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

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();
        }
    });
}

其他回答

我希望下面的所有内容/数据都属于“内部存储”。但是,您应该能够写入/sdcard。

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

我也有同样的问题,但没有一个建议有用。但我发现了一个有趣的原因,那就是在实体设备Galaxy Tab上。

当USB存储打开时,外部存储的读写权限没有任何影响。 只要关闭USB存储,并使用正确的权限,你就会有问题解决。

谷歌在Android Q上有一个新功能:外部存储的过滤视图。一个快速的修复方法是在AndroidManifest.xml文件中添加以下代码:

<manifest ... >
    <!-- This attribute is "false" by default on apps targeting Android Q. -->
    <application android:requestLegacyExternalStorage="true" ... >
     ...
    </application>
</manifest>

你可以在这里阅读更多信息:https://developer.android.com/training/data-storage/use-cases

编辑:我开始得到反对票,因为这个答案是过时的安卓11。看到答案的同学请点击上面的链接阅读说明。

对于API 23+,您需要请求读/写权限,即使它们已经在您的清单中。

// Storage Permissions
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
};

/**
 * Checks if the app has permission to write to device storage
 *
 * If the app does not has permission then the user will be prompted to grant permissions
 *
 * @param activity
 */
public static void verifyStoragePermissions(Activity activity) {
    // Check if we have write permission
    int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);

    if (permission != PackageManager.PERMISSION_GRANTED) {
        // We don't have permission so prompt the user
        ActivityCompat.requestPermissions(
                activity,
                PERMISSIONS_STORAGE,
                REQUEST_EXTERNAL_STORAGE
        );
    }
}

AndroidManifest.xml

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

有关请求API 23+权限的官方文档,请查看https://developer.android.com/training/permissions/requesting.html