带有片段的Recyclrview适配器中的问题

Question

当我尝试点击First Fragments列表中的项目列表时，它不会转到另一个片段。任何人都可以解决这个问题吗？让我知道适配器类中的问题是什么？我无法理解我的问题是什么？

String[] text;
String[] text1;
String str;
Context context;
public ExampleAdapter(Context context,String[] text, String[] text1) {
    this.text = text;
    this.text1 = text1;
    this.context=context;
}

@Override
public ExampleAdapter.ViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {
    LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
    View view = layoutInflater.inflate(R.layout.items_layout, parent, false);
    return new ViewHolders(view);
}
@Override
public void onBindViewHolder(ExampleAdapter.ViewHolders holder, final int position) {

    holder.moviename.setText(text[position]);
    holder.date.setText(text1[position]);

    holder.layout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
                android.support.v4.app.Fragment castFragment = new CastFragment();
            android.support.v4.app.FragmentManager fragmentManager =((FragmentActivity)context).getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.add(R.id.linear,castFragment);
            fragmentTransaction.commit();
        }
    });
    if (position % 2 == 1) {
        holder.layout.setBackgroundColor(Color.parseColor("#eeeeee"));


    } else {
        holder.layout.setBackgroundColor(Color.parseColor("#ffffff"));
    }
}

@Override
public int getItemCount() {
    return  text.length;
}
class ViewHolders extends RecyclerView.ViewHolder {
    TextView moviename, date;
    LinearLayout layout;
    public ViewHolders(View view) {
        super(view);
        moviename = (TextView) view.findViewById(R.id.text);
        date = (TextView) view.findViewById(R.id.text1);
        layout=(LinearLayout)view.findViewById(R.id.layout);
    }
}

logactr erros：

FATAL EXCEPTION: main
                                                          Process:    ctel.animation, PID: 3168
                                                          java.lang.NullPointerException: Attempt to invoke virtual method 'android.support.v4.app.FragmentManager android.support.v4.app.FragmentActivity.getSupportFragmentManager()' on a null object reference
                                                              at ctel.animation.ExampleAdapter$1.onClick(ExampleAdapter.java:48)
                                                              at android.view.View.performClick(View.java:5198)
                                                              at android.view.View$PerformClick.run(View.java:21147)
                                                              at android.os.Handler.handleCallback(Handler.java:739)
                                                              at android.os.Handler.dispatchMessage(Handler.java:95)
                                                              at android.os.Looper.loop(Looper.java:148)
                                                              at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                              at java.lang.reflect.Method.invoke(Native Method)
                                                              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)