Android简单实现滚动悬停效果

import android.content.Context;
import android.support.design.widget.TabLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.MotionEvent;
import android.view.View;

public class DesignStickyActivity extends AppCompatActivity {
    private LinearLayoutManager manager;
    private RecyclerView recyclerview;
    private String[] tabTxt = {"android", "java", "视频", "UI", "ios", "产品","老板","下午茶"};
    private TabLayout tabLayout;
    //判读是否是recyclerView主动引起的滑动，true- 是，false- 否，由tablayout引起的
    private boolean isRecyclerScroll;
    //记录上一次位置，防止在同一内容块里滑动 重复定位到tablayout
    private int lastPos;
    //用于recyclerView滑动到指定的位置
    private boolean canScroll;
    private int scrollToPosition;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_design_scroll);

        recyclerview = findViewById(R.id.recyclerview);
        tabLayout = findViewById(R.id.tablayout);


        //tablayout设置标签
        for (int i = 0; i < tabTxt.length; i++) {
            tabLayout.addTab(tabLayout.newTab().setText(tabTxt[i]));
        }
        //计算内容块所在的高度，全屏高度-状态栏高度-tablayout的高度(这里固定高度50dp)，用于recyclerView的最后一个item view填充高度
        int screenH = getScreenHeight();
        int statusBarH = getStatusBarHeight(this);
        int tabH = 50 * 3;
        int lastH = screenH - statusBarH - tabH;
        manager = new LinearLayoutManager(this);
        recyclerview.setLayoutManager(manager);
        recyclerview.setAdapter(new MyAdapter(this, tabTxt, lastH));

        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                //点击标签，使recyclerView滑动，isRecyclerScroll置false
                int pos = tab.getPosition();
                isRecyclerScroll = false;
                moveToPosition(manager, recyclerview, pos);
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });


        recyclerview.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                //当滑动由recyclerView触发时，isRecyclerScroll 置true
                if (event.getAction() == MotionEvent.ACTION_DOWN) {
                    isRecyclerScroll = true;
                }
                return false;
            }
        });

        recyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                if (canScroll) {
                    canScroll = false;
                    moveToPosition(manager, recyclerView, scrollToPosition);
                }
            }

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                if (isRecyclerScroll) {
                    //第一个可见的view的位置，即tablayou需定位的位置
                    int position = manager.findFirstVisibleItemPosition();
                    if (lastPos != position) {
                        tabLayout.setScrollPosition(position, 0, true);
                    }
                    lastPos = position;
                }
            }
        });

    }
    public void moveToPosition(LinearLayoutManager manager, RecyclerView mRecyclerView, int position) {
        // 第一个可见的view的位置
        int firstItem = manager.findFirstVisibleItemPosition();
        // 最后一个可见的view的位置
        int lastItem = manager.findLastVisibleItemPosition();
        if (position <= firstItem) {
            // 如果跳转位置firstItem 之前(滑出屏幕的情况)，就smoothScrollToPosition可以直接跳转，
            mRecyclerView.smoothScrollToPosition(position);
        } else if (position <= lastItem) {
            // 跳转位置在firstItem 之后，lastItem 之间（显示在当前屏幕），smoothScrollBy来滑动到指定位置
            int top = mRecyclerView.getChildAt(position - firstItem).getTop();
            mRecyclerView.smoothScrollBy(0, top);
        } else {
            // 如果要跳转的位置在lastItem 之后，则先调用smoothScrollToPosition将要跳转的位置滚动到可见位置
            // 再通过onScrollStateChanged控制再次调用当前moveToPosition方法，执行上一个判断中的方法
            mRecyclerView.smoothScrollToPosition(position);
            scrollToPosition = position;
            canScroll = true;
        }
    }

    private int getScreenHeight() {
        return getResources().getDisplayMetrics().heightPixels;
    }

    public int getStatusBarHeight(Context context) {
        int result = 0;
        int resourceId = context.getResources()
                .getIdentifier("status_bar_height", "dimen", "android");
        if (resourceId > 0) {
            result = context.getResources().getDimensionPixelSize(resourceId);
        }
        return result;
    }
}

布局：

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"
    android:layout_width="match_parent"

    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/gray"
        app:elevation="0dp">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="200dp"
            android:background="@android:color/holo_orange_light"
            android:gravity="center"
            android:text="这是头部滚动部分"
            app:layout_scrollFlags="scroll"/>

        <android.support.design.widget.TabLayout
            android:id="@+id/tablayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:tabIndicatorColor="@color/colorAccent"
            app:tabMode="scrollable"
            app:tabSelectedTextColor="@color/colorAccent" />

    android.support.design.widget.AppBarLayout>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

android.support.design.widget.CoordinatorLayout>

RecyclerView中的adapter

package com.tabscroll;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

public class MyAdapter extends RecyclerView.Adapter {

    private Context context;
    private String[] tabTxt;
    private int lastH;

    public MyAdapter(Context context, String[] tabTxt, int lastH) {
        this.context = context;
        this.tabTxt = tabTxt;
        this.lastH = lastH;
    }

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

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        holder.anchorView.setContentTxt(tabTxt[position]);
        holder.anchorView.setAnchorTxt(tabTxt[position]);
        //判断最后一个view
        if (position == tabTxt.length - 1) {
            System.out.println("positon 》"+position);
            if (holder.anchorView.getHeight() < lastH) {
                LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
                params.height = lastH;
                holder.anchorView.setLayoutParams(params);
            }
        }else {
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
            holder.anchorView.setLayoutParams(params);

        }
    }

    @Override
    public int getItemCount() {
        return tabTxt.length;
    }

    public static class MyViewHolder extends RecyclerView.ViewHolder {
        private AnchorView anchorView;

        public MyViewHolder(View itemView) {
            super(itemView);
            anchorView = itemView.findViewById(R.id.anchorView);
        }
    }


}

效果如下：

 

转载于:https://www.cnblogs.com/loaderman/p/10511836.html