Developing Android applications often requires fine-grained control over the user interface, and one common requirement is to hide the action bar before activity is created, and then show it again when the activity is fully initialized. This can be useful for creating splash screens, onboarding flows, or immersive experiences where the action bar would be distracting during the initial loading phase. Managing the action bar’s visibility dynamically enhances the user experience by providing a cleaner and more focused interface at specific times. Understanding how to properly implement this behavior ensures a seamless transition for users as they navigate through your app. This approach allows developers to create a more polished and professional Android application.

Understanding the Action Bar Lifecycle

The action bar, also known as the app bar, is a crucial element in Android’s UI design, providing a consistent way for users to interact with the application. Its lifecycle is tightly coupled with the activity lifecycle, meaning its behavior must be managed within the context of activity creation, resumption, and destruction. Before an activity is created, the action bar doesn’t exist, so attempting to directly manipulate it will result in errors. The key is to understand the different stages of the activity lifecycle and choose the appropriate point to modify the action bar’s visibility. Using themes and styles can predefine certain aspects of the action bar, but dynamic control requires programmatic intervention during the activity’s runtime.

One common pitfall is attempting to access the action bar too early in the activity lifecycle, such as in the onCreate() method before the content view is set. According to Google’s official documentation on app bars (Android Developers), accessing the action bar should ideally occur after setContentView() has been called. This ensures that the activity’s layout is fully inflated and the action bar is properly initialized. Alternatively, you can also use onPostCreate() to further ensure that the action bar is ready to be manipulated. Developers should also consider the compatibility implications of hiding and showing the action bar across different Android versions, as the specific APIs may vary.

To effectively manage the action bar’s visibility, developers often utilize a combination of themes and programmatic control. For instance, a theme can be used to initially hide the action bar, and then the activity can programmatically show it when necessary. This approach provides a clean separation of concerns, with the theme handling the initial state and the activity managing the dynamic behavior. Correctly implementing this lifecycle management prevents common UI glitches and ensures a smooth user experience, especially during transitions between different screens or application states. This is especially important when dealing with full-screen activities or immersive modes. For example, a video playback application might hide the action bar during video playback to maximize screen real estate.

Hiding the Action Bar Before Activity Creation

The most reliable method to hide the action bar before activity is created involves using a custom theme. This theme can be applied to the activity in the AndroidManifest.xml file, ensuring that the action bar is hidden right from the start. Defining a theme allows you to control the initial visual appearance of your activity before any code is executed. A common approach is to set the windowActionBar attribute to false and the windowNoTitle attribute to true within the theme. This effectively removes the action bar from the activity’s initial layout. This method is crucial for splash screens or activities that require a full-screen experience from the moment they launch.

Featured Snippet: To hide the action bar before an Android activity is created, define a custom theme in your styles.xml file. Set windowActionBar to false and windowNoTitle to true within this theme. Then, apply this theme to your activity in the AndroidManifest.xml file using the android:theme attribute. This ensures that the action bar is hidden from the very beginning of the activity’s lifecycle.

Here’s how to implement this in detail:

1. Create a new style in res/values/styles.xml: ```

2. Apply the theme to your activity in AndroidManifest.xml: ```

By applying this theme, you ensure that the action bar is not displayed when the activity starts. This is a clean and efficient way to manage the initial visibility of the action bar. Remember that this method only hides the action bar initially; you’ll still need to programmatically show it later if required. Consider using a different base theme depending on your desired visual style (e.g., Theme.MaterialComponents.Light.NoActionBar).

Showing the Action Bar Programmatically

Once you’ve successfully hidden the action bar initially, you’ll often need to show it again at some point during the activity’s lifecycle. This is typically done programmatically within the activity’s code. The recommended approach is to use the getSupportActionBar() method to obtain a reference to the action bar and then call the show() method on that reference. This ensures that the action bar is properly displayed after the activity has been initialized. However, you must make sure to call getSupportActionBar() after setContentView() so the action bar is properly initialized.

Here’s an example of how to show the action bar:

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); if (getSupportActionBar() != null) { getSupportActionBar().show(); } } 

This code snippet demonstrates how to check if the action bar is available and then show it if it exists. The null check is crucial to prevent errors in cases where the activity doesn’t have an action bar. You can also use the hide() method to hide the action bar again if needed. Remember to handle configuration changes properly, such as device rotation, to ensure that the action bar’s visibility is maintained. You can also utilize ActionBar.setDisplayShowHomeEnabled(true) to show the app icon in the action bar. Proper management of the action bar’s visibility contributes significantly to a polished and professional user experience. According to a study by Nielsen Norman Group (Nielsen Norman Group), consistent UI elements like the action bar improve usability and learnability.

Advanced Techniques and Considerations

Beyond the basic hiding and showing of the action bar, there are several advanced techniques and considerations to keep in mind. One important aspect is handling transitions smoothly. When showing or hiding the action bar, you can use animations to create a more visually appealing effect. The ActionBar.hide() and ActionBar.show() methods are instant, so you might want to animate it with a slide up/down animation instead. This can be achieved using ViewPropertyAnimator or other animation techniques. Another consideration is the use of immersive mode, which is a full-screen mode that hides both the system bars (status bar and navigation bar) and the action bar. Immersive mode provides the most screen real estate for your application, but it requires careful handling of user interactions to ensure a seamless experience. You can use the setSystemUiVisibility() method to enter and exit immersive mode. This can be useful for applications that display videos, images, or games.

It is also important to consider the user experience when deciding when and how to show or hide the action bar before activity is created. Abrupt changes in UI visibility can be jarring and disorienting for users. Therefore, it’s essential to provide clear visual cues and smooth transitions. For example, you might delay showing the action bar until after a loading animation has completed. Additionally, consider providing users with a way to manually control the visibility of the action bar, such as a toggle in the settings menu. This gives users more control over their experience and can improve satisfaction. According to UX Matters (UX Matters), user control and consistency are key principles of good UI design.

• Consider using animations for smooth transitions.
• Provide user controls for action bar visibility.

• Test thoroughly on different devices and Android versions.
• Stay up-to-date with the latest Android development practices.

FAQ Section

Q: Why is the action bar not hiding when I use windowActionBar=false?

A: Make sure you are using a NoActionBar theme as the parent for your custom theme. Also, ensure that you are applying the correct theme to your activity in the AndroidManifest.xml file.

Q: How can I change the action bar's title programmatically?

A: You can use getSupportActionBar().setTitle("Your Title") after the activity has been created and the support action bar has been initialized.

Q: Is it possible to hide the status bar as well as the action bar?

A: Yes, you can hide the status bar using getWindow().setFlags(WindowManager.LayoutParams.FLAG\_FULLSCREEN, WindowManager.LayoutParams.FLAG\_FULLSCREEN); before calling setContentView(). Remember to handle this carefully to avoid unexpected behavior.

Question & Answer :
I need to implement splash screen in my honeycomb app. I use this code in activity’s onCreate to show splash:

setContentView(R.layout.splash); getActionBar().hide(); 

and this code to show main UI after sometime:

setContentView(R.layout.main); getActionBar().show(); 

But before onCreate is called and splash appears, there is small amount of time when action bar shown.

How can I make action bar invisible?

I tried to apply theme to activity without action bar:

<item name="android:windowActionBar">false</item> 

but in that case getActionBar() always returns null and I found no way to show it again.

Setting android:windowActionBar="false" truly disables the ActionBar but then, as you say, getActionBar(); returns null. This is solved by:

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getWindow().requestFeature(Window.FEATURE_ACTION_BAR); getActionBar().hide(); setContentView(R.layout.splash); // be sure you call this AFTER requestFeature 

This creates the ActionBar and immediately hides it before it had the chance to be displayed.

But now there is another problem. After putting windowActionBar="false" in the theme, the Activity draws its normal Window Title instead of an ActionBar.
If we try to avoid this by using some of the *.NoTitleBar stock themes or we try to put <item name="android:windowNoTitle">true</item> in our own theme, it won’t work.
The reason is that the ActionBar depends on the Window Title to display itself - that is the ActionBar is a transformed Window Title.
So the trick which can help us out is to add one more thing to our Activity theme xml:

<item name="android:windowActionBar">false</item> <item name="android:windowTitleSize">0dp</item> 

This will make the Window Title with zero height, thus practically invisible .

In your case, after you are done with displaying the splash screen you can simply call

setContentView(R.layout.main); getActionBar().show(); 

and you are done. The Activity will start with no ActionBar flickering, nor Window Title showing.

ADDON: If you show and hide the ActionBar multiple times maybe you have noticed that the first showing is not animated. From then on showing and hiding are animated. If you want to have animation on the first showing too you can use this:

protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_ACTION_BAR); // delaying the hiding of the ActionBar Handler h = new Handler(); h.post(new Runnable() { @Override public void run() { getActionBar().hide(); } }); 

The same thing can be achieved with:

protected void onPostResume() { super.onPostResume(); getActionBar().hide(); 

but it may need some extra logic to check if this is the first showing of the Activity.

The idea is to delay a little the hiding of the ActionBar. In a way we let the ActionBar be shown, but then hide it immediately. Thus we go beyond the first non-animated showing and next showing will be considered second, thus it will be animated.

As you may have guessed there is a chance that the ActionBar could be seen before it has been hidden by the delayed operation. This is actually the case. Most of the time nothing is seen but yet, once in a while, you can see the ActionBar flicker for a split second.

In any case this is not a pretty solution, so I welcome any suggestions.

Addition for v7 support actionbar user, the code will be:

getWindow().requestFeature(Window.FEATURE_ACTION_BAR); getSupportActionBar().hide();