Java tutorial
/* * Copyright (C) 2014-2016 Dominik Schrmann <dominik@dominikschuermann.de> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.sufficientlysecure.keychain.ui.util; import android.Manifest; import android.annotation.SuppressLint; import android.app.Activity; import android.content.ContentResolver; import android.content.Context; import android.content.pm.PackageManager; import android.net.Uri; import android.os.Build; import android.support.v4.app.Fragment; import android.support.v4.content.ContextCompat; import android.widget.Toast; import org.sufficientlysecure.keychain.R; public class PermissionsUtil { private static final int PERMISSION_READ_EXTERNAL_STORAGE = 1; /** * Request READ_EXTERNAL_STORAGE permission on Android >= 6.0 to read content from "file" Uris. * <p/> * This method returns true on Android < 6, or if permission is already granted. It * requests the permission and returns false otherwise. * <p/> * see https://commonsware.com/blog/2015/10/07/runtime-permissions-files-action-send.html */ @SuppressLint("NewApi") // Api level is checked in checkReadPermission public static boolean checkAndRequestReadPermission(Activity activity, Uri uri) { boolean result = checkReadPermission(activity, uri); if (!result) { activity.requestPermissions(new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, PERMISSION_READ_EXTERNAL_STORAGE); } return result; } public static boolean checkAndRequestReadPermission(Fragment fragment, Uri uri) { boolean result = checkReadPermission(fragment.getContext(), uri); if (!result) { fragment.requestPermissions(new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, PERMISSION_READ_EXTERNAL_STORAGE); } return result; } private static boolean checkReadPermission(Context context, Uri uri) { if (!ContentResolver.SCHEME_FILE.equals(uri.getScheme())) { return true; } // Additional check due to: // https://commonsware.com/blog/2015/11/09/you-cannot-hold-nonexistent-permissions.html if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) { return true; } if (ContextCompat.checkSelfPermission(context, Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) { return true; } return false; } public static boolean checkReadPermissionResult(Context context, int requestCode, int[] grantResults) { if (requestCode != PERMISSION_READ_EXTERNAL_STORAGE) { return false; } boolean permissionWasGranted = grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED; if (permissionWasGranted) { return true; } else { Toast.makeText(context, R.string.error_denied_storage_permission, Toast.LENGTH_LONG).show(); return false; } } }