Android 滑动定位和吸附悬停效果实现代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical">

  <com.tabscroll.CustomScrollView
    android:id="@+id/scrollView"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

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

      <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <LinearLayout
          android:layout_width="match_parent"
          android:layout_height="200dp"
          android:background="#ccc"
          android:gravity="center">

          <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="这里是顶部内容区域"
            android:textSize="16sp" />

        </LinearLayout>

        <!--占位的tablayout-->
        <android.support.design.widget.TabLayout
          android:id="@+id/tablayout_holder"
          android:layout_width="match_parent"
          android:layout_height="50dp"
          android:background="#ffffff"
          app:tabIndicatorColor="@color/colorPrimary"
          app:tabMode="scrollable"
          app:tabSelectedTextColor="@color/colorPrimary" />

        <LinearLayout
          android:id="@+id/container"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:orientation="vertical"
          android:padding="16dp" />

      </LinearLayout>


      <!--实际用户操作的tablayout-->
      <android.support.design.widget.TabLayout
        android:id="@+id/tablayout_real"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="#ffffff"
        android:visibility="invisible"
        app:tabIndicatorColor="@color/colorPrimary"
        app:tabMode="scrollable"
        app:tabSelectedTextColor="@color/colorPrimary" />
    </FrameLayout>


  </com.tabscroll.CustomScrollView>

</LinearLayout>

/**
 * 占位tablayout，用于滑动过程中去确定实际的tablayout的位置
 */
private TabLayout holderTabLayout;
/**
 * 实际操作的tablayout，
 */
private TabLayout realTabLayout;
private CustomScrollView scrollView;
private LinearLayout container;
private String[] tabTxt = {"客厅", "卧室", "餐厅", "书房", "阳台", "儿童房"};

private List<AnchorView> anchorList = new ArrayList<>();

//判读是否是scrollview主动引起的滑动，true-是，false-否，由tablayout引起的
private boolean isScroll;
//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 = 0;
//监听判断最后一个模块的高度，不满一屏时让最后一个模块撑满屏幕
private ViewTreeObserver.OnGlobalLayoutListener listener;

for (int i = 0; i < tabTxt.length; i++) {
  AnchorView anchorView = new AnchorView(this);
  anchorView.setAnchorTxt(tabTxt[i]);
  anchorView.setContentTxt(tabTxt[i]);
  anchorList.add(anchorView);
  container.addView(anchorView);
}
for (int i = 0; i < tabTxt.length; i++) {
  holderTabLayout.addTab(holderTabLayout.newTab().setText(tabTxt[i]));
  realTabLayout.addTab(realTabLayout.newTab().setText(tabTxt[i]));
}

listener = new ViewTreeObserver.OnGlobalLayoutListener() {
  @Override
  public void onGlobalLayout() {
    //计算让最后一个view高度撑满屏幕
    int screenH = getScreenHeight();
    int statusBarH = getStatusBarHeight(AliHomeMoreActivity.this);
    int tabH = holderTabLayout.getHeight();
    int lastH = screenH - statusBarH - tabH - 16 * 3;
    AnchorView anchorView = anchorList.get(anchorList.size() - 1);
    if (anchorView.getHeight() < lastH) {
      LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
      params.height = lastH;
      anchorView.setLayoutParams(params);
    }

    //一开始让实际的tablayout 移动到 占位的tablayout处，覆盖占位的tablayout
    realTabLayout.setTranslationY(holderTabLayout.getTop());
    realTabLayout.setVisibility(View.VISIBLE);
    container.getViewTreeObserver().removeOnGlobalLayoutListener(listener);

  }
};
container.getViewTreeObserver().addOnGlobalLayoutListener(listener);

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;
}

scrollView.setOnTouchListener(new View.OnTouchListener() {
  @Override
  public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
      isScroll = true;
    }
    return false;
  }
});

//监听scrollview滑动
scrollView.setCallbacks(new CustomScrollView.Callbacks() {
  @Override
  public void onScrollChanged(int x, int y, int oldx, int oldy) {
    //根据滑动的距离y(不断变化的) 和 holderTabLayout距离父布局顶部的距离(这个距离是固定的)对比，
    //当y < holderTabLayout.getTop()时，holderTabLayout 仍在屏幕内，realTabLayout不断移动holderTabLayout.getTop()距离，覆盖holderTabLayout
    //当y > holderTabLayout.getTop()时，holderTabLayout 移出，realTabLayout不断移动y，相对的停留在顶部，看上去是静止的
    int translation = Math.max(y, holderTabLayout.getTop());
    realTabLayout.setTranslationY(translation);

    if (isScroll) {
      for (int i = tabTxt.length - 1; i >= 0; i--) {
        //需要y减去顶部内容区域的高度(具体看项目的高度，这里demo写死的200dp)
        if (y - 200 * 3 > anchorList.get(i).getTop() - 10) {
          setScrollPos(i);
          break;
        }
      }
    }

  }
});

private void setScrollPos(int newPos) {
  if (lastPos != newPos) {
    realTabLayout.setScrollPosition(newPos, 0, true);
  }
  lastPos = newPos;
}

//实际的tablayout的点击切换
realTabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
  @Override
  public void onTabSelected(TabLayout.Tab tab) {
    isScroll = false;
    int pos = tab.getPosition();
    int top = anchorList.get(pos).getTop();
    //同样这里滑动要加上顶部内容区域的高度(这里写死的高度)
    scrollView.smoothScrollTo(0, top + 200 * 3);
  }

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

  }

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

  }
});