Android之ListView分页数据加载

时间：2024-10-19 20:05:56

1、效果如下：

Android之ListView分页数据加载Android之ListView分页数据加载

实例如下：  上图的添加数据按钮可以换成一个进度条  因为没有数据所以我加了一个按钮添加到数据库用于测试；一般在服务器拉去数据需要一定的时间，所以可以弄个进度条来提示用户：

点击加载按钮的时候，向数据库读取一次数据，把读取的数据追加到原来的数据集中；然后显示出来

package com.exampleandroid.xiong.listviewpages;

public class News {

	private String title;

	private int id;

	/**

	 *

	 * @return 返回新闻标题

	 */

	public String getTitle() {

		return title;

	}

	/**

	 *

	 * @param title

	 *            设置新闻标题

	 */

	public void setTtitle(String title) {

		this.title = title;

	}

	/**

	 *

	 * @return 返回新闻标识

	 */

	public int getId() {

		return id;

	}

	/**

	 *

	 * @param id

	 *            设置新闻标识

	 */

	public void setId(int id) {

		this.id = id;

	}

}

package com.exampleandroid.xiong.listviewpages;

import java.util.ArrayList;

import java.util.List;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

public class GetNews {

	/**

	 *

	 * @param page

	 *            需要加载的页数 每页数据5条

	 * @param dbnews

	 *            SQLiteOpenHelper子类

	 * @return 返回新闻加载的数据

	 */

	public List<News> getListNews(int page, DbSqliteNews dbnews) {

		List<News> list = new ArrayList<News>();

		String sql = "select  * from tb_newstile  where news_id not in(select news_id from tb_newstile  LIMIT "

				+ 5 * (page - 1) + ")  LIMIT " + 5 * page;

		Cursor cursor = dbnews.getReadableDatabase().rawQuery(sql, null);

		while (cursor.moveToNext()) {

			News news = new News();

			news.setTtitle(cursor.getString(1));

			news.setId(cursor.getInt(0));

			list.add(news);

		}

		cursor.close();

		return list;

	}

	/**

	 * 插入100条数据用于测试

	 *

	 * @param dbnews

	 *            SQLiteOpenHelper子类

	 */

	public void insertData(DbSqliteNews dbnews) {

		SQLiteDatabase datas = dbnews.getWritableDatabase();

		datas.beginTransaction();

		try {

			for (int i = 0; i < 100; i++) {

				datas.execSQL("insert into tb_newstile values(?,?)",

						new Object[] { i, "新闻标题" + i });

			}

			datas.setTransactionSuccessful();

		} catch (Exception e) {

			System.out.println("数据插入失败！");

			e.printStackTrace();

		} finally {

			datas.endTransaction();

		}

	}

}

package com.exampleandroid.xiong.listviewpages;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

public class DbSqliteNews extends SQLiteOpenHelper {

	public DbSqliteNews(Context context, String name, CursorFactory factory,

			int version) {

		super(context, name, factory, version);

	}

	// 创建数据库表

	@Override

	public void onCreate(SQLiteDatabase db) {

		db.execSQL("create table tb_newstile(news_id integer ,news_title varchar(100))");

	}

	@Override

	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

	}

}

package com.exampleandroid.xiong.listviewpages;

import java.util.List;

import android.app.Activity;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.ListView;

import android.widget.TextView;

public class MainActivity extends Activity {

	private ListView newShow_list;

	private Button loadmore, adddata;

	// ListView加载的数据

	private List<News> shownews;

	private GetNews getnews;

	private DbSqliteNews dbnews;

	// 加载的页数

	private int pagecount = 1;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		newShow_list = (ListView) findViewById(R.id.newsShow_list);

		loadmore = (Button) findViewById(R.id.loadmore_bt);

		adddata = (Button) findViewById(R.id.adddata);

		dbnews = new DbSqliteNews(this, "new.db", null, 1);

		getnews = new GetNews();

		final ListAdpaterNews listadpter=new ListAdpaterNews();

		//此按钮只为添加测试数据

		adddata.setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

				//插入数据

				getnews.insertData(dbnews);

				//获取数据

				shownews = getnews.getListNews(pagecount, dbnews);

				//显示数据

				newShow_list.setAdapter(listadpter);

			}

		});

		loadmore.setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

				pagecount++;

				//将数据追加到原集合

				shownews.addAll(getnews.getListNews(pagecount, dbnews));

				//刷新数据

				listadpter.notifyDataSetInvalidated();

			}

		});

		// 第一次加载的数据

		shownews = getnews.getListNews(pagecount, dbnews);

		newShow_list.setAdapter(listadpter);

	}

	class ListAdpaterNews extends BaseAdapter {

		@Override

		public int getCount() {

			return pagecount * 5;

		}

		@Override

		public Object getItem(int position) {

			return position;

		}

		@Override

		public long getItemId(int position) {

			return position;

		}

		@Override

		public View getView(int position, View convertView, ViewGroup parent) {

			View view = LayoutInflater.from(MainActivity.this).inflate(

					R.layout.news_title, null);

			TextView txttitle = (TextView) view.findViewById(R.id.txt_title);

			ImageView images = (ImageView) view

					.findViewById(R.id.showimage_title);

			images.setBackgroundResource(R.drawable.n_me_l);

			txttitle.setText(shownews.get(position).getTitle());

			return view;

		}

	}

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		getMenuInflater().inflate(R.menu.main, menu);

		return true;

	}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MainActivity" >

    <ListView

        android:id="@+id/newsShow_list"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

    </ListView>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_alignParentBottom="true" >

        <Button

            android:id="@+id/adddata"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:text="添加数据" />

        <Button

            android:id="@+id/loadmore_bt"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:text="@string/loadmore" />

    </LinearLayout>

</RelativeLayout>
<?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:padding="15dp"

    android:orientation="horizontal" >

    <ImageView

        android:id="@+id/showimage_title"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:background="@drawable/n_me_l"

        android:contentDescription="@string/imagenews" />

    <TextView

        android:id="@+id/txt_title"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" />

</LinearLayout>

源码下载：http://download.****.net/detail/x605940745/6800461

转载请注明出处：http://blog.****.net/x605940745

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