Android 如何在片段外部访问片段回收视图？

我有一个活动，其中有5个片段，每个片段中都有recyclerview…我想在我的活动中有一个按钮来保存片段，当我单击该按钮时，recycler视图开始滚动到顶部…我得到滚动部分，从片段中我可以轻松地执行该操作，但如何获得片段recyclerview活动。。。请帮忙

Activity.java

package com.example.khaalijeb.newlistview_module;

import android.content.Intent;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class Search extends AppCompatActivity {

    ImageView navbut;
    ViewPager pager;
    ViewPager mPager;
    TabLayout mTabLayout;
    SearchPagerAdapter mAdapter;
    SlidingTabLayout1 tabs;
    FloatingActionButton fab2;
    String title[] = {"All", "Restaurant", "Wellness", "Fashion", "Others"};
    int numoftab = 5;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search);
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
        ImageView back = (ImageView)findViewById(R.id.back);
        back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                onBackPressed();
            }
        });



        TextView location = (TextView)findViewById(R.id.location);
        location.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent i =new Intent(Search.this,locationsearch.class);
                startActivity(i);

            }
        });

        ImageView locationlogo = (ImageView)findViewById(R.id.locationlogo);
        locationlogo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(Search.this,locationsearch.class);
                startActivity(i);
            }
        });

        Button b = (Button)findViewById(R.id.click);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


            }
        });
        mAdapter = new SearchPagerAdapter(getSupportFragmentManager(),title,numoftab);
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
        mTabLayout = (TabLayout) findViewById(R.id.tab_layout);
        mPager = (ViewPager) findViewById(R.id.pager);
        mPager.setAdapter(mAdapter);
        mTabLayout.setTabsFromPagerAdapter(mAdapter);


        mTabLayout.setupWithViewPager(mPager);
        mPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_search, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Fragment.java

 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.d("hii", "oncreate");
        View view;
        view = inflater.inflate(R.layout.activity_all, container, false);
        NO_MERCHANT = (TextView) getActivity().findViewById(R.id.no_merchant);

        font = Typeface.createFromAsset(getActivity().getAssets(), "fonts/cae.ttf");

        mRecyclerView = (RecyclerView) view.findViewById(R.id.my_recycler_view);

        mRecyclerView.setHasFixedSize(true);
        final LinearLayoutManager l = new LinearLayoutManager(c);
        mRecyclerView.setLayoutManager(l);
        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
     //   mAdapter.setClickListener(this);
        page = 0;
        preLast = 0;
        adapterinitialised = false;

       final FloatingActionButton fab2 = (FloatingActionButton)view.findViewById(R.id.fab2);
        fab2.setVisibility(View.INVISIBLE);
        fab2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                mRecyclerView.smoothScrollToPosition(0);

            }
        });
        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {


            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);


                if(dy != 0) {
                    Log.i("RecyclerView scrolled: ", "scroll up!");
                    fab2.setVisibility(View.VISIBLE);

                }
                else
                    Log.i("RecyclerView scrolled: ", "scroll down!");
                    fab2.setVisibility(View.GONE);




        /*        Log.d("hiii", "scroll hua hai");
                RecyclerView.Recycler recycler = null;
                Log.d("scroll", "dx: " + dx + " dy: " + dy);
                Integer visibleItemCount = mRecyclerView.getChildCount();
                Integer totalItemCount = mLayoutManager.getItemCount();
                Integer firstVisibleItem = ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition();
                //    Integer firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
                Log.d("scroll", "visibleitemcount " + visibleItemCount);
                Log.d("scroll", "totalitemcount " + totalItemCount);
                Log.d("scroll", "firstvisibleitem " + firstVisibleItem);
                final int lastItem = firstVisibleItem + visibleItemCount;
                Log.d("scroll", "lastitem " + lastItem);
                Log.d("hii", "lastitem " + lastItem);

                Log.d("smooth", "firstvis : " + firstVis + " lastItem : " + lastItem);

                if (page == 0 && visibleItemCount == totalItemCount) {
                    Log.d("hii", "did nothing ");
                } else {
                    if (stay_on_this_page == false) {
                        Log.d("hii", "ItemCountLast");
                        Log.d("hii", "" + preLast + "" + lastItem);
                        if (preLast != lastItem) { //to avoid multiple calls for last item
                            if (lastItem >= totalItemCount - 5) {
                                preLast = lastItem;
                                //                  preLast = firstVisibleItem;
                                firstVis = firstVisibleItem + 1;
                                Log.d("llll", "preLast :" + preLast);
                                page++;
                                stay_on_this_page = true;
                                Momoe_Search_requestData();
                            } else {
                                Log.d("hii", "Last");
                            }
                        } else {
                            Log.d("smooth_scroll", "khali");
                        }
                    }

                }*/
            }
        });
        return view;

    }

---

您可以直接从活动中调用片段中的方法。此方法反过来将循环视图滚动到零位置。活动将调用顶部片段实例进行滚动

currentFragment.scrollToTop();

片段将要求滚动recyclerView

scrollToTop()
{
mRecyclerView.smoothScrollToPosition(0);
}