Java tutorial
/* * Copyright Google Inc. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.ag.common.permission; import android.app.Activity; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.content.pm.PackageManager; import android.support.annotation.StringRes; import android.support.v4.app.ActivityCompat; import android.support.v4.app.Fragment; import android.support.v4.content.ContextCompat; import android.util.Log; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.Arrays; import java.util.List; /** * Utility to request and check System permissions for apps targeting Android M (API >= 23). */ public class EasyPermissions { private static final String TAG = "EasyPermissions"; public interface PermissionCallbacks extends ActivityCompat.OnRequestPermissionsResultCallback { void onPermissionsGranted(int requestCode, List<String> perms); void onPermissionsDenied(int requestCode, List<String> perms); } /** * Check if the calling context has a set of permissions. * * @param context the calling context. * @param perms one ore more permissions, such as {@code android.Manifest.permission.CAMERA}. * @return true if all permissions are already granted, false if at least one permission * is not yet granted. */ public static boolean hasPermissions(Context context, String... perms) { for (String perm : perms) { boolean hasPerm = (ContextCompat.checkSelfPermission(context, perm) == PackageManager.PERMISSION_GRANTED); if (!hasPerm) { return false; } } return true; } /** * Request a set of permissions, showing rationale if the system requests it. * * @param object Activity or Fragment requesting permissions. Should implement * {@link android.support.v4.app.ActivityCompat.OnRequestPermissionsResultCallback} * or * {@link android.support.v13.app.FragmentCompat.OnRequestPermissionsResultCallback} * @param rationale a message explaining why the application needs this set of permissions, will * be displayed if the user rejects the request the first time. * @param requestCode request code to track this request, must be < 256. * @param perms a set of permissions to be requested. */ public static void requestPermissions(final Object object, String rationale, final int requestCode, final String... perms) { requestPermissions(object, rationale, android.R.string.ok, android.R.string.cancel, requestCode, perms); } /** * Request a set of permissions, showing rationale if the system requests it. * * @param object Activity or Fragment requesting permissions. Should implement * {@link android.support.v4.app.ActivityCompat.OnRequestPermissionsResultCallback} * or * {@link android.support.v13.app.FragmentCompat.OnRequestPermissionsResultCallback} * @param rationale a message explaining why the application needs this set of permissions, will * be displayed if the user rejects the request the first time. * @param positiveButton custom text for positive button * @param negativeButton custom text for negative button * @param requestCode request code to track this request, must be < 256. * @param perms a set of permissions to be requested. */ public static void requestPermissions(final Object object, String rationale, @StringRes int positiveButton, @StringRes int negativeButton, final int requestCode, final String... perms) { checkCallingObjectSuitability(object); final PermissionCallbacks callbacks = (PermissionCallbacks) object; boolean shouldShowRationale = false; for (String perm : perms) { shouldShowRationale = shouldShowRationale || shouldShowRequestPermissionRationale(object, perm); } if (shouldShowRationale) { AlertDialog dialog = new AlertDialog.Builder(getActivity(object)).setMessage(rationale) .setPositiveButton(positiveButton, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { executePermissionsRequest(object, perms, requestCode); } }).setNegativeButton(negativeButton, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // act as if the permissions were denied callbacks.onPermissionsDenied(requestCode, Arrays.asList(perms)); } }).create(); dialog.show(); } else { executePermissionsRequest(object, perms, requestCode); } } /** * Handle the result of a permission request, should be called from the calling Activity's * {@link android.support.v4.app.ActivityCompat.OnRequestPermissionsResultCallback#onRequestPermissionsResult(int, String[], int[])} * method. * <p/> * If any permissions were granted or denied, the Activity will receive the appropriate * callbacks through {@link PermissionCallbacks} and methods annotated with * {@link AfterPermissionGranted} will be run if appropriate. * * @param requestCode requestCode argument to permission result callback. * @param permissions permissions argument to permission result callback. * @param grantResults grantResults argument to permission result callback. * @param object the calling Activity or Fragment. * @throws IllegalArgumentException if the calling Activity does not implement * {@link PermissionCallbacks}. */ public static void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults, Object object) { checkCallingObjectSuitability(object); PermissionCallbacks callbacks = (PermissionCallbacks) object; // Make a collection of granted and denied permissions from the request. ArrayList<String> granted = new ArrayList<>(); ArrayList<String> denied = new ArrayList<>(); for (int i = 0; i < permissions.length; i++) { String perm = permissions[i]; if (grantResults[i] == PackageManager.PERMISSION_GRANTED) { granted.add(perm); } else { denied.add(perm); } } // Report granted permissions, if any. if (!granted.isEmpty()) { // Notify callbacks callbacks.onPermissionsGranted(requestCode, granted); } // Report denied permissions, if any. if (!denied.isEmpty()) { callbacks.onPermissionsDenied(requestCode, denied); } // If 100% successful, call annotated methods if (!granted.isEmpty() && denied.isEmpty()) { runAnnotatedMethods(object, requestCode); } } private static boolean shouldShowRequestPermissionRationale(Object object, String perm) { if (object instanceof Activity) { return ActivityCompat.shouldShowRequestPermissionRationale((Activity) object, perm); } else if (object instanceof Fragment) { return ((Fragment) object).shouldShowRequestPermissionRationale(perm); } else { return false; } } private static void executePermissionsRequest(Object object, String[] perms, int requestCode) { checkCallingObjectSuitability(object); if (object instanceof Activity) { ActivityCompat.requestPermissions((Activity) object, perms, requestCode); } else if (object instanceof Fragment) { ((Fragment) object).requestPermissions(perms, requestCode); } } private static Activity getActivity(Object object) { if (object instanceof Activity) { return ((Activity) object); } else if (object instanceof Fragment) { return ((Fragment) object).getActivity(); } else { return null; } } private static void runAnnotatedMethods(Object object, int requestCode) { Class clazz = object.getClass(); for (Method method : clazz.getDeclaredMethods()) { if (method.isAnnotationPresent(AfterPermissionGranted.class)) { // Check for annotated methods with matching request code. AfterPermissionGranted ann = method.getAnnotation(AfterPermissionGranted.class); if (ann.value() == requestCode) { // Method must be void so that we can invoke it if (method.getParameterTypes().length > 0) { throw new RuntimeException("Cannot execute non-void method " + method.getName()); } try { // Make method accessible if private if (!method.isAccessible()) { method.setAccessible(true); } method.invoke(object); } catch (IllegalAccessException e) { Log.e(TAG, "runDefaultMethod:IllegalAccessException", e); } catch (InvocationTargetException e) { Log.e(TAG, "runDefaultMethod:InvocationTargetException", e); } } } } } private static void checkCallingObjectSuitability(Object object) { // Make sure Object is an Activity or Fragment if (!((object instanceof Fragment) || (object instanceof Activity))) { throw new IllegalArgumentException("Caller must be an Activity or a Fragment."); } // Make sure Object implements callbacks if (!(object instanceof PermissionCallbacks)) { throw new IllegalArgumentException("Caller must implement PermissionCallbacks."); } } }