Android fragment 管理器 fragment 变化监听器

Question

当使用 FragmentManager 替换 fragment 时，是否可以添加事件完成时的监听器？

所以

myFragmentManager
            .beginTransaction()
            .replace(R.id.fragmentContainer, fragment, FRAGMENT_TAG)
            .commit()

我可以向 myFragmentManager 添加一个监听器以便我知道 fragment 何时被替换了吗？

Answer 1

FragmentManager (android.support.v4.app.FragmentManager) 有一个很好的方法叫做 registerFragmentLifecycleCallbacks，它可以帮助注册一个 FragmentManager.FragmentLifecycleCallbacks。这允许我们在 fragment 的生命周期内采取行动。您可以根据需要在 onFragmentCreated() 中执行某些操作。

FragmentManager fragmentManager =  getSupportFragmentManager();
        fragmentManager.registerFragmentLifecycleCallbacks(new FragmentManager.FragmentLifecycleCallbacks() {
            @Override
            public void onFragmentPreAttached(FragmentManager fm, Fragment f, Context context) {
                super.onFragmentPreAttached(fm, f, context);
                Log.v("FragXX1", f.getTag());
            }

            @Override
            public void onFragmentAttached(FragmentManager fm, Fragment f, Context context) {
                super.onFragmentAttached(fm, f, context);
                Log.v("FragXX2", f.getTag());
            }

            @Override
            public void onFragmentCreated(FragmentManager fm, Fragment f, Bundle savedInstanceState) {
                super.onFragmentCreated(fm, f, savedInstanceState);
                Log.v("FragXX3", f.getTag());
            }

            @Override
            public void onFragmentActivityCreated(FragmentManager fm, Fragment f, Bundle savedInstanceState) {
                super.onFragmentActivityCreated(fm, f, savedInstanceState);
                Log.v("FragXX4", f.getTag());
            }

            @Override
            public void onFragmentViewCreated(FragmentManager fm, Fragment f, View v, Bundle savedInstanceState) {
                super.onFragmentViewCreated(fm, f, v, savedInstanceState);
                Log.v("FragXX5", f.getTag());
            }

            @Override
            public void onFragmentStarted(FragmentManager fm, Fragment f) {
                super.onFragmentStarted(fm, f);
                Log.v("FragXX6", f.getTag());
            }

            @Override
            public void onFragmentResumed(FragmentManager fm, Fragment f) {
                super.onFragmentResumed(fm, f);
                Log.v("FragXX7", f.getTag());
            }

            @Override
            public void onFragmentPaused(FragmentManager fm, Fragment f) {
                super.onFragmentPaused(fm, f);
                Log.v("FragXX8", f.getTag());
            }

            @Override
            public void onFragmentStopped(FragmentManager fm, Fragment f) {
                super.onFragmentStopped(fm, f);
                Log.v("FragXX9", f.getTag());
            }

            @Override
            public void onFragmentSaveInstanceState(FragmentManager fm, Fragment f, Bundle outState) {
                super.onFragmentSaveInstanceState(fm, f, outState);
                Log.v("FragXX10", f.getTag());
            }

            @Override
            public void onFragmentViewDestroyed(FragmentManager fm, Fragment f) {
                super.onFragmentViewDestroyed(fm, f);
                Log.v("FragXX11", f.getTag());
            }

            @Override
            public void onFragmentDestroyed(FragmentManager fm, Fragment f) {
                super.onFragmentDestroyed(fm, f);
                Log.v("FragXX12", f.getTag());
            }

            @Override
            public void onFragmentDetached(FragmentManager fm, Fragment f) {
                super.onFragmentDetached(fm, f);
                Log.v("FragXX13", f.getTag());
            }
        }, true);

        FragmentTransaction ft = fragmentManager.beginTransaction();
        ft.replace(R.id.container, new TradeFragment(), "trien");
        ft.commit();