参考文章：

效果图：

实现步骤：

1. 1. 将需要悬浮的layout放到CollapsingToolbarLayout之外，AppBarLayout之内
   2. 将CollapsingToolbarLayout的app:layout_scrollFlags设置为scroll
   3. 给滚动的NestedScroolView设置
      app:layout_behavior="@String/appbar_scrolling_view_behavior"
      就大功告成了(记得根布局要是CoordinatorLayout)

import android.content.Context;import android.util.AttributeSet;import android.widget.ListView;/** * Created by Administrator on 2017/5/5. */public class MyListView extends ListView {    public MyListView(Context context) {        super(context);    }    public MyListView(Context context, AttributeSet attrs) {        super(context, attrs);    }    public MyListView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @Override    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,                MeasureSpec.AT_MOST);        super.onMeasure(widthMeasureSpec, expandSpec);    }}

import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.widget.ArrayAdapter;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    private MyListView lv;    private List
     
       list;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        lv = (MyListView) findViewById(R.id.lv);        list = new ArrayList<>();        for (int i = 0; i < 100; i++) {            list.add(i + "");        }        ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, list);        lv.setAdapter(adapter);    }}