尝试设置动作条样式自定义样式，然后更改文本样式

Try setting a custom style for actionBar Style and then change the text style

<style name="myTheme.ActionBar" parent="@style/Widget.AppCompat.ActionBar.Solid">
    <item name="android:actionBarStyle">@style/myTheme.ActionBar.Text</item>
</style>

<style name="myTheme.ActionBar.Text" parent="@style/Widget.AppCompat.ActionBar.Solid">
    <item name="android:titleTextStyle">@style/actionBarText</item>
</style>

<style name="actionBarText" parent="@android:style/TextAppearance">
    <item name="android:textColor">@android:color/white</item>
</style>