这是一个完全的hack，但这是我所做的…

因此，在设置DocumentsProvider时，我注意到样例代码(在getDocIdForFile中，大约在第450行)根据文件相对于指定根的路径(即在第96行中设置mBaseDir的路径)为所选文档生成了唯一的id。

所以URI最终看起来像这样:

内容:/ / com.example.provider /文档/根:路径/ / /文件

正如文档所说，它假设只有一个根(在我的情况下是Environment.getExternalStorageDirectory()，但你可以在其他地方使用…然后它获取文件路径，从根目录开始，并使其成为唯一的ID，前置“root:”。所以我可以通过消除uri.getPath()中的“/document/root:”部分来确定路径，通过这样做来创建一个实际的文件路径:

public void onActivityResult(int requestCode, int resultCode, Intent data) {
// check resultcodes and such, then...
uri = data.getData();
if (uri.getAuthority().equals("com.example.provider"))  {
    String path = Environment.getExternalStorageDirectory(0.toString()
                 .concat("/")
                 .concat(uri.getPath().substring("/document/root:".length())));
    doSomethingWithThePath(path); }
else {
    // another provider (maybe a cloud-based service such as GDrive)
    // created this uri.  So handle it, or don't.  You can allow specific
    // local filesystem providers, filter non-filesystem path results, etc.
}

我知道。这很可耻，但它奏效了。同样，这依赖于您在应用程序中使用自己的文档提供程序来生成文档ID。

(此外，还有一种更好的方法来构建路径，不假设“/”是路径分隔符，等等。但你懂的。)

这个Android库处理奇巧的情况变化(包括旧版本- 2.1+): https://github.com/iPaulPro/aFileChooser

使用String path = FileUtils。getPath(context, uri)将返回的uri转换为可用于所有OS版本的路径字符串。 更多信息请访问:https://stackoverflow.com/a/20559175/860488

正如commonware提到的，你不应该假设，你通过ContentResolver得到的流可以转换成文件。

你真正应该做的是从ContentProvider打开InputStream，然后从中创建一个位图。而且它在4.4和更早的版本上也可以工作，不需要反射。

    //cxt -> current context

    InputStream input;
    Bitmap bmp;
    try {
        input = cxt.getContentResolver().openInputStream(fileUri);
        bmp = BitmapFactory.decodeStream(input);
    } catch (FileNotFoundException e1) {

    }

当然，如果你处理大图片，你应该用适当的inSampleSize: http://developer.android.com/training/displaying-bitmaps/load-bitmap.html加载它们。但那是另一个话题了。

我已经将多个答案组合成一个工作解决方案，结果与文件路径

Mime类型与示例目的无关。

            Intent intent;
            if(Build.VERSION.SDK_INT >= 19){
                intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
                intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, false);
                intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);
            }else{
                intent = new Intent(Intent.ACTION_GET_CONTENT);
            }
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            intent.setType("application/octet-stream");
            if(isAdded()){
                startActivityForResult(intent, RESULT_CODE);
            }

处理结果

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if( requestCode == RESULT_CODE && resultCode == Activity.RESULT_OK) {
        Uri uri = data.getData();
        if (uri != null && !uri.toString().isEmpty()) {
            if(Build.VERSION.SDK_INT >= 19){
                final int takeFlags = data.getFlags() & Intent.FLAG_GRANT_READ_URI_PERMISSION;
                //noinspection ResourceType
                getActivity().getContentResolver()
                        .takePersistableUriPermission(uri, takeFlags);
            }
            String filePath = FilePickUtils.getSmartFilePath(getActivity(), uri);
            // do what you need with it...
        }
    }
}

FilePickUtils

import android.annotation.SuppressLint;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;

public class FilePickUtils {
    private static String getPathDeprecated(Context ctx, Uri uri) {
        if( uri == null ) {
            return null;
        }
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = ctx.getContentResolver().query(uri, projection, null, null, null);
        if( cursor != null ){
            int column_index = cursor
                    .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
        }
        return uri.getPath();
    }

    public static String getSmartFilePath(Context ctx, Uri uri){

        if (Build.VERSION.SDK_INT < 19) {
            return getPathDeprecated(ctx, uri);
        }
        return  FilePickUtils.getPath(ctx, uri);
    }

    @SuppressLint("NewApi")
    public static String getPath(final Context context, final Uri uri) {
        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];
                }

                // TODO handle non-primary volumes
            }
            // 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 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 column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_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());
    }

}

Just wanted to say that this answer is brilliant and I'm using it for a long time without problems. But some time ago I've stumbled upon a problem that DownloadsProvider returns URIs in format content://com.android.providers.downloads.documents/document/raw%3A%2Fstorage%2Femulated%2F0%2FDownload%2Fdoc.pdf and hence app is crashed with NumberFormatException as it's impossible to parse its uri segments as long. But raw: segment contains direct uri which can be used to retrieve a referenced file. So I've fixed it by replacing isDownloadsDocument(uri) if content with following:

final String id = DocumentsContract.getDocumentId(uri);
if (!TextUtils.isEmpty(id)) {
if (id.startsWith("raw:")) {
    return id.replaceFirst("raw:", "");
}
try {
    final Uri contentUri = ContentUris.withAppendedId(
            Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
    return getDataColumn(context, contentUri, null, null);
} catch (NumberFormatException e) {
    Log.e("FileUtils", "Downloads provider returned unexpected uri " + uri.toString(), e);
    return null;
}
}

我在这里尝试了几个答案，我认为我有一个解决方案，每次都可以工作，并且还可以管理权限。

这是基于LEO的巧妙解决方案。这篇文章应该包含所有的代码，你需要使这个工作，它应该工作在任何手机和Android版本;)

为了能够从SD卡中选择文件，你需要在你的清单中这样做:

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

常量:

private static final int PICK_IMAGE = 456; // Whatever number you like
public static final int MY_PERMISSIONS_REQUEST_READ_EXTERNAL = 28528; // Whatever number you like
public static final String FILE_TEMP_NAME = "temp_image"; // Whatever file name you like

检查权限和launchImagePick如果可能的话

if (ContextCompat.checkSelfPermission(getThis(),
        Manifest.permission.READ_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED) {

    ActivityCompat.requestPermissions(getThis(),
            new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
            MY_PERMISSIONS_REQUEST_READ_EXTERNAL);
}
else {
    launchImagePick();
}

允许响应

@Override
public void onRequestPermissionsResult(int requestCode,
                                       @NonNull
                                         String permissions[],
                                       @NonNull
                                         int[] grantResults) {

    if (manageReadExternalPermissionResponse(this, requestCode, grantResults)) {
        launchImagePick();
    }
}

管理权限响应

public static boolean manageReadExternalPermissionResponse(final Activity activity, int requestCode, int[] grantResults) {

    if (requestCode == MY_PERMISSIONS_REQUEST_READ_EXTERNAL) {

        // If request is cancelled, the result arrays are empty.

        if (grantResults.length > 0
                && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

            // Permission was granted, yay! Do the
            // contacts-related task you need to do.
            return true;

        } else if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_DENIED) {

            boolean showRationale = ActivityCompat.shouldShowRequestPermissionRationale(activity,
                    Manifest.permission.READ_EXTERNAL_STORAGE);

            if (!showRationale) {
                // The user also CHECKED "never ask again".
                // You can either enable some fall back,
                // disable features of your app
                // or open another dialog explaining
                // again the permission and directing to
                // the app setting.

            } else {
                // The user did NOT check "never ask again".
                // This is a good place to explain the user
                // why you need the permission and ask if he/she wants
                // to accept it (the rationale).
            }
        } else {
            // Permission denied, boo! Disable the
            // functionality that depends on this permission.
        }
    }
    return false;
}

发射图像选择

private void launchImagePick() {

    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("image/*");
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    startActivityForResult(intent, PICK_IMAGE);

    // see onActivityResult
}

管理图像选择响应

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == PICK_IMAGE) {

        if (resultCode == Activity.RESULT_OK) {
            if (data != null && data.getData() != null) {

                try {
                     InputStream inputStream = getContentResolver().openInputStream(data.getData())
                     if (inputStream != null) {

                        // No special persmission needed to store the file like that
                        FileOutputStream fos = openFileOutput(FILE_TEMP_NAME, Context.MODE_PRIVATE);

                        final int BUFFER_SIZE = 1 << 10 << 3; // 8 KiB buffer
                        byte[] buffer = new byte[BUFFER_SIZE];
                        int bytesRead = -1;
                        while ((bytesRead = inputStream.read(buffer)) > -1) {
                            fos.write(buffer, 0, bytesRead);
                        }
                        inputStream.close();
                        fos.close();

                        File tempImageFile = new File(getFilesDir()+"/"+FILE_TEMP_NAME);

                        // Do whatever you want with the File

                        // Delete when not needed anymore
                        deleteFile(FILE_TEMP_NAME);
                    }
                }
                catch (Exception e) {
                    e.printStackTrace();
                }
            } else {
                // Error display
            }
        } else {
            // The user did not select any image
        }
    }
}

这就是所有的人;这在我所有的电话上都适用。