mobile/android/base/gfx/SubdocumentScrollHelper.java@fc2d59ddac77 (annotated)
mobile/android/base/gfx/SubdocumentScrollHelper.java
Wed, 31 Dec 2014 07:22:50 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 07:22:50 +0100
- branch
- TOR_BUG_3246
- changeset 4
- fc2d59ddac77
- permissions
- -rw-r--r--
Correct previous dual key logic pending first delivery installment.
| michael@0 | 1 | /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*- |
| michael@0 | 2 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | package org.mozilla.gecko.gfx; |
| michael@0 | 7 | |
| michael@0 | 8 | import org.mozilla.gecko.GeckoAppShell; |
| michael@0 | 9 | import org.mozilla.gecko.GeckoEvent; |
| michael@0 | 10 | import org.mozilla.gecko.EventDispatcher; |
| michael@0 | 11 | import org.mozilla.gecko.util.GeckoEventListener; |
| michael@0 | 12 | |
| michael@0 | 13 | import org.json.JSONException; |
| michael@0 | 14 | import org.json.JSONObject; |
| michael@0 | 15 | |
| michael@0 | 16 | import android.graphics.PointF; |
| michael@0 | 17 | import android.os.Handler; |
| michael@0 | 18 | import android.util.Log; |
| michael@0 | 19 | |
| michael@0 | 20 | class SubdocumentScrollHelper implements GeckoEventListener { |
| michael@0 | 21 | private static final String LOGTAG = "GeckoSubdocScroll"; |
| michael@0 | 22 | |
| michael@0 | 23 | private static String MESSAGE_PANNING_OVERRIDE = "Panning:Override"; |
| michael@0 | 24 | private static String MESSAGE_CANCEL_OVERRIDE = "Panning:CancelOverride"; |
| michael@0 | 25 | private static String MESSAGE_SCROLL = "Gesture:Scroll"; |
| michael@0 | 26 | private static String MESSAGE_SCROLL_ACK = "Gesture:ScrollAck"; |
| michael@0 | 27 | |
| michael@0 | 28 | private final Handler mUiHandler; |
| michael@0 | 29 | private final EventDispatcher mEventDispatcher; |
| michael@0 | 30 | |
| michael@0 | 31 | /* This is the amount of displacement we have accepted but not yet sent to JS; this is |
| michael@0 | 32 | * only valid when mOverrideScrollPending is true. */ |
| michael@0 | 33 | private final PointF mPendingDisplacement; |
| michael@0 | 34 | |
| michael@0 | 35 | /* When this is true, we're sending scroll events to JS to scroll the active subdocument. */ |
| michael@0 | 36 | private boolean mOverridePanning; |
| michael@0 | 37 | |
| michael@0 | 38 | /* When this is true, we have received an ack for the last scroll event we sent to JS, and |
| michael@0 | 39 | * are ready to send the next scroll event. Note we only ever have one scroll event inflight |
| michael@0 | 40 | * at a time. */ |
| michael@0 | 41 | private boolean mOverrideScrollAck; |
| michael@0 | 42 | |
| michael@0 | 43 | /* When this is true, we have a pending scroll that we need to send to JS; we were unable |
| michael@0 | 44 | * to send it when it was initially requested because mOverrideScrollAck was not true. */ |
| michael@0 | 45 | private boolean mOverrideScrollPending; |
| michael@0 | 46 | |
| michael@0 | 47 | /* When this is true, the last scroll event we sent actually did some amount of scrolling on |
| michael@0 | 48 | * the subdocument; we use this to decide when we have reached the end of the subdocument. */ |
| michael@0 | 49 | private boolean mScrollSucceeded; |
| michael@0 | 50 | |
| michael@0 | 51 | SubdocumentScrollHelper(EventDispatcher eventDispatcher) { |
| michael@0 | 52 | // mUiHandler will be bound to the UI thread since that's where this constructor runs |
| michael@0 | 53 | mUiHandler = new Handler(); |
| michael@0 | 54 | mPendingDisplacement = new PointF(); |
| michael@0 | 55 | |
| michael@0 | 56 | mEventDispatcher = eventDispatcher; |
| michael@0 | 57 | registerEventListener(MESSAGE_PANNING_OVERRIDE); |
| michael@0 | 58 | registerEventListener(MESSAGE_CANCEL_OVERRIDE); |
| michael@0 | 59 | registerEventListener(MESSAGE_SCROLL_ACK); |
| michael@0 | 60 | } |
| michael@0 | 61 | |
| michael@0 | 62 | void destroy() { |
| michael@0 | 63 | unregisterEventListener(MESSAGE_PANNING_OVERRIDE); |
| michael@0 | 64 | unregisterEventListener(MESSAGE_CANCEL_OVERRIDE); |
| michael@0 | 65 | unregisterEventListener(MESSAGE_SCROLL_ACK); |
| michael@0 | 66 | } |
| michael@0 | 67 | |
| michael@0 | 68 | private void registerEventListener(String event) { |
| michael@0 | 69 | mEventDispatcher.registerEventListener(event, this); |
| michael@0 | 70 | } |
| michael@0 | 71 | |
| michael@0 | 72 | private void unregisterEventListener(String event) { |
| michael@0 | 73 | mEventDispatcher.unregisterEventListener(event, this); |
| michael@0 | 74 | } |
| michael@0 | 75 | |
| michael@0 | 76 | boolean scrollBy(PointF displacement) { |
| michael@0 | 77 | if (! mOverridePanning) { |
| michael@0 | 78 | return false; |
| michael@0 | 79 | } |
| michael@0 | 80 | |
| michael@0 | 81 | if (! mOverrideScrollAck) { |
| michael@0 | 82 | mOverrideScrollPending = true; |
| michael@0 | 83 | mPendingDisplacement.x += displacement.x; |
| michael@0 | 84 | mPendingDisplacement.y += displacement.y; |
| michael@0 | 85 | return true; |
| michael@0 | 86 | } |
| michael@0 | 87 | |
| michael@0 | 88 | JSONObject json = new JSONObject(); |
| michael@0 | 89 | try { |
| michael@0 | 90 | json.put("x", displacement.x); |
| michael@0 | 91 | json.put("y", displacement.y); |
| michael@0 | 92 | } catch (JSONException e) { |
| michael@0 | 93 | Log.e(LOGTAG, "Error forming subwindow scroll message: ", e); |
| michael@0 | 94 | } |
| michael@0 | 95 | GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent(MESSAGE_SCROLL, json.toString())); |
| michael@0 | 96 | |
| michael@0 | 97 | mOverrideScrollAck = false; |
| michael@0 | 98 | mOverrideScrollPending = false; |
| michael@0 | 99 | // clear the |mPendingDisplacement| after serializing |displacement| to |
| michael@0 | 100 | // JSON because they might be the same object |
| michael@0 | 101 | mPendingDisplacement.x = 0; |
| michael@0 | 102 | mPendingDisplacement.y = 0; |
| michael@0 | 103 | |
| michael@0 | 104 | return true; |
| michael@0 | 105 | } |
| michael@0 | 106 | |
| michael@0 | 107 | void cancel() { |
| michael@0 | 108 | mOverridePanning = false; |
| michael@0 | 109 | } |
| michael@0 | 110 | |
| michael@0 | 111 | boolean scrolling() { |
| michael@0 | 112 | return mOverridePanning; |
| michael@0 | 113 | } |
| michael@0 | 114 | |
| michael@0 | 115 | boolean lastScrollSucceeded() { |
| michael@0 | 116 | return mScrollSucceeded; |
| michael@0 | 117 | } |
| michael@0 | 118 | |
| michael@0 | 119 | // GeckoEventListener implementation |
| michael@0 | 120 | |
| michael@0 | 121 | @Override |
| michael@0 | 122 | public void handleMessage(final String event, final JSONObject message) { |
| michael@0 | 123 | // This comes in on the Gecko thread; hand off the handling to the UI thread. |
| michael@0 | 124 | mUiHandler.post(new Runnable() { |
| michael@0 | 125 | @Override |
| michael@0 | 126 | public void run() { |
| michael@0 | 127 | try { |
| michael@0 | 128 | if (MESSAGE_PANNING_OVERRIDE.equals(event)) { |
| michael@0 | 129 | mOverridePanning = true; |
| michael@0 | 130 | mOverrideScrollAck = true; |
| michael@0 | 131 | mOverrideScrollPending = false; |
| michael@0 | 132 | mScrollSucceeded = true; |
| michael@0 | 133 | } else if (MESSAGE_CANCEL_OVERRIDE.equals(event)) { |
| michael@0 | 134 | mOverridePanning = false; |
| michael@0 | 135 | } else if (MESSAGE_SCROLL_ACK.equals(event)) { |
| michael@0 | 136 | mOverrideScrollAck = true; |
| michael@0 | 137 | mScrollSucceeded = message.getBoolean("scrolled"); |
| michael@0 | 138 | if (mOverridePanning && mOverrideScrollPending) { |
| michael@0 | 139 | scrollBy(mPendingDisplacement); |
| michael@0 | 140 | } |
| michael@0 | 141 | } |
| michael@0 | 142 | } catch (Exception e) { |
| michael@0 | 143 | Log.e(LOGTAG, "Exception handling message", e); |
| michael@0 | 144 | } |
| michael@0 | 145 | } |
| michael@0 | 146 | }); |
| michael@0 | 147 | } |
| michael@0 | 148 | } |
