说明

这是因为，交易你操纵的ViewGroup 等 FrameLayouts 是容器碎片。但是，当你直接把你的片段XML布局，那么它就变成永久性 View层次结构中的一部分，因为它是永久性的，它不能从code删除。

一旦你得到你的布局固定的，删除（）通话已不再需要 - 这将足以只是更换（）

My requirement is quite simple: I have a button that should replace a FragmentA by FragmentB.

This sounds easy and nearly work, the big problem is that the old fragment is not removed and the new placed on the front of the old one and they are "living" together in my layout.

The Code:

FragmentManager fragMgr = a.getSupportFragmentManager();
Fragment currentFragment = (Fragment) fragMgr.findFragmentById(R.id.fragmentitself);

if(currentFragment!=null){

     FragmentTransaction fragTrans = fragMgr.beginTransaction();
     fragTrans.remove(currentFragment);

     FragmentB newFragment = new FragmentB();
     fragTrans.replace(R.id.fragmentcontainer, newFragment);
     // I have also tried with R.id.fragmentitself
     fragTrans.addToBackStack(null);
     fragTrans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
     fragTrans.commit();
}

The Layout:

<FrameLayout
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:layout_weight="2" 
    android:id="@+id/fragmentcontainer">

    <fragment
        android:id="@+id/fragmentitself"
        android:name="com.WazaBe.MyApp.FragmentA"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</FrameLayout>

Solution

First, you have to remove your fragment from XML and just keep empty container there:

<FrameLayout
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:layout_weight="2" 
    android:id="@+id/fragmentcontainer" />

Then you need to add your com.WazaBe.MyApp.FragmentA fragment from code, i.e. in onCreate() of your parent Activity.

Explanation

It is because with transactions you manipulate ViewGroup such as FrameLayouts that is container for Fragments. But when you place your Fragment directly in XML layout, then it becomes permanent part of the View hierarchy and because it is permanent, it cannot be removed from code.

Once you get your layout fixed, the remove() call is no longer needed - it will suffice to just do replace()