一. 图示

（支付宝）（实现的效果）

二. 思路讲解

TabLayout+ScrollView实现即可。每一个tab对应scrollview中包裹的一层布局，以上有4个tab，也就需要inflate 4个布局文件，用来表示每一层的样式内容。

1.页面加载完毕后，记住每一层父布局在Screen中所要滑动至顶部的距离Distance；

2.操作：

a. 当点击tab时：滑动scrollview该层的距离Distance；

b. 当滑动scrollview至对应的层时：选定对应的tab。

三. 代码

1. 布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.ganshenml.tabscrollviewdemo.MainActivity">

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.design.widget.TabLayout
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"></android.support.design.widget.TabLayout>

        <FrameLayout
            android:id="@+id/wrapperFl"
            android:layout_width="match_parent"
            android:layout_height="match_parent"></FrameLayout>
    </FrameLayout>

    <com.ganshenml.tabscrollviewdemo.ObservableScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

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

        </LinearLayout>

    </com.ganshenml.tabscrollviewdemo.ObservableScrollView>
</LinearLayout>

布局代码很简单，可能会有的疑问点有：

a. wrapperFl是用来干啥的？

b. ObservableScrollView又是个什么东西？

（后面说明）

2. 逻辑代码

public class MainActivity extends AppCompatActivity implements ObservableScrollView.ScrollViewListener {
    private static final String TAG = "MainActivity";
    private FrameLayout wrapperFl;
    private TabLayout tabLayout;
    private ObservableScrollView scrollView;
    private LinearLayout containerLl;
    private boolean firstAlreadyInflated = true;
    private ViewGroup firstFloorVg;
    private ViewGroup secondFloorVg;
    private ViewGroup thirdFloorVg;
    private ViewGroup fourthFloorVg;
    private int secondFloorVgPositionDistance;//第二层滑动至顶部的距离
    private int thirdFloorVgPositionDistance;
    private int fourthFloorVgPositionDistance;
    private int currentPosition = 0;
    private boolean tabInterceptTouchEventTag = true;//标志位，用来区分是点击了tab还是手动滑动scrollview

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
        initListeners();
    }

    private void initViews() {
        wrapperFl = (FrameLayout) findViewById(R.id.wrapperFl);
        tabLayout = (TabLayout) findViewById(R.id.tabLayout);
        scrollView = (ObservableScrollView) findViewById(R.id.scrollView);
        containerLl = (LinearLayout) findViewById(R.id.containerLl);
        for (int i = 0; i < 4; i++) {
            tabLayout.addTab(tabLayout.newTab().setText("tab" + (i + 1)));
        }

        firstFloorVg = (ViewGroup) LayoutInflater.from(this).inflate(R.layout.item_floor_first, null);
        secondFloorVg = (ViewGroup) LayoutInflater.from(this).inflate(R.layout.item_floor_second, null);
        thirdFloorVg = (ViewGroup) LayoutInflater.from(this).inflate(R.layout.item_floor_third, null);
        fourthFloorVg = (ViewGroup) LayoutInflater.from(this).inflate(R.layout.item_floor_fourth, null);

        containerLl.addView(firstFloorVg);
        containerLl.addView(secondFloorVg);
        containerLl.addView(thirdFloorVg);
        containerLl.addView(fourthFloorVg);

    }

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if (firstAlreadyInflated) {//获取各层离screen顶部的位置以及计算滑动值相应顶部所需要的距离
            firstAlreadyInflated = false;
            int[] firstFloorVgPosition = new int[2];
            int[] secondFloorVgPosition = new int[2];
            int[] thirdFloorVgPosition = new int[2];
            int[] fourthFloorVgPosition = new int[2];
            firstFloorVg.getLocationOnScreen(firstFloorVgPosition);
            secondFloorVg.getLocationOnScreen(secondFloorVgPosition);
            thirdFloorVg.getLocationOnScreen(thirdFloorVgPosition);
            fourthFloorVg.getLocationOnScreen(fourthFloorVgPosition);
            int firstFloorVgPositionAnchor = firstFloorVgPosition[1];
            int secondFloorVgPositionAnchor = secondFloorVgPosition[1];
            int thirdFloorVgPositionAnchor = thirdFloorVgPosition[1];
            int fourthFloorVgPositionAnchor = fourthFloorVgPosition[1];

            Log.d(TAG, "第一层距离屏幕的距离是：" + firstFloorVgPosition[1]);
            Log.d(TAG, "第二层距离屏幕的距离是：" + secondFloorVgPosition[1]);
            Log.d(TAG, "第三层距离屏幕的距离是：" + thirdFloorVgPosition[1]);
            Log.d(TAG, "第四层距离屏幕的距离是：" + fourthFloorVgPosition[1]);

            secondFloorVgPositionDistance = secondFloorVgPositionAnchor - firstFloorVgPositionAnchor;
            thirdFloorVgPositionDistance = thirdFloorVgPositionAnchor - firstFloorVgPositionAnchor;
            fourthFloorVgPositionDistance = fourthFloorVgPositionAnchor - firstFloorVgPositionAnchor;
        }
    }

    private void initListeners() {
        wrapperFl.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                Log.d(TAG,"wrapperFl onTouch");
                tabInterceptTouchEventTag = true;//让tab来处理滑动
                return false;
            }
        });
        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                currentPosition = tab.getPosition();
                if(!tabInterceptTouchEventTag){//手动滑动页面时则不再次处理滑动
                    return;
                }
                scrollView.computeScroll();
                switch (currentPosition) {
                    case 0:
                        scrollView.smoothScrollTo(0, 0);
                        break;
                    case 1:
                        scrollView.smoothScrollTo(0, secondFloorVgPositionDistance);
                        break;
                    case 2:
                        scrollView.smoothScrollTo(0, thirdFloorVgPositionDistance);
                        break;
                    case 3:
                        scrollView.smoothScrollTo(0, fourthFloorVgPositionDistance);
                        break;
                    default:
                        break;
                }
            }

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

            }

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

            }
        });
        scrollView.setScrollViewListener(this);
        scrollView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                Log.d(TAG, "scrollView onTouch");
                tabInterceptTouchEventTag = false;//让scrollview处理滑动
                return false;
            }
        });
    }

    @Override
    public void onScrollChanged(ObservableScrollView scrollView, int x, int y, int oldx, int oldy) {
        if (tabInterceptTouchEventTag) {//让tab来处理滑动
            return;
        }
        Log.d(TAG, "当前scrollView的位置——>" + y);
        if (y < secondFloorVgPositionDistance) {
            if (currentPosition != 0) {
                scrollView.computeScroll();
                tabLayout.getTabAt(0).select();
            }
        } else if (y < thirdFloorVgPositionDistance) {
            if (currentPosition != 1) {
                scrollView.computeScroll();
                tabLayout.getTabAt(1).select();
            }
        } else if (y < fourthFloorVgPositionDistance) {
            if (currentPosition != 2) {
                scrollView.computeScroll();
                tabLayout.getTabAt(2).select();
            }
        } else {
            if (currentPosition != 3) {
                scrollView.computeScroll();
                tabLayout.getTabAt(3).select();
            }
        }
    }
}

a. tabInterceptTouchEventTag 作为标志位是为了防止因scrollview触发了tab Selected从而再次引起scrollview滑动导致的滑动不流畅。

b. wrapperFl的存在则是要去给 tabInterceptTouchEventTag 赋值，因为TabLayout的Touch、Click、Focus等事件被消化掉了，无法在这些事件中监听到对应的值的变化，所以通过wrapperFl来进行Touch事件的监听。

c. ObservableScrollView 是继承自Scrollview，新增和改变了其中的以下方法：

  public void setScrollViewListener(ScrollViewListener scrollViewListener) {
        this.scrollViewListener = scrollViewListener;
    }

    @Override
    protected void onScrollChanged(int x, int y, int oldx, int oldy) {
        super.onScrollChanged(x, y, oldx, oldy);
        if (scrollViewListener != null) {
            scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);
        }
    }

    public interface ScrollViewListener {

        void onScrollChanged(ObservableScrollView scrollView, int x, int y, int oldx, int oldy);

    }

这样就可以在activity主界面中监听到scrollview的滑动事件，从而获取当前整个scrollview所处的位置，进而去判定是否需要选定对应的tab。

ps：如果要做成支付宝那样TabLayout上还有个TopView的内容样式，则可以参考之前写过的博客的做法：View滑动固定效果实现>>

最后，完整代码可以查看GitHub>>