android 使用Tabhost 发生could not create tab content because could not find view with id 错误

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TabHost

        android:id="@+id/tabhost"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" >
　　

　　　　<RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

　　　　<TabWidget
            android:id="@android:id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >
        </TabWidget>

        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >
        </FrameLayout>

　　</RelativeLayout>

</TabHost>

</RelativeLayout>

protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sign_core);
        
     
        TabHost tabHost = (TabHost) findViewById(R.id.tabhost);
        tabHost.setup();
        
      
        Intent intent = new Intent(this, TestActivity.class);
        TabSpec tab1 = tabHost.newTabSpec("A").setIndicator("A")
                .setContent(intent);
        tabHost.addTab(tab1);
        
    }

　　　　 LocalActivityManager localActivityManager = new LocalActivityManager(this, true);
        localActivityManager.dispatchCreate(savedInstanceState);
        
        TabHost tabHost = (TabHost) findViewById(R.id.tabhost);
        tabHost.setup(localActivityManager);