ActionBar ID不是直接可用的，所以你必须做一点hack。

int actionBarTitleId = Resources.getSystem().getIdentifier("action_bar_title", "id", "android");
if (actionBarTitleId > 0) {
    TextView title = (TextView) findViewById(actionBarTitleId);
    if (title != null) {
        title.setTextColor(Color.RED);
    }
}

就我而言，我切换到AndroidX工具栏，而不是使用本机操作栏。此外，我依赖于视图绑定从活动访问工具栏，但您可以使用findViewById(…)。

(我删除了不相关的代码)。

styles.xml:

...
<style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">
  ...
</style>
...

activity_main.xml:

...
<androidx.appcompat.widget.Toolbar
  android:id="@+id/toolbarMain"
  android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
  app:titleTextColor="@color/colorOnPrimary"
  ...
/>
...

MainActivity.kt:

class MainActivity : AppCompatActivity() {

  private lateinit var binding: ActivityMainBinding
  ...

  override fun onCreate(savedInstanceState: Bundle?) {
    ...
    binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
    setSupportActionBar(binding.toolbarMain)
    ...
  }

  ...
}

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>    

<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]

这些函数运行良好

在Java中

private void setActionbarTextColor(ActionBar actBar, int color) {

    String title = actBar.getTitle().toString();
    Spannable spannablerTitle = new SpannableString(title);
    spannablerTitle.setSpan(new ForegroundColorSpan(color), 0, spannablerTitle.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    actBar.setTitle(spannablerTitle);

}

然后使用它只需输入你的动作栏和新的颜色。

ActionBar actionBar = getActionBar();    // Or getSupportActionBar() if using appCompat
int red = Color.RED
setActionbarTextColor(actionBar, red);

在Kotlin

你可以像这样使用扩展函数:

private fun ActionBar.setTitleColor(color: Int) {
    val text = SpannableString(title ?: "")
    text.setSpan(ForegroundColorSpan(color),0,text.length, Spannable.SPAN_INCLUSIVE_INCLUSIVE)
    title = text
}

然后应用到你的动作栏

actionBar?.setTitleColor(Color.RED)

对于Android 5(棒棒糖)，你必须使用Android:actionBarPopupTheme来设置溢出菜单的textColor。