找到答案，使用android.support.design:hintTextAppearance属性设置自己的浮动标签外观。

例子:

<android.support.design.widget.TextInputLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:hintTextAppearance="@style/TextAppearance.AppCompat">

    <EditText
        android:id="@+id/password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/prompt_password"/>
</android.support.design.widget.TextInputLayout>

你不需要使用android:theme="@style/TextInputLayoutTheme"来改变浮动标签的颜色，因为它会影响到整个主题的小TextView用作标签。相反，你可以使用app:hintTextAppearance="@style/TextInputLayout。HintText”:

<style name="TextInputLayout.HintText">
  <item name="android:textColor">?attr/colorPrimary</item>
  <item name="android:textSize">@dimen/text_tiny_size</item>
  ...
</style>

让我知道解决方案是否有效:-)

  <style name="AppTheme2" parent="AppTheme">
    <!-- Customize your theme here. -->
    <item name="colorControlNormal">#fff</item>
    <item name="colorControlActivated">#fff</item></style>    

将此添加到styles并将TextInputLayout Theam设置为App2，它将工作;)

我解决了问题。 这是布局:

 <android.support.design.widget.TextInputLayout
           android:id="@+id/til_username"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:hint="@string/username"
           >

           <android.support.v7.widget.AppCompatEditText android:id="@+id/et_username"
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:singleLine="true"
               />
       </android.support.design.widget.TextInputLayout>

这就是风格:

<style name="AppBaseTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!--
            Theme customizations available in newer API levels can go in
            res/values-vXX/styles.xml, while customizations related to
            backward-compatibility can go here.
        -->
    </style>
<!-- Application theme. -->


 <style name="AppTheme" parent="AppBaseTheme">
        <!-- All customizations that are NOT specific to a particular API-level can go here. -->
        <item name="colorAccent">@color/pink</item>
        <item name="colorControlNormal">@color/purple</item>
        <item name="colorControlActivated">@color/yellow</item>
    </style>

你应该在应用程序中使用你的主题:

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
</application>

<com.google.android.material.textfield.TextInputLayout
    android:hint="Hint"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/TextInputLayoutHint">

    <androidx.appcompat.widget.AppCompatEditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="text"
        android:maxLines="1"
        android:paddingTop="@dimen/_5sdp"
        android:paddingBottom="@dimen/_5sdp"
        android:textColor="#000000"
        android:textColorHint="#959aa6" />

</com.google.android.material.textfield.TextInputLayout>

res /价值/ styles.xml

<style name="TextInputLayoutHint" parent="">
    <item name="android:textColorHint">#545454</item>
    <item name="colorControlActivated">#2dbc99</item>
    <item name="android:textSize">11sp</item>
</style>

我如何改变浮动标签文本颜色?

使用材质组件库，您可以自定义TextInputLayout提示文本颜色使用(它需要版本1.1.0)

在布局中: app:hintTextColor属性:标签折叠和文本字段激活时的颜色 android:textColorHint属性:标签的颜色在所有其他文本字段的状态(如休息和禁用)

<com.google.android.material.textfield.TextInputLayout
     app:hintTextColor="@color/mycolor"
     android:textColorHint="@color/text_input_hint_selector"
     .../>

扩展材质样式Widget.MaterialComponents.TextInputLayout.*:

<style name="MyFilledBox" parent="Widget.MaterialComponents.TextInputLayout.FilledBox">
    <item name="hintTextColor">@color/mycolor</item>
    <item name="android:textColorHint">@color/text_input_hint_selector</item>
</style>

android:textColorHint的默认选择器是:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:alpha="0.38" android:color="?attr/colorOnSurface" android:state_enabled="false"/>
  <item android:alpha="0.6" android:color="?attr/colorOnSurface"/>
</selector>