方向更改时片段Z顺序更改

Question

My main xml file has a FrameLayout, with one fragment defined in the XML. At runtime, I am adding another fragment on top of this, and then a third fragment on top of this. When I add the runtime fragments, I don't give containerIds to attach them to. This is all fine until the orientation changes. After the orientation change, the third fragment has gone beneath the second fragment. But obviously I want the z-order to stay how it was before the orientation change, ie the last fragment added should be on top and visible.

I've tried using containerIds when adding the fragments, and adding them to the FrameLayout defined in XML, but when I put in containerIds, the runtime fragments simply don't show up at all.

So I'm wondering why the fragments added at runtime don't show when I use a containerId. Is it because they are being added to a container which already contains a fragment (the one defined in XML)? How can I get around this? I've tried adding additional containers to the XML to hold the runtime fragments, but this doesn't seem to work. The only way to get the fragments to show is to remove the containerId from the call to FragmentTransaction.add().

Also, is it possible to change the z-order of fragments manually? I've searched Google quite a lot to find this out and haven't found any answers. I've tried using ViewGroup.bringChildToFront() and using the view returned by the fragment's getView() but this hasn't worked. I've also found out that you can nest fragments on Android 4.2+ with getChildFragmentManager(), but I'm supporting older APIs, and this method doesn't seem to be in the support library.

Any help greatly appreciated!

Answer 1

我解决这个问题的方法是在方向更改后手动重新创建第三个片段，并删除系统创建的片段。