Java Android open失败:尝试读取data/data中的文件时EACCES(权限被拒绝)
我需要读取用户选择的文件,因此我使用以下代码:Java Android open失败:尝试读取data/data中的文件时EACCES(权限被拒绝),java,android,file,file-permissions,Java,Android,File,File Permissions,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) { i
//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
我也将相对权限放在清单中:
我是这样读文件的:
@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,在本例中是下载的图像)
通过代码,我得到了以下异常:
/data/data/com.android.browser/cache/2016-04-25-17-17-49-1205395195.jpg: open failed: EACCES (Permission denied)
我不知道是什么问题
我想补充一些细节:
//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?你不是
com.android.browser
应用程序的作者。您无法在上访问该应用程序的文件。您的权限为。好的,我解决了!问题部分出在模拟器上。。。我为那些有同样问题的人发布代码(感谢Commonware的帮助):
使用文件管理器
。哪个文件管理器应用程序允许用户从内存中选择?Android版本?我希望出现FileNotFoundException
。是的,是默认的文件管理器。好的,但是我怎么能做到呢?我认为这是可能的,因为文件管理器应用程序允许您复制、移动文件等。@m3x:唯一允许您在内部存储上浏览其他应用程序文件内容的“文件管理器应用程序”需要根设备。我会更好地解释:我在模拟器中下载了一个图像进行测试(但它可能是任何类型的文件),在这之后,我想得到这个文件,所以我这样做:Intent Intent=newintent(Intent.ACTION\u get\u CONTENT);intent.setType(“*/*”);intent.addCategory(intent.CATEGORY\u可打开)
打开默认的文件管理器,最后我选择了下载的文件。要获取文件,我需要它的路径,因此我检索了它,并且文件事实上是存在的;现在我只想读它。我做错了什么?@m3x:“打开默认文件管理器”--Android没有“默认文件管理器”,而ACTION\u GET\u CONTENT
与文件无关。“获取文件”--您没有获取文件。您正在为一段内容获取一个Uri
。Uri
不是文件@M3X:您刚才添加到问题中的代码不适用于许多设备,也不适用于许多类型的内容,并且不是必需的。使用ContentResolver
和openInputStream()
读入内容。
//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