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>

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。

我建议你为TextInputLayout做风格主题，只改变强调色。设置父主题为你的应用程序基础主题:

 <style name="MyTextInputLayout" parent="MyAppThemeBase">
     <item name="colorAccent">@color/colorPrimary</item>
 </style>

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

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>

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="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;)