Custom notification layouts and text colors

My application shows some notifications, and depending on user preferences it might use a custom layout in a notification. It works well, but there is a small problem -- text colors. Stock Android and almost all manufacturer skins use black text against a light background for notification text, but Samsung doesn't: their notification pulldown has a dark background and the text in the default notification layout is white.

So this causes a problem: the notifications that don't use any fancy layouts show up fine, but the one that uses a custom layout is hard to read because the text is black instead of the default white. Even the official documentation just sets a #000 color for a TextView, so I couldn't find any pointers there.

A user was kind enough to take a screenshot of the problem:

So how do I use the default notification text color from the device in my layouts? I'd rather not start dynamically altering the text color based on phone model, since that requires a lot of updating and people with custom ROM's might still get the problem, depending on the skin they're using.

Solution 1:

The solution is to use built-in styles. The style you need is called TextAppearance.StatusBar.EventContent in Android 2.3 and Android 4.x. In Android 5.x material notifications use several other styles: TextAppearance.Material.Notification, TextAppearance.Material.Notification.Title, and TextAppearance.Material.Notification.Line2. Just set the appropriate text appearance for the text view, and you will get the necessary colors.

If you are interested how I have arrived at this solution, here's my trail of breadcrumbs. The code excerpts are taken from Android 2.3.

1. When you use Notification and set the text by using built-in means, the following line creates the layout:

   RemoteViews contentView = new RemoteViews(context.getPackageName(),
           com.android.internal.R.layout.status_bar_latest_event_content);
   

2. The mentioned layout contains the following View which is responsible for viewing notification text:

   <TextView android:id="@+id/text"
       android:textAppearance="@style/TextAppearance.StatusBar.EventContent"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_weight="1"
       android:singleLine="true"
       android:ellipsize="marquee"
       android:fadingEdge="horizontal"
       android:paddingLeft="4dp"
       />
   

3. So the conclusion is that the needed style is TextAppearance.StatusBar.EventContent, which definition looks like this:

   <style name="TextAppearance.StatusBar.EventContent">
       <item name="android:textColor">#ff6b6b6b</item>
   </style>
   

   You should note here that this style doesn't actually reference any of the built-in colors, so the safest way is to apply this style instead of some built-in color.

One more thing: before Android 2.3 (API Level 9), there were neither styles, nor colors, there were only hard-coded values. If you happen to have to support such old versions for some reason, see the answer by Gaks .

Solution 2:

Solution by Malcolm works fine with API>=9. Here's the solution for older API:

The trick is to create the standard notification object and then traverse the default contentView created by Notification.setLatestEventInfo(...). When you find the right TextView, just get the tv.getTextColors().getDefaultColor().

Here's the code that extracts the default text color and text size (in scaled density pixels - sp).

private Integer notification_text_color = null;
private float notification_text_size = 11;
private final String COLOR_SEARCH_RECURSE_TIP = "SOME_SAMPLE_TEXT";

private boolean recurseGroup(ViewGroup gp)
{
    final int count = gp.getChildCount();
    for (int i = 0; i < count; ++i)
    {
        if (gp.getChildAt(i) instanceof TextView)
        {
            final TextView text = (TextView) gp.getChildAt(i);
            final String szText = text.getText().toString();
            if (COLOR_SEARCH_RECURSE_TIP.equals(szText))
            {
                notification_text_color = text.getTextColors().getDefaultColor();
                notification_text_size = text.getTextSize();
                DisplayMetrics metrics = new DisplayMetrics();
                WindowManager systemWM = (WindowManager)getSystemService(Context.WINDOW_SERVICE);
                systemWM.getDefaultDisplay().getMetrics(metrics);
                notification_text_size /= metrics.scaledDensity;
                return true;
            }
        }
        else if (gp.getChildAt(i) instanceof ViewGroup)
            return recurseGroup((ViewGroup) gp.getChildAt(i));
    }
    return false;
}

private void extractColors()
{
    if (notification_text_color != null)
        return;

    try
    {
        Notification ntf = new Notification();
        ntf.setLatestEventInfo(this, COLOR_SEARCH_RECURSE_TIP, "Utest", null);
        LinearLayout group = new LinearLayout(this);
        ViewGroup event = (ViewGroup) ntf.contentView.apply(this, group);
        recurseGroup(event);
        group.removeAllViews();
    }
    catch (Exception e)
    {
        notification_text_color = android.R.color.black;
    }
}

Call extractColors ie. in onCreate() of your service. Then when you're creating the custom notification, the color and text size you want are in notification_text_color and notification_text_size:

Notification notification = new Notification();
RemoteViews notification_view = new RemoteViews(getPackageName(), R.layout.notification);       
notification_view.setTextColor(R.id.label, notification_text_color);
notification_view.setFloat(R.id.label, "setTextSize", notification_text_size);

Solution 3:

Here is solution for any SDK version using only resources.

res/values/styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="NotificationTitle">
      <item name="android:textColor">?android:attr/textColorPrimaryInverse</item>
      <item name="android:textStyle">bold</item>
    </style>
    <style name="NotificationText">
      <item name="android:textColor">?android:attr/textColorPrimaryInverse</item>
    </style>
</resources>

res/values-v9/styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="NotificationText" parent="android:TextAppearance.StatusBar.EventContent" />
    <style name="NotificationTitle" parent="android:TextAppearance.StatusBar.EventContent.Title" />
</resources>

res/layout/my_notification.xml

...
<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="title"
    style="@style/NotificationTitle"
    />
<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="text"
    style="@style/NotificationText"
    />
...

P.S: Hard coded values are used for 2.2-. So problems can occur with some rare old custom firmwares.