InflateException with TextInputLayout and AlertDialog

This happened to me as well, and I came up with a solution inspired by AHTOH's. It requires simply changing the Theme of the TextInputLayout:

<android.support.design.widget.TextInputLayout
    android:id="@+id/testingInputLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/Theme.AppCompat">

   <EditText
       android:id="@+id/testingEditText"
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:hint="@string/testText"
       android:inputType="textEmailAddress" />

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

You will need to add the appCompat library if you have not already:

compile 'com.android.support:appcompat-v7:23.0.1'

I had similar error:

android.view.InflateException: Binary XML file line #1: Error inflating class android.support.design.widget.TextInputLayout

Trying to reproduce it for a new project I found that the problem for me was in App Theme! Try to set android:theme field in application tag of Android Manifest like this:

 <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.AppCompat">

• extend your activity from AppCompatActivity
• extend your (dialog)fragment from android.support.v4.app.Fragment.
• use latest version of design library.

• Instead of using EditText, use android.support.v7.widget.AppCompatEditText. For example:

      <android.support.design.widget.TextInputLayout
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"
                      app:errorEnabled="true">
  
                      <android.support.v7.widget.AppCompatEditText
                          android:layout_width="match_parent"
                          android:layout_height="wrap_content"
                          android:hint="First Name"
                          android:inputType="textPersonName"
                          android:singleLine="true" />
  
      </android.support.design.widget.TextInputLayout>
  

Also, if you didn't do so already: Set AppCompat theme in your manifest application tag:

<application
   ...
   android:theme="@style/Theme.AppCompat">

And inherit AppCompat at your styles.xml as root for your activity styles etc.:

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar"/>