android - 如何下载内部存储中特定文件夹中的文件

Question

我正在尝试在手机的内部存储中创建一个单独的文件夹，供应用程序下载文件。但该文件夹未在手机中创建。是什么原因？我的应用程序中还有另一个问题，即当我单击下载按钮时没有下载照片。

这里是下载函数

    public void download() {
    for (MediaModel item : Items) {

       if (item.isSelected) {

            Log.d("check", "download");
            final String url = item.getFullDownloadURL();
            BaseDownloadTask task = FileDownloader.getImpl().create(url);
            task.setListener(mFileDownloadListener)
            .setPath(Environment.getDataDirectory() + "/" + Constants.STORED_FOLDER, true)
                    .setAutoRetryTimes(1)
                    .setCallbackProgressTimes(0)
                    .asInQueueTask()
                    .enqueue();

            if (FileDownloader.getImpl().start(mFileDownloadListener, true)) {
                item.setTaskId(task.getId());
                item.setStatus(ItemStatus.DOWNLOADING);
                Logging.e(TAG, "start download task: " + task.getId());
            } else {
                item.setTaskId(task.getId());
                item.setStatus(ItemStatus.NORMAL);
                Logging.e(TAG, "error download task: " + task.getId());
            }
        }
    }
}

Answer 1

在Android studio中使用内部存储首先在manifest中添加权限像这样:

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

然后使用这行代码在内部存储中创建新目录:

   File sdCardRoot = new File(Environment.getExternalStorageDirectory(), "MyProfile");

        if (!sdCardRoot.exists()) {
            sdCardRoot.mkdirs();
        }

        Log.e("check_path", "" + sdCardRoot.getAbsolutePath());

这是我的完整代码:

在此代码中检查目录是否存在，如果目录不存在则创建目录并使用 asyntask 从 url 下载图片

在这个例子中我使用了 Java 语言

代码

  MyAsyncTasks asyncTasks = new MyAsyncTasks();
                asyncTasks.execute(Imageurl);

和异步类:

class MyAsyncTasks extends AsyncTask<String, String, String> {

File sdCardRoot;

@Override
protected String doInBackground(String... strings) {

    HttpURLConnection urlConnection = null;
    try {
        URL url = new URL(strings[0]);
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestMethod("GET");
        urlConnection.setDoOutput(true);
        urlConnection.connect();


        sdCardRoot = new File(Environment.getExternalStorageDirectory(), "MyProfile");

        if (!sdCardRoot.exists()) {
            sdCardRoot.mkdirs();
        }

        Log.e("check_path", "" + sdCardRoot.getAbsolutePath());

        String fileName =
                strings[0].substring(strings[0].lastIndexOf('/') + 1, strings[0].length());
        Log.e("dfsdsjhgdjh", "" + fileName);
        File imgFile =
                new File(sdCardRoot, fileName);
        if (!sdCardRoot.exists()) {
            imgFile.createNewFile();
        }
        InputStream inputStream = urlConnection.getInputStream();
        int totalSize = urlConnection.getContentLength();
        FileOutputStream outPut = new FileOutputStream(imgFile);
        int downloadedSize = 0;
        byte[] buffer = new byte[2024];
        int bufferLength = 0;
        while ((bufferLength = inputStream.read(buffer)) > 0) {
            outPut.write(buffer, 0, bufferLength);
            downloadedSize += bufferLength;
            Log.e("Progress:", "downloadedSize:" + Math.abs(downloadedSize * 100 / totalSize));
        }
        Log.e("Progress:", "imgFile.getAbsolutePath():" + imgFile.getAbsolutePath());

        Log.e(TAG, "check image path 2" + imgFile.getAbsolutePath());

        mImageArray.add(imgFile.getAbsolutePath());
        outPut.close();
    } catch (IOException e) {
        e.printStackTrace();
        Log.e("checkException:-", "" + e);
    }
    return null;
}

@Override
protected void onPostExecute(String s) {
    super.onPostExecute(s);
    imagecount++;
    Log.e("check_count", "" + totalimagecount + "==" + imagecount);
    if (totalimagecount == imagecount) {
        pDialog.dismiss();
        imagecount = 0;
    }
    Log.e("ffgnjkhjdh", "checkvalue checkvalue" + checkvalue);


   }


  }