Using the App ToolBar

Overview

ToolBar was introduced in Android Lollipop, API 21 release and is the spiritual successor of the ActionBar. It's a ViewGroup that can be placed anywhere in your XML layouts. ToolBar's appearance and behavior can be more easily customized than the ActionBar.

ToolBar works well with apps targeted to API 21 and above. However, Android has updated the AppCompat support libraries so the ToolBar can be used on lower Android OS devices as well. In AppCompat, ToolBar is implemented in the android.support.v7.widget.Toolbar class.

There are two ways to use Toolbar:

1. Use a Toolbar as an Action Bar when you want to use the existing ActionBar facilities (such as menu inflation and selection, ActionBarDrawerToggle, and so on) but want to have more control over its appearance.
2. Use a standalone Toolbar when you want to use the pattern in your app for situations that an Action Bar would not support; for example, showing multiple toolbars on the screen, spanning only part of the width, and so on.

ToolBar vs ActionBar

The ToolBar is a generalization of the ActionBar system. The key differences that distinguish the ToolBar from the ActionBar include:

• ToolBar is a View included in a layout like any other View
• As a regular View, the toolbar is easier to position, animate and control
• Multiple distinct ToolBar elements can be defined within a single activity

Keep in that you can also configure any ToolBar as an Activity’s ActionBar, meaning that your standard options menu actions will be display within.

Note that the ActionBar continues to work and if all you need is a static bar at the top that can host icons and a back button, then you can safely continue to use ActionBar.

Using ToolBar as ActionBar

To use Toolbar as an ActionBar, first ensure the AppCompat-v7 support library is added to your application build.gradle (Module:app) file:

dependencies {
  ...
  compile 'com.android.support:appcompat-v7:23.1.0+'
}

Second, let's disable the theme-provided ActionBar. The easiest way is to have your theme extend from Theme.AppCompat.NoActionBar (or the light variant) within the res/styles.xml file:

<resources>
  <!-- Base application theme. -->
  <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
  </style>
</resources>

Now you need to add a Toolbar to your Activity layout file. One of the biggest advantages of using the Toolbar widget is that you can place the view anywhere within your layout. Below we place the toolbar at the top of a LinearLayout like the standard ActionBar:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
      android:id="@+id/toolbar"
      android:minHeight="?attr/actionBarSize"  
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:titleTextColor="@android:color/white"
      android:background="?attr/colorPrimary">
    </android.support.v7.widget.Toolbar>

    <!-- Layout for content is here. This can be a RelativeLayout  -->

</LinearLayout>

As Toolbar is just a ViewGroup and can be styled and positioned like any other view. Note that this means if you are in a RelativeLayout, you need to ensure that all other views are positioned below the toolbar explicitly. The toolbar is not given any special treatment as a view.

Next, in your Activity or Fragment, set the Toolbar to act as the ActionBar by calling the setSupportActionBar(Toolbar) method:

Note: When using the support library, make sure that you are importing android.support.v7.widget.Toolbar and not android.widget.Toolbar.

import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

public class MyActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        // Find the toolbar view inside the activity layout
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        // Sets the Toolbar to act as the ActionBar for this Activity window.
        // Make sure the toolbar exists in the activity and is not null
        setSupportActionBar(toolbar);
    }

    // Menu icons are inflated just as they were with actionbar
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
}

The above code results in the toolbar fully replacing the ActionBar at the top:

From this point on, all menu items are displayed in your Toolbar, populated via the standard options menu callbacks.

Reacting to Scroll

We can configure the ToolBar to react and change as the page scrolls:

Refer to the guide on CoordinatorLayout and AppBarLayout for the specifics.

Styling the Toolbar

The Toolbar can be customized in many ways leveraging various style properties including android:theme, app:titleTextAppearance, app:popupTheme. Each of these can be mapped to a style. Start with:

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"  
    android:theme="@style/ToolbarTheme"
    app:titleTextAppearance="@style/Toolbar.TitleText"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
/>

Now, we need to create the custom styles in res/styles.xml with:

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
  <!-- Customize your theme here. -->
  <item name="colorPrimary">@color/colorPrimary</item>
  <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
  <item name="colorAccent">@color/colorAccent</item>
</style>

<style name="ToolbarTheme" parent="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
  <!-- This would set the toolbar's background color -->
  <item name="android:background">@color/colorPrimary</item>
  <!-- android:textColorPrimary is the color of the title text in the Toolbar  -->
  <item name="android:textColorPrimary">@android:color/holo_blue_light</item>
  <!-- android:actionMenuTextColor is the color of the text of action (menu) items  -->
  <item name="actionMenuTextColor">@android:color/holo_green_light</item>
  <!-- Enable these below if you want clicking icons to trigger a ripple effect -->
  <!-- 
  <item name="selectableItemBackground">?android:selectableItemBackground</item>
  <item name="selectableItemBackgroundBorderless">?android:selectableItemBackground</item> 
  -->
</style>

<!-- This configures the styles for the title within the Toolbar  -->
<style name="Toolbar.TitleText" parent="TextAppearance.Widget.AppCompat.Toolbar.Title">
    <item name="android:textSize">21sp</item>
    <item name="android:textStyle">italic</item>
</style>

This results in:

Custom Title View

A Toolbar is just a decorated ViewGroup and as a result, the title contained within can be completely customized by embedding a view within the Toolbar such as:

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:minHeight="?attr/actionBarSize"  
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:titleTextColor="@android:color/white"
    android:background="?attr/colorPrimary">

     <TextView
        android:id="@+id/toolbar_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Toolbar Title"
        android:textColor="@android:color/white"
        style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title"
        android:layout_gravity="center"
     />

</android.support.v7.widget.Toolbar>

This means that you can style the TextView like any other. You can access the TextView inside your activity with:

/* Inside the activity */
// Sets the Toolbar to act as the ActionBar for this Activity window.
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Remove default title text
getSupportActionBar().setDisplayShowTitleEnabled(false);
// Get access to the custom title view
TextView mTitle = (TextView) toolbar.findViewById(R.id.toolbar_title);

Note that you must hide the default title using setDisplayShowTitleEnabled. This results in:

Animating Toolbar when Scrolling

One common behavior seen in many modern apps is to hide or show the toolbar or make other changes as the user scrolls through a list:

The proper way of reacting to scroll behavior is leveraging the CoordinatorLayout built into the Design Support Library. There are a few other relevant resources around reacting to scrolling events:

• Hiding or Showing Toolbar on Scroll - Great guide on an alternate strategy not requiring the CoordinatorLayout to replicate the behavior of the "Google Play Music" app. Sample code can be found here.
• Hiding or Showing Toolbar using CoordinatorLayout - Great guide that outlines how to use CoordinatorLayout to hide the Toolbar and the FAB when the user scrolls.

With these methods, your app can replicate any scrolling behaviors seen in common apps with varying levels of difficulty.