XML : How can I figure "android.view.InflateException: Binary XML file line #6: Error inflating class fragemnt" out?

This error occurs when the application starts

Can anybody explain why this error occurs? And what I can do to fix this problem?

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Android Monitor:

  12-05 00:06:28.842 13607-13607/com.thefat.lingjunqi.enricher E/AndroidRuntime: FATAL EXCEPTION: main    12-05 00:06:28.842 13607-13607/com.thefat.lingjunqi.enricher E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.thefat.lingjunqi.enricher/com.thefat.lingjunqi.enricher.MainActivity}: android.view.InflateException: Binary XML file line #6: Error inflating class fragment    

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This error occurs when the application starts

Here is a result of XML, however such error occurs in other xmls

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  <?xml version="1.0" encoding="utf-8"?>  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"      android:layout_width="match_parent"      android:layout_height="match_parent">    <fragment      android:id="@+id/reading_title_fragment"      android:name="com.thefat.lingjunqi.enricher.ReadingTitleFragment"      android:layout_width="match_parent"      android:layout_height="match_parent" />    </LinearLayout>    

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  <?xml version="1.0" encoding="utf-8"?>  <manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.thefat.lingjunqi.enricher" >        <application          android:allowBackup="true"          android:icon="@mipmap/ic_launcher"          android:label="@string/app_name"          android:supportsRtl="true"          android:theme="@style/AppTheme" >          <activity android:name=".MainActivity" >              <intent-filter>                  <action android:name="android.intent.action.MAIN" />                    <category android:name="android.intent.category.LAUNCHER" />              </intent-filter>          </activity>          <activity android:name=".ReadingContentActivity" >          </activity>      </application>    </manifest>