/* * Copyright (C) 2020 The Android Open Source Project * * 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.android.settings.network.telephony; import android.app.Activity; import android.os.Bundle; import androidx.annotation.Nullable; import androidx.fragment.app.DialogFragment; import androidx.fragment.app.Fragment; /** * Base dialog fragment class with the functionality to make a fragment or an activity as a listener * which can survive through the activity restarts. */ public abstract class BaseDialogFragment extends DialogFragment { // Tags for the listener which receives event callbacks. private static final String ARG_LISTENER_TAG = "listener_tag"; private static final String ARG_IN_CALLER_TAG = "in_caller_tag"; /** * @param activity The caller activity or the activity attached with the fragment. * @param listener The original caller, that is, the listener. The listener can be the fragment * to receive event callbacks. If it is null, will use the activity to handle the event * callback instead. * @param callbackInterfaceClass The interface that the listener should implements. * @param arguments The arguments bundle of the dispatcher fragment used to store the listener's * info. * @param tagInCaller An integer given by the listener to distinguish the action when calling * the listener's callback function. */ protected static void setListener( Activity activity, @Nullable Fragment listener, Class callbackInterfaceClass, int tagInCaller, Bundle arguments) { checkValidity(activity, listener, callbackInterfaceClass); if (listener != null && listener.getParentFragment() != null) { throw new IllegalArgumentException("The listener must be attached to an activity."); } arguments.putInt(ARG_IN_CALLER_TAG, tagInCaller); if (listener != null) { arguments.putString(ARG_LISTENER_TAG, listener.getTag()); } } /** * @param callbackInterfaceClass The interface that the listener should implements. * @param Template type. * @return The listener class. */ @SuppressWarnings("unchecked") protected T getListener(Class callbackInterfaceClass) { Object listener; String listenerTag = getArguments().getString(ARG_LISTENER_TAG); if (listenerTag == null) { listener = getActivity(); } else { listener = getActivity().getFragmentManager().findFragmentByTag(listenerTag); } if (callbackInterfaceClass.isInstance(listener)) { return (T) listener; } throw new IllegalArgumentException("The caller should implement the callback function."); } /** @return The tag set in the listener. */ protected int getTagInCaller() { return getArguments().getInt(ARG_IN_CALLER_TAG); } private static void checkValidity( Activity activity, @Nullable Fragment listener, Class callbackInterfaceClass) { if (listener != null) { if (!callbackInterfaceClass.isInstance(listener)) { throw new IllegalArgumentException( "The listener fragment should implement the callback function."); } } else { if (!callbackInterfaceClass.isInstance(activity)) { throw new IllegalArgumentException( "The caller activity should implement the callback function."); } } } }