ANDROID HttpURLConnection,HttpClient和最简单的handler机制

标签：

handler机制在Android开发中主要用于主线程和子线程的沟通，子线程发送必要的信息给主线程，然后在主线程中更新ui；

package com.example.webview;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity implements OnClickListener{
	
	public static final int SHOW_RESPONSE=0;
	private TextView reponseText;
	private Button sendButton;
	
	private Handler handler=new Handler(){

		/* (non-Javadoc)
		 * @see android.os.Handler#handleMessage(android.os.Message)
		 */
		@Override
		public void handleMessage(Message msg) {
//			接收消息并且去更新UI线程上的控件内容
			switch (msg.what) {
			case SHOW_RESPONSE:
				String response=(String) msg.obj;
				reponseText.setText(response);
				break;
			default:
				Toast.makeText(MainActivity.this, "show fail!!", Toast.LENGTH_SHORT).show();
				break;
			}
		}
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		sendButton=(Button) findViewById(R.id.send_request_id);
		reponseText=(TextView) findViewById(R.id.text_id);
		sendButton.setOnClickListener(this);
		
	}

	/* (non-Javadoc)
	 * @see android.view.View.OnClickListener#onClick(android.view.View)
	 */
	@Override
	public void onClick(View v) {
		sendRequestWithHttpURLConnection();
		Toast.makeText(MainActivity.this, "onclick!1", Toast.LENGTH_SHORT).show();
	}

	/**
	 * 开启线程来发起网路请求
	 */
	private void sendRequestWithHttpURLConnection() {
		new Thread(new Runnable() {
			
			@Override
			public void run() {
				HttpURLConnection connection=null;
				try {
					URL url=new URL("http://www.baidu.com");
					connection=(HttpURLConnection) url.openConnection();
					connection.setRequestMethod("GET");
//					设置连接超时
					connection.setConnectTimeout(8000);
//					设置读取超时
					connection.setReadTimeout(8000);
//					获取输入流，进行读取
					InputStream inputStream=connection.getInputStream();
					BufferedReader reader=new BufferedReader(new InputStreamReader(inputStream));
//					下面这个StringBuilder 的作用相当于一个String
					StringBuilder response=new StringBuilder();
					while (reader.readLine()!=null) {
//						读一行就，把读到的添加到response里面
						response.append(reader.readLine());
					}
//					调用dandler的obtainmessage方法，得到一个message对象
					Message message=handler.obtainMessage();
/*					一个message对象，public static Message obtain(Handler h, int what, int arg1, int arg2, Object obj)，
					h：处理消息的目标Handler对象；
					what：消息的编码；
					arg1：附加的整数数据；
					arg2：附加的整数数据；
					obj：附件的Object类型数据。
					返回值：从全局的对象池中返回一个Message对象。*/
					message.what=SHOW_RESPONSE;
					message.obj=response.toString();
//					这里是子线程，这个用handler发送信息给主线程
					handler.sendMessage(message);
					
				} catch (Exception e) {
					// TODO: handle exception
				}finally{
					connection.disconnect();
				}
			}
		}).start();
		
		Toast.makeText(MainActivity.this, "thread start", 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;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		int id = item.getItemId();
		if (id == R.id.action_settings) {
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
}

ANDROID HttpURLConnection,HttpClient和最简单的handler机制

标签：

原文地址：http://blog.csdn.net/ericzengyan/article/details/46455541