Getting started with Android app and material design:Toolbar and Navigation drawer

After all, these two libraries are imported by default when a developer starts a new project using Android Studio.

You can select the schema you like. The first result is shown in the picture below:

Now it is time to create our theme that uses the colors we selected before. The app should support the largest number of smartphones not only those running Lollipop or later.
For this reason, it is necessary to create two themes one for the devices that run Android 5 or later and those that run pre-lollipop version.
So let us create two directories under values:

style
style-v21

The first one is used by all smartphones running pre-Lollipop version while the second folder is used by smartphones with OS starting from Lollipop.
In the first directory let us style.xml:

while in the second directory we simply add:

Finally in the Manifest.xml modify the file:

Android Toolbar

One of the most important components in developing an Android app is the Toolbar. The toolbar plays the role that was played before by Android action bar.The toolbar can be used to hold:

• Navigation button
• App tile and subtitle
• Action menu
• Brand logo

<include layout=”@layout/toolbar”/>

</RelativeLayout>
[/xml]

where toolbar layout is:

Notice at line 5 we set the default height of the toolbar using ?attr/actionBarSize and at line 6 the toolbar background.
In the activity it is necessary to set the toolbar:

Running the example we get:

Add action menu to Toolbar

Once the is configured correctly, it is possible to add action menu or menu items that appear on the Toolbar, to do it under res/menu add a file called main_menu.xml:

<item android:id=”@+id/menu_settings”
android:title=”Settings”
android:icon=”@android:drawable/ic_menu_preferences”
app:showAsAction=”always”
android:orderInCategory=”100″/>

<item android:id=”@+id/menu_help”
android:title=”Help”
android:icon=”@android:drawable/ic_menu_help”
app:showAsAction=”ifRoom”
android:orderInCategory=”110″/>

<item android:id=”@+id/menu_compass”
android:title=”Compass”
android:icon=”@android:drawable/ic_menu_compass”
app:showAsAction=”never”
android:orderInCategory=”105″/>

</menu>
[/xml]

Now in the activity there is:

Running the example the app looks like:

When user selects one of this item the app should detect it and take the right action, to do it it is necessary to override a method:

switch(itemId) {
case R.id.menu_settings:
btnName = “Settings”;
break;
case R.id.menu_compass:
btnName = “Compass”;
break;
case R.id.menu_help:
btnName = “Help”;
break;
}

Snackbar.make(layout, “Button ” + btnName,
Snackbar.LENGTH_SHORT).show();
return true;
}
[/java]

In this case, we simply show an info message using a Snackbar.

Android Navigation drawer

Navigation drawer is one of the most import UI pattern introduced by Google in developing Android app.Navigation drawer is a side menu that helps to organize the navigation inside the app. It is a uniform way to access different pages and information inside the app. You can refer to official google page to know more.
The implementation is very easy. The custom view that represents the navigation drawer must be the first element in the layout:

<LinearLayout
android:layout_width=”match_parent”
android:layout_height=”match_parent”
android:orientation=”vertical”>

<include layout=”@layout/toolbar”/>

<!– Let’s add fragment –>
<FrameLayout
android:layout_width=”match_parent”
android:layout_height=”match_parent”
android:id=”@+id/frame”/>

</LinearLayout>

<android.support.design.widget.NavigationView
android:id=”@+id/navigation”
android:layout_width=”wrap_content”
android:layout_height=”match_parent”
android:layout_gravity=”start”
app:menu=”@menu/nav_items”/>

</android.support.v4.widget.DrawerLayout>
[/xml]

In this case, the toolbar is inside a LinearLayout but the way the app handles it is the same shown before.
In this case, there is a FrameLayout to hold the page content shown through fragments.
The NavigationView is the “real” menu of our app. The menu items are written in nav_items.

<item android:id=”@+id/star”
android:title=”Star”
android:icon=”@drawable/ic_action_star”/>

<item android:id=”@+id/uploadr”
android:title=”Star”
android:icon=”@drawable/ic_action_upload”/>
</group>
</menu>[/xml]

To handle when user clicks on an item is very easy, it is necessary to write:

Fragment frag = null;
int itemId = menuItem.getItemId();

if (itemId == R.id.fab) {
frag = new Fragment1();
}
else if (itemId == R.id.star) {
frag = new Fragment2();
}

if (frag != null) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();

transaction.replace(R.id.frame, frag);
transaction.commit();
dLayout.closeDrawers();
return true;
}

return false;
}
});
}
[/java]

We simply add a listener to know when one of the menu item is pressed by user and then set the right fragment. The last step is opening the drawer when user clicks on the home icon, to do it:

switch(itemId) {
…
// Android home
case android.R.id.home: {
dLayout.openDrawer(GravityCompat.START);
return true;
}
}
…..
}
[/java]

Running the example app we have:

At the end of this post, you know how to use Android navigation drawer and toolbar according to material design guide lines.

If you want to know how to create a real app using material design give a look at this link describing how to create a weather app in android with material design.

At the end of this post, you hopefully gained the knowledge about how to develop an Android app with material design.