Introduce a mechanism to hide the indicator speculatively

This is an optional optimization to reduce the UI latency.

Imagine that the commit indicator is now displayed and the
composing text is being updated, it is highly likely that
the commit indicator will disappear unless the application
rejects the setComposingText request.

If we assume that the application will accept the new
composing text without any modifications, we can hide the
indicator without waiting for the arrival of new
CursorAnchorInfo event.

This optimization isn't dangerous because we can show the
indicator again when we receive new CursorAnchorInfo event
and the assumption is turned out to be invalid.

Change-Id: Id59c6607a1029782410611e768791af9984f14ac

1 files changed, 25 insertions, 8 deletions

diff --git a/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java b/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
index 0f2ba53d5..e83f494b3 100644
--- a/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
+++ b/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
@@ -649,7 +649,7 @@ public final class InputLogic {
             // message, this is called outside any batch edit. Potentially, this may result in some
             // janky flickering of the screen, although the display speed makes it unlikely in
             // the practice.
-            mConnection.setComposingText(textWithUnderline, 1);
+            setComposingTextInternal(textWithUnderline, 1);
         }
     }
 
@@ -672,7 +672,7 @@ public final class InputLogic {
             inputTransaction.setDidAffectContents();
         }
         if (mWordComposer.isComposingWord()) {
-            mConnection.setComposingText(mWordComposer.getTypedWord(), 1);
+            setComposingTextInternal(mWordComposer.getTypedWord(), 1);
             inputTransaction.setDidAffectContents();
             inputTransaction.setRequiresUpdateSuggestions();
         }
@@ -908,8 +908,7 @@ public final class InputLogic {
             if (mWordComposer.isSingleLetter()) {
                 mWordComposer.setCapitalizedModeAtStartComposingTime(inputTransaction.mShiftState);
             }
-            mConnection.setComposingText(getTextWithUnderline(
-                    mWordComposer.getTypedWord()), 1);
+            setComposingTextInternal(getTextWithUnderline(mWordComposer.getTypedWord()), 1);
         } else {
             final boolean swapWeakSpace = tryStripSpaceAndReturnWhetherShouldSwapInstead(event,
                     inputTransaction);
@@ -1072,7 +1071,7 @@ public final class InputLogic {
                 mWordComposer.applyProcessedEvent(event);
             }
             if (mWordComposer.isComposingWord()) {
-                mConnection.setComposingText(getTextWithUnderline(mWordComposer.getTypedWord()), 1);
+                setComposingTextInternal(getTextWithUnderline(mWordComposer.getTypedWord()), 1);
             } else {
                 mConnection.commitText("", 1);
             }
@@ -1640,7 +1639,7 @@ public final class InputLogic {
             final int[] codePoints = StringUtils.toCodePointArray(stringToCommit);
             mWordComposer.setComposingWord(codePoints,
                     mLatinIME.getCoordinatesForCurrentKeyboard(codePoints));
-            mConnection.setComposingText(textToCommit, 1);
+            setComposingTextInternal(textToCommit, 1);
         }
         // Don't restart suggestion yet. We'll restart if the user deletes the separator.
         mLastComposedWord = LastComposedWord.NOT_A_COMPOSED_WORD;
@@ -1973,10 +1972,10 @@ public final class InputLogic {
             }
             final String lastWord = batchInputText.substring(indexOfLastSpace);
             mWordComposer.setBatchInputWord(lastWord);
-            mConnection.setComposingText(lastWord, 1);
+            setComposingTextInternal(lastWord, 1);
         } else {
             mWordComposer.setBatchInputWord(batchInputText);
-            mConnection.setComposingText(batchInputText, 1);
+            setComposingTextInternal(batchInputText, 1);
         }
         mConnection.endBatchEdit();
         // Space state must be updated before calling updateShiftState
@@ -2175,6 +2174,24 @@ public final class InputLogic {
                 inputStyle, sequenceNumber, callback);
     }
 
+    /**
+     * Used as an injection point for each call of
+     * {@link RichInputConnection#setComposingText(CharSequence, int)}.
+     *
+     * <p>Currently using this method is optional and you can still directly call
+     * {@link RichInputConnection#setComposingText(CharSequence, int)}, but it is recommended to
+     * use this method whenever possible to optimize the behavior of {@link TextDecorator}.<p>
+     * <p>TODO: Should we move this mechanism to {@link RichInputConnection}?</p>
+     *
+     * @param newComposingText the composing text to be set
+     * @param newCursorPosition the new cursor position
+     */
+    private void setComposingTextInternal(final CharSequence newComposingText,
+            final int newCursorPosition) {
+        mConnection.setComposingText(newComposingText, newCursorPosition);
+        mTextDecorator.hideIndicatorIfNecessary(newComposingText);
+    }
+
     //////////////////////////////////////////////////////////////////////////////////////////////
     // Following methods are tentatively placed in this class for the integration with
     // TextDecorator.