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Don't distrust the cursor pos so much as to bug on IPC delay

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When the cursor is moved by the user, the RichInputConnection
is told about it. However, to work around a framework bug, it
also looks at how many characters are in the buffer before the
cursor, and if that's more than the value it's been passed, it
deduces that's a framework bug and there are at least as many
characters as seen before the cursor, so it puts the expected
cursor position there.

When you move the cursor, TextView calls onUpdateSelection,
and when you move it fast, you'll get rapid-fire calls to
onUpdateSelection. This is fine, the RIC is equipped to
deal with that.

However, these calls take some time to make it to the IME. In
this instance, when the first call gets through and the IME
calls TextView (synchronously) for text before the cursor, the
cursor has already moved in the app, and TextView returns more
characters than the cursor position was declared to be in this
instance, so the RIC sets that as the expected cursor position.
Sure enough, a split second later, the second call to
onUpdateSelection arrives, with the new cursor position set
where the RIC had found it too early. The RIC takes that as an
"expected" cursor move, and the input does not get reset.

Luckily, we have a way out. As far as we know, the framework bug
only manifests itself upon rotation, which means we should only
have to adjust for it in onStartInputView. Doing it in
onUpdateSelection is too zealous (and probably too distrustful of
the app to send the correct cursor positions).

So we should just take care of the rotation case (by calling
tryFixLyingCursorPosition in onStartInputView) and remove the
compensating code in resetCachesUponCursorMoves.

Bug: 12982502
Change-Id: Ic3c1408a1ec45deaea63b01d98376a79ae567d77
This commit is contained in:
Jean Chalard 2014-02-19 22:28:20 +09:00
parent 475f9f35b6
commit 3c84eb8822
2 changed files with 6 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
java/src/com/android/inputmethod/latin/LatinIME.java
View file

@ -799,19 +799,22 @@ public class LatinIME extends InputMethodService implements KeyboardActionListen
suggest = mInputLogic.mSuggest;
}
// Sometimes, while rotating, for some reason the framework tells the app we are not
// connected to it and that means we can't refresh the cache. In this case, schedule a
// refresh later.
// TODO[IL]: Can the following be moved to InputLogic#startInput?
final boolean canReachInputConnection;
if (!mInputLogic.mConnection.resetCachesUponCursorMoveAndReturnSuccess(
editorInfo.initialSelStart, editorInfo.initialSelEnd,
false /* shouldFinishComposition */)) {
// Sometimes, while rotating, for some reason the framework tells the app we are not
// connected to it and that means we can't refresh the cache. In this case, schedule a
// refresh later.
// We try resetting the caches up to 5 times before giving up.
mHandler.postResetCaches(isDifferentTextField, 5 /* remainingTries */);
// mLastSelection{Start,End} are reset later in this method, don't need to do it here
canReachInputConnection = false;
} else {
// When rotating, initialSelStart and initialSelEnd sometimes are lying. Make a best
// effort to work around this bug.
mInputLogic.mConnection.tryFixLyingCursorPosition();
if (isDifferentTextField) {
mHandler.postResumeSuggestions();
}

14
java/src/com/android/inputmethod/latin/RichInputConnection.java
View file

@ -172,20 +172,6 @@ public final class RichInputConnection {
Log.d(TAG, "Will try to retrieve text later.");
return false;
}
final int lengthOfTextBeforeCursor = mCommittedTextBeforeComposingText.length();
if (lengthOfTextBeforeCursor > newSelStart
|| (newSelStart != lengthOfTextBeforeCursor
&& lengthOfTextBeforeCursor < Constants.EDITOR_CONTENTS_CACHE_SIZE
&& newSelStart < Constants.EDITOR_CONTENTS_CACHE_SIZE)) {
// newSelStart and newSelEnd may be lying -- when rotating the device (probably a
// framework bug). If the values don't agree and we have less chars than we asked
// for, then we know how many chars we have. If we got more than newSelStart says, then
// we also know it was lying. In both cases the length is more reliable. Note that we
// only have to check newSelStart (not newSelEnd) since if newSelEnd is wrong, then
// newSelStart will be wrong as well.
mExpectedSelStart = lengthOfTextBeforeCursor;
mExpectedSelEnd = lengthOfTextBeforeCursor;
}
if (null != mIC && shouldFinishComposition) {
mIC.finishComposingText();
if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {