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>

在最新版本的支持库(23.0.0+)中，TextInputLayout采用以下XML属性来编辑浮动标签颜色:

<style name="TextAppearance.App.TextInputLayout" parent="@android:style/TextAppearance">
    <item name="android:textColor">@color/red</item>
    <item name="android:textSize">14sp</item>
</style>

<android.support.design.widget.TextInputLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textColorHint="@color/gray"  //support 23.0.0
    app:hintTextAppearance="@style/TextAppearence.App.TextInputLayout" >

    <android.support.v7.widget.AppCompatEditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/hint" />
</android.support.design.widget.TextInputLayout>

当您聚焦文本标签时，更改文本标签的颜色。也就是在里面打字。你必须加上specify

<item name="android:textColorPrimary">@color/yourcolorhere</item>

请注意: 您必须将所有这些实现添加到您的主题中。

试试下面的代码，它在正常状态下工作

 <android.support.design.widget.TextInputLayout
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:theme="@style/TextLabel">

     <android.support.v7.widget.AppCompatEditText
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="Hiiiii"
         android:id="@+id/edit_id"/>

 </android.support.design.widget.TextInputLayout>

在样式文件夹TextLabel代码

 <style name="TextLabel" parent="TextAppearance.AppCompat">
    <!-- Hint color and label color in FALSE state -->
    <item name="android:textColorHint">@color/Color Name</item> 
    <item name="android:textSize">20sp</item>
    <!-- Label color in TRUE state and bar color FALSE and TRUE State -->
    <item name="colorAccent">@color/Color Name</item>
    <item name="colorControlNormal">@color/Color Name</item>
    <item name="colorControlActivated">@color/Color Name</item>
 </style>

设置为应用程序的主题，它只突出显示状态

 <item name="colorAccent">@color/Color Name</item>

更新:

UnsupportedOperationException:不能转换为颜色:类型=0x2在api 16或以下

解决方案

更新:

你在使用材料组件库吗

你可以在你的主题中添加以下几行

 <item name="colorPrimary">@color/your_color</item> // Activated State
 <item name="colorOnSurface">@color/your_color</item> // Normal State

或者你想要不同的颜色在正常状态和激活状态和自定义遵循下面的代码

<style name="Widget.App.TextInputLayout" parent="Widget.MaterialComponents.TextInputLayout.OutlinedBox">
    <item name="materialThemeOverlay">@style/ThemeOverlay.App.TextInputLayout</item>
    <item name="shapeAppearance">@style/ShapeAppearance.App.SmallComponent</item> //Changes the Shape Apperance
    <!--<item name="hintTextColor">?attr/colorOnSurface</item>-->   //When you added this line it will applies only one color in normal and activate state i.e colorOnSurface color
</style>

<style name="ThemeOverlay.App.TextInputLayout" parent="">
    <item name="colorPrimary">@color/colorPrimaryDark</item>  //Activated color
    <item name="colorOnSurface">@color/colorPrimary</item>    //Normal color
    <item name="colorError">@color/colorPrimary</item>        //Error color

    //Text Appearance styles
    <item name="textAppearanceSubtitle1">@style/TextAppearance.App.Subtitle1</item>
    <item name="textAppearanceCaption">@style/TextAppearance.App.Caption</item>

    <!--Note: When setting a materialThemeOverlay on a custom TextInputLayout style, don’t forget to set editTextStyle to either a @style/Widget.MaterialComponents.TextInputEditText.* style or to a custom one that inherits from that.
    The TextInputLayout styles set materialThemeOverlay that overrides editTextStyle with the specific TextInputEditText style needed. Therefore, you don’t need to specify a style tag on the edit text.-->
    <item name="editTextStyle">@style/Widget.MaterialComponents.TextInputEditText.OutlinedBox</item>
</style>

<style name="TextAppearance.App.Subtitle1" parent="TextAppearance.MaterialComponents.Subtitle1">
    <item name="fontFamily">@font/your_font</item>
    <item name="android:fontFamily">@font/your_font</item>
</style>

<style name="TextAppearance.App.Caption" parent="TextAppearance.MaterialComponents.Caption">
    <item name="fontFamily">@font/your_font</item>
    <item name="android:fontFamily">@font/your_font</item>
</style>

<style name="ShapeAppearance.App.SmallComponent" parent="ShapeAppearance.MaterialComponents.SmallComponent">
    <item name="cornerFamily">cut</item>
    <item name="cornerSize">4dp</item>
</style>

添加下面的行到您的主题，否则您可以设置样式textinputlayout在您的xml

<item name="textInputStyle">@style/Widget.App.TextInputLayout</item>

有太多复杂的解决方案。下面是一个改变浮动标签颜色的程序。

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

除了更改其他属性:

更改框描边颜色:

<com.google.android.material.textfield.TextInputLayout
    app:boxStrokeColor="@color/green"

更改方框描边宽度:

<com.google.android.material.textfield.TextInputLayout 
     app:boxStrokeWidth="1.5dp"

更改编辑TextInputEditText提示颜色:

<com.google.android.material.textfield.TextInputEditText
     android:textColorHint="@color/white"

更改TextInputEditText的颜色:

<com.google.android.material.textfield.TextInputEditText           
            android:textColor="@color/white" />