diff --git a/Aria/src/main/java/com/arialyy/aria/core/inf/AbsTarget.java b/Aria/src/main/java/com/arialyy/aria/core/inf/AbsTarget.java
index cc4be12c..41d39541 100644
--- a/Aria/src/main/java/com/arialyy/aria/core/inf/AbsTarget.java
+++ b/Aria/src/main/java/com/arialyy/aria/core/inf/AbsTarget.java
@@ -81,7 +81,11 @@ public abstract class AbsTarget<TARGET extends AbsTarget, ENTITY extends AbsEnti
    * @param str 扩展数据
    */
   public TARGET setExtendField(String str) {
-    mEntity.setStr(str);
+    if (TextUtils.isEmpty(str)) return (TARGET) this;
+    if (TextUtils.isEmpty(mEntity.getStr()) || !mEntity.getStr().equals(str)) {
+      mEntity.setStr(str);
+      mEntity.save();
+    }
     return (TARGET) this;
   }
 
diff --git a/app/src/main/java/com/arialyy/simple/download/SingleTaskActivity.java b/app/src/main/java/com/arialyy/simple/download/SingleTaskActivity.java
index aaab2bb9..67825479 100644
--- a/app/src/main/java/com/arialyy/simple/download/SingleTaskActivity.java
+++ b/app/src/main/java/com/arialyy/simple/download/SingleTaskActivity.java
@@ -18,6 +18,7 @@ package com.arialyy.simple.download;
 
 import android.os.Bundle;
 import android.os.Environment;
+import android.os.Handler;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -31,6 +32,7 @@ import com.arialyy.aria.core.download.DownloadTarget;
 import com.arialyy.aria.core.Aria;
 import com.arialyy.aria.core.download.DownloadTask;
 import com.arialyy.aria.core.inf.IEntity;
+import com.arialyy.frame.util.show.L;
 import com.arialyy.frame.util.show.T;
 import com.arialyy.simple.R;
 import com.arialyy.simple.base.BaseActivity;
@@ -200,8 +202,10 @@ public class SingleTaskActivity extends BaseActivity<ActivitySingleBinding> {
         Aria.download(this)
             .load(DOWNLOAD_URL)
             .addHeader("groupName", "value")
+            .setExtendField("str___ggggggg")
             .setDownloadPath(Environment.getExternalStorageDirectory().getPath() + "/gggg.apk")
             .start();
+
         break;
       case R.id.stop:
         Aria.download(this).load(DOWNLOAD_URL).stop();