FragNav

Android library for managing multiple stacks of fragments (e.g., Bottom Navigation , Navigation Drawer). This library does NOT include the UI for bottom tab bar layout. For that, I recommend either BottomBar (which is the library shown in the demo) or AHBottomNavigation. This library helps maintain order after pushing onto and popping from multiple stacks(tabs). It also helps with switching between desired tabs and clearing the stacks.

Sample

With Material Design Bottom Navigation pattern, and other tabbed navigation, managing multiple stacks of fragments can be a real headache. The example file shows best practice for navigating deep within a tab stack.

Gradle

compile 'com.ncapdevi:frag-nav:2.0.0'

How do I implement it?

Initialize using a builder and one of two methods

builder = FragNavController.newBuilder(savedInstanceState, getSupportFragmentManager(), R.id.container);

1.

Create a list of fragments and pass them in

List<Fragment> fragments = new ArrayList<>(5);

fragments.add(RecentsFragment.newInstance());
fragments.add(FavoritesFragment.newInstance());
fragments.add(NearbyFragment.newInstance());
fragments.add(FriendsFragment.newInstance());
fragments.add(FoodFragment.newInstance());

builder.rootFragments(fragments);

2.

Allow for dynamically creating the base class by implementing the NavListener in your class and overriding the getRootFragment method

public class YourActivity extends AppCompatActivity implements FragNavController.RootFragmentListener {

builder.rootFragmentListener(this, 5)

    @Override
    public Fragment getRootFragment(int index) {
        switch (index) {
            case INDEX_RECENTS:
                return RecentsFragment.newInstance(0);
            case INDEX_FAVORITES:
                return FavoritesFragment.newInstance(0);
            case INDEX_NEARBY:
                return NearbyFragment.newInstance(0);
            case INDEX_FRIENDS:
                return FriendsFragment.newInstance(0);
            case INDEX_FOOD:
                return FoodFragment.newInstance(0);
        }
        throw new IllegalStateException("Need to send an index that we know");
    }

3.

mFragNavController = builder.build();

SaveInstanceState

Send in the supportFragment Manager, a list of base fragments, the container that you'll be using to display fragments. After that, you have four main functions that you can use In your activity, you'll also want to override your onSaveInstanceState like so

   @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mNavController != null) {
            mNavController.onSaveInstanceState(outState);
        }
    }

Switch tabs

Tab switching is indexed to try to prevent you from sending in wrong indices. It also will throw an error if you try to switch to a tab you haven't defined a base fragment for.

fragNavController.switchTab(NavController.TAB1);

Push a fragment

You can only push onto the currently selected index

        fragNavController.pushFragment(FoodFragment.newInstance())

Pop a fragment

You can only pop from the currently selected index. This can throw an UnsupportedOperationException if trying to pop the root fragment

        fragNavController.popFragment();

Pop multiple fragments

You can pop multiple fragments at once, with the same rules as above applying. If the pop depth is deeper than possible, it will stop when it gets to the root fragment

       fragNavController.popFragments(3);

Replacing a fragment

You can only replace onto the currently selected index

        fragNavController.replaceFragment(Fragment fragment);

You can also clear the stack to bring you back to the base fragment

        fragNavController.clearStack();

You can also navigate your DialogFragments using

        showDialogFragment(dialogFragment);
        clearDialogFragment();
        getCurrentDialogFrag()

Transaction Options

All of the above transactions can also be done with defined transaction options. The FragNavTransactionOptions have a builder that can be used.

public class FragNavTransactionOptions {
    List<Pair<View, String>> sharedElements;
    @FragNavController.Transit
    int transition = FragmentTransaction.TRANSIT_NONE;
    @AnimRes
    int enterAnimation = 0;
    @AnimRes
    int exitAnimation = 0;
    @AnimRes
    int popEnterAnimation = 0;
    @AnimRes
    int popExitAnimation = 0;
    @StyleRes
    int transitionStyle = 0;
    String breadCrumbTitle;
    String breadCrumbShortTitle;
    }  

Get informed of fragment transactions

Have your activity implement FragNavController.TransactionListener and you will have methods that inform you of tab switches or fragment transactions

A sample application is in the repo if you need to see how it works.

Fragment Transitions

Use FragNavController.setTransitionMode();

Helper functions

   /**
     * Get the number of fragment stacks
     *
     * @return the number of fragment stacks
     */
    @CheckResult
    public int getSize()
    
    
    /**
     * Get a copy of the stack at a given index
     *
     * @return requested stack
     */
    @SuppressWarnings("unchecked")
    @CheckResult
    @Nullable
    public Stack<Fragment> getStack(@TabIndex int index)
    
        /**
         * Get a copy of the current stack that is being displayed
         *
         * @return Current stack
         */
        @SuppressWarnings("unchecked")
        @CheckResult
        @Nullable
        public Stack<Fragment> getCurrentStack()
        
            /**
             * Get the index of the current stack that is being displayed
             *
             * @return Current stack index
             */
            @CheckResult
            @TabIndex
            public int getCurrentStackIndex()
            
            
    /**
     * @return If true, you are at the bottom of the stack
     * (Consider using replaceFragment if you need to change the root fragment for some reason)
     * else you can popFragment as needed as your are not at the root
     */
    @CheckResult
    public boolean isRootFragment()
    
        /**
         * @return Current DialogFragment being displayed. Null if none
         */
        @Nullable
        @CheckResult
        public DialogFragment getCurrentDialogFrag()
    

Apps Using FragNav

Feel free to send me a pull request with your app and I'll link you here:

Contributions

If you have any problems, feel free to create an issue or pull request.

The sample app in the repository uses BottomBar library.

License

FragNav Android Fragment Navigation Library
Copyright (c) 2016 Nic Capdevila (http://github.com/ncapdevi).

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.