java.io.FileNotFoundException:打开失败:android中出现ENOENT错误

Question

我正在尝试从照片中拾取图像并获取意图数据，将文件保存在内部内存中，并使用该文件加载图像视图。

但我得到的错误如下：

java.io.FileNotFoundException：/storage/emulated/0/Android/data/com.dailyfaithapp.dailyfaith/Files/MI_10052020_1711.png:打开失败：ENOENT(没有这样的文件或目录(

我检查了较低版本的api，即在24上它工作了一两次，但再次失败。

在api 29上，它根本不起作用。为此，我关注了这个网址：https://medium.com/@sriramaripirala/android-10-打开失败的访问权限-取消da8b630a89df

我检查了java中的代码，并尝试了同样的操作，但仍然出现了错误。

我还在检查运行时权限，并在清单文件中指定了权限。

以下是我的代码：

<uses-permission android:name = "android.permission.INTERNET" />
<uses-permission android:name = "android.permission.SYSTEM_ALERT_WINDOW" />
<uses-permission android:name = "android.permission.WAKE_LOCK" />
<uses-permission android:name = "android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name = "android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name = "android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name = "com.google.android.apps.photos.permission.GOOGLE_PHOTOS" />

检查运行时权限：

private boolean checkPermission() {
return ContextCompat.checkSelfPermission(this, WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
&& ContextCompat.checkSelfPermission(this, READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
;
}
private void requestPermissionAndContinue() {
if (ContextCompat.checkSelfPermission(this, WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
&& ContextCompat.checkSelfPermission(this, READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(this, WRITE_EXTERNAL_STORAGE)
&& ActivityCompat.shouldShowRequestPermissionRationale(this, READ_EXTERNAL_STORAGE)) {
AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
alertBuilder.setCancelable(true);
alertBuilder.setTitle("Allow Daily Faith to access photos," +
"media, and files on your device?");
alertBuilder.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
public void onClick(DialogInterface dialog, int which) {
ActivityCompat.requestPermissions(ThemesActivity.this,
new String[]{WRITE_EXTERNAL_STORAGE
, READ_EXTERNAL_STORAGE}, 200);
}
});
AlertDialog alert = alertBuilder.create();
alert.show();
Log.e("", "permission denied, show dialog");
} else {
ActivityCompat.requestPermissions(ThemesActivity.this,
new String[]{WRITE_EXTERNAL_STORAGE,
READ_EXTERNAL_STORAGE}, 200);
}
} else {
selectImageFromGallery();
}
}

检查是否授予权限：

if (!checkPermission()) {
selectImageFromGallery();
} else {
if (checkPermission()) {
requestPermissionAndContinue();
} else {
selectImageFromGallery();
}
}

开业意向：

public void selectImageFromGallery()
{
Intent pickPhoto = new Intent(Intent.ACTION_PICK,
MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(pickPhoto , 2);
}

获取结果的意向数据：

@RequiresApi(api = Build.VERSION_CODES.KITKAT) @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// Check which request we're responding to
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 2) {
// Make sure the request was successful
if (resultCode == RESULT_OK) {
// The user picked a image.
// The Intent's data Uri identifies which item was selected.
if (data != null) {
customTheme = true;
// This is the key line item, URI specifies the name of the data
mImageUri = data.getData();
// Saves image URI as string to Default Shared Preferences
SharedPreferencesData sharedPreferencesData =
new SharedPreferencesData(this);
sharedPreferencesData.setStr("customThemeSet","true");

try {
Bitmap bitmap =
MediaStore.Images.Media.getBitmap(getContentResolver(), mImageUri);
/*         Utils.storeImage(bitmap,
ThemesActivity.this);
File file = Utils.getOutputMediaFile(ThemesActivity.this);
*/
try {
final ParcelFileDescriptor parcelFileDescriptor = getContentResolver().openFileDescriptor(
mImageUri, "r");
final FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
bitmap = BitmapFactory.decodeFileDescriptor(fileDescriptor);
parcelFileDescriptor.close();
Utils.storeImage(bitmap,
ThemesActivity.this);
File file = Utils.getOutputMediaFile(ThemesActivity.this);
int color = Utils.getDominantColor(bitmap);
Log.d("Bitmap", bitmap.toString());
Boolean isDark = Utils.isColorDark(color);
if(customTheme) {
for (Themes themes : themesArrayList) {
themes.setCustomTheme(file.getPath());
themes.setDark(isDark);
}
if(isDark)
sharedPreferencesData.setStr("ThemeColor","dark");
else
sharedPreferencesData.setStr("ThemeColor","light");
themesAdapter = new ThemesAdapter(themesArrayList, this,customTheme);
recyclerView.setAdapter(themesAdapter);
}
} catch (Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
Log.e("Failed", "Failed to Parse Image Uri", e);
try {
throw new Exception("failed to parse image uri");
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
}
}

保存和获取文件

public static File getOutputMediaFile(Context context){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
+ "/Android/data/"
+ context.getApplicationContext().getPackageName()
+ "/Files");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
mediaStorageDir.mkdirs();
}
else {
return null;
}
// Create a media file name
String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmm").format(new Date());
File mediaFile;
String mImageName="MI_"+ timeStamp +".png";
mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName);
return mediaFile;
}
public static void storeImage(Bitmap image,Context context) {
File pictureFile = getOutputMediaFile(context);
if (pictureFile == null) {
Log.d(TAG,
"Error creating media file, check storage permissions: ");// e.getMessage());
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
image.compress(Bitmap.CompressFormat.PNG, 90, fos);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}

在我得到EACCESS错误之前，我只使用上面两个函数来保存文件。

后来我尝试了地块文件描述符，但不起作用为什么我会出现此错误？它是否也只在api级别29或更低级别？有什么解决方案可以在所有设备上运行？

Answer 1

以下是对我有用的方法使用所有新旧手机都可以公开访问的下载文件夹

尝试｛

File csvfile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/brcOrdersaved.csv");
final String filename = csvfile.toString();
if (!csvfile.exists()) {
// displayMsg(context, "No Saved Order: ");
return (false);
} 
FileReader fr = new FileReader(filename);
BufferedReader reader = new BufferedReader(fr);
String csvLine = "";
final char Separator = ',';
final char Delimiter = '"';
final char LF = 'n';
final char CR = 'r';
boolean quote_open = false;
if (reader.equals(null)) {
displayMsg(context, "NULL");
return (false);//rww 11/13/2021
}
int i = 0;
while (!myendofcsvfile) {
csvLine = reader.readLine();
if (csvLine == null) {
myendofcsvfile = true;
} 
// do stuff here
}
fr.close();
fileexists = true;
} catch (Exception e) {
String msg = "Can not Load Saved Order ";
fileexists = false;
return (fileexists);
}

Answer 2

我添加了这个权限，它就工作了。

<uses-permission
enter code hereandroid:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"
tools:ignore="ProtectedPermissions" />