Android ProgressDialog 显示但进度未更新

Question

我正在尝试在创建后更新进度条(均在 AsyncTask 中)。进度对话框显示并关闭但未更新，它始终设置为 0。这是我的代码: 公共(public)类 ImageTask 扩展 AsyncTask {

    @Override
    protected Void doInBackground(String... saleId) {

        //Drawable drawable = getActivity().getResources().getDrawable(R.drawable.sale_image_holder);
        //Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
        //ByteArrayOutputStream stream = new ByteArrayOutputStream();
        //bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
        //byte[] imageInAsByteArray = stream.toByteArray(); // here
        ImgService imgService = new ImgService();
        imgService.addImgToSale(imageInAsByteArray, saleId[0], this);
        return null;
    }

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

    @Override
    protected void onPostExecute(Void result) {
        dialog.dismiss();
    }

    public void doProgress(int value){
        publishProgress(value);
    }
}

这是 ImgService 类:

public class ImgService 
{
    public void addImgToSale(byte[] img, final String saleId, final ImageTask task)
    {
        final ParseFile file = new ParseFile(saleId + ".jpeg", img);
        try {
            file.save();
        } catch (ParseException e1) {
            e1.printStackTrace();
            return;
        }
        task.doProgress(50);
        ParseObject image = new ParseObject(DBDictionary.SALE_IMAGES);
        ParseObject sale = new ParseObject(DBDictionary.SALE);
        sale.setObjectId(saleId);
        image.put(DBDictionary.SALE_IMAGES_SALE_ID_P, ParseObject.createWithoutData(DBDictionary.SALE, saleId));
        image.put("image", file);
        try {
            image.save();
        } catch (ParseException e1) {
            e1.printStackTrace();
            return;
        }
        task.doProgress(100);
    }
}

在网上，我发现了很多关于显示和关闭 ProgressDialog 的问题，而不是关于进度更新的问题。

谢谢!

Answer 1

来自 android 文档:在您的异步任务中使用 onProgressUpdate 函数。

 private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
  protected Long doInBackground(URL... urls) {
     int count = urls.length;
     long totalSize = 0;
     for (int i = 0; i < count; i++) {
         totalSize += Downloader.downloadFile(urls[i]);
         publishProgress((int) ((i / (float) count) * 100));//this function updates the progress bar ...
         // Escape early if cancel() is called
         if (isCancelled()) break;
     }
     return totalSize;
 }

 protected void onProgressUpdate(Integer... progress) {
     setProgressPercent(progress[0]);
 }

 protected void onPostExecute(Long result) {
     showDialog("Downloaded " + result + " bytes");
 }
}