Android中使用fragment出现异常，Error inflating class fragment

异常：
在xml文件中静态引用fragment，出现了以下异常：

Caused by: android.view.InflateException: Binary XML file line #9 in com.hsf.fragmenttest:layout/activity_main: Binary XML file line #9 in com.hsf.fragmenttest:layout/activity_main: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #9 in com.hsf.fragmenttest:layout/activity_main: Error inflating class fragment
Caused by: java.lang.IllegalArgumentException: Binary XML file line #9: Must specify unique android:id, android:tag, or have a parent with an id for com.hsf.fragmenttest.LeftFragment

解决方法：
在xml中给fragment添加id属性