如何在 Android/Java 中使用 AsyncTask 将 URI 传递给 API？

Question

我正在尝试使用以下方法通过 Web API 发送 PDF 文件：

public static <function> JSONObject uploadFile(String url, Context context, JSONObject jsondata, String imagepath) {
        sJsonObj = null;
        sb = null;

        try {
            sUrl = new URL(url);

            sHttpUrlConnection = (HttpURLConnection) sUrl.openConnection();
            sHttpUrlConnection.setDoInput(true);
            sHttpUrlConnection.setDoOutput(true);
            sHttpUrlConnection.setUseCaches(false);
            sHttpUrlConnection.setReadTimeout(sTimeout);
            sHttpUrlConnection.setConnectTimeout(sTimeout);
            sHttpUrlConnection.setRequestMethod(HttpPost.METHOD_NAME);
            sHttpUrlConnection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + BOUNDARY);
            sHttpUrlConnection.setRequestProperty("fileName", imagepath);
            sHttpUrlConnection.setRequestProperty("Connection", "Keep-Alive");


            sPrintWriter = new PrintWriter(sHttpUrlConnection.getOutputStream());

            sPrintWriter.append(TWO_HYPHENS + BOUNDARY)
                    .append(LINE_END)
                    .append("Content-Disposition: form-data;name=\"body\"")
                    .append(LINE_END)
                    .append(LINE_END)
                    .append(jsondata.toString())
                    .append(LINE_END)

                    .append(TWO_HYPHENS + BOUNDARY)
                    .append(LINE_END)
                    .append("Content-Disposition: form-data; name=\"fileName\"; filename=\"" + new File(imagepath).getAbsoluteFile() + "\"")
                    .append(LINE_END)
                    .append("Content-Type: "
                            + URLConnection.guessContentTypeFromName(imagepath))
                    .append(LINE_END)
                    .append("Content-Transfer-Encoding: binary")
                    .append(LINE_END)
                    .append(LINE_END);

            sPrintWriter.flush();

            FileInputStream fileStream = new FileInputStream(imagepath);
            byte[] buffer = new byte[4096];
            int bytesRead = -1;
            while ((bytesRead = fileStream.read(buffer)) != -1) {
                sHttpUrlConnection.getOutputStream().write(buffer, 0, bytesRead);
            }

            fileStream.close();

            sPrintWriter.append(LINE_END);
            sPrintWriter.append(TWO_HYPHENS);
            sPrintWriter.append(BOUNDARY);
            sPrintWriter.append(TWO_HYPHENS);
            sPrintWriter.flush();
            sHttpUrlConnection.getOutputStream().close();

            if (true) {
                BufferedReader reader = null;
                reader = new BufferedReader(new InputStreamReader(sHttpUrlConnection.getInputStream()));
                sb = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {
                    sb.append(line + "\n");
                }
                reader.close();

                sJsonObj = new JSONObject(sb.toString());
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            sHttpUrlConnection.disconnect();
        }
        return sJsonObj;
    }

如果你仔细看uploadFile方法的参数，你会发现最后一个参数是filePath，

在Stack Overflow上连续2天搜索后，我发现在某些较新的Android版本中我无法获取filePath。

而且我的应用支持Api level 21到30，所以大家都建议只通过传递URI试试。

现在，在这个 uploadFile 方法中，如果我尝试将最后一个参数从 String 更改为 Uri，那么很多地方都会出现编译器错误。现在我不明白我应该在这个方法中改变什么？

任何人都可以用相同的方法发布一些修改的答案，这将非常感激。

FileNotFound 异常即将到来，如果我将通过 uri.getPath

Answer 1

你可以试试吗？我提供了一些代码：

public static String getPath(final Context context, final Uri uri) {

    // check here to KITKAT or new version
    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {

        // ExternalStorageProvider
        if (isExternalStorageDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type)) {
                return Environment.getExternalStorageDirectory() + "/" + split[1];
            }
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri)) {

            final String id = DocumentsContract.getDocumentId(uri);
            final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            Uri contentUri = null;
            if ("image".equals(type)) {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            } else if ("video".equals(type)) {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            } else if ("audio".equals(type)) {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }

            final String selection = "_id=?";
            final String[] selectionArgs = new String[] { split[1] };

            return getDataColumn(context, contentUri, selection, selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme())) {

        // Return the remote address
        if (isGooglePhotosUri(uri))
            return uri.getLastPathSegment();

        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
}

/**
 * Get the value of the data column for this Uri. This is useful for
 * MediaStore Uris, and other file-based ContentProviders.
 *
 * @param context
 *            The context.
 * @param uri
 *            The Uri to query.
 * @param selection
 *            (Optional) Filter used in the query.
 * @param selectionArgs
 *            (Optional) Selection arguments used in the query.
 * @return The value of the _data column, which is typically a file path.
 */
public static String getDataColumn(Context context, Uri uri,
                                   String selection, String[] selectionArgs) {

    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = { column };

    try {
        cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
        if (cursor != null && cursor.moveToFirst()) {
            final int index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is ExternalStorageProvider.
 */
public static boolean isExternalStorageDocument(Uri uri) {
    return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is DownloadsProvider.
 */
public static boolean isDownloadsDocument(Uri uri) {
    return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is MediaProvider.
 */
public static boolean isMediaDocument(Uri uri) {
    return "com.android.providers.media.documents".equals(uri.getAuthority());
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is Google Photos.
 */
public static boolean isGooglePhotosUri(Uri uri) {
    return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}