diff --git a/src/main/res/values/attrs.xml b/src/main/res/values/attrs.xml
index 85c250f1..cb3046aa 100644
--- a/src/main/res/values/attrs.xml
+++ b/src/main/res/values/attrs.xml
@@ -1,8 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <declare-styleable name="SummaryPreference">
-        <attr name="summary" format="string" />
-    </declare-styleable>
     <declare-styleable name="DropDownPreference">
         <attr name="entries" format="reference" />
         <attr name="entryValues" format="reference" />
diff --git a/src/main/scala/com/github/shadowsocks/preferences/DropDownPreference.scala b/src/main/scala/com/github/shadowsocks/preferences/DropDownPreference.scala
index c42891f3..0067f403 100644
--- a/src/main/scala/com/github/shadowsocks/preferences/DropDownPreference.scala
+++ b/src/main/scala/com/github/shadowsocks/preferences/DropDownPreference.scala
@@ -38,7 +38,6 @@ final class DropDownPreference(private val mContext: Context, attrs: AttributeSe
     mSpinner.performClick
     true
   })
-  initSummary(mContext, attrs)
   val a: TypedArray = mContext.obtainStyledAttributes(attrs, R.styleable.DropDownPreference)
   setEntries(a.getTextArray(R.styleable.DropDownPreference_entries))
   mEntryValues = a.getTextArray(R.styleable.DropDownPreference_entryValues)
diff --git a/src/main/scala/com/github/shadowsocks/preferences/NumberPickerPreference.scala b/src/main/scala/com/github/shadowsocks/preferences/NumberPickerPreference.scala
index 9fa2d7aa..bbdcc833 100644
--- a/src/main/scala/com/github/shadowsocks/preferences/NumberPickerPreference.scala
+++ b/src/main/scala/com/github/shadowsocks/preferences/NumberPickerPreference.scala
@@ -22,7 +22,6 @@ final class NumberPickerPreference(context: Context, attrs: AttributeSet = null)
     setMax(a.getInt(R.styleable.NumberPickerPreference_max, Int.MaxValue - 1))
     a.recycle
   }
-  initSummary(context, attrs)
 
   def getValue = value
   def getMin = if (picker == null) 0 else picker.getMinValue
diff --git a/src/main/scala/com/github/shadowsocks/preferences/SummaryPreference.scala b/src/main/scala/com/github/shadowsocks/preferences/SummaryPreference.scala
index 15e59970..4e5339a1 100644
--- a/src/main/scala/com/github/shadowsocks/preferences/SummaryPreference.scala
+++ b/src/main/scala/com/github/shadowsocks/preferences/SummaryPreference.scala
@@ -1,23 +1,12 @@
 package com.github.shadowsocks.preferences
 
-import android.content.Context
 import android.preference.Preference
-import android.util.AttributeSet
-import com.github.shadowsocks.R
 
 /**
   * Make your preference support %s in summary. Override getSummaryValue to customize what to put in.
   * @author Mygod
   */
 trait SummaryPreference extends Preference {
-  private var mSummary: String = _
-
-  protected def initSummary(context: Context, attrs: AttributeSet) {
-    val a = context.obtainStyledAttributes(attrs, R.styleable.SummaryPreference)
-    mSummary = a.getString(R.styleable.SummaryPreference_summary)
-    a.recycle
-  }
-
   protected def getSummaryValue: AnyRef
 
   /**
@@ -26,19 +15,5 @@ trait SummaryPreference extends Preference {
     *
     * @return the summary with appropriate string substitution
     */
-  override def getSummary = {
-    val entry = getSummaryValue
-    if (mSummary == null || entry == null) super.getSummary else String.format(mSummary, entry)
-  }
-  /**
-    * Sets the summary for this Preference with a CharSequence. If the summary has a String formatting marker in it
-    * (i.e. "%s" or "%1$s"), then the current entry value will be substituted in its place when it's retrieved.
-    *
-    * @param summary The summary for the preference.
-    */
-  override def setSummary(summary: CharSequence) {
-    super.setSummary(summary)
-    if (summary == null && mSummary != null) mSummary = null
-    else if (summary != null && summary != mSummary) mSummary = summary.toString
-  }
+  override def getSummary = String.format(super.getSummary.toString, getSummaryValue)
 }