屌炸天的 Fragment Manager

README.md

fragmentManager = new FuckingFragmentManager(this, R.id.container);

navigation.setNavigationItemSelectedListener(menuItem -> {
    if (switchFragment(menuItem.getItemId())) {
        drawer.closeDrawers();
        return true;
    } else {
        return false;
    }
});

private boolean switchFragment(@IdRes int id) {
    switch (id) {
        case R.id.home:
            fragmentManager.switchTo(FeedFragment.class);
            return true;
        case R.id.explore:
            fragmentManager.switchTo(ExploreFragment.class);
            return true;
        default:
            return false;
    }
}

FuckingFragmentManager.java

import android.support.annotation.IdRes;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;

import java.util.HashMap;

public class FuckingFragmentManager {

    private final HashMap<String, Fragment> fragments = new HashMap<>();

    private final FragmentActivity activity;
    private final FragmentManager fragmentManager;

    private final int container;

    private String current;

    public FuckingFragmentManager(FragmentActivity activity, @IdRes int container) {
        this.activity = activity;
        this.fragmentManager = activity.getSupportFragmentManager();
        this.container = container;
    }

    public void switchTo(Class<? extends Fragment> fragment) {
        String name = fragment.getName();

        if (current != null) {
            fragmentManager.beginTransaction().hide(fragments.get(current)).commit();
        }

        if (fragmentManager.findFragmentByTag(name) == null) {
            Fragment instance = Fragment.instantiate(activity, name);
            fragments.put(name, instance);
            fragmentManager.beginTransaction().add(container, instance, name).commit();
        } else {
            fragmentManager.beginTransaction().show(fragments.get(name)).commit();
        }

        current = name;
    }

    @Nullable
    public Fragment getFragment(Class<? extends Fragment> fragment) {
        return fragments.get(fragment.getName());
    }

}