根据@ hammer的回答，这里是伪代码，它应该如何工作。 假设你的主活动名为BaseActivity，它有子片段(就像SlidingMenu库的例子一样)。 以下是步骤:

首先，我们需要创建接口和类，实现它的接口具有泛型方法

Create class interface OnBackPressedListener public interface OnBackPressedListener { public void doBack(); } Create class which implements skills of OnBackPressedListener public class BaseBackPressedListener implements OnBackPressedListener { private final FragmentActivity activity; public BaseBackPressedListener(FragmentActivity activity) { this.activity = activity; } @Override public void doBack() { activity.getSupportFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE); } } Since now, we will work on our code BaseActivity and its fragments Create private listener on top of your class BaseActivity protected OnBackPressedListener onBackPressedListener; create method to set listener in BaseActivity public void setOnBackPressedListener(OnBackPressedListener onBackPressedListener) { this.onBackPressedListener = onBackPressedListener; } in override onBackPressed implement something like that @Override public void onBackPressed() { if (onBackPressedListener != null) onBackPressedListener.doBack(); else super.onBackPressed(); in your fragment in onCreateView you should add our listener @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { activity = getActivity(); ((BaseActivity)activity).setOnBackPressedListener(new BaseBackPressedListener(activity)); View view = ... ; //stuff with view return view; }

瞧，现在当你在片段中单击返回时，你应该捕获你的自定义on back方法。

解决方法很简单:

如果您有一个所有片段都扩展的基片段类，那么将此代码添加到它的类中，否则创建这样一个基片段类

/* 
* called when on back pressed to the current fragment that is returned
*/
public void onBackPressed()
{
    // add code in super class when override
}

在你的Activity类中，重写onBackPressed如下:

private BaseFragment _currentFragment;

@Override
public void onBackPressed()
{
      super.onBackPressed();
     _currentFragment.onBackPressed();
}

在Fragment类中，添加你想要的代码:

@Override
public void onBackPressed()
{
    setUpTitle();
}

好了，伙计们，我终于找到一个好办法了。

在你的onCreate()在你的活动中容纳你的片段添加一个backstack更改监听器，如下所示:

    fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
        @Override
        public void onBackStackChanged() {
            List<Fragment> f = fragmentManager.getFragments();
            //List<Fragment> f only returns one value
            Fragment frag = f.get(0);
            currentFragment = frag.getClass().getSimpleName();
        }
    });

(同时添加我的fragmenManager是在活动O 现在每次你改变fragment，当前的fragment String就会变成当前fragment的名字。然后在onBackPressed()活动中，你可以这样控制后退按钮的动作:

    @Override
    public void onBackPressed() {

    switch (currentFragment) {
        case "FragmentOne":
            // your code here
            return;
        case "FragmentTwo":
            // your code here
            return;
        default:
            fragmentManager.popBackStack();
            // default action for any other fragment (return to previous)
    }

}

我可以确认这个方法对我有用。

更新:OnBackPressedDispatcher应该被使用。

指南如何使用可在developer.android.com/guide/navigation/navigation-custom-back

你可以在activity中注册fragment来处理背按:

interface BackPressRegistrar {
    fun registerHandler(handler: BackPressHandler)
    fun unregisterHandler(handler: BackPressHandler)
}

interface BackPressHandler {
    fun onBackPressed(): Boolean
}

用法:

在片段:

private val backPressHandler = object : BackPressHandler {
    override fun onBackPressed(): Boolean {
        showClosingWarning()
        return false
    }
}

override fun onResume() {
    super.onResume()
    (activity as? BackPressRegistrar)?.registerHandler(backPressHandler)
}

override fun onStop() {
    (activity as? BackPressRegistrar)?.unregisterHandler(backPressHandler)
    super.onStop()
}

在活动:

class MainActivity : AppCompatActivity(), BackPressRegistrar {


    private var registeredHandler: BackPressHandler? = null
    override fun registerHandler(handler: BackPressHandler) { registeredHandler = handler }
    override fun unregisterHandler(handler: BackPressHandler) { registeredHandler = null }

    override fun onBackPressed() {
        if (registeredHandler?.onBackPressed() != false) super.onBackPressed()
    }
}

如果你使用androidx.appcompat:appcompat:1.1.0或以上，那么你可以添加一个OnBackPressedCallback到你的片段，如下所示

requireActivity()
    .onBackPressedDispatcher
    .addCallback(this, object : OnBackPressedCallback(true) {
        override fun handleOnBackPressed() {
            Log.d(TAG, "Fragment back pressed invoked")
            // Do custom work here    

            // if you want onBackPressed() to be called as normal afterwards
            if (isEnabled) {
                isEnabled = false
                requireActivity().onBackPressed()
            }
        }
    }
)

参见https://developer.android.com/guide/navigation/navigation-custom-back

在kotlin的情况下使用这个onAttach回调

        override fun onAttach(context: Context) {
          super.onAttach(context)
           val callback: OnBackPressedCallback = object : 
                 OnBackPressedCallback(true) {
                 override fun handleOnBackPressed() {
                 // your onbackpressed code 


            }
          }
      requireActivity().onBackPressedDispatcher.addCallback(this, callback)
      }