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，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我们网站的支持！