在它们之间切换时避免刷新片段

Question

我使用导航栏创建了一个活动，在其中我通过按下它们来切换内容（片段）。问题是每次我这样做时，我都会刷新片段，而在从它们切换之前无法看到内容。这是我的代码：

private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
        = new BottomNavigationView.OnNavigationItemSelectedListener() {

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {

        Fragment fragment;
        switch (item.getItemId()) {
            case R.id.bbn_item1:
                onResume();
                if(isNetworkAvailable()){
                    fragment = new HomeFragment();
                }else {
                    fragment= new NetworkNotAvailable();
                }
                currentIndex=0;
                FragmentTransaction transaction = getSupportFragmentManager()
                        .beginTransaction()
                        .setCustomAnimations(R.anim.pull_in_left,R.anim.push_out_right);
                transaction.replace(R.id.fragment_container, fragment);
                transaction.addToBackStack(null);
                transaction.commit();

                return true;
            case R.id.bbn_item2:
                if(isNetworkAvailable()){
                    fragment = new PopularFragment();
                }else {
                    fragment= new NetworkNotAvailable();
                }
                try{
                    if(currentIndex < 1 ){
                        FragmentTransaction transactionb = getSupportFragmentManager()
                                .beginTransaction()
                                .setCustomAnimations(R.anim.pull_in_right,R.anim.push_out_left);
                        transactionb.replace(R.id.fragment_container, fragment);
                        transactionb.addToBackStack(null);
                        transactionb.commit();
                        currentIndex=1;

                    }else if (currentIndex > 1){
                        FragmentTransaction transactionb = getSupportFragmentManager()
                                .beginTransaction()
                                .setCustomAnimations(R.anim.pull_in_left,R.anim.push_out_right);
                        transactionb.replace(R.id.fragment_container, fragment);
                        transactionb.addToBackStack(null);
                        transactionb.commit();
                        currentIndex=1;
                    }

                } catch (Exception e) {
                    e.printStackTrace();
                }


                return true;
            case R.id.bbn_item3:
                if(isNetworkAvailable()){
                    fragment = new PlayingFragment();
                }else {
                    fragment= new NetworkNotAvailable();
                }
                currentIndex=2;
                FragmentTransaction transactionc = getSupportFragmentManager()
                        .beginTransaction()
                        .setCustomAnimations(R.anim.pull_in_right,R.anim.push_out_left);
                transactionc.replace(R.id.fragment_container, fragment);
                transactionc.addToBackStack(null);
                transactionc.commit();
                return true;
        }
        return false;
    }
};

在我的活动中，我已经实现了 onResume() 方法，但它似乎在我打开片段后立即被调用（它作为 onCreate() 工作）

Answer 1

我通过保存每个片段的实例并将其作为参数传递给活动过滤器而不是通用的“new Fragment()”来解决。