommend checking out the official material design guidelines for navigation drawers to learn more about how to properly design and use navigation drawers in Android.   

To learn more about coding for Android, check out some of our other courses and tutorials here on Envato Tuts+!

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