public class CustomViewAcyivity extends BaseActivity {

  Toolbar toolbar;
  WindowManager mWindowManager;
  WindowManager.LayoutParams mWindowLayoutParams;
  TextView mTv;
  boolean isShowing;//是否正在顯示

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_custom_view);

    mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

    List<String> list = new ArrayList<>();
    for (int i = 0; i < 30; i++) {
      list.add("我是第" + (i + 1) + "個選擇項");
    }

    toolbar = $(R.id.toolbar);
    ListView listView = $(R.id.view_list);
    listView.setAdapter(new ArrayAdapter<>(this, R.layout.item_text, list));

    listView.setOnScrollListener(new AbsListView.OnScrollListener() {
      @Override
      public void onScrollStateChanged(AbsListView view, int scrollState) {
      }

      @Override
      public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        if (firstVisibleItem > 8) {//滑動到目的項時，顯示懸停布局
          if (!isShowing)
            show();
        } else {
          if (isShowing)
            hide();
        }
      }
    });

  }


  //顯示懸停布局
  public void show() {
    isShowing = true;
    mWindowLayoutParams = new WindowManager.LayoutParams();
    mWindowLayoutParams.format = PixelFormat.TRANSLUCENT; //圖片之外的其他地方透明
    mWindowLayoutParams.gravity = Gravity.TOP;
    mWindowLayoutParams.y = toolbar.getHeight() - SystemUtil.getStatusHeight(this);//設(shè)置懸停布局顯示的Y坐標
    mWindowLayoutParams.width = WindowManager.LayoutParams.MATCH_PARENT;
    mWindowLayoutParams.height = UnitUtil.dp2px(this, 50);//設(shè)置懸停布局顯示的高度
    mWindowLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
        | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;

    //設(shè)置懸停布局，為了看起來是懸停效果，布局的內(nèi)容要設(shè)置成與ItemView一致
    mTv = new TextView(this);
    mTv.setGravity(Gravity.CENTER);
    mTv.setBackgroundColor(getResources().getColor(R.color.white));
    mTv.setTextSize(UnitUtil.px2sp(this, UnitUtil.dp2px(this, 16)));
    mTv.setText("我是第10個選擇項");

    //添加懸停布局
    mWindowManager.addView(mTv, mWindowLayoutParams);
  }

  //隱藏懸停布局
  public void hide() {
    if (mTv != null) {
      isShowing = false;
      mWindowManager.removeView(mTv);
      mTv = null;
    }
  }

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical">

  <include layout="@layout/view_toolbar" />

  <ListView
    android:id="@+id/view_list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />

</LinearLayout>