为什么我的图片在Android中无法滚动？

Question

<ScrollView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/image_scroll_id">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/image_iv"
            android:layout_width="match_parent"
            android:layout_height="220dp"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:adjustViewBounds="true"
            android:contentDescription="@string/sandwich_picture_content_description"
            android:cropToPadding="false"
            android:scaleType="centerCrop" />
    </LinearLayout>
</ScrollView>