java - How can we call one fragment from another class that doesn't contain that fragment?

Question

I am having one activity class : IdeaBoxActivity Here is the layout code of the activity-

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.asif047">


    <android.support.v4.widget.DrawerLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/dl"
        >

        <LinearLayout
            android:id="@+id/flcontent"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar_idea_box"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="?attr/colorPrimary"
                android:minHeight="?attr/actionBarSize"
                app:contentInsetLeft="0dp"
                app:contentInsetStart="16dp"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />



            <android.support.design.widget.TabLayout
                android:id="@+id/tabs_idea"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="?attr/colorPrimary"
                app:tabTextColor="#ffffff"
                />


        <android.support.v4.view.ViewPager
            android:id="@+id/container_idea"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />



        </LinearLayout>

        <android.support.design.widget.NavigationView

            android:id="@+id/nv"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            android:background="#ffffff"
            app:headerLayout="@layout/header"
            app:itemIconTint="#000000"
            app:itemTextColor="#000000"
            app:menu="@menu/drawermenu"

            >


        </android.support.design.widget.NavigationView>


    </android.support.v4.widget.DrawerLayout>



</android.support.design.widget.CoordinatorLayout>

I have added some fragments in the IdeaBoxActivity .

I have added the fragments using following method-

private void setupViewPager(ViewPager viewPager) {
    SectionPageadapter sectionPageadapter = new SectionPageadapter(getSupportFragmentManager());
    sectionPageadapter.addFragment(new IdeasFragment(), "Ideas");
    sectionPageadapter.addFragment(new WriteIdeaFragment(), "Write Idea");
    sectionPageadapter.addFragment(new MyIdeasFragment(), "My Ideas");

    viewPager.setAdapter(sectionPageadapter);
}

Among these fragments one is : IdeasFragment

I have another activity which named: HappyWallActivity From this Activity I have called one adapter class named: RecyclerAdapterSeeAll

public class RecyclerAdapterSeeAll extends RecyclerView.Adapter<RecyclerAdapterSeeAll.MyViewHolder>{

    private List<ModelHappySeeAll> modelHappySeeAlls;
    private Context context;
    private int id = 0;
    private String status = "";

    public RecyclerAdapterSeeAll( Context context, List<ModelHappySeeAll> modelHappySeeAlls) {
        this.modelHappySeeAlls = modelHappySeeAlls;
        this.context = context;
    }


    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_item_see_all, parent, false);
        return  new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {

        holder.tvName.setText(modelHappySeeAlls.get(position).getName());
        holder.tvDetails.setText(modelHappySeeAlls.get(position).getDetails());

        holder.setItemClickListener(new ItemClickListener() {
            @Override
            public void onItemClick(int pos) {


            }
        });



    }

    @Override
    public int getItemCount() {
        return modelHappySeeAlls.size();
    }


    public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        TextView tvName, tvDetails;
        ItemClickListener itemClickListener;

        public MyViewHolder(View itemView) {
            super(itemView);
            tvName = itemView.findViewById(R.id.textview_name_see_all);
            tvDetails = itemView.findViewById(R.id.textview_happy_post_see_all);
        }

        public void setItemClickListener ( ItemClickListener itemClickListener){
            this.itemClickListener = itemClickListener;
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View view) {
            this.itemClickListener.onItemClick(this.getLayoutPosition());
        }
    }

}

In this class inside holder.setItemClickListener I want to call IdeasFragment of the IdeaBoxActivity.

Is there any way of doing this? If yes, then please help me with the code that should work.

Answer 1

You have to use the same instance of Ideas fragment by probably storing the original instance made on new IdeasFragment() to a global variable, or you could pass the instance when you do new RecyclerAdapterSeeAll(IdeasFragment instance) and use it like that. Either way the idea here is to use the same instances on both classes.

Globals in java

public static IdeasFragment myInstance= new IdeasFragment(); 

private void setupViewPager(ViewPager viewPager) {
    SectionPageadapter sectionPageadapter = new 
    SectionPageadapter(getSupportFragmentManager());
    sectionPageadapter.addFragment(myInstance, "My Ideas");

    viewPager.setAdapter(sectionPageadapter);
} 

And on the click listener:

public void setItemClickListener ( ItemClickListener itemClickListener){

    IdeaBoxActivity.myInstance.start(); // call the function needed to start the IdeasFragment here
}