无法将URL图像保存到Android工作室模拟器SD卡，打开失败:ENOENT(没有这样的文件或目录)

Question

我无法在我的安卓工作室模拟器SD卡上保存URL图像，我没有收到这样的文件和目录错误。

/**
 * Background Async Task to download file
 * */
class DownloadFileFromURL extends AsyncTask<String, String, String> {
        /**
         * Before starting background thread
         * Show Progress Bar Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            showDialog(progress_bar_type);
        }
        /**
         * Downloading file in background thread
         * */
        @Override
        protected String doInBackground(String... f_url) {
            int count;
            try {
                URL url = new URL(f_url[0]);
                URLConnection conection = url.openConnection();
                conection.connect();
                // getting file length
                int lenghtOfFile = conection.getContentLength();
                // input stream to read file - with 8k buffer
                InputStream input = new BufferedInputStream(url.openStream(), 8192);
                // Output stream to write file
                OutputStream output = new FileOutputStream("/sdcard/Download/downloadedfile.jpg");
                byte data[] = new byte[1024];
                long total = 0;
                while ((count = input.read(data)) != -1) {
                    total += count;
                    // publishing the progress....
                    // After this onProgressUpdate will be called
                    publishProgress(""+(int)((total*100)/lenghtOfFile));
                    // writing data to file
                    output.write(data, 0, count);
                }
                // flushing output
                output.flush();
                // closing streams
                output.close();
                input.close();
            } catch (Exception e) {
                Log.e("Error: ", e.getMessage());
            }
            return null;
        }
        /**
         * Updating progress bar
         * */
        protected void onProgressUpdate(String... progress) {
            // setting progress percentage
            pDialog.setProgress(Integer.parseInt(progress[0]));
       }
        /**
         * After completing background task
         * Dismiss the progress dialog
         * **/
        @Override
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after the file was downloaded
            dismissDialog(progress_bar_type);
            // Displaying downloaded image into image view
            // Reading image path from sdcard
            String imagePath = "/sdcard/Download/downloadedfile.jpg";
            // setting downloaded into image view
            my_image.setImageDrawable(Drawable.createFromPath(imagePath));
        }
    }
}

无法将图像保存在Android工作室模拟器SD卡中，我必须将其保存在imageview中。

我收到此错误。

com.example.androidhive E/Error:: /sdcard/Download/downloadedfile.jpg: open failed: EACCES (Permission denied)
com.example.androidhive E/Surface: getSlotFromBufferLocked: unknown buffer: 0xac1b6c70
com.example.androidhive E/BitmapFactory: Unable to decode stream:
java.io.FileNotFoundException: /sdcard/Download/downloadedfile.jpg: open failed: ENOENT (No such file or directory)

Answer 1

尝试在 Android 清单中添加权限.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>