Android Http访问网络 学习（慕课网学习）

一：通过Http 下载百度源码加载到 WebView显示

1：需要访问网络必须先要获取网络权限：

2：在xml文件 定义Webview。

3：因为网络数据加载延迟问题，所以必须要用线程类来显示网页：

package testHttp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.http.HttpConnection;

import android.R.string;
import android.os.Handler;
import android.webkit.WebView;

public class HttpThread extends Thread{

	private String url;
	private WebView webView;
	private Handler handler;
	HttpThread(String url,WebView webView,Handler handler){
		this.url=url;
		this.webView=webView;
		this.handler=handler;
	}
	
	@Override
	public void run() {
		try {
			URL httpUrl=new URL(url); 
			
			try {
				HttpURLConnection httpConnection=(HttpURLConnection) httpUrl.openConnection();//建立http连接
				httpConnection.setReadTimeout(5000);//设置超时时间
				httpConnection.setRequestMethod("GET");//设置请求为GET方法
				
				final StringBuffer bufferString=new StringBuffer();//用Stringbuffer来存储读到的代码
				BufferedReader reader=new BufferedReader(new InputStreamReader(
						httpConnection.getInputStream()));
				
				String str;
				while((str=reader.readLine())!=null)
				{
					bufferString.append(str);
				}
				
				handler.post(new Runnable() {
					
					@Override
					public void run() {

						webView.loadData(bufferString.toString(), 

								"text/html;charset=utf-8", null);//将webView显示到网页上，还是要想 Web一样设置其编码
						
					}
				});
				
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

4：在MainActivity中建立线程，并传参数到Thread：

package testHttp;

import com.example.androidtest.R;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.webkit.WebView;

public class TestHttpActivity extends Activity{
	
	private WebView webView;
	private String urlString="http://www.baidu.com";
	Handler handler=new Handler();
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.http_main_activity);
		webView=(WebView) findViewById(R.id.httpWebView);
		new HttpThread(urlString, webView, handler).start();
	}

}

二：使用http协议在app中加载图片：

1：手写也是网络权限；

2：在xml文件 定义ImageView。

3：使用http获取网络图片，但是不同的是现在要通过二进制流来获取图片了。

先用二进制流获取到图片到本地之后，再用本地地址打开图片到ImageView：

package testHttp;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.http.HttpConnection;

import android.R.string;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.os.Handler;
import android.webkit.WebView;
import android.widget.ImageView;

public class HttpThread extends Thread{

	private String url;
	private ImageView imageView;
	private Handler handler;
	HttpThread(String url,ImageView imageView,Handler handler){
		this.url=url;
		this.imageView=imageView;
		this.handler=handler;
	}
	
	@Override
	public void run() {
		try {
			URL httpUrl=new URL(url);
			
			try {
				HttpURLConnection httpConnection=(HttpURLConnection) httpUrl.openConnection();
				httpConnection.setReadTimeout(5000);
				httpConnection.setRequestMethod("GET");
				httpConnection.setDoInput(true); //允许写
				
				InputStream inputStream=httpConnection.getInputStream();
				FileOutputStream fileOutputStream=null;
				File downFile=null;
				String fileNameString=String.valueOf(System.currentTimeMillis());
				
				if(Environment.getExternalStorageState().equals(
						Environment.MEDIA_MOUNTED)){
					File parentFile=Environment.getExternalStorageDirectory();//获取本地路径
					downFile=new File(parentFile, fileNameString);
					
					fileOutputStream = new FileOutputStream(downFile);
					}
				
				byte[] bt=new byte[2*1024];
				
				int len;
				
				if(fileOutputStream!=null){
					while((len=inputStream.read(bt))!=-1)
					{
						fileOutputStream.write(bt, 0, len);
					}
				}
				final Bitmap bitmap=BitmapFactory.decodeFile(downFile.getAbsolutePath());
				
				handler.post(new Runnable() {
					
					@Override
					public void run() {
						// TODO Auto-generated method stub
						imageView.setImageBitmap(bitmap);
					}
				});
				
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}