Android获取网络上的图片

fmms 12年前

网络的访问在我们日常生活中太重要了,如果没有网络我们的生活将会是什么样子呢?android手机和浏览器也是一样的,也可以通过网络通讯获取数据,如调用webservice,EJB等。下面就通过一个小例子从网络获取一幅图片并显示在手机上,开发中将会使用到一个新的组件ImageView.

1.写一个用来处理字节流的工具类

package org.lxh.util;    import java.io.ByteArrayOutputStream;  import java.io.InputStream;    public class StreamTool {   public static byte[] readInputStream(InputStream in) throws Exception{    int len=0;    byte buf[]=new byte[1024];    ByteArrayOutputStream out=new ByteArrayOutputStream();    while((len=in.read(buf))!=-1){     out.write(buf,0,len);  //把数据写入内存    }    out.close();  //关闭内存输出流    return out.toByteArray(); //把内存输出流转换成byte数组   }    }
2.写一个得到图片byte数组的service类
package org.lxh.service;    import java.io.ByteArrayOutputStream;  import java.io.File;  import java.io.FileOutputStream;  import java.io.IOException;  import java.io.InputStream;  import java.net.HttpURLConnection;  import java.net.MalformedURLException;  import java.net.URL;    import org.lxh.util.StreamTool;    import android.util.Log;    public class WebService {   public static byte[] getImage(String path){        URL url;    byte[] b=null;    try {     url = new URL(path);   //设置URL     HttpURLConnection con;             con = (HttpURLConnection)url.openConnection();  //打开连接         con.setRequestMethod("GET"); //设置请求方法     //设置连接超时时间为5s     con.setConnectTimeout(5000);     InputStream in=con.getInputStream();  //取得字节输入流            b=StreamTool.readInputStream(in);         } catch (Exception e) {          e.printStackTrace();    }    return b;  //返回byte数组       }     }
3.写一个用户操作界面
<?xml version="1.0" encoding="utf-8"?>  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"      android:orientation="vertical"      android:layout_width="fill_parent"      android:layout_height="fill_parent"      >  <TextView        android:layout_width="fill_parent"       android:layout_height="wrap_content"       android:text="@string/hello"      />      <TextView        android:layout_width="fill_parent"       android:layout_height="wrap_content"       android:text="@string/picaddress"      />      <EditText      android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:text="http://www.desk9.com/Desk9Image/21/Desk9_21_1690_35790_S.jpg"      android:id="@+id/imageaddress"      />      <Button       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:text="@string/look"      android:id="@+id/button"      />      <ImageView       android:layout_width="fill_parent"       android:layout_height="fill_parent"       android:id="@+id/image"/>  </LinearLayout>
4.写一个activity类
package org.lxh.net;    import org.lxh.service.WebService;    import android.app.Activity;  import android.graphics.Bitmap;  import android.graphics.BitmapFactory;  import android.os.Bundle;  import android.util.Log;  import android.view.View;  import android.widget.Button;  import android.widget.EditText;  import android.widget.ImageView;  import android.widget.Toast;    public class NetActivity extends Activity {     private EditText picaddress;     private Button button;     private ImageView imageView;      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.main);          button=(Button)this.findViewById(R.id.button);          imageView=(ImageView)this.findViewById(R.id.image);          picaddress=(EditText)this.findViewById(R.id.imageaddress);          button.setOnClickListener(new View.OnClickListener() {          public void onClick(View v) {      String address=picaddress.getText().toString();            try {             byte[] data=WebService.getImage(address); //得到图片的输入流              //二进制数据生成位图       Bitmap bit=BitmapFactory.decodeByteArray(data, 0, data.length);              imageView.setImageBitmap(bit);            } catch (Exception e) {          Log.e("NetActivity", e.toString());              Toast.makeText(NetActivity.this, R.string.error, 1).show();      }     }    });      }  }
5.添加网络访问的权限
<?xml version="1.0" encoding="utf-8"?>  <manifest xmlns:android="http://schemas.android.com/apk/res/android"        package="org.lxh.net"        android:versionCode="1"        android:versionName="1.0">      <application android:icon="@drawable/icon" android:label="@string/app_name">          <activity android:name=".NetActivity"                    android:label="@string/app_name">              <intent-filter>                  <action android:name="android.intent.action.MAIN" />                  <category android:name="android.intent.category.LAUNCHER" />              </intent-filter>          </activity>        </application>      <uses-sdk android:minSdkVersion="7" />        <uses-permission android:name="android.permission.INTERNET"/>  </manifest> 
6.这里把strings.xml文件也贴出来
<?xml version="1.0" encoding="utf-8"?>  <resources>      <string name="hello">Hello World, NetActivity!</string>      <string name="app_name">图片查看</string>      <string name="picaddress">图片地址</string>      <string name="look">查看</string>      <string name="error">网络连接异常</string>  </resources>
下面是运行效果图,代码我也上传给大家。0_1328621629f0pz.gif.png

来自:http://blog.csdn.net/chenwill3/article/details/7240587