Programmatically set TextInputLayout Hint Text Color and Floating Label Color

With the Material Components library you can use:

In the layout:

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

in a style:

<style name="..." parent="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/mtrl_indicator_text_color</item>
</style>

in the code:

// Sets the text color used by the hint in both the collapsed and expanded states
textInputLayout.setDefaultHintTextColor(...);

//Sets the collapsed hint text color
textInputLayout.setHintTextColor(....);

I changed focused color with reflection. Here's the snippet it may help someone.

private void setUpperHintColor(int color) {
    try {
        Field field = textInputLayout.getClass().getDeclaredField("mFocusedTextColor");
        field.setAccessible(true);
        int[][] states = new int[][]{
                new int[]{}
        };
        int[] colors = new int[]{
                color
        };
        ColorStateList myList = new ColorStateList(states, colors);
        field.set(textInputLayout, myList);

        Method method = textInputLayout.getClass().getDeclaredMethod("updateLabelState", boolean.class);
        method.setAccessible(true);
        method.invoke(textInputLayout, true);

    } catch (Exception e) {
        e.printStackTrace();
    }
}

EDIT 2018-08-01:

If you are using design library v28.0.0 and later, fields had changed from mDefaultTextColorto defaultHintTextColor and from mFocusedTextColor to focusedTextColor.

Check decompiled class for other fields.