Android从网络中获得一张图片并显示在屏幕上的实例详解

<?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>  

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() {              @Override       public 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());         }                }     });   } } 

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;        } } 

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();        } } 

<?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> 

<?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>