Unable to start activity

java.lang.RuntimeException: Unable to start activity 
ComponentInfo{com.example.fragmentdemoone/com.example.fragmentdemoone.MainActivity}: 
android.view.InflateException: Binary XML file line #13 in com.example.fragmentdemoone:layout/activity_main: Binary XML file line #13 in com.example.fragmentdemoone:layout/activity_main: Error inflating class fragment

在相应的xml控件中添加name属性即可：

android:name="com.example.fragmentdemoone.Fragment1"