复制文件时显示进度百分比

Question

目前

我正在从库中挑选一个文件并将其复制到指定的文件夹中。在复制时，我显示的是ProgressDialog，我正在使用AsyncTask 进行此操作。

我试图用百分比显示正在复制的文件的进度，但我遇到的问题是进度显示为 50% 并保持在 50% 直到文件完成复制。

这方面有很多问题，但都是与从URL下载有关。

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我的问题

如何获取正在复制的文件的当前进度并将其显示为百分比？

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请看我在下面的尝试：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    if(requestCode == SELECT_VIDEO_REQUEST && resultCode == RESULT_OK)
    {
        if(data.getData()!=null)
        {
            new MyCopyTask().execute(data.getData());

    }else{

        Toast.makeText(getApplicationContext(), "Failed to select video" , Toast.LENGTH_LONG).show();

        }
    }
}

private class MyCopyTask extends AsyncTask<Uri, Integer, File> {
    ProgressDialog progressDialog;

    @Override
    protected void onPreExecute() {
        progressDialog = new ProgressDialog(MainActivity.this);
        progressDialog.setCancelable(false);
        progressDialog.setIndeterminate(false);
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        progressDialog.setMax(100);
        progressDialog.show();
    }


    @Override
    protected File doInBackground(Uri... params) {
        //copy file to new folder
        Uri selectedImageUri = params[0];
        String sourcePath = getRealPathFromURI(selectedImageUri);

        File source = new File(sourcePath);



        String filename = sourcePath.substring(sourcePath.lastIndexOf("/")+1);

        //onProgressUpdate(50);

        publishProgress(50);

        File destination = new File(Environment.getExternalStorageDirectory(), "MyFolder/Videos/"+filename);
        try
        {
            FileUtils.copyFile(source, destination);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        return destination;
    }

    @Override
    protected void onProgressUpdate(Integer... values){
        super.onProgressUpdate(values);
        progressDialog.setProgress(values[0]);
    }


    @Override
    protected void onPostExecute(File result) {
        if(result.exists()) {
            sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(result)));

            Toast.makeText(getApplicationContext(),"Stored at:  "+"---"+result.getParent()+"----"+"with name:   "+result.getName(), Toast.LENGTH_LONG).show();
            progressDialog.dismiss();


        } else {
            Toast.makeText(getApplicationContext(),"File could not be copied", Toast.LENGTH_LONG).show();
            progressDialog.dismiss();
        }

    }



}

Answer 1

手动复制并以百分比更新进度：

InputStream in = new FileInputStream(source);
OutputStream out = new FileOutputStream(destination);

long lenghtOfFile = source.length();
byte[] buf = new byte[512];
int len;
long total;
while ((len = in.read(buf)) != -1) {
  total += len;

  publishProgress((int)((total*100)/lenghtOfFile));
  out.write(buf, 0, len);
}

in.close();
out.close();

Answer 2

错误在于 publishProgress(50); 您必须发布每个百分比的进度 像这样 发布进度（i）； i++;