我得到了

open failed: EACCES(权限被拒绝)

myOutput = new FileOutputStream(outFileName);

我检查了根目录,并尝试了android.permission.WRITE_EXTERNAL_STORAGE。

我该如何解决这个问题?

try {
    InputStream myInput;

    myInput = getAssets().open("XXX.db");

    // Path to the just created empty db
    String outFileName = "/data/data/XX/databases/"
            + "XXX.db";

    // Open the empty db as the output stream
    OutputStream myOutput = new FileOutputStream(outFileName);

    // Transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer)) > 0) {
        myOutput.write(buffer, 0, length);
    }

    // Close the streams
    myOutput.flush();
    myOutput.close();
    myInput.close();
    buffer = null;
    outFileName = null;
}
catch (IOException e1) {
    // TODO Auto-generated catch block
    e1.printStackTrace();
}

当前回答

也许答案是这样的:

在API >= 23个设备上,如果你安装了app (app不是系统app),你应该在“设置-应用程序”中检查存储权限,每个应用程序都有权限列表,你应该检查它!试一试

其他回答

修改/system/etc/permission/platform.xml中的权限属性 和小组需要提到如下。

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE">
    <group android:gid="sdcard_rw" />
    <group android:gid="media_rw" />    
</uses-permission>

我在小米设备(android 10)上也遇到了同样的错误。下面的代码解决了我的问题。 图书馆:Dexter(https://github.com/Karumi/Dexter)和Image picker(https://github.com/Dhaval2404/ImagePicker)

添加manifest (android:requestLegacyExternalStorage="true")

    public void showPickImageSheet(AddImageModel model) {
    BottomSheetHelper.showPickImageSheet(this, new BottomSheetHelper.PickImageDialogListener() {
        @Override
        public void onChooseFromGalleryClicked(Dialog dialog) {
            selectedImagePickerPosition = model.getPosition();
            Dexter.withContext(OrderReviewActivity.this)                   .withPermissions(Manifest.permission.READ_EXTERNAL_STORAGE)
                    .withListener(new MultiplePermissionsListener() {
                        @Override
                        public void onPermissionsChecked(MultiplePermissionsReport report) {
                            if (report.areAllPermissionsGranted()) {
                                ImagePicker.with(OrderReviewActivity.this)
                                        .galleryOnly()
                                        .compress(512)
                                        .maxResultSize(852,480)
                               .start();
                            }
                        }

                        @Override
                        public void onPermissionRationaleShouldBeShown(List<PermissionRequest> list, PermissionToken permissionToken) {
                            permissionToken.continuePermissionRequest();
                        }

                    }).check();

            dialog.dismiss();
        }

        @Override
        public void onTakePhotoClicked(Dialog dialog) {
            selectedImagePickerPosition = model.getPosition();
            ImagePicker.with(OrderReviewActivity.this)
                    .cameraOnly()
                    .compress(512)
                    .maxResultSize(852,480)
                    .start();

            dialog.dismiss();
        }

        @Override
        public void onCancelButtonClicked(Dialog dialog) {
            dialog.dismiss();
        }
    });
}

我也有同样的问题……<uses-permission在错误的地方。这是正确的:

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

users -permission标记需要在application标记之外。

2022 Kotlin请求许可的方式:

private val writeStoragePermissionResult =
   registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { permissions ->}

private fun askForStoragePermission(): Boolean =
   if (hasPermissions(
           requireContext(),
           Manifest.permission.READ_EXTERNAL_STORAGE,
           Manifest.permission.WRITE_EXTERNAL_STORAGE
       )
   ) {
       true
   } else {
       writeStoragePermissionResult.launch(
           arrayOf(
               Manifest.permission.READ_EXTERNAL_STORAGE,
               Manifest.permission.WRITE_EXTERNAL_STORAGE,
           )
       )
       false
   }

fun hasPermissions(context: Context, vararg permissions: String): Boolean = permissions.all {
    ActivityCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
}

将文件存储在与应用程序目录无关的目录中受API 29+以上限制。因此,要生成一个新文件或创建一个新文件,使用你的应用程序目录,就像这样

所以正确的做法是:-

val file = File(appContext.applicationInfo.dataDir + File.separator + "anyRandomFileName/")

您可以将任何数据写入这个生成的文件!

上面的文件是可访问的,不会抛出任何异常,因为它位于您自己开发的应用程序的目录中。

另一个选项是android:requestLegacyExternalStorage="true"在清单应用程序标签,由Uriel建议,但它不是一个永久的解决方案!