how to change color of TextinputLayout's label and edittext underline android

Change bottom line color:

<item name="colorControlNormal">#c5c5c5</item>
<item name="colorControlActivated">@color/accent</item>
<item name="colorControlHighlight">@color/accent</item>

For more info check this thread.

Change hint color when it is floating

<style name="MyHintStyle" parent="@android:style/TextAppearance">
    <item name="android:textColor">@color/main_color</item>
</style>

and use it like this:

<android.support.design.widget.TextInputLayout
    ...
    app:hintTextAppearance="@style/MyHintStyle">

Change hint color when it is not a floating label:

<android.support.design.widget.TextInputLayout
    ...
    app:hintTextAppearance="@style/MyHintStyle"
    android:textColorHint="#c1c2c4">

Thanks to @AlbAtNf

Based on Fedor Kazakov and others answers, I created a default config.

styles.xml

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="Widget.Design.TextInputLayout" parent="AppTheme">
        <item name="hintTextAppearance">@style/AppTheme.TextFloatLabelAppearance</item>
        <item name="errorTextAppearance">@style/AppTheme.TextErrorAppearance</item>
        <item name="counterTextAppearance">@style/TextAppearance.Design.Counter</item>
        <item name="counterOverflowTextAppearance">@style/TextAppearance.Design.Counter.Overflow</item>
    </style>

    <style name="AppTheme.TextFloatLabelAppearance" parent="TextAppearance.Design.Hint">
        <!-- Floating label appearance here -->
        <item name="android:textColor">@color/colorAccent</item>
        <item name="android:textSize">20sp</item>
    </style>

    <style name="AppTheme.TextErrorAppearance" parent="TextAppearance.Design.Error">
        <!-- Error message appearance here -->
        <item name="android:textColor">#ff0000</item>
        <item name="android:textSize">20sp</item>
    </style>

</resources>

activity_layout.xml

<android.support.design.widget.TextInputLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.AppCompatEditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Text hint here"
        android:text="5,2" />

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

---

Focused:

Without focus:

Error message:

With the Material Components Library you can use the com.google.android.material.textfield.TextInputLayout.

You can apply a custom style to change the colors.

To change the hint color you have to use these attributes:
hintTextColor and android:textColorHint.

<style name="Custom_textinputlayout_filledbox" parent="@style/Widget.MaterialComponents.TextInputLayout.FilledBox">
    <!-- The color of the label when it is collapsed and the text field is active -->
    <item name="hintTextColor">?attr/colorPrimary</item>

    <!-- The color of the label in all other text field states (such as resting and disabled) -->
    <item name="android:textColorHint">@color/selector_hint_text_color</item>
</style>

You should use a selector for the android:textColorHint. Something like:

<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>

To change the bottom line color you have to use the attribute: boxStrokeColor.

<style name="Custom_textinputlayout_filledbox" parent="@style/Widget.MaterialComponents.TextInputLayout.FilledBox">
    ....
    <item name="boxStrokeColor">@color/selector_stroke_color</item>
</style>

Also in this case you should use a selector. Something like:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:color="?attr/colorPrimary" android:state_focused="true"/>
  <item android:alpha="0.87" android:color="?attr/colorOnSurface" android:state_hovered="true"/>
  <item android:alpha="0.12" android:color="?attr/colorOnSurface" android:state_enabled="false"/>
  <item android:alpha="0.38" android:color="?attr/colorOnSurface"/>
</selector>

You can also apply these attributes in your layout:

<com.google.android.material.textfield.TextInputLayout
    style="@style/Widget.MaterialComponents.TextInputLayout.FilledBox"
    app:boxStrokeColor="@color/selector_stroke_color"
    app:hintTextColor="?attr/colorPrimary"
    android:textColorHint="@color/selector_hint_text_color"
    ...>