Widget Using Constraint Layout

Question

I am Trying to use constraintLayout for my widget but it gave me an error at line #0(Doesn't xml start at line 1?).

Here is the code:

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFF"
    android:padding="@dimen/widget_margin">


    <TextView
        android:id="@+id/appwidget_text"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:layout_margin="8dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:background="#09C"
        android:text="@string/appwidget_text"
        android:textColor="#ffffff"
        android:textSize="24sp"
        android:textStyle="bold|italic"
        android:gravity="center"
        app:layout_constraintBottom_toTopOf="@+id/split2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.501"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:contentDescription="@string/appwidget_text"/>

    <Button
        android:id="@+id/flip"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginBottom="8dp"
        android:layout_marginStart="8dp"
        android:text="@string/show_answer"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/split"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/split2" />

    <Button
        android:id="@+id/next"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:text="@string/next_question"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="@+id/split"
        app:layout_constraintTop_toBottomOf="@+id/split2" />

    <android.support.constraint.Guideline
        android:id="@+id/split"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.5" />

    <android.support.constraint.Guideline
        android:id="@+id/split2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.75" />

</android.support.constraint.ConstraintLayout>

Error:

Binary XML file line #0: Binary XML file line #0: Error inflating class android.support.constraint.ConstraintLayout

Note: I tried it using Linear layout and it worked, but I prefer to do it using constraintLayout.

Answer 1

There are only a few View classes that you can use in an app widget. ConstraintLayout is not among them.