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Bug 722657 - Fix glaring bug in subdocument scrolling where scroll amounts got discarded. r=Cwiiis

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This commit is contained in:
Kartikaya Gupta
2012-05-02 13:12:46 -04:00
parent 6bf174192b
commit a99f2668c6
2 changed files with 28 additions and 6 deletions
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30
mobile/android/base/ui/SubdocumentScrollHelper.java
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@@ -57,15 +57,31 @@ class SubdocumentScrollHelper implements GeckoEventListener {
private final PanZoomController mPanZoomController;
private final Handler mUiHandler;
/* This is the amount of displacement we have accepted but not yet sent to JS; this is
* only valid when mOverrideScrollPending is true. */
private final PointF mPendingDisplacement;
/* When this is true, we're sending scroll events to JS to scroll the active subdocument. */
private boolean mOverridePanning;
/* When this is true, we have received an ack for the last scroll event we sent to JS, and
* are ready to send the next scroll event. Note we only ever have one scroll event inflight
* at a time. */
private boolean mOverrideScrollAck;
/* When this is true, we have a pending scroll that we need to send to JS; we were unable
* to send it when it was initially requested because mOverrideScrollAck was not true. */
private boolean mOverrideScrollPending;
/* When this is true, the last scroll event we sent actually did some amount of scrolling on
* the subdocument; we use this to decide when we have reached the end of the subdocument. */
private boolean mScrollSucceeded;
SubdocumentScrollHelper(PanZoomController controller) {
mPanZoomController = controller;
// mUiHandler will be bound to the UI thread since that's where this constructor runs
mUiHandler = new Handler();
mPendingDisplacement = new PointF();
GeckoAppShell.registerGeckoEventListener(MESSAGE_PANNING_OVERRIDE, this);
GeckoAppShell.registerGeckoEventListener(MESSAGE_CANCEL_OVERRIDE, this);
@@ -79,12 +95,11 @@ class SubdocumentScrollHelper implements GeckoEventListener {
if (! mOverrideScrollAck) {
mOverrideScrollPending = true;
mPendingDisplacement.x += displacement.x;
mPendingDisplacement.y += displacement.y;
return true;
}
mOverrideScrollAck = false;
mOverrideScrollPending = false;
JSONObject json = new JSONObject();
try {
json.put("x", displacement.x);
@@ -94,6 +109,13 @@ class SubdocumentScrollHelper implements GeckoEventListener {
}
GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent(MESSAGE_SCROLL, json.toString()));
mOverrideScrollAck = false;
mOverrideScrollPending = false;
// clear the |mPendingDisplacement| after serializing |displacement| to
// JSON because they might be the same object
mPendingDisplacement.x = 0;
mPendingDisplacement.y = 0;
return true;
}
@@ -128,7 +150,7 @@ class SubdocumentScrollHelper implements GeckoEventListener {
mOverrideScrollAck = true;
mScrollSucceeded = message.getBoolean("scrolled");
if (mOverridePanning && mOverrideScrollPending) {
scrollBy(mPanZoomController.getDisplacement());
scrollBy(mPendingDisplacement);
}
}
} catch (Exception e) {