It's simple PasswordView, easy to use

Usage

compile 'com.tieudieu.passwordview:passwordview:0.0.1'

    <com.tieudieu.passwordview.PasswordView
        android:id="@+id/password_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:tdpi_input_type="free"
        app:tdpi_password_length="5"
        app:tdpi_password_type="password" />

Demo