package com.bi.demo;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.AbsListView;

import android.widget.AdapterView;

import android.widget.ArrayAdapter;

import android.widget.ListView;

import android.widget.TextView;

import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private ListView listView1,listView2;

    private TextView tv;

    private List1Adapter adapter1;

    private int item;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        listView1= (ListView) findViewById(R.id.listView1);

        listView2= (ListView) findViewById(R.id.listView2);

        tv= (TextView) findViewById(R.id.tv);

        ArrayList <Lei>list1=new ArrayList<Lei>();

        list1.add(new Lei("weocio",R.mipmap.ic_launcher));

        list1.add(new Lei("cvnxmvm",R.mipmap.ic_launcher));

        list1.add(new Lei("wwwww",R.mipmap.ic_launcher));

        list1.add(new Lei("ckkkkkkm",R.mipmap.ic_launcher));

        adapter1=new List1Adapter(this,list1);

        listView1.setAdapter(adapter1);

       listView1.setOnScrollListener(new AbsListView.OnScrollListener() {

           @Override

           public void onScrollStateChanged(AbsListView view, int scrollState) {

               if(scrollState== AbsListView.OnScrollListener.SCROLL_STATE_IDLE) {

                   View v=adapter1.getView(0, null, listView1);

                   v.measure(0, 0);

                   int itemHeight=v.getMeasuredHeight();

                   int total=getScrollY();

                   if((total%itemHeight)>(itemHeight/2))item++;

                   //Log.d("xx",""+getScrollY());

                   //Log.d("xxy",itemHeight+"");

                   //listView1.setSelection(item);

                   listView1.setSelection(item);

                   tv.setText("" + item);

               }

           }

           @Override

           public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

              /* View c = listView1.getChildAt(0);

               int firstVisiblePosition = listView1.getFirstVisiblePosition();

               Log.d("xx",firstVisiblePosition+"");

               int top = c.getTop();

               Log.d("xxy",top+"");

               Log.d("xxyy", -top + firstVisiblePosition * c.getHeight() + "");

*/

               item=firstVisibleItem;

           }

       });

    }

    public int getScrollY() {

        View c = listView1.getChildAt(0);

        if (c == null) {        return 0;    }

        int firstVisiblePosition = listView1.getFirstVisiblePosition();

        int top = c.getTop();//这里计算的是最上边能看到的item滑上去的距离

        Log.d("xxy",top+"");

        return -top + firstVisiblePosition * c.getHeight() ;

    }

}