androidx.fragment.app.FragmentTransaction#setPrimaryNavigationFragment ( )源码实例Demo

private void setChildFragmentsInternal(List<AwesomeFragment> fragments) {
    FragmentManager fragmentManager = getChildFragmentManager();
    FragmentTransaction transaction = fragmentManager.beginTransaction();
    for (int i = 0, size = fragments.size(); i < size; i++) {
        AwesomeFragment fragment = fragments.get(i);
        fragmentTags.add(fragment.getSceneId());
        transaction.add(R.id.tabs_content, fragment, fragment.getSceneId());
        if (i == selectedIndex) {
            transaction.setMaxLifecycle(fragment, Lifecycle.State.RESUMED);
            transaction.setPrimaryNavigationFragment(fragment);
        } else {
            transaction.setMaxLifecycle(fragment, Lifecycle.State.STARTED);
            transaction.hide(fragment);
        }
    }
    transaction.commit();
    FragmentHelper.executePendingTransactionsSafe(fragmentManager);
}
 

private void setSelectedIndexInternal(int index) {
    if (tabBarProvider != null) {
        tabBarProvider.setSelectedIndex(index);
    }

    if (selectedIndex == index) {
        return;
    }

    selectedIndex = index;
    FragmentManager fragmentManager = getChildFragmentManager();
    AwesomeFragment previous = (AwesomeFragment) fragmentManager.getPrimaryNavigationFragment();
    AwesomeFragment current = fragments.get(index);
    FragmentTransaction transaction = fragmentManager.beginTransaction();
    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
    transaction.setPrimaryNavigationFragment(current);
    if (previous != null && previous.isAdded()) {
        setPresentAnimation(current, previous);
        transaction.setMaxLifecycle(previous, Lifecycle.State.STARTED);
        transaction.hide(previous);
    }
    transaction.setMaxLifecycle(current, Lifecycle.State.RESUMED);
    transaction.show(current);
    transaction.commit();
    FragmentHelper.executePendingTransactionsSafe(fragmentManager);

    if (tabBar != null) {
        NavigationFragment navigationFragment = current.getNavigationFragment();
        if (navigationFragment != null && navigationFragment.shouldHideTabBarWhenPushed()) {
            if (navigationFragment.getChildFragmentCountAtBackStack() <= 1) {
                showTabBar();
            } else {
                hideTabBar();
            }
        } else {
            showTabBar();
        }
    }
}
 

public static void addFragmentToAddedList(@NonNull FragmentManager fragmentManager, int containerId, @NonNull AwesomeFragment fragment, @NonNull Lifecycle.State maxLifecycle, boolean primary) {
    if (fragmentManager.isDestroyed()) {
        return;
    }

    FragmentTransaction transaction = fragmentManager.beginTransaction();
    transaction.add(containerId, fragment, fragment.getSceneId());
    if (primary) {
        transaction.setPrimaryNavigationFragment(fragment); // primary
    }
    transaction.setMaxLifecycle(fragment, maxLifecycle);
    transaction.commit();
    executePendingTransactionsSafe(fragmentManager);
}
 

void showFragment(String tag, Bundle args, boolean addToBackstack) {
    if (isFinishing() || isDestroyed()) {
        return;
    }

    FragmentManager fm = getSupportFragmentManager();

    Fragment fragment = fm.findFragmentByTag(tag);
    if (fragment == null) {
        switch (tag) {
            case FRAGMENT_MESSAGES:
                fragment = new MessagesFragment();
                break;
            case FRAGMENT_INFO:
                fragment = new TopicInfoFragment();
                break;
            case FRAGMENT_PERMISSIONS:
                fragment = new TopicPermissionsFragment();
                break;
            case FRAGMENT_EDIT_MEMBERS:
                fragment = new EditMembersFragment();
                break;
            case FRAGMENT_VIEW_IMAGE:
                fragment = new ImageViewFragment();
                break;
            case FRAGMENT_FILE_PREVIEW:
                fragment = new FilePreviewFragment();
                break;
            case FRAGMENT_INVALID:
                fragment = new InvalidTopicFragment();
                break;
        }
    } else if (args == null) {
        // Retain old arguments.
        args = fragment.getArguments();
    }
    if (fragment == null) {
        throw new NullPointerException();
    }

    args = args != null ? args : new Bundle();
    args.putString("topic", mTopicName);
    args.putString(MessagesFragment.MESSAGE_TO_SEND, mMessageText);
    if (fragment.getArguments() != null) {
        fragment.getArguments().putAll(args);
    } else {
        fragment.setArguments(args);
    }

    FragmentTransaction trx = fm.beginTransaction();
    if (!fragment.isAdded()) {
        trx = trx.replace(R.id.contentFragment, fragment, tag)
                .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
    } else if (!fragment.isVisible()) {
        trx = trx.show(fragment);
    } else {
        addToBackstack = false;
    }

    if (FRAGMENT_MESSAGES.equals(tag)) {
        trx.setPrimaryNavigationFragment(fragment);
    }

    if (addToBackstack) {
        trx.addToBackStack(tag);
    }
    if (!trx.isEmpty()) {
        trx.commit();
    }
}