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Fix an off-by-one bug in EditableInputConnection#endBatchEdit() return value

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This is a follow up CL to our previous CL [1], which had an off-by-one
bug when determining the return value of

   EditableInputConnection#endBatchEdit().

According to the API document of InputConnection#endBatchEdit(), the
following test should pass.

   EditText editText = new EditText(context);
   EditorInfo editorInfo = new EditorInfo();
   InputConnection editableInputConnection =
           editText.onCreateInputConnection(editorInfo);
   assertThat(editableInputConnection.beginBatchEdit()).isTrue();
   assertThat(editableInputConnection.beginBatchEdit()).isTrue();
   assertThat(editableInputConnection.endBatchEdit()).isTrue();
   assertThat(editableInputConnection.endBatchEdit()).isFalse(); // (*)
   assertThat(editableInputConnection.endBatchEdit()).isFalse();

However, the last assertion marked with (*) actually fails due to an
off-by-one bug.  This CL finally fixes it.

The risk of app compat breakages because of fixing this long standing
bug is supposed to be low, mainly because:

 * the system has not relied on this return value yet.
 * Widgets like WebView have correctly implemented this API.
 * IME has always received true no matter what the app returned, which
   is the same behavior as other async InputConnection APIs.

This CL adds several notes to InputConnection#endBatchEdit() document
to help developers correctly implement and use this API.

 [1]: I1ec5518fdc16fb0551fbce9d13f5d92eb4bc78c0
      c478c171e9

Fix: 209958658
Fix: 210165648
Test: atest -c CtsInputMethodTestCases:EditTextImeSupportTest
Change-Id: Ibc40072fa11a4d6e3c24b8d7860c914ccdbcbc8a
Merged-In: Ibc40072fa11a4d6e3c24b8d7860c914ccdbcbc8a
(cherry picked from commit beda2b7f76)
This commit is contained in:
Yohei Yukawa
2021-12-14 15:15:54 -08:00
parent 361e9e1da9
commit 1fdc14b8a9
2 changed files with 17 additions and 12 deletions
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27
core/java/android/view/inputmethod/InputConnection.java
View File

@@ -770,20 +770,25 @@ public interface InputConnection {
boolean beginBatchEdit();
/**
* Tell the editor that you are done with a batch edit previously
* initiated with {@link #beginBatchEdit}. This ends the latest
* batch only.
* Tell the editor that you are done with a batch edit previously initiated with
* {@link #beginBatchEdit()}. This ends the latest batch only.
*
* <p><strong>IME authors:</strong> make sure you call this
* exactly once for each call to {@link #beginBatchEdit}.</p>
* <p><strong>IME authors:</strong> make sure you call this exactly once for each call to
* {@link #beginBatchEdit()}.</p>
*
* <p><strong>Editor authors:</strong> please be careful about
* batch edit nesting. Updates still to be held back until the end
* of the last batch edit.</p>
* <p><strong>Editor authors:</strong> please be careful about batch edit nesting. Updates still
* to be held back until the end of the last batch edit. In case you are delegating this API
* call to the one obtained from
* {@link android.widget.EditText#onCreateInputConnection(EditorInfo)}, there was an off-by-one
* that had returned {@code true} when its nested batch edit count becomes {@code 0} as a result
* of invoking this API. This bug is fixed in {@link android.os.Build.VERSION_CODES#TIRAMISU}.
* </p>
*
* @return true if there is still a batch edit in progress after closing
* the latest one (in other words, if the nesting count is > 0), false
* otherwise or if the input connection is no longer valid.
* @return For editor authors, you must return {@code true} if a batch edit is still in progress
* after closing the latest one (in other words, if the nesting count is still a
* positive number). Return {@code false} otherwise. For IME authors, you will
* always receive {@code true} as long as the request was sent to the editor, and
* receive {@code false} only if the input connection is no longer valid.
*/
boolean endBatchEdit();

2
core/java/com/android/internal/widget/EditableInputConnection.java
View File

@@ -92,7 +92,7 @@ public class EditableInputConnection extends BaseInputConnection
// contribution to mTextView's nested batch edit count is zero.
mTextView.endBatchEdit();
mBatchEditNesting--;
return true;
return mBatchEditNesting > 0;
}
}
return false;