Android打开失败：尝试读取数据/数据中的文件时，EACCES（权限被拒绝）

M3M3X 发表于 Dev

M3M3X

我需要读取用户选择的文件，因此我使用以下代码：

//This code is called by a button to ask the permission
private void startUpload(){

    if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {

            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, WRITE_PERMISSION_GRANTED);

        } else {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, WRITE_PERMISSION_GRANTED);
        }
    }

}//startUpload

我也将相对权限放入清单中：

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

我以这种方式读取文件：

@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
        case WRITE_PERMISSION_GRANTED: {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                try {
                    FileInputStream stream = new FileInputStream(toUpload.getCanonicalFile());
                    byte[] data = new byte[(int) toUpload.length()];
                    stream.read(data);
                    stream.close();
                    Log.e("FUNZIONA!!!!", "OK!");
                }catch (Exception e){
                    Log.e("ECCEZIONE", e.getMessage());
                }
            } else {
                Log.e("PERMISSION", "DEINED");
            }
            return;
        }

        // other 'case' lines to check for other
        // permissions this app might request
    }
}

（toUpload是用户使用文件管理器选择的文件，在这种情况下为下载的图像）使用代码，我得到此异常：

/data/data/com.android.browser/cache/2016-04-25-17-17-49-1205395195.jpg: open failed: EACCES (Permission denied)

我不知道问题是什么。

我添加一些细节：

//this code opens the defualt file manager
private void showFileChooser() {

    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("*/*");
    intent.addCategory(Intent.CATEGORY_OPENABLE);

    try {
        startActivityForResult(
                Intent.createChooser(intent, "Select a File to Upload"),
                FILE_SELECT_CODE);
    } catch (android.content.ActivityNotFoundException ex) {

        Snackbar.make(uploadView, "Nessun file manager trovato!", Snackbar.LENGTH_LONG).setAction("Response", null).show();
    }

}//showFileChooser

//this is for getting the selected file
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    switch (requestCode) {
        case FILE_SELECT_CODE:
            if (resultCode == RESULT_OK) {
                Uri uri = data.getData();
                String path = getPath(this, uri);
                toUpload = new File(path);
                //Log.d("LOG", "File Path: " + path);
            }
            break;
    }
    super.onActivityResult(requestCode, resultCode, data);

}//onActivityResult

这是获取路径的代码：

private 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];
            }
        }
        // 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;

}//getPath

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;

}//getDataColumn

public static boolean isExternalStorageDocument(Uri uri) {

    return "com.android.externalstorage.documents".equals(uri.getAuthority());

}//isExternalStorageDocument

public static boolean isDownloadsDocument(Uri uri) {

    return "com.android.providers.downloads.documents".equals(uri.getAuthority());

}//isDownloadsDocument

public static boolean isMediaDocument(Uri uri) {

    return "com.android.providers.media.documents".equals(uri.getAuthority());

}//isMediaDocument

public static boolean isGooglePhotosUri(Uri uri) {

    return "com.google.android.apps.photos.content".equals(uri.getAuthority());

}//isMediaDocument

怎么了？

M3M3X

好的，我解决了！问题部分是模拟器...我将代码发布给有相同问题的人（感谢CommonsWare的帮助）：

//It requires a file manager installed
private void showFileChooser() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("file/*");
    try {
        startActivityForResult(intent, FILE_SELECT_CODE);
    } catch (android.content.ActivityNotFoundException ex) {
        Snackbar.make(uploadView, "No file manager founded!", Snackbar.LENGTH_LONG).setAction("Response", null).show();
    }

}//showFileChooser

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    switch (requestCode) {
        case FILE_SELECT_CODE:
            if (resultCode == RESULT_OK) {
                Uri uri = data.getData();
                uriToUpload = uri;
            }
            break;
    }
    super.onActivityResult(requestCode, resultCode, data);

}//onActivityResult 

private byte[] getFileData() throws IOException{

    Cursor cursor = getContentResolver().query(uriToUpload, null, null, null, null);
    cursor.moveToFirst();
    long size = cursor.getLong(cursor.getColumnIndex(OpenableColumns.SIZE));
    cursor.close();
    InputStream stream = getContentResolver().openInputStream(uriToUpload);
    byte[] data = new byte[(int)size];
    stream.read(data);
    stream.close();

    return data;

}//getFileData

本文收集自互联网，转载请注明来源。

如有侵权，请联系 [email protected] 删除。