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<MyAdapter.MyViewHolder> {

    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：

巴特西

Android简单实现滚动悬停效果

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