简单实现Android读取网络图片到本地

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical" >  <EditText     android:id="@+id/et_website"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:hint="please type the url "    />  <Button     android:id="@+id/btn_get"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="Check"    />  <ImageView     android:id="@+id/iv_picture"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:src="@drawable/ic_launcher"    /></LinearLayout>

package com.example.getphotobyxml;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.ImageView;import android.widget.Toast;import com.example.service.ImageService;public class MainActivity extends Activity {  private EditText mEt_url;  private ImageView mIv_picture;  private Button mBtn_get;  /**   * 初始化相关的需要使用到的ID   */  public void init() {    mEt_url = (EditText) findViewById(R.id.et_website);    mIv_picture = (ImageView) findViewById(R.id.iv_picture);    mBtn_get = (Button) findViewById(R.id.btn_get);  }  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    //记得要调用哦    init();    mBtn_get.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        String website = mEt_url.getText().toString();        if (website == null || website.equals("")) {          Toast.makeText(MainActivity.this, "请输入正确的网址哦！",              Toast.LENGTH_LONG).show();          return;        }        byte[] bytes;        try {          bytes = ImageService.getImage(website);          Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0,              bytes.length);          mIv_picture.setImageBitmap(bitmap);        } catch (Exception e) {          // TODO Auto-generated catch block          e.printStackTrace();        }      }    });  }  /**   * 从网络以XML的方式获得一张图片，并显示到一个ImageView上   * 按钮事件可以直接不注册onClickListener，而使用这个方法   * @param view   */  public void getPicture(View view) {    String website = mEt_url.getText().toString();    if (website == null || website.equals("")) {      Toast.makeText(this, "请输入正确的网址哦！", Toast.LENGTH_LONG).show();      return;    }    byte[] bytes;    try {      bytes = ImageService.getImage(website);      Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0,          bytes.length);      mIv_picture.setImageBitmap(bitmap);    } catch (Exception e) {      // TODO Auto-generated catch block      e.printStackTrace();    }  }}

package com.example.service;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;import com.example.utils.StreamTool;/***图片服务的业务类*/public class ImageService {  public static byte[] getImage(String website) throws Exception {    URL url = new URL(website);    HttpURLConnection conn = (HttpURLConnection) url.openConnection();    conn.setConnectTimeout(5000);    conn.setRequestMethod("GET");    if(conn.getResponseCode()==200){      InputStream inputStream = conn.getInputStream();      byte[] bytes = StreamTool.read(inputStream);      return bytes;    }    return "读取网络数据失败".getBytes();  }}

package com.example.utils;import java.io.ByteArrayOutputStream;import java.io.InputStream;/***专门用于将输入流转换成一个字节数组的utils类*/public class StreamTool {  public static byte[] read(InputStream inputStream) throws Exception {    ByteArrayOutputStream baos = new ByteArrayOutputStream();    byte[] buf = new byte[1024];    int len = 0;    while((len = inputStream.read(buf))!=-1){      baos.write(buf, 0 ,len);    }    baos.close();    return buf;  }}