Android activity as dialog, but without a title bar

I have an activity that has the following set as theme:

android:theme="@android:style/Theme.Dialog"

However, there is a title bar in the activity-dialog that appears, that uses up the little available space that I have. How can I remove it?

Try doing requestWindowFeature(Window.FEATURE_NO_TITLE); in onCreate. It'll need to be done immediately after calling super.onCreate and just before setContentView.

For those who are using AppCompatActivity, above answers may not work.

Try this

supportRequestWindowFeature(Window.FEATURE_NO_TITLE);

immediately before setContentView(R.layout.MyDialogActivity);

You can define your own theme:

<style name="NoTitleDialog" parent="@android:style/Theme.Dialog">
    <item name="android:windowNoTitle">true</item>
</style>

(Tip of the hat to @Rehan) If you're using the compatibility library, you should pick an AppCompat parent theme and leave off the android: prefix. For example:

<style name="NoTitleDialog" parent="@style/Theme.AppCompat.Dialog">
    <item name="windowNoTitle">true</item>
</style>

If you are using AppCompatActivity in which you are forced to use Theme.AppCompat.xxx for everything, you can remove the dialog title or actionbar in styles.xml using this:

<style name="Theme.MyDialog" parent="Theme.AppCompat.Light.Dialog">
    <item name="windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
</style>

Notice the use of name="windowActionBar", instead of name="android:windowActionBar".