Android 大文件上传时，处理上传进度问题
openkk
12年前
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
代码如下：
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); } returnnull; } @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