Custom Translucent Android ActionBar

问题:

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>

回答1:

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();

回答2:

In addition to the correct answer, if you are using AppcomatActivity, call supportRequestWindowFeature instead of

Old Version: getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);

You want to use:

@Override
protected void onCreate(Bundle savedInstanceState) {
    supportRequestWindowFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
    super.onCreate(savedInstanceState);
}

回答3:

I think you should be able to do this using the Window flag FEATURE_ACTION_BAR_OVERLAY.

Before you call setContentView() in your activity,

Call:

getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);

And it will use an overlaid ActionBar instead of pushing down your window.

回答4:

The above code is absolutely correct for making an action bar.

Instead of

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

use

getActionBar().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));

In this way, you will able to see the action bar fully transparent.

回答5:

Here is how I got this to work:

1) Request for actionbar overlay programmatically by calling

       getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);

this 'requestFeature()' must be requested from your activity 'onCreate()' method before calling for 'setContentView(R.layout.my_layout)':

2) set the actionbar color by calling setBackgroundDrawable() like so:

getSupportActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#00212121")) );

this method requires either a reference to a drawable or you can also use a color parser to parse a hex color value (first 2 digits are used for alpha channel starting at #00 to #FF)

Note that I am using actionBarSherlok getSupportActionBar() but this should work with any action bar.

If you still cant get this to work, try adding this to your theme style

<item name="windowActionBarOverlay">true</item>
 <item name="android:actionBarStyle">@style/ActionBar.Transparent.Example</item>
 <item name="android:windowActionBarOverlay">true</item>

回答6:

I just like to share with you the steps I took to achieve this:

1) At the OnCreate of your activity,

getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);

then

getWindow().setFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION,
            WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);

This is done before setContentView.

2) After setContentView, you can do the following

 getSupportActionBar().setBackgroundDrawable(new ColorDrawable(Color.argb(0, 100, 181, 246)));

Where the alpha value of 0 means it is fully transparent.