Android 异步任务，通过PHP访问数据库，多线程，线程间通讯

2022-12-02 10:34:09

文章列表MainActivity.java

package com.eric.asynctask;

import java.io.IOException;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import org.apache.http.HttpResponse;

import org.apache.http.HttpStatus;

import org.apache.http.NameValuePair;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.HttpClient;

import org.apache.http.client.entity.UrlEncodedFormEntity;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.protocol.HTTP;

import org.apache.http.util.EntityUtils;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import android.app.Activity;

import android.content.Context;

import android.content.Intent;

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

import android.os.AsyncTask;

import android.os.Bundle;

import android.view.Menu;

import android.view.View;

import android.widget.AdapterView;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.Toast;

public class MainActivity extends Activity {

	final static String EXTRA_POST_ID = "com.eric.asynctask.POST_ID";

	String extra_post_id;

	String url = "http://www.zhangjianghome.net/android/title-select.php";

	int offset = 0;

	int num = 30;

	ListView titleList;

	SimpleAdapter adapter;

	ArrayList<HashMap<String, String>> list;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		ConnectivityManager connMgr = (ConnectivityManager) this

				.getSystemService(Context.CONNECTIVITY_SERVICE);

		NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

		if (networkInfo != null && networkInfo.isConnected()) {

			new DownloadTitleListTask().execute(offset, num);

		} else {

			Toast.makeText(MainActivity.this,

					"No network connection available.", Toast.LENGTH_SHORT)

					.show();

		}

	}

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

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

		return true;

	}

	private class DownloadTitleListTask extends

			AsyncTask<Integer, Void, String> {

		@Override

		protected String doInBackground(Integer... arg0) {

			// TODO Auto-generated method stub

			try {

				HttpClient httpClient = new DefaultHttpClient();

				HttpPost httpPost = new HttpPost(url);

				List<NameValuePair> formEntity = new ArrayList<NameValuePair>();

				formEntity.add(new BasicNameValuePair("offset", String

						.valueOf(arg0[0])));

				formEntity.add(new BasicNameValuePair("num", String

						.valueOf(arg0[1])));

				httpPost.setEntity(new UrlEncodedFormEntity(formEntity,

						HTTP.UTF_8));

				HttpResponse httpResponse = httpClient.execute(httpPost);

				if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

					String strResult = EntityUtils.toString(httpResponse

							.getEntity());

					return strResult;

				} else {

					Toast.makeText(MainActivity.this, "http请求失败",

							Toast.LENGTH_SHORT).show();

					return null;

				}

			} catch (ClientProtocolException e) {

				// TODO Auto-generated catch block

				e.printStackTrace();

				return null;

			} catch (IOException e) {

				// TODO Auto-generated catch block

				e.printStackTrace();

				return null;

			}

		}

		protected void onPostExecute(String result) {

			adapter = getAdapterFromJSONString(result);

			titleList = (ListView) MainActivity.this

					.findViewById(R.id.ListView1);

			titleList.setAdapter(adapter);

			titleList

					.setOnItemClickListener(new AdapterView.OnItemClickListener() {

						@SuppressWarnings("unchecked")

						@Override

						public void onItemClick(AdapterView<?> parent,

								View view, int position, long id) {

							// TODO Auto-generated method stub

							HashMap<String, String> map = (HashMap<String, String>) ((ListView) parent)

									.getItemAtPosition(position);

							extra_post_id = map.get("ID").toString();

							Intent intent = new Intent();

							intent.setClass(MainActivity.this,

									DetailActivity.class);

							intent.putExtra(EXTRA_POST_ID, extra_post_id);

							MainActivity.this.startActivity(intent);

						}

					});

		}

	}

	private SimpleAdapter getAdapterFromJSONString(String JSONString) {

		list = new ArrayList<HashMap<String, String>>();

		try {

			JSONArray jsonArray = new JSONArray(JSONString);// JSONArray的元素必须全为JSONObject

			for (int i = 0; i < jsonArray.length() - 1; i++) {

				HashMap<String, String> map = new HashMap<String, String>();

				JSONObject jsonObject = jsonArray.getJSONObject(i);

				map.put("ID", jsonObject.getString("ID"));

				map.put("post_title", jsonObject.optString("post_title"));

				map.put("post_date", jsonObject.optString("post_date"));

				map.put("post_content", jsonObject.optString("jsonObject"));

				list.add(map);

			}

		} catch (JSONException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		return new SimpleAdapter(

				MainActivity.this,

				list,

				R.layout.list_item,

				new String[] { "ID", "post_title", "post_date", "post_content" },

				new int[] { R.id.post_id, R.id.post_title, R.id.post_date,

						R.id.post_content });

	}

}

　　列表视图的每一项布局：list_item.xml

<?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" >

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

        <TextView

            android:id="@+id/post_id"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="@string/hello_world"

            android:textColor="@color/buue" />

        <TextView

            android:id="@+id/post_date"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

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

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

        <TextView

            android:id="@+id/post_title"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

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

        <TextView

            android:id="@+id/post_content"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="@string/hello_world"

            android:visibility="gone" />

    </LinearLayout>

</LinearLayout>

　　文章详情DetailActivity.java

package com.eric.asynctask;

import java.io.IOException;

import org.apache.http.HttpResponse;

import org.apache.http.HttpStatus;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.util.EntityUtils;

import org.json.JSONException;

import org.json.JSONObject;

import android.annotation.SuppressLint;

import android.app.Activity;

import android.content.Context;

import android.content.Intent;

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.Menu;

import android.widget.TextView;

import android.widget.Toast;

public class DetailActivity extends Activity {

	TextView postContentView;

	String str_url = "http://www.zhangjianghome.net/android/content-select.php";

	private final static int handler_flag = 0x1234;

	private Handler HttpHandler;

	String postID;

	@SuppressLint("HandlerLeak")

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_detail);

		Intent intent = this.getIntent();

		postID = intent.getStringExtra(MainActivity.EXTRA_POST_ID);

		postContentView = (TextView) this.findViewById(R.id.textView1);// 竟然是这个id搞错了，草。。。

		ConnectivityManager connMgr = (ConnectivityManager) this

				.getSystemService(Context.CONNECTIVITY_SERVICE);

		NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

		if (networkInfo != null && networkInfo.isConnected()) {

			new Thread(new HttpRunnable()).start();

			HttpHandler = new Handler() {

				public void handleMessage(Message msg) {

					switch (msg.what) {

					case handler_flag:

						postContentView.setText("文章ID："

								+ getJSONFromString(msg.obj.toString())

										.optString("ID")

								+ "\n"

								+ "文章标题："

								+ getJSONFromString(msg.obj.toString())

										.optString("post_title")

								+ "\n"

								+ "发表日期："

								+ getJSONFromString(msg.obj.toString())

										.optString("post_date")

								+ "\n"

								+ "文章内容："

								+ getJSONFromString(msg.obj.toString())

										.optString("post_content"));

						break;

					default:

						break;

					}

					super.handleMessage(msg);

				}

			};

		} else {

			Toast.makeText(DetailActivity.this,

					"No network connection available.", Toast.LENGTH_SHORT)

					.show();

		}

	}

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

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

		return true;

	}

	private String getResultStringHttp(String ID) {

		try {

			HttpClient httpClient = new DefaultHttpClient();

			HttpGet httpGet = new HttpGet(str_url + "?ID=" + ID);

			HttpResponse httpResponse = httpClient.execute(httpGet);

			if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

				String strResult = EntityUtils.toString(httpResponse

						.getEntity());

				return strResult;

			} else {

				return null;

			}

		} catch (ClientProtocolException e) {

			e.printStackTrace();

			return null;

		} catch (IOException e) {

			e.printStackTrace();

			return null;

		}

	}

	class HttpRunnable implements Runnable {

		@Override

		public void run() {

			do {

				String str_result = getResultStringHttp(postID);

				//Thread.sleep(1000);

				Message msg = Message.obtain();

				msg.what = handler_flag;

				msg.obj = str_result;

				DetailActivity.this.HttpHandler.sendMessage(msg);

			} while (Thread.interrupted() == false);

		}

	}

	private JSONObject getJSONFromString(String jsonString) {

		try {

			JSONObject jsonObject;

			jsonObject = new JSONObject(jsonString);

			return jsonObject;

		} catch (JSONException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

			return null;

		}

	}

}

　　php访问数据库：

<?php

$con = mysql_connect("localhost", "db163810_f", "1e6969e2");

if (!$con)

  {

  die('不能建立连接: ' . mysql_error());

  }

$db_selected = mysql_select_db("db163810",$con);

mysql_query("SET NAMES 'utf8'");

if (!$db_selected)

  {

  die ("这个数据库不能被选: " . mysql_error());

  }

$sql = "SELECT `ID` , `post_date` , `post_title` , `post_content` FROM `wp_posts` where  `post_status`='publish' order by `post_date` desc LIMIT ".$_REQUEST["offset"].",".$_REQUEST["num"];

$result = mysql_query($sql,$con);

echo "[";

while($row = mysql_fetch_assoc($result))

  {

  //print_r(json_encode($row));

  //print(json_encode($row));

  //print_r($row);

  //echo "<br/><br/>";

  //print($row);

  echo json_encode($row);

  echo ",";

  }

  echo "{\"EOF\":\"EOF\"}]";

mysql_close($con);

?>

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