一、功能分析----ListView“加载更多”,功能如下图所示:
这个效果是当你上拉拖动页面时（注意有区别于下拉刷新），页面提示正在加载，2秒后显示留言更多内容；具体功能知道那我就来讲解下如何实现这个功能。
二、创建自定义ListView及其底部布局footer
①首先做一个加载提示布局，布局footer_layout如下图：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/load_layout" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_gravity="center" > <ProgressBar android:layout_width="wrap_content" android:layout_height="wrap_content" style="?android:attr/progressBarStyleSmall"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="正在加载..." /> </LinearLayout>
②将布局添加至ListView，自定义一个ListView
package com.mg.message.view;
import android.content.Context; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.View; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; import android.widget.ListView; import com.mg.message.R;
public class LX_LoadListView extends ListView implements OnScrollListener{ View footer;//底部布局 int totalItemCount;//总数量 int lastVisibleItem;//最后一个可见的Item boolean isLoading;//正在加载 ILoadListener iLoadListener; public LX_LoadListView(Context context) { super(context); initView(context); } public LX_LoadListView(Context context, AttributeSet attrs) { super(context, attrs); initView(context); } public LX_LoadListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(context); } /** * 添加底部加载提示布局到listview * @param context */ private void initView(Context context) { LayoutInflater layoutInflater=LayoutInflater.from(context); footer=layoutInflater.inflate(R.layout.lx_footer_layout, null); footer.findViewById(R.id.load_layout).setVisibility(View.GONE); this.addFooterView(footer); this.setOnScrollListener(this); }
@Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { this.lastVisibleItem=firstVisibleItem+visibleItemCount; this.totalItemCount=totalItemCount; }
@Override public void onScrollStateChanged(AbsListView view, int scrollState) { if (totalItemCount==lastVisibleItem&&scrollState==SCROLL_STATE_IDLE) { if (!isLoading) { isLoading=true; footer.findViewById(R.id.load_layout).setVisibility(View.VISIBLE); iLoadListener.onLoad();//加载更多数据 } } } //加载完毕 public void loadComplete() { isLoading=false; footer.findViewById(R.id.load_layout).setVisibility(View.GONE); } public void setInterface(ILoadListener iLoadListener) { this.iLoadListener=iLoadListener; } //加载更多数据的回调接口 public interface ILoadListener { public void onLoad(); } }
三、给ListView设置Adapter并实现接口中的Load方法
①自定义ListView布局，lx_get_content_activity
<?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" android:layout_marginTop="2dp" android:layout_marginBottom="2dp" android:layout_marginLeft="2dp" android:layout_marginRight="2dp" android:background="@drawable/edit_normal"> <com.mg.message.view.LX_LoadListView android:id="@+id/list_content" android:layout_width="match_parent" android:background="@drawable/edit_normal" android:layout_height="0dip" android:focusable="true" android:layout_weight="1.20" > </com.mg.message.view.LX_LoadListView> </LinearLayout>
②给ListView设置Adapter，并实现接口的Load方法package com.mg.message.ui;
import java.util.ArrayList; import java.util.List; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.AdapterView.OnItemLongClickListener; import android.widget.AdapterView.OnItemClickListener; import com.mg.core.base.BaseActivity; import com.mg.core.net.OperateCode; import com.mg.core.net.ThreadMessage; import com.mg.message.R; import com.mg.message.data.GetMessageData; import com.mg.message.domain.Message; import com.mg.message.ui.adapter.ContentAdapter; import com.mg.message.utils.ViewUtil; import com.mg.message.view.LX_LoadListView; import com.mg.message.view.LX_LoadListView.ILoadListener; /* * 获得留言*/ public class LX_GetContentActivity extends BaseActivity implements ILoadListener { private LX_LoadListView listView; private List<Message> totalMessages=new ArrayList<Message>(); private static ContentAdapter myAdapter; private int totalSize; List<Message> messages=new ArrayList<Message>(); @Override protected void initEvents() { listView.setOnItemClickListener(new OnItemClickListener() //进入删除页 { @Override public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) { Bundle bundle = new Bundle(); //传递多参数时使用Bundle bundle.putString("ID", messages.get(position).getID()); bundle.putString("UContent", messages.get(position).getContent().toString()); bundle.putString("UTime", messages.get(position).getCreateTime()); startCOActivity(LX_DeleteActivity.class,bundle); finish(); } }); //修改留言 listView.setOnItemLongClickListener(new OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> arg0, View arg1, int position, long arg3) { Bundle bundle = new Bundle(); //传递多参数时使用Bundle bundle.putString("ID", messages.get(position).getID()); startCOActivity(LX_AddMessageActivity.class,bundle); finish(); return false; } }); }
@Override protected void initViews() { setContentView(R.layout.lx_get_content_activity); mTopBar.setVisibility(View.VISIBLE); mTopBar.SetTvName("查看留言"); listView=(LX_LoadListView)findViewById(R.id.list_content); listView.setInterface(this); myAdapter=new ContentAdapter(messages); listView.setAdapter(myAdapter); } @Override protected void onResume() { super.onResume(); showToast("onResume", false); sendToBackgroud(OperateCode.i_getMessageInfo); } @Override protected void receiveRequest(ThreadMessage threadMessage) { hideProgressDialog(); OperateCode operateCode = threadMessage.getOperateCode(); List<Message> messageList; switch (operateCode) { //查看留言 case i_getMessageInfo: messageList=GetMessageData.getMessagesList(); if(ViewUtil.isNotEmpty(messageList)) { totalMessages.clear(); messages.clear(); totalMessages.addAll(messageList); totalSize=totalMessages.size(); getData(); myAdapter.notifyDataSetChanged(); } break; default: break; } } //listview初始化条数 private void getData() { try { if (totalSize<9) { messages.addAll(GetMessageData.getMessagesList()); showToast("留言小于9加载完毕", false); } else { messages.addAll(GetMessageData.getMessagesList().subList(0, 8)); } } catch (Exception e) { } } //加载数据 private void getLoadData() { int lastsize=totalSize-messages.size(); if(messages.size()<totalSize) { if (lastsize<5) { messages.clear(); messages.addAll(GetMessageData.getMessagesList()); showToast("加载项<5加载完毕", false); } else { messages.addAll(totalMessages.subList(messages.size(), messages.size()+5)); } } else { messages.clear(); messages.addAll(GetMessageData.getMessagesList()); showToast("全部加载完毕", false); } myAdapter.notifyDataSetChanged(); } @Override public void onLoad() { android.os.Handler handler=new android.os.Handler(); handler.postDelayed(new Runnable() { @Override public void run() { getLoadData();//获取更多数据 listView.loadComplete();//通知listview加载完毕 } }, 2000); } }
转载于:https://www.cnblogs.com/wucaiyun1/p/4733998.html
相关资源：android ListView分页加载Demo