从服务器使用JSON的Android下载图像

我的应用程序包含几个按钮，我想要的是通过单击任何按钮，它将引导我到一个URL，然后带我到一个JSON对象页面，然后为我提供一个图像源显示在我的Android设备上。从服务器使用JSON的Android下载图像

例如：按钮1 - >http://a.b.c.d/loadview.htm?buttonid=B1 - > Json对象（img src- url到图像文件） - >显示在我的android设备上。

感谢提前:)

2012-02-07 Rohit Sangal

这是工作代码：从服务器下载图像和Android的

public void onCreate(Bundle savedInstanceState) 

{ 

Bitmap bitmap = DownloadImage("http://www.aaa.com/images//29_13.jpeg"); 

ImageView img = (ImageView) findViewById(R.id.imagefromserver); 

img.setImageBitmap(bitmap); 

} 


private InputStream OpenHttpConnection(String urlString) 
    throws IOException 

{ 

InputStream in = null; 

     int response = -1; 

     URL url = new URL(urlString); 
     URLConnection conn = url.openConnection(); 

     if (!(conn instanceof HttpURLConnection))      
      throw new IOException("Not an HTTP connection"); 

     try{ 
      HttpURLConnection httpConn = (HttpURLConnection) conn; 
      httpConn.setAllowUserInteraction(false); 
      httpConn.setInstanceFollowRedirects(true); 
      httpConn.setRequestMethod("GET"); 
      httpConn.connect(); 

      response = httpConn.getResponseCode();     
      if (response == HttpURLConnection.HTTP_OK) { 
       in = httpConn.getInputStream();         
      }      
     } 
     catch (Exception ex) 
     { 
      throw new IOException("Error connecting");    
     } 
     return in;  
    } 
    private Bitmap DownloadImage(String URL) 
    {   
     Bitmap bitmap = null; 
     InputStream in = null;   
     try { 
      in = OpenHttpConnection(URL); 
      bitmap = BitmapFactory.decodeStream(in); 
      in.close(); 
     } catch (IOException e1) { 
      // TODO Auto-generated catch block 
      e1.printStackTrace(); 
     } 
     return bitmap;     
    }

来源

2012-12-07 08:16:10 AndroidRaji

你们的榜样网址不工作，但我会尽量尝试解释：

WebRequest request = HttpWebRequest.Create("test.aspx"); 
    WebResponse response = request.GetResponse(); 

    using (StreamReader streamReader = new StreamReader(response.GetResponseStream())) 
    { 
     string json = streamReader.ReadToEnd(); 

     JavaScriptSerializer ser = new JavaScriptSerializer(); 
     var deserializedObject = ser.Deserialize(json, typeof(ControllerBuilder)); 

     if(deserializedObject != null) 
      //cast object to the correct type and use it. 
    }

我不建议使用内置的JavaScriptSerializer类，只是因为我有性能问题。使用更好的工具是：

http://james.newtonking.com/pages/json-net.aspx

希望这可以帮助你！

来源

2012-02-07 13:02:42

You need to open a HttpConnection with the url to image source and download it. 
Here is the code: 

Bitmap getTheBitmap(String yourImgSrcUrl) 
{ 
URL url = null; 
Bitmap bitmap = null; 
DataInputStream fileInputStream = null; 
try 
{ 
String urlPath = yourImgSrcUrl; 
urlPath = urlPath.replace(" ", "%20"); // to replace any blank spaces 
url = new URL(urlPath); 
connection = (HttpURLConnection) url.openConnection(); 
connection.setDoInput(true); 
connection.setUseCaches(false); 
connection.setRequestMethod("GET"); 

fileInputStream = new DataInputStream(connection.getInputStream()); 
byte[] bitmapBytes= new byte[fileInputStream.available()]; 
fileInputStream.read(bitmapBytes); 
fileInputStream.close(); 
bitmap = BitmapFactory.decodeByteArray(bitmapBytes, 0, bitmapBytes.length); 
return bitmap; 
} 
catch (IOException e) 
     { 
      e.printStackTrace(); 
return null; 
     } 
} 


Kindly check that Bitmap you are getting is not null before setting in the ImageView else it will throw exception.

来源

2012-02-07 13:15:31 SAMD

喜显示它我得到的位图作为空。可能是什么问题。 – AndroidRaji 2012-12-07 05:31:54

从服务器使用JSON的Android下载图像

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