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 { 
  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，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对考高分网网站的支持！