about pulltorefreshdemo-优快云博客

本文链接：https://blog.youkuaiyun.com/wang725/article/details/46708053

本文详细介绍了在Android应用中实现下拉刷新功能的步骤，包括使用PullToRefreshListView组件，设置监听器来处理下拉刷新和上拉加载事件，并提供了完整的代码示例。同时，还展示了如何更新UI以显示加载状态和最后更新时间。

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实现效果：

贴代码：

MainActivity.java

package com.example.pulltorefreshdemo;

import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.LinkedList;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.example.pulltorefreshdemo.view.pullrefreshview.PullToRefreshBase;
import com.example.pulltorefreshdemo.view.pullrefreshview.PullToRefreshBase.OnRefreshListener;
import com.example.pulltorefreshdemo.view.pullrefreshview.PullToRefreshListView;

public class MainActivity extends Activity {

	private static final Void down = null;
	private PullToRefreshListView ptrLv;
    private LinkedList<String> mListItems;
	private String[] mStrings = {
            "keep practice", "learn more", "and more"};
	private ArrayAdapter<String> adapter;
	private String[] pullDownFlag = {"down"};
	private String pullUpFlag = "up";
	
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.pull_to_refresh);
        
        ptrLv = (PullToRefreshListView) findViewById(R.id.ptrLv);
        mListItems = new LinkedList<String>();
        
        // 上拉加载不可用 
 		ptrLv.setPullLoadEnabled(true);
 		// 滚动到底自动加载可用  
// 		ptrLv.setScrollLoadEnabled(true);
        
        mListItems.addAll(Arrays.asList(mStrings));
        adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, mListItems);
        
        ptrLv.getRefreshableView().setAdapter(adapter);
        
        // 设置Listener监听
        ptrLv.setOnRefreshListener(new OnRefreshListener<ListView>() {

			@Override
			public void onPullDownToRefresh(
					PullToRefreshBase<ListView> refreshView) {
				setLastUpdateTime();
//				new MyAsyncTask().execute(pullDownFlag);
				mListItems.addFirst(getStringDate());
				adapter.notifyDataSetChanged();
				ptrLv.onPullDownRefreshComplete();// 隐藏加载信息
			}

			@Override
			public void onPullUpToRefresh(
					PullToRefreshBase<ListView> refreshView) {
//				new MyAsyncTask().execute(pullUpFlag);
				mListItems.addLast(getStringDate());
				adapter.notifyDataSetChanged();
				ptrLv.onPullUpRefreshComplete();// 隐藏加载信息
			}
        });

        // 设置点击监听
        ptrLv.getRefreshableView().setOnItemClickListener(new OnItemClickListener() {
        	@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				Toast.makeText(getApplicationContext(), "onItemClick...", Toast.LENGTH_SHORT).show();
			}
		});
    }
    
    private void setLastUpdateTime() {
		String text = getStringDate();
		ptrLv.setLastUpdatedLabel(text);
	}
    
    /**
	 * 获取现在时间
	 * 
	 * @return 返回短时间字符串格式yyyy-MM-dd HH:mm:ss
	 */
	public static String getStringDate() {
		Date currentTime = new Date();
		SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		String dateString = formatter.format(currentTime);
		return dateString;
	}
	
//	private class MyAsyncTask extends AsyncTask<String, Void, String[]> {
//		
//		@Override
//		protected void onPostExecute(String[] result) {
//			super.onPostExecute(result);
//		}
//
//		@Override
//		protected String[] doInBackground(String... params) {
//			if("down".equals(params[0])) {
//				mListItems.addFirst(getStringDate());
//			} else if("up".equals(params[0])) {
//				mListItems.addLast(getStringDate());
//			}
//			return null;
//		}
//	}
}

pull_to_refresh.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <!--
    The PullToRefreshListView replaces a standard ListView widget.
    -->
    <com.example.pulltorefreshdemo.view.pullrefreshview.PullToRefreshListView
        android:id="@+id/ptrLv"
        android:layout_height="fill_parent"
        android:layout_width="fill_parent"
        />
</LinearLayout>

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