Java tutorial
/* * Copyright 2012 Benjamin Weiss * Copyright 2012 Neofonie Mobile GmbH * * 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.aboveware.common.crouton; import java.util.Iterator; import java.util.Queue; import java.util.concurrent.LinkedBlockingQueue; import android.app.Activity; import android.content.Context; import android.os.Build; import android.os.Handler; import android.os.Message; import android.support.v4.view.accessibility.AccessibilityEventCompat; import android.view.View; import android.view.ViewGroup; import android.view.ViewParent; import android.view.accessibility.AccessibilityEvent; import android.view.accessibility.AccessibilityManager; /** * Manages the lifecycle of {@link Crouton}s. */ public final class Manager extends Handler { private static final class Messages { private Messages() { /* no-op */ } public static final int DISPLAY_CROUTON = 0xc2007; public static final int ADD_CROUTON_TO_VIEW = 0xc20074dd; public static final int REMOVE_CROUTON = 0xc2007de1; } private static Manager INSTANCE; private Queue<Crouton> croutonQueue; private Manager() { croutonQueue = new LinkedBlockingQueue<Crouton>(); } /** * @return The currently used instance of the {@link Manager}. */ public static synchronized Manager getInstance() { if (INSTANCE == null) { INSTANCE = new Manager(); } return INSTANCE; } /** * Inserts a {@link Crouton} to be displayed. * * @param crouton * The {@link Crouton} to be displayed. */ void add(Crouton crouton) { croutonQueue.add(crouton); displayCrouton(); } /** * Displays the next {@link Crouton} within the queue. */ private void displayCrouton() { if (croutonQueue.isEmpty()) { return; } // First peek whether the Crouton has an activity. final Crouton currentCrouton = croutonQueue.peek(); // If the activity is null we poll the Crouton off the queue. if (currentCrouton.getActivity() == null) { croutonQueue.poll(); } if (!currentCrouton.isShowing()) { // Display the Crouton sendMessage(currentCrouton, Messages.ADD_CROUTON_TO_VIEW); if (currentCrouton.getLifecycleCallback() != null) { currentCrouton.getLifecycleCallback().onDisplayed(); } } else { sendMessageDelayed(currentCrouton, Messages.DISPLAY_CROUTON, calculateCroutonDuration(currentCrouton)); } } private long calculateCroutonDuration(Crouton crouton) { long croutonDuration = 0; croutonDuration += crouton.getStyle().durationInMilliseconds; croutonDuration += crouton.getInAnimation().getDuration(); croutonDuration += crouton.getOutAnimation().getDuration(); return croutonDuration; } /** * Sends a {@link Crouton} within a {@link Message}. * * @param crouton * The {@link Crouton} that should be sent. * @param messageId * The {@link Message} id. */ private void sendMessage(Crouton crouton, final int messageId) { final Message message = obtainMessage(messageId); message.obj = crouton; sendMessage(message); } /** * Sends a {@link Crouton} within a delayed {@link Message}. * * @param crouton * The {@link Crouton} that should be sent. * @param messageId * The {@link Message} id. * @param delay * The delay in milliseconds. */ private void sendMessageDelayed(Crouton crouton, final int messageId, final long delay) { Message message = obtainMessage(messageId); message.obj = crouton; sendMessageDelayed(message, delay); } /* * (non-Javadoc) * * @see android.os.Handler#handleMessage(android.os.Message) */ @Override public void handleMessage(Message message) { final Crouton crouton = (Crouton) message.obj; switch (message.what) { case Messages.DISPLAY_CROUTON: { displayCrouton(); break; } case Messages.ADD_CROUTON_TO_VIEW: { addCroutonToView(crouton); break; } case Messages.REMOVE_CROUTON: { removeCrouton(crouton); if (crouton.getLifecycleCallback() != null) { crouton.getLifecycleCallback().onRemoved(); } break; } default: { super.handleMessage(message); break; } } } /** * Adds a {@link Crouton} to the {@link ViewParent} of it's {@link Activity}. * * @param crouton * The {@link Crouton} that should be added. */ private void addCroutonToView(Crouton crouton) { // don't add if it is already showing if (crouton.isShowing()) { return; } View croutonView = crouton.getView(); if (croutonView.getParent() == null) { ViewGroup.LayoutParams params = croutonView.getLayoutParams(); if (params == null) { params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); } // display Crouton in ViewGroup is it has been supplied if (crouton.getViewGroup() != null) { // TODO implement add to last position feature (need to align with how this will be requested for activity) crouton.getViewGroup().addView(croutonView, 0, params); } else { crouton.getActivity().addContentView(croutonView, params); } } croutonView.startAnimation(crouton.getInAnimation()); announceForAccessibilityCompat(crouton.getActivity(), crouton.getText()); sendMessageDelayed(crouton, Messages.REMOVE_CROUTON, crouton.getStyle().durationInMilliseconds + +crouton.getInAnimation().getDuration()); } /** * Removes the {@link Crouton}'s view after it's display * durationInMilliseconds. * * @param crouton * The {@link Crouton} added to a {@link ViewGroup} and should be * removed. */ private void removeCrouton(Crouton crouton) { View croutonView = crouton.getView(); ViewGroup croutonParentView = (ViewGroup) croutonView.getParent(); if (croutonParentView != null) { croutonView.startAnimation(crouton.getOutAnimation()); // Remove the Crouton from the queue. Crouton removed = croutonQueue.poll(); // Remove the crouton from the view's parent. croutonParentView.removeView(croutonView); if (removed != null) { removed.detachActivity(); removed.detachViewGroup(); if (removed.getLifecycleCallback() != null) { removed.getLifecycleCallback().onRemoved(); } removed.detachLifecycleCallback(); } // Send a message to display the next crouton but delay it by the out // animation duration to make sure it finishes sendMessageDelayed(crouton, Messages.DISPLAY_CROUTON, crouton.getOutAnimation().getDuration()); } } /** * Removes a {@link Crouton} immediately, even when it's currently being * displayed. * * @param crouton * The {@link Crouton} that should be removed. */ void removeCroutonImmediately(Crouton crouton) { // if Crouton has already been displayed then it may not be in the queue (because it was popped). // This ensures the displayed Crouton is removed from its parent immediately, whether another instance // of it exists in the queue or not. // Note: crouton.isShowing() is false here even if it really is showing, as croutonView object in // Crouton seems to be out of sync with reality! if (crouton.getActivity() != null && crouton.getView() != null && crouton.getView().getParent() != null) { ((ViewGroup) crouton.getView().getParent()).removeView(crouton.getView()); // remove any messages pending for the crouton removeAllMessagesForCrouton(crouton); } // remove any matching croutons from queue if (croutonQueue != null) { final Iterator<Crouton> croutonIterator = croutonQueue.iterator(); while (croutonIterator.hasNext()) { final Crouton c = croutonIterator.next(); if (c.equals(crouton) && (c.getActivity() != null)) { // remove the crouton from the content view if (crouton.isShowing()) { ((ViewGroup) c.getView().getParent()).removeView(c.getView()); } // remove any messages pending for the crouton removeAllMessagesForCrouton(c); // remove the crouton from the queue croutonIterator.remove(); // we have found our crouton so just break break; } } } } /** * Removes all {@link Crouton}s from the queue. */ void clearCroutonQueue() { removeAllMessages(); if (croutonQueue != null) { // remove any views that may already have been added to the activity's // content view for (Crouton crouton : croutonQueue) { if (crouton.isShowing()) { ((ViewGroup) crouton.getView().getParent()).removeView(crouton.getView()); } } croutonQueue.clear(); } } /** * Removes all {@link Crouton}s for the provided activity. This will remove * crouton from {@link Activity}s content view immediately. */ public void clearCroutonsForActivity(Activity activity) { if (croutonQueue != null) { Iterator<Crouton> croutonIterator = croutonQueue.iterator(); while (croutonIterator.hasNext()) { Crouton crouton = croutonIterator.next(); if ((crouton.getActivity() != null) && crouton.getActivity().equals(activity)) { // remove the crouton from the content view if (crouton.isShowing()) { ((ViewGroup) crouton.getView().getParent()).removeView(crouton.getView()); } removeAllMessagesForCrouton(crouton); // remove the crouton from the queue croutonIterator.remove(); } } } } private void removeAllMessages() { removeMessages(Messages.ADD_CROUTON_TO_VIEW); removeMessages(Messages.DISPLAY_CROUTON); removeMessages(Messages.REMOVE_CROUTON); } private void removeAllMessagesForCrouton(Crouton crouton) { removeMessages(Messages.ADD_CROUTON_TO_VIEW, crouton); removeMessages(Messages.DISPLAY_CROUTON, crouton); removeMessages(Messages.REMOVE_CROUTON, crouton); } /** * Generates and dispatches an SDK-specific spoken announcement. * <p> * For backwards compatibility, we're constructing an event from scratch * using the appropriate event type. If your application only targets SDK * 16+, you can just call View.announceForAccessibility(CharSequence). * </p> * * note: AccessibilityManager is only available from API lvl 4. * * Adapted from https://http://eyes-free.googlecode.com/files/accessibility_codelab_demos_v2_src.zip * via https://github.com/coreform/android-formidable-validation * * @param context Used to get {@link AccessibilityManager} * @param text The text to announce. */ public static void announceForAccessibilityCompat(Context context, CharSequence text) { if (Build.VERSION.SDK_INT >= 4) { AccessibilityManager accessibilityManager = (AccessibilityManager) context .getSystemService(Context.ACCESSIBILITY_SERVICE); if (!accessibilityManager.isEnabled()) { return; } // Prior to SDK 16, announcements could only be made through FOCUSED // events. Jelly Bean (SDK 16) added support for speaking text verbatim // using the ANNOUNCEMENT event type. final int eventType; if (Build.VERSION.SDK_INT < 16) { eventType = AccessibilityEvent.TYPE_VIEW_FOCUSED; } else { eventType = AccessibilityEventCompat.TYPE_ANNOUNCEMENT; } // Construct an accessibility event with the minimum recommended // attributes. An event without a class name or package may be dropped. final AccessibilityEvent event = AccessibilityEvent.obtain(eventType); event.getText().add(text); event.setClassName(Manager.class.getName()); event.setPackageName(context.getPackageName()); // Sends the event directly through the accessibility manager. If your // application only targets SDK 14+, you should just call // getParent().requestSendAccessibilityEvent(this, event); accessibilityManager.sendAccessibilityEvent(event); } } }