更改片段而无需重新创建 [英] Change fragments without re-creation

问题描述

我正在研究MVP.

我在nav菜单上有活动，并且我从菜单中更改片段如下:

I have and activity with nav menu and I change fragments from menu like this:

switch (id) {
    case R.id.nav_status:
        fragmentManager.beginTransaction().replace(R.id.fr_main, mAppProductFragment).commit();
        Log.d(TAG, "Выбрано меню статус");
        break;           
    case R.id.nav_schemas:
        AppRedirectFragment schemasFragment = new AppRedirectFragment();
        fragmentManager.beginTransaction().replace(R.id.fr_main, schemasFragment).commit();
        Log.d(TAG, "Выбрано меню переадресация");
        break;
}

问题是，当我更改片段时，我之前的片段被破坏了.它调用以下回调:

The problem is that when I change the fragment, my previous fragment is destroyed. It calls the following callbacks:

D/AppProductPresenter: onStopDetouchView()
D/AppProductFragment:  onDestroyView
D/AppProductFragment: onDestroy()

它失去了对演示者的引用，并且放弃了所有的改装请求. mPresenter.onDestroyView(); ，所以我所有的网络操作都被破坏了.但我想在后台运行它们.但其处置.

It loses its reference to the presenter and also dsipose all retrofit requests. mPresenter.onDestroyView();, so all my network operations are destroyd. But Id like to run them in backgroud. But its disposed.

public void onDestroy() {
        super.onDestroy();
        mPresenter.onDestroyView();
    }

那么如何在不调用onDestroy的情况下更改片段?我读到我必须使用 add 而不是 fragmentManager.beginTransaction().replace 那怎么正确呢?

So how can change fragments without calling onDestroy being called? I read that I have to use add instead of fragmentManager.beginTransaction().replace So how do it correctly?

推荐答案

我解决了一个问题.答案是使用以下方法的组合: .add .attach 和 .detach 方法.我创建了一个函数来替换这样的碎片:

I solve a problem. The answer is use combo of: .add .attach and .detach methods. I create a function that replace a fragmetns like this:

 switch (id) {
            case R.id.nav_product:
                replaceFragment(PRODUCT_FRAGMENT);
                break;
            case R.id.nav_redirection:
                replaceFragment(REDIRECTION_FRAGMENT);
                break;
}

private void replaceFragment(String tag) {
    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction transaction = fragmentManager.beginTransaction();
    Fragment currentFragment = fragmentManager.findFragmentById(R.id.fr_container);
    Fragment nextFragment = fragmentManager.findFragmentByTag(tag);

    Log.d(TAG, "f detached: " + currentFragment.toString());
    transaction.detach(currentFragment);

    if (nextFragment == null) {
        nextFragment = createFragment(tag);
        transaction.add(R.id.fr_container, nextFragment, tag);
    } else {
        Log.d(TAG, "f attach: " + nextFragment.toString());
        transaction.attach(nextFragment);
    }
    transaction.commit();
}

private Fragment createFragment(String tag) {
    Fragment result = null;
    switch (tag) {
        case CALLHISTORY_FRAGMENT:
            result = new AppCallHistoryFragment();
            break;
        case CALLTRACKING_FRAGMENT:
            result = new AppCallTrackingFragment();
            break;
        case REDIRECTION_FRAGMENT:
            result = new AppRedirectFragment();
            break;
    }
    Log.d(TAG, "create: " + result.toString());
    return result;
}

现在可以了.碎片只有在Activity销毁时才被销毁.

Now its ok. Fragments are Destroyed only when Activity is destroying.

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