android从网络中获得一张图片，并显示在屏幕上

1：androidmanifest.xml的内容

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="cn.capinftotech.image"      android:versionCode="1"      android:versionName="1.0">    <application android:icon="@drawable/icon" android:label="@string/app_name">        <activity android:name=".MainActivity"                  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="8" />    <uses-permission android:name="android.permission.INTERNET" /></manifest> 

注意访问网络中的数据需要添加android.permission.INTERNET权限

2：MainActivity的内容

package cn.capinftotech.image;import java.io.IOException;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;import com.capinfotech.service.ImageService;public class MainActivity extends Activity {private static final String TAG = "MainActivity";private EditText urlPath = null;private Button button = null;private ImageView imageView = null;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                urlPath = (EditText)findViewById(R.id.urlpath);        button = (Button)findViewById(R.id.button);        imageView = (ImageView)findViewById(R.id.imageView);                button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {String urlPathContent = urlPath.getText().toString();try {byte[] data = ImageService.getImage(urlPathContent);Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);  //生成位图imageView.setImageBitmap(bitmap);   //显示图片} catch (IOException e) {Toast.makeText(MainActivity.this, R.string.error, Toast.LENGTH_LONG).show();  //通知用户连接超时信息Log.i(TAG, e.toString());}}});    }}

3：ImageService类的内容

package com.capinfotech.service;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;import com.capinfotech.utils.StreamTool;public class ImageService {public static byte[] getImage(String path) throws IOException {URL url = new URL(path);HttpURLConnection conn = (HttpURLConnection)url.openConnection();conn.setRequestMethod("GET");   //设置请求方法为GET conn.setReadTimeout(5*1000);    //设置请求过时时间为5秒InputStream inputStream = conn.getInputStream();   //通过输入流获得图片数据byte[] data = StreamTool.readInputStream(inputStream);     //获得图片的二进制数据return data;}}

4：StreamTool的内容

package com.capinfotech.utils;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;public class StreamTool {    /*     * 从数据流中获得数据     */public static  byte[] readInputStream(InputStream inputStream) throws IOException {byte[] buffer = new byte[1024];int len = 0;ByteArrayOutputStream bos = new ByteArrayOutputStream();while((len = inputStream.read(buffer)) != -1) {bos.write(buffer, 0, len);}bos.close();return bos.toByteArray();}}

5：程序中用到的字符串资源strings.xml里的内容

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello World, MainActivity!</string>    <string name="app_name">图片浏览器</string>    <string name="urlpath">网络图片地址</string>    <string name="button">显示</string>    <string name="error">网络连接超时</string></resources>

6：程序布局文件main.xml的内容

<?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/urlpath"    /><EditText     android:id="@+id/urlpath"    android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="http://www.eoeandroid.com/data/attachment/forum/201107/18/142935bbi8d3zpf3d0dd7z.jpg"    /><Button    android:id="@+id/button"    android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="@string/button"    /><ImageView    android:id="@+id/imageView"    android:layout_width="wrap_content"     android:layout_height="wrap_content" /></LinearLayout>

7：程序界面及测试结果