Juggler (0.1.22 with support libs, 0.1.23 with androidx libs)

What is it?

Juggler is an Android framework represents navigation as a state machine. You need a Juggler if you want to operate not separated fragments, activities and layouts but combinations of them.

How to use it?

Add dependency.

In your root build.gradle add my bintray repository:

allprojects {
    repositories {
        ...
        maven {
            url 'https://dl.bintray.com/dsokolov/maven'
        }
    }
}

In your project build.gradle (usually app/build.gralde or mobile/build.gralde):

dependencies {
    ...
    compile 'me.ilich:juggler:0.1.18'
}

Terms

State is a combination of layout and its fragments. This is a screen user see and interact with.

State stack is a stack of states. The last item in stack is a current screen.

Transition is a process on changing state. It includes two phases:

Transition remove is a removing some items from state stack (pop);
Transition add is an adding items to stack (push).

Usage

First of all, you should create all fragments you need:

public class MainFragment extends JugglerFragment {

    public static MainFragment newInstance() {
        return new MainFragment();
    }
    
    ...
    
}

public class StandardToolbarFragment extends JugglerToolbarFragment {

    public static StandardToolbarFragment create() {
        StandardToolbarFragment f = new StandardToolbarFragment();
        Bundle b = new Bundle();
        addDisplayOptionsToBundle(b, ActionBar.DISPLAY_SHOW_TITLE);
        f.setArguments(b);
        return f;
    }

    @Override
    protected int getToolbarId() {
        return R.id.toolbar;
    }
    
    ...

}

public class StandardNavigationFragment extends JugglerNavigationFragment {

    public static StandardNavigationFragment create(int itemId) {
        StandardNavigationFragment f = new StandardNavigationFragment();
        Bundle b = new Bundle();
        addSelectedItemToBundle(b, itemId);
        f.setArguments(b);
        return f;
    }

    ...

}

Then link it together by state:

public class MainState extends ContentToolbarNavigationState<VoidParams> {

    public MainState() {
        super(VoidParams.instance());
    }

    @Override
    protected JugglerFragment onConvertContent(VoidParams params, JugglerFragment fragment) {
        return MainFragment.newInstance();
    }

    @Override
    protected JugglerFragment onConvertToolbar(VoidParams params, JugglerFragment fragment) {
        return StandardToolbarFragment.create();
    }

    @Override
    protected JugglerFragment onConvertNavigation(VoidParams params, JugglerFragment fragment) {
        return StandardNavigationFragment.create(0);
    }

}

You have to had only one activity extends java JugglerActivity. Probably it should be solile and main activity:

public class HelloActivity extends JugglerActivity {

    @Override
    protected State createState() {
        return new MainState();
    }
    
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="me.ilich.juggler.hello">

    <application>

        <activity android:name=".gui.HelloActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

That is all. Now you can use navigateTo method of JugglerFragment to replace one or many fragments on current activity.

If you need use java android.transition for navigate screens you can use:

addSharedElement(View view, String transitionName) off your State object if you used Add.deeper
or addActivityOptions(Bundle activityOptions) off your State object if you used Add.newActivity or Add.newActivityForResult

But if you used second variant you need used getJugglerActivity().supportStartPostponedEnterTransition() in your Fragment after setting transitionName your Views.