Android代码（Handler的运用），HttpURLConnection的应用，将url图片地址转换成图片。

<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"

    tools:context=".MainActivity" >

    <ImageView

        android:id="@+id/iv_icon"

        android:layout_width="fill_parent"

        android:layout_height="0dip"

        android:layout_weight="1" />

    <LinearLayout

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:orientation="horizontal" >

        <EditText

            android:id="@+id/et_url"

            android:layout_width="0dip"

            android:text="http://img0.hao123.com/data/1_489a5f7dfbcbb624a231f372e4bdffce_310"

            android:layout_height="wrap_content"

            android:singleLine="true"

            android:layout_weight="1" />

        <Button

            android:id="@+id/btn_submit"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="Go"

            android:textSize="20sp" />

    </LinearLayout>

</LinearLayout>

package com.itheim28.submitdata;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

    private static final String TAG = "MainActivity";

    protected static final int ERROR = 1;

    private EditText etUrl;

    private ImageView ivIcon;

    private final int SUCCESS = 0;

    private Handler handler = new Handler() {

       public void handleMessage(Message msg) {

           super.handleMessage(msg);

           Log.i(TAG, "what = " + msg.what);

           if (msg.what == SUCCESS) {

              ivIcon.setImageBitmap((Bitmap)msg.obj);

           } else if (msg.what == ERROR) {

              Toast.makeText(MainActivity.this, "抓起失败", 0).show();

           }

       }

    };

    @Override

    protected void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       setContentView(R.layout.activity_main);

       ivIcon = (ImageView) findViewById(R.id.iv_icon);

       etUrl = (EditText) findViewById(R.id.et_url);

       findViewById(R.id.btn_submit).setOnClickListener(this);

    }

    @Override

    public void onClick(View v) {

       final String url = etUrl.getText().toString();

       new Thread(new Runnable() {

           @Override

           public void run() {

              Bitmap bitmap = getImageFromNet(url);

//            ivIcon.setImageBitmap(bitmap);     // 设置imageView显示的图片

              if(bitmap != null) {

                  Message msg = new Message();

                  msg.what = SUCCESS;

                  msg.obj = bitmap;

                  handler.sendMessage(msg);

              } else {

                  Message msg = new Message();

                  msg.what = ERROR;

                  handler.sendMessage(msg);

              }

           }}).start();

    }

    /**

     * 根据url连接取网络抓去图片返回

     * @param url

     * @return url对应的图片

     */

    private Bitmap getImageFromNet(String url) {

       HttpURLConnection conn = null;

       try {

           URL mURL = new URL(url); // 创建一个url对象

           // 得到http的连接对象

           conn = (HttpURLConnection) mURL.openConnection();

           conn.setRequestMethod("GET");      // 设置请求方法为Get

           conn.setConnectTimeout(10000);     // 设置连接服务器的超时时间, 如果超过10秒钟, 没有连接成功, 会抛异常

           conn.setReadTimeout(5000);      // 设置读取数据时超时时间, 如果超过5秒, 抛异常

           conn.connect();      // 开始链接

           int responseCode = conn.getResponseCode(); // 得到服务器的响应码

           if(responseCode == 200) {

              // 访问成功

              InputStream is = conn.getInputStream();   // 获得服务器返回的流数据

              Bitmap bitmap = BitmapFactory.decodeStream(is); // 根据 流数据 创建一个bitmap位图对象

              return bitmap;

           } else {

              Log.i(TAG, "访问失败: responseCode = " + responseCode);

           }

       } catch (Exception e) {

           e.printStackTrace();

       } finally {

           if(conn != null) {

              conn.disconnect();       // 断开连接

           }

       }

       return null;

    }

}