Android 大文件上传时处理上传进度问题小结

进行大文件上传时，显示上传进度是很好的用户体验，可以有效的缓解用户急躁的情绪。今天android it 分享一个好的显示上传进度的解决方案。

我们用到以下两个类就可实现带进度条的文件上传：

1、custommultipartentity extends multipartentity,

2、httpmultipartpost extends asynctask

import java.io.filteroutputstream; 
import java.io.ioexception; 
import java.io.outputstream; 
import java.nio.charset.charset; 
import org.apache.http.entity.mime.httpmultipartmode; 
import org.apache.http.entity.mime.multipartentity;  
public class custommultipartentity extends multipartentity { 
  private final progresslistener listener; 
  public custommultipartentity(final progresslistener listener) { 
    super(); 
    this.listener = listener; 
  } 
  public custommultipartentity(final httpmultipartmode mode, final progresslistener listener) { 
    super(mode); 
    this.listener = listener; 
  } 
  public custommultipartentity(httpmultipartmode mode, final string boundary, 
      final charset charset, final progresslistener listener) { 
    super(mode, boundary, charset); 
    this.listener = listener; 
  } 
  @override 
  public void writeto(final outputstream outstream) throws ioexception { 
    super.writeto(new countingoutputstream(outstream, this.listener)); 
  } 
  public static interface progresslistener { 
    void transferred(long num); 
  } 
  public static class countingoutputstream extends filteroutputstream { 
    private final progresslistener listener; 
    private long transferred; 
    public countingoutputstream(final outputstream out, final progresslistener listener) { 
      super(out); 
      this.listener = listener; 
      this.transferred = 0; 
    } 
    public void write(byte[] b, int off, int len) throws ioexception { 
      out.write(b, off, len); 
      this.transferred += len; 
      this.listener.transferred(this.transferred); 
    } 
    public void write(int b) throws ioexception { 
      out.write(b); 
      this.transferred++; 
      this.listener.transferred(this.transferred); 
    } 
  } 
} 

该类计算写入的字节数，我们需要在实现progresslistener中的trasnfered()方法，更行进度条 

public class httpmultipartpost extends asynctask<httpresponse, integer, typeuploadimage> { 
  progressdialogpd; 
  longtotalsize; 
  @override 
  protectedvoidonpreexecute(){ 
    pd= newprogressdialog(this); 
    pd.setprogressstyle(progressdialog.style_horizontal); 
    pd.setmessage("uploading picture..."); 
    pd.setcancelable(false); 
    pd.show(); 
  }  
  @override 
  protectedtypeuploadimagedoinbackground(httpresponse... arg0) { 
    httpclienthttpclient = newdefaulthttpclient(); 
    httpcontexthttpcontext = newbasichttpcontext(); 
    httpposthttppost = newhttppost("http://herpderp.com/uploadimage.php"); 
    try{ 
      custommultipartentitymultipartcontent = newcustommultipartentity( 
          newprogresslistener() { 
            @override 
            public void transferred(longnum){ 
              publishprogress((int) ((num / (float) totalsize) * 100)); 
            } 
          }); 
      // we use filebody to transfer an image 
      multipartcontent.addpart("uploaded_file", newfilebody( 
          newfile(m_userselectedimagepath))); 
      totalsize= multipartcontent.getcontentlength(); 
      // send it 
      httppost.setentity(multipartcontent); 
      httpresponseresponse = httpclient.execute(httppost, httpcontext); 
      string serverresponse = entityutils.tostring(response.getentity()); 
      responsefactoryrp = newresponsefactory(serverresponse); 
      return(typeimage) rp.getdata(); 
    } catch(exception e) { 
      system.out.println(e); 
    } 
    return null; 
  } 
  @override 
  protectedvoidonprogressupdate(integer... progress){ 
    pd.setprogress((int) (progress[0])); 
  } 
  @override 
  protectedvoidonpostexecute(typeuploadimageui) { 
    pd.dismiss(); 
  } 
} 

在 transferred()函数中调用publishprogress((int) ((num / (float) totalsize) * 100));

在onprogressupdate()实现上传进度的更新操作

以上所述是小编给大家介绍的android 大文件上传时处理上传进度问题小结，希望对大家有所帮助