android - android 中的 Fragments 问题

Question

当我单击布局中的后退图标时，它会转到上一个 fragment ，但不会转到它被杀死的 fragment 。解决方案是什么？
我正在使用 finish() 和 backstack 但它对我不起作用

    back.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

                android.support.v4.app.Fragment onlineFragments = new OnlineFragments();
                android.support.v4.app.FragmentManager fragmentManagerprofile = getActivity().getSupportFragmentManager();
                android.support.v4.app.FragmentTransaction fragmentprofileTransaction = fragmentManagerprofile.beginTransaction();
                fragmentprofileTransaction.replace(R.id.background_fragment, onlineFragments);
                fragmentprofileTransaction.commit();
        }
    });

fragment A

        case R.id.recharge:
            HomeActvity.toolbar.setVisibility(View.GONE);
            android.support.v4.app.Fragment Recharge = new Prepaid_recharge();
            android.support.v4.app.FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
            android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.replace(R.id.containerView, Recharge);
            fragmentTransaction.commit();
            break;

Answer 1

每当你在 fragment 之间进行事务并且你想导航回到前一个 fragment (后退按钮)时，在事务中，你必须在提交之前将此事务添加到 backStack:

Android 文档:

“然而，在您调用 commit() 之前，您可能想要调用 addToBackStack()，以便将事务添加到 fragment 事务的后退栈中。此返回堆栈由 Activity 管理，允许用户通过按“返回”按钮返回到之前的 fragment 状态。”

https://developer.android.com/guide/components/fragments.html#Transactions

// Create new fragment and transaction
Fragment newFragment = new ExampleFragment();
FragmentTransaction transaction = getFragmentManager().beginTransaction();

// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack
transaction.replace(R.id.fragment_container, newFragment);
transaction.addToBackStack(null);

// Commit the transaction
transaction.commit();