session-android/res/layout/enter_backup_passphrase_dialog.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:padding="16dp">

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

        <android.support.design.widget.TextInputEditText
                android:id="@+id/restore_passphrase_input"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/enter_backup_passphrase_dialog__backup_passphrase"
                android:imeOptions="actionDone"
                android:inputType="number" />

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