<android.support.v7.widget.Toolbar
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:id="@+id/toolbar"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@color/color_primary"
  android:theme="@style/GalaxyZooThemeToolbarDarkOverflow"
  app:popupTheme="@style/Theme.AppCompat.NoActionBar" />


<style name="GalaxyZooThemeToolbarDarkOverflow" parent="Theme.AppCompat.NoActionBar">
  <!-- android:textColorPrimary is the  color of the title text
       in the Toolbar, in the Theme.AppCompat theme:  -->
  <item name="android:textColorPrimary">@color/abc_primary_text_material_light</item>
 
  <!-- android:textColorPrimaryInverse is the  color of the title
       text in the Toolbar, in the Theme.AppCompat.Light theme:  -->
  <!-- <item name="android:textColorPrimaryInverse">@color/abc_primary_text_material_light</item> -->
 
  <!-- android:actionMenuTextColor is the color of the text of
        action (menu) items in the Toolbar, at least in the
        Theme.AppCompat theme.
        For some reason, they already get the textColorPrimary
        when running on API 21, but not on older versions of
        Android, so this is only necessary to support older
        Android versions.-->
        <item name="actionMenuTextColor">@color/abc_primary_text_material_light</item>
  <!-- android:textColorSecondary is the color of the menu
       overflow icon (three vertical dots) -->
  <item name="android:textColorSecondary">@color/abc_secondary_text_material_light</item>
 
  <!-- This would set the toolbar's background color,
        but setting this also changes the popup menu's background,
        even if we define popupTheme for our <Toolbar> -->
  <!-- <item name="android:background">@color/color_primary</item> -->
</style>


**Reference:**
[https://www.murrayc.com/permalink/2014/10/28/android-changing-the-toolbars-text-color-and-overflow-icon-color/][1]

我发现了一种适用于任何类型的ActionBar (Sherlock, Compat和Native)的方法:

只需使用html设置标题，并指定文本颜色。例如，要将ActionBar文本颜色设置为红色，只需这样做:

getActionBar()/* or getSupportActionBar() */.setTitle(Html.fromHtml("<font color=\"red\">" + getString(R.string.app_name) + "</font>"));

你也可以使用红色十六进制代码#FF0000来代替单词red。如果你对此有问题，请参阅Android Html.fromHtml(String)不适用于<font color='#'>text</font>。

此外，如果你想使用颜色资源，这段代码可以用来获得正确的HEX字符串，并在需要时删除alpha(字体标签不支持alpha):

int orange = getResources().getColor(R.color.orange);
String htmlColor = String.format(Locale.US, "#%06X", (0xFFFFFF & Color.argb(0, Color.red(orange), Color.green(orange), Color.blue(orange))));

如果你需要以编程方式设置颜色，这是一种方法:

static void setActionBarTextColor(Activity activity, int color)
{
      ActionBar actionBar = activity instanceof AppCompatActivity
                    ? ((AppCompatActivity) activity).getSupportActionBar()
                    : activity.getActionBar();
      String title = activity.getTitle(); // or any title you want
      SpannableString ss = new SpannableString(title);
      ss.setSpan(new ForegroundColorSpan(color), 0, title.length(), Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
      actionBar.setTitle(ss);
}

尝试了很多方法，在低版本的API中，一个可行的方法是<item name="actionMenuTextColor">@color/your_color</item>，不要使用Android命名空间，希望可以帮助到你

ps:

  <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="actionMenuTextColor">@color/actionMenuTextColor</item>
</style>

在操作栏上设置HTML字符串在SDK v21+的Material主题上不起作用

如果你想改变它，你应该在style.xml中设置主文本颜色

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="android:Theme.Material.Light">
        <!-- Customize your theme here. -->
        <item name="android:textColorPrimary">@color/actionbar-text-color</item>
    </style>
</resources>    

我们需要在工具栏中使用app:theme属性定义主题，如下面的代码片段所示。

<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:theme="@style/AppTheme.ToolbarFont" />

在此之前，我们必须在我们的styles.xml文件中添加主题，我们必须像下面的代码片段那样定义该样式的font-family。

<style name="AppTheme.ToolbarFont" parent="AppTheme">
<!--This line changes the color of text in Toolbar-->
<item name="android:textColorPrimary">@color/black</item>
<!--This line changes the color of icons in toolbar (back, overflow menu icons)-->
<item name="android:textColorSecondary">@color/azul</item>
<item name="textAllCaps">false</item>
<item name="android:textSize">16sp</item>
<item name="android:fontFamily">@font/montserrat_semi_bold</item>

为了添加自定义字体，我们需要在res目录中创建一个名为“font”的文件夹，如下面的截图所示。

我们已经在工具栏中实现了自定义字体。