Overriding android:ellipsize on ActionBar subtitle

Question

My activity makes use of the ActionBar.setSubtitle function to display the currently displayed file system location's full path. This means that the substring towards the end of the subtitle is more relevant than the beginning, so I thought I would override the ActionBar style to ellipsize text at the start, rather than the end, like so:

res/values/themes.xml

<style name="Theme.Holo" parent="android:Theme.Holo">
    <!-- Action bar styles -->
    <item name="android:actionBarStyle">@style/Widget.Holo.ActionBar</item>
</style>

res/values/styles.xml

<style name="Widget.Holo.ActionBar" parent="@android:style/Widget.Holo.ActionBar">
    <item name="android:subtitleTextStyle">@style/TextAppearance.Holo.Widget.ActionBar.Subtitle</item>
</style>

<style name="TextAppearance.Holo.Widget.ActionBar.Subtitle"
       parent="@android:style/TextAppearance.Holo.Widget.ActionBar.Subtitle">
    <item name="android:ellipsize">start</item>
</style>

When I install this onto my ICS device (Nexus S), the text is still (incorrectly) ellipsized at the end. If I modify my version of TextAppearance.Holo.Widget.ActionBar.Subtitle to include an item for android:textSize, the subtitle's text size does get altered accordingly, so it would seem as if I am poking around in the right style; I just can't figure out why it's not honouring my android:ellipsize override.

To put all this into a question format: how can I override, using styles/themes, the android:ellipsize property of the subtitle view in the ActionBar?

Answer 1

It seems to me that it's not possible with themes and styles, but I've found a workaround to set ellipsize value in runtime.

The most difficult is to find title (or subtitle) TextView, because the id of this view is in internal android package.

So you need create stub class in your project

package com.android.internal;

public class R {

public static final class id {
    public static int action_bar_title = 0;
    public static int action_bar_subtitle = 0;
}

}

After that you need to find this view in code (I do this with the following code, it works both with sherlock and default actionbars)

public class ActionBarUtils {

public static TextView getActionbarTitle(Activity activity) {

    TextView title = (TextView) activity.findViewById(R.id.abs__action_bar_title);// for ActionBarSerlock
    if (title == null) title = (TextView) activity.findViewById(com.android.internal.R.id.action_bar_title);// for default action bar

    return title;
}
}

Now you can set ellipsize value in activity code:

getActionBarTitle().setEllipsize(TextUtils.TruncateAt.MIDDLE)

---

PS: Make sure, that you call getActionBarTitle when title is visible (after setDisplayShowTitleEnabled(true) call), otherwise you'll get NullPointerException.

PPS: If you use proguard obfuscation, you should add in proguard.cfg:

-keep class com.android.internal.R*{
    *;
}