Android – Custom Translucent Android ActionBar

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I've been scouring the interwebs (e.g. Android documentation, answers here, etc.) for the answer to what I thought would be a fairly trivial question. How do you achieve a translucent action bar like the ones in Google Music and YouTube (links are image examples)?

I want video content to be full screen and not constrained/pushed down by the action bar while still leveraging the benefits of a built in UI component. I can obviously use a completely custom view, but I'd rather leverage the ActionBar if possible.

Manifest

<activity
    android:name="videoplayer"
    android:theme="@android:style/Theme.Holo"
    android:launchMode="singleTop"
    android:configChanges="keyboardHidden|orientation"/>

Activity

// Setup action bar
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
View customActionBarView = getLayoutInflater().inflate(R.layout.player_custom_action_bar, null);
actionBar.setCustomView(customActionBarView,
                        new ActionBar.LayoutParams(ActionBar.LayoutParams.MATCH_PARENT,
                                                   R.dimen.action_bar_height));
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);

Menu

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/button1"
        android:icon="@drawable/button1"
        android:showAsAction="always"/>

    <item
        android:id="@+id/button2"
        android:icon="@drawable/button2"
        android:showAsAction="always"/>
</menu>

Custom ActionBar View

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/custom_action_bar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:gravity="center"
    android:background="@color/TranslucentBlack">

    <!--Home icon with arrow-->
    <ImageView
        android:id="@+id/home"
        android:src="@drawable/home"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"/>

    <!--Another image-->
    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:visibility="visible"/>

    <!--Text if no image-->
    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:gravity="center_vertical"
        android:visibility="gone"/>

    <!--Title-->
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:paddingLeft="20dp"
        android:gravity="center_vertical"/>
</LinearLayout>

Best Answer

If you want your activity to be fullscreen but still show an actionbar, but with an alpha you have to request overlaymode for the actionbar in onCreate() of your activity:

getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);

//getWindow().requestFeature(WindowCompat.FEATURE_ACTION_BAR_OVERLAY); << Use this for API 7+ (v7 support library)

Then after you call setContentView(..) (since setContentView(..) also initializes the actionbar next to setting the content) you can set a background drawable on your actionbar:

getActionBar().setBackgroundDrawable(getResources().getDrawable(R.drawable.actionbar_bg));

which can be a shape drawable with an alpha put in res/drawable:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle"> 
    <solid android:color="#BB000000" /> 
</shape>

You could also do this completely programatically by creating a ColorDrawable:

getActionBar().setBackgroundDrawable(new ColorDrawable(Color.argb(128, 0, 0, 0)));

Otherwise ofcourse you can hide the actionbar completely; in that case you can set a custom theme on your activity in your manifest:

@android:style/Theme.NoTitleBar.Fullscreen

or programmatically by calling 

getActionBar().hide();
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