Android：处理图像时AsyncTask崩溃

Question

我想将图像上传到我的网络服务器。 我有服务器和所有的响应，所以这不是问题。 当我将以下代码粘贴到代码中时，它大多会崩溃。

我在调试器中看到AsyncTask的RuntimeException，就这样。

另一个问题：我可以将位图解压缩成一个字节数组，所以我可以用原始文件结尾上传原始文件吗？

这里有问题行：

 // create the image for the server 
    Bitmap bm=BitmapFactory.decodeFile(Values.imageFilePath); 
     ByteArrayOutputStream stream=new ByteArrayOutputStream(); 
     bm.compress(Bitmap.CompressFormat.JPEG, 100, stream); 
     byte[] byte_array=stream.toByteArray(); 
     String byteString=Base64.encodeToString(byte_array, Base64.DEFAULT); 

这里是整个的AsyncTask类，上面的代码被注释掉，它运行。 什么问题？ （ProgressDialog将在主要活动中创建） u 谢谢。

class UploadThread extends AsyncTask<String, Void, String> 
    { 
     private Context _context; 
     private ProgressDialog pd; 

     public UploadThread(Context context) 
     { 
      super(); 
      _context=context; 
     } 

     protected String doInBackground(String... urls) 
     { 
      String response="Android says \"Nothing happened.\"";  
      InputStream is = null; 
      StringBuilder sb=null; 

      //http post 
      try{ 
       HttpClient httpclient = new DefaultHttpClient(); 
       HttpPost httppost = new HttpPost(Values.hostname); 

       ArrayList<NameValuePair> nvp=new ArrayList<NameValuePair>(); 
       // This is the Post data. 
       nvp.add(new BasicNameValuePair("plog_android_upload","plogupload")); 
       nvp.add(new BasicNameValuePair("thecomment",Values.comment)); 

       // get the image and process it. 
//   Values.progressDialog.setMessage("Processing image.."); 
     // create the image for the server 
    // Bitmap bm=BitmapFactory.decodeFile(Values.imageFilePath); 
    // ByteArrayOutputStream stream=new ByteArrayOutputStream(); 
    // bm.compress(Bitmap.CompressFormat.JPEG, 100, stream); 
    // byte[] byte_array=stream.toByteArray(); 
    // String byteString=Base64.encodeToString(byte_array, Base64.DEFAULT); 

     //Values.progressDialog.setMessage("Uploading.."); 
     //nvp.add(new BasicNameValuePair("upload_file",byteString)); 

     httppost.setEntity(new UrlEncodedFormEntity(nvp)); 

     HttpResponse httpresponse = httpclient.execute(httppost); 
     HttpEntity entity = httpresponse.getEntity(); 
     is = entity.getContent(); 
     response="Connection established."; 
    }catch(UnknownHostException eu){ // gets thrown on unknown host. 
     return "No connection!\n(or wrong hostname)"; 
    }catch(HttpHostConnectException ex){ // gets thrown on unknown connection. 
     return "No connection!\n(or wrong hostname)"; 
    }catch(Exception e){ 
     return "Error in http connection:"+e.toString(); 
    } 

    //convert response to string 
    try{ 
     BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8); 
     sb = new StringBuilder(); 
     sb.append(reader.readLine() + "\n"); 
     String line="0"; 
     while ((line = reader.readLine()) != null) { 
      sb.append(line + "\n"); 
     } 
     is.close(); 
     response="Server says: "+sb.toString(); 
    }catch(Exception e){ 
     response= "Error converting HTTP result: "+e.toString(); 
     return response; 
    } 

    return response; 
} 

@Override 
protected void onPostExecute(String result) 
{ 
    super.onPostExecute(result); 
    // dismiss the progress dialog. 
    Values.progressDialog.dismiss(); 
    // Show the user some feedback. 
    Toast.makeText(_context,result, Toast.LENGTH_LONG).show();  
} 

}

Answer 1

我想你用

代码

  HttpClient httpclient = new DefaultHttpClient(); 
      HttpPost httppost = new HttpPost(Values.hostname); 

      ArrayList<NameValuePair> nvp=new ArrayList<NameValuePair>(); 
      // This is the Post data. 
      nvp.add(new BasicNameValuePair("plog_android_upload","plogupload")); 
      nvp.add(new BasicNameValuePair("thecomment",Values.comment)); 

不应在doInBackground执行，我也面临同样的问题，当我在doInBackground使用ArrayList中，所以我将该部分代码更改为在UIThread中工作的onPreExecute（），并将精确的行号与精确的行号一起发送到UIThread