public void alertDialogWithText(){
    AlertDialog.Builder adb = new AlertDialog.Builder(new ContextThemeWrapper(MainActivity.this, R.style.EditTextAlertDialog));
    adb.setTitle("Title");
    inputET = new EditText(this);
    inputET.setInputType(InputType.TYPE_CLASS_TEXT);
    inputET.setTextColor(getResources().getColor(android.R.color.white));
    adb.setView(inputET);

    adb.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {

        }
    });

    adb.show();
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="colorPrimary">#303030</color>
<color name="colorPrimaryDark">#000</color>
<color name="colorAccent">#fff</color>
</resources>

<style name="EditTextAlertDialog">
    <item name="android:textColor">@android:color/white</item>
    <item name="android:background">#444</item>
</style>