Android学习笔记---23_网络通信之网络图片查看器
Android学习笔记---23_网络通信之网络图片查看器23_网络通信之网络图片查看器----------------------------------------------1.从Internet获取数据------------------------------利用HttpURLConnection对象,我们可以从网络中获取网页数据.URL url = new URL("http://www.sohu.com");HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setConnectTimeout(5* 1000);//设置连接超时conn.setRequestMethod(“GET”);//以get方式发起请求if (conn.getResponseCode() != 200) throw new RuntimeException("请求url失败");InputStream is = conn.getInputStream();//得到网络返回的输入流String result = readData(is, "GBK");conn.disconnect();//第一个参数为输入流,第二个参数为字符集编码public static String readData(InputStream inSream, String charsetName) throws
Exception{ByteArrayOutputStream outStream = new ByteArrayOutputStream();byte[] buffer = new byte[1024];int len = -1;while( (len = inSream.read(buffer)) != -1 ){outStream.write(buffer, 0, len);}byte[] data = outStream.toByteArray();outStream.close();inSream.close();return new String(data, charsetName);}利用HttpURLConnection对象,我们可以从网络中获取文件数据.URL url = new URL("http://photocdn.sohu.com/20100125/Img269812337.jpg");HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setConnectTimeout(5* 1000);conn.setRequestMethod("GET");if (conn.getResponseCode() != 200) throw new RuntimeException("请求url失败");InputStream is = conn.getInputStream();readAsFile(is, "Img269812337.jpg");
public static void readAsFile(InputStream inSream, File file) throws Exception{FileOutputStream outStream = new FileOutputStream(file);byte[] buffer = new byte[1024];int len = -1;while( (len = inSream.read(buffer)) != -1 ){outStream.write(buffer, 0, len);} outStream.close();inSream.close();}
----------------------------2.下面是一个应用: 通过用户输入的一个网络图片的地址,来获取网络图片----------------------3.创建项目:netimage/netimage/src/com/credream/netimage/NetimageActivity.java package com.credream.netimage;
import com.credream.service.ImageService;
import android.app.Activity;
import android.graphics.Bitmap;import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;import android.widget.SimpleAdapter.ViewBinder;
public class NetimageActivity extends Activity { /** Called when the activity is first created. */ private EditText pathText; private ImageView imageView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); pathText=(EditText)this.findViewById(R.id.imagepath); imageView=(ImageView)this.findViewById(R.id.imageview); Button button=
(Button)this.findViewById(R.id.button); button.setOnClickListener(new
ButtonOnClickListener());
} private final class ButtonOnClickListener implements View.OnClickListener{
@Overridepublic void onClick(View v){String path=pathText.getText().toString();
//以字节数组存放图片的数据byte[] data;try{data = ImageService.getImage(path);Bitmap bitmap=BitmapFactory.decodeByteArray(data, 0, data.length);//使用数组的全部数据来创建位图对象imageView.setImageBitmap(bitmap);}
catch (Exception e){e.printStackTrace();Toast.makeText(getApplicationContext(), R.string.error, 1).show();
//当用户访问网络的时候,需要访问网络权限,因为可能把用户手机的东西传到网上}} } }-------------------------------------3./netimage/src/com/credream/service/ImageService.javapackage com.credream.service;
import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;
import com.credream.util.StreamTool;
public class ImageService{/** * 获取网络图片的数据 * @param path 网络图片的路径 * @return */public static byte[] getImage(String path)throws Exception{URL url=new URL(path);HttpURLConnection conn=(HttpURLConnection) url.openConnection();//基于
Http协议链接对象conn.setConnectTimeout(5000);conn.setRequestMethod("GET");//InputStream inputStream=conn.getInputStream();//得到的返回数据,可能是错
误的比如,404//错误的时候,也返回数据,但是返回的事错误数据不是所需要的if(conn.getResponseCode()==200){InputStream inStream=conn.getInputStream();returnStreamTool.read(inStream);//返回从流中读取的2进制数据}return null;}
}----------------------4./netimage/src/com/credream/util/StreamTool.javapackage com.credream.util;
import java.io.ByteArrayOutputStream;import java.io.InputStream;/** * 读取流中的数据 * @author xiaofeng * */public class StreamTool{public static byte[] read(InputStream inStream) throws Exception{ByteArrayOutputStream outStream=new ByteArrayOutputStream();byte[] buffer=new byte[1024];int len=0;while((len=inStream.read(buffer))!=-1){outStream.write(buffer,0,len);//往内存写数据}inStream.close();return outStream.toByteArray();}
}---------------------------------------------4./netimage/res/layout/main.xml<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" >
<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/imagepath" /> <EditText android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="@+id/imagepath" android:text="http://192.168.1.110:6118/web/logo.gif"/> <!--http://localhost:6118/web/logo.gif注意这个网站的地址是不能访问的,因为这个时
候,他会从android的系统中找这个 部署的项目,但是找不到所以,要使用局域网的ip来访问,这个地址 http://192.168.1.110:6118/web/logo.gif也就是本机的ip地址.--> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/button" android:id="@+id/button" /> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/imageview" /> </LinearLayout>----------------------------------------------------5./netimage/res/values/strings.xml<?xml version="1.0" encoding="utf-8"?><resources>
<string name="hello">Hello World, NetimageActivity!</string> <string name="app_name">网络通信之网络图片查看器</string> <string name="imagepath">网络图片路径</string> <string name="button">查看图片</string> <string name="error">获取图片失败</string>
</resources>-----------------------------------------6./netimage/AndroidManifest.xml<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.credream.netimage" android:versionCode="1" android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:label="@string/app_name" android:name=".NetimageActivity" > <intent-filter > <action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application><!-- 访问internet权限 --><uses-permission android:name="android.permission.INTERNET"/> </manifest>------------------------7.新建一个web项目:web a./web/WebContent/logo.gif 直接访问就好了------------------------------------8.开始测试: a.首先把netimage项目部署在android的平台上 c.运行web项目,右键run on server----------------------------1.注意获取网络上的任何数据都是一样的: a.首先获取数据流 b.得到二进制数据,得到二进制数据后,然后就可以生成你需要格式的文件---------------------------
