listView不会触发onScroll事件

问题描述

| 我正在开发一个需要显示列表视图控件的应用程序。我只是在活动中实现“ 0”以监视我的Listview内容，但在为活动设置布局时并没有调用onScroll事件。如果我评论该块，那么它调用它就好了。我该如何解决这个问题？

package com.Threadtest;

import com.Threadtest.main.myRunnable;

import android.app.Activity;
import android.app.ListActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AbsListView.OnScrollListener;

public class TestList extends ListActivity implements OnScrollListener {

    aleph0 adapter = new aleph0();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test);
        ListView listview=(ListView)findViewById(android.R.id.list);
        listview.setAdapter(adapter);
        /*setlistadapter(adapter); 
        getListView().setonScrollListener(this);*/
    }

    public void onScroll(AbsListView view,int firstVisible,final int visibleCount,int totalCount) {

        Log.i(\"TestList\",\"firstVisible=\"+firstVisible+\" visibleCount=\"+visibleCount+\" totalCount=\"+totalCount);
        boolean loadMore = /* maybe add a padding */
            firstVisible + visibleCount >= totalCount;

        if(loadMore) {
            Log.i(\"TestList\",\"In Notify\");
            Thread thread = new Thread()
            {
                  @Override
                  public void run() {
                      try {
                        this.sleep(10000);
                        runOnUiThread(new myRunnable(adapter,visibleCount));
                    } catch (InterruptedException e) {
                        // Todo Auto-generated catch block
                        e.printstacktrace();
                    }


                  }
              };

            thread.start();

        }
    }

    public void onScrollStateChanged(AbsListView v,int s) { } 

    class myRunnable implements Runnable
    {
        aleph0 adapter;

        public myRunnable(aleph0 adapter,int visibleCount)
        {

            this.adapter=adapter;
            this.adapter.count += visibleCount;
        }
        public void run() {
            // Todo Auto-generated method stub
             Log.i(\"TestList\",\"List Count=\"+adapter.count);
                adapter.notifyDataSetChanged();
        }

    }

    class aleph0 extends BaseAdapter {
        int count = 40; /* starting amount */

        public int getCount() { return count; }
        public Object getItem(int pos) { return pos; }
        public long getItemId(int pos) { return pos; }

        public View getView(int pos,View v,ViewGroup p) {
            if(pos!=count-1)
            {
                TextView view = new TextView(TestList.this);
                view.setText(\"entry \" + pos);
                return view;
            }
            TextView view = new TextView(TestList.this);
            view.setText(\"Loading.. \" + pos);
            return view;

        }
    }
}

    

解决方法

        

getListView().setOnScrollListener(this)

是将侦听器绑定到

ListView

所必需的。

ListActivity

类没有提供绑定大多数侦听器的“自动”方式，它仅提供了

OnItemClickListener

的自动绑定方式。签出ListActivity代码。     ,        如果将onScroll签名更改为

public void onScroll(AbsListView view,int firstVisible,int visibleCount,int totalCount)

，它将被调用吗？通过添加“ 7”限定符，您已经更改了方法签名，这将导致看不到您覆盖的方法。将visibleCount int复制到新的（最终）int，以便您可以在线程中访问它。     ,        

import android.widget.AbsListView.OnScrollListener;

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

        ListView listview=(ListView)findViewById(android.R.id.list); 
        listview.setAdapter(adapter); 
        listview.setOnScrollListener(onLstScroll);    
} 


OnScrollListener onLstScroll= new OnScrollListener()
{
    @Override
    public void onScroll(AbsListView view,int firstVisibleItem,int visibleItemCount,int totalItemCount)
   {
       //Do something
   }

   @Override
   public void onScrollStateChanged(AbsListView view,int scrollState)
   {
      //Do something
   }
};

    ,        您在

onScroll()

和

onScrollStateChanged()

方法上缺少

@Override

表示法。