下载和保存文件

Question

我有一个问题。我尝试下载一个 pdf 文件并将此文件保存在我的应用程序文件夹中。但是当我尝试这样做时，我有一个错误并且文件没有保存......

这是我的提供者

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path
        name="external_files"
        path="Android/data/xxx/files/Download" />
</paths>

我把它放在清单中

    <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="xxx.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/provider_paths2" />
    </provider>

我这样做：

    public static void parseBase64ToPDFAndNoOpen(String base64, String cardId ,Context context) throws IOException {

        FileOutputStream os;
        String path;
        Uri photoURI = null;
        try {
            photoURI = FileProvider.getUriForFile(context.getApplicationContext(),
                    BuildConfig.APPLICATION_ID + ".provider", createImageFile(context,cardId));
        } catch (IOException e) {
            e.printStackTrace();
        }
        File dwldsPath = new File(photoURI.toString());
//            File dwldsPath = new File(Environment.getExternalStorageDirectory() + "/" + File.separator + cardId + ".pdf");
        if (!dwldsPath.exists()) {
            dwldsPath.createNewFile();
            byte[] pdfAsBytes = Base64.decode(base64, 0);
            os = new FileOutputStream(dwldsPath, false);
            os.write(pdfAsBytes);
            os.flush();
            os.close();
        }
    }

private static File createImageFile(Context context,String name) throws IOException {
   File imagesDir = new File(getDefaultTempFilesPath(context));
    return File.createTempFile(
            name, /* prefix */
            ".pdf", /* suffix */
            imagesDir /* directory */
    );
}




   private static String getDefaultTempFilesPath(Context context) {
        if (context != null) {
            File f = context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS);
            if (f != null)
                return f.getPath();
            else {
                f = context.getFilesDir();
                if (f != null)
                    return f.getPath();
            }
        }
        return null;
    }

我有：java.io.IOException: 没有这样的文件或目录

Answer 1

确保您已在清单中添加写入外部存储权限。

或请参考how to save a downloaded file into internal storage in android?

希望链接对您有所帮助。

Answer 2

尝试像这样更改这两种方法：

private static File createImageFile(Context context, String name) {
    return new File(getDefaultTempFilesPath(context), name + ".pdf");
}

private static File getDefaultTempFilesPath(Context context) {
    File f = null;
    if (context != null) {
        f = context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS);
        if (f == null)
            f = context.getFilesDir();
    }
    return f;
}

另外你可能需要改变

path="Android/data/xxx/files/Download"

到

path="."

Answer 3

在 xml/path.xml 文件中：

<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path
    name="external_files"
    path="." />
</paths>

为 AndroidManifest.xml 添加权限：

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

添加到 AndroidManifest.xml 中的应用程序标签：

        <provider
        android:name=".Modules.ContentProviders"
        android:authorities="${applicationId}.provider"
        android:exported="true"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/path" />
    </provider>

主活动：

DownloadFileFromURL sdsa = new DownloadFileFromURL();
sdsa.execute(downloadurl);

从 URL 下载文件：

  class DownloadFileFromURL extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        showDialog(progress_bar_type);

    }

    @Override
    protected String doInBackground(String... f_url) {
        int count;
        try {

            URL as = new URL(f_url[0]);
            URLConnection conection = as.openConnection();
            conection.connect();
            int lenghtOfFile = conection.getContentLength();
            InputStream input = new BufferedInputStream(as.openStream(), 8192);
            String diskurl = as.toString().replace(Constants.Download_url, "");
            String diskurlSpace = diskurl.replaceAll("%20", " ");
            OutputStream output = new 
            FileOutputStream(Environment.getExternalStorageDirectory() + 
             "/DocManager" + diskurlSpace);
            byte data[] = new byte[1024];
            long total = 0;
            while ((count = input.read(data)) != -1) {
                total += count;
                publishProgress("" + (int) ((total * 100) / lenghtOfFile));
                output.write(data, 0, count);
            }
            output.flush();
            output.close();
            input.close();
        } catch (Exception e) {
            Log.e("Error: ", e.getMessage());
        }
        return null;
    }

    protected void onProgressUpdate(String... progress) {
        pDialog.setProgress(Integer.parseInt(progress[0]));
    }

    @Override
    protected void onPostExecute(String file_url) {
        dismissDialog(progress_bar_type);
        Snackbar.make(rayMain, "download and saved", 
     Snackbar.LENGTH_LONG).show();
    }

   }