因为你必须在主应用主题中添加colorControlNormal, colorControlActivated, colorControlHighLight三项:

<!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>

        <item name="colorControlActivated">@color/yellow_bright</item>
        <item name="colorControlNormal">@color/yellow_black</item>

    </style>

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>

现在，简单地使用colorAccent和colorPrimary就可以完美地工作了。

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" />

你可以在程序上使用:

/* Here you get int representation of an HTML color resources */
int yourColorWhenEnabled = ContextCompat.getColor(getContext(), R.color.your_color_enabled);
int yourColorWhenDisabled = ContextCompat.getColor(getContext(), R.color.your_color_disabled);

/* Here you get matrix of states, I suppose it is a matrix because using a matrix you can set the same color (you have an array of colors) for different states in the same array */
int[][] states = new int[][]{new int[]{android.R.attr.state_enabled}, new int[]{-android.R.attr.state_enabled}};

/* You pass a ColorStateList instance to "setDefaultHintTextColor" method, remember that you have a matrix for the states of the view and an array for the colors. So the color in position "colors[0x0]" will be used for every states inside the array in the same position inside the matrix "states", so in the array "states[0x0]". So you have "colors[pos] -> states[pos]", or "colors[pos] -> color used for every states inside the array of view states -> states[pos] */
myTextInputLayout.setDefaultHintTextColor(new ColorStateList(states, new int[]{yourColorWhenEnabled, yourColorWhenDisabled})

解释:

Get int color value from a color resource (a way to present rgb colors used by android). I wrote ColorEnabled, but really it should be, for this answer, ColorHintExpanded & ColorViewCollapsed. Anyway this is the color you will see when the hint of a view "TextInputLayout" is on Expanded or Collapsed state; you will set it by using next array on function "setDefaultHintTextColor" of the view. Reference: Reference for TextInputLayout - search in this page the method "setDefaultHintTextColor" for more info

查看上面的文档，你可以看到函数通过使用ColorStateList来设置展开和折叠提示的颜色。

ColorStateList docs

To create the ColorStateList I first created a matrix with the states I want, in my case state_enabled & state_disabled (whose are, in TextInputLayout, equals to Hint Expanded and Hint Collapsed [I don't remember in which order lol, anyway I found it just doing a test]). Then I pass to the constructor of the ColorStateList the arrays with int values of color resources, these colors have a correspondences with the states matrix (every element in colors array correspond to the respective array in states matrix at same position). So the first element of the colors array will be used as color for every state in the first array of the states matrix (in our case the array has only 1 element: enabled state = hint expanded state for TextInputLayut). Last things states have positive / negative values, and you have only the positive values, so the state "disabled" in android attrs is "-android.state.enabled", the state "not focused" is "-android.state.focused" ecc.. ecc..

希望这对你有帮助。 再见，祝你编码愉快。

你应该换一下颜色

<style name="Base.Theme.DesignDemo" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="colorPrimary">#673AB7</item>
        <item name="colorPrimaryDark">#512DA8</item>
        <item name="colorAccent">#FF4081</item>
        <item name="android:windowBackground">@color/window_background</item>
    </style>