有没有一种方法可以在片段中检查popBackStack调用

Question

我有几个片段的后退栈，我需要知道我从另一个返回到其中一个。

就像你有onActivityResult时一样，我想知道是否可以在片段中检查popBackStack()调用？

我在这里调用它:

@Override
public void postFinished(){
    getFragmentManager().popBackStack();
}

在Android Java中有类似的东西吗？

- Lewis Smith

---

返回堆栈更改监听器是唯一的方法，就像@SHIDHIN.T.S在下面发布的答案一样。 - Akshay Paliwal

Answer 1

您可以在Activity页面上添加BackStackChange监听器，例如：

     getSupportFragmentManager().addOnBackStackChangedListener(
            new FragmentManager.OnBackStackChangedListener() {
                public void onBackStackChanged() {

                       // Your Code Here

                }
            });

- SHIDHIN.T.S

Answer 2

 getSupportFragmentManager().addOnBackStackChangedListener(
                new FragmentManager.OnBackStackChangedListener() {
                    public void onBackStackChanged() {
                        FragmentManager fm = getSupportFragmentManager();

                        if (fm != null) {
                            int backStackCount = fm.getBackStackEntryCount();
                            if (backStackCount == 0) {


                            }
                        }
                    }
                });

您可以使用 addOnBackStackChangedListener 和 fm.getBackStackEntryCount();，这将返回片段的后退栈计数。

- Suraj Vaishnav

Answer 3

you can do in onViewCreated() method:

if (savedInstanceState == null && !mAlreadyLoaded) {
    mAlreadyLoaded = true;

    // Do this code only first time, not after rotation or reuse fragment from backstack
}
Because when android put fragment on backstack, it only destroy its view, but don't kill instance itself, so mAlreadyLoaded will be still true when fragment will be restored from backstack.

- Chetan Ansel