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Handle BadTokenException exception more reliably.

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This is a follow up for I2c21573cf972145ab08e66604cdb9344139a3f31, which
added BadTokenException handler so that we can deal with unavoidable
runtime exceptions. However, it turns out that CL does not work well
in a certain case.

One problem in I2c21573cf972145ab08e66604cdb9344139a3f31 that it added
the exception handler in the call site of
InputMethodService#showWindow(boolean) rather than callee side as
follows.

    try {
        showWindow(true);
    } catch (BadTokenException e) {
        if (DEBUG) Log.v(TAG, "BadTokenException: IME is done.");
        mWindowVisible = false;
    }

However, the above code fails to update #mWindowVisible if an IME
overrides InputMethodService#showWindow(boolean) but catch-and-ignore
BadTokenException as follows.

    @Override
    public void showWindow(boolean showInput) {
        try {
            super.showWindow(showInput);
            // Do something if super.showWindow() succeeds.
        } catch (BadTokenException ex) {
            // Do something if super.showWindow() fails.
        }
    }

With this CL, InputMethodService#mWindowVisible is always updated in
the callee side whenever it should be.

Note that this CL does not change anything about which method can
throw BadTokenException and which method catch-and-ignores it so as
not to break existing IMEs unexpectedly.

Bug: 23798142
Change-Id: Id1e5f236f48c8ef01b7f157ba3f6e7ab2c26b135
This commit is contained in:
Yohei Yukawa
2015-09-14 16:48:15 -07:00
parent 0f07424dc5
commit 6fcbb56290
1 changed files with 18 additions and 3 deletions
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21
core/java/android/inputmethodservice/InputMethodService.java
View File

@@ -436,9 +436,12 @@ public class InputMethodService extends AbstractInputMethodService {
try {
showWindow(true);
} catch (BadTokenException e) {
if (DEBUG) Log.v(TAG, "BadTokenException: IME is done.");
mWindowVisible = false;
mWindowAdded = false;
// We have ignored BadTokenException here since Jelly Bean MR-2 (API Level 18).
// We could ignore BadTokenException in InputMethodService#showWindow() instead,
// but it may break assumptions for those who override #showWindow() that we can
// detect errors in #showWindow() by checking BadTokenException.
// TODO: Investigate its feasibility. Update JavaDoc of #showWindow() of
// whether it's OK to override #showWindow() or not.
}
}
clearInsetOfPreviousIme();
@@ -1445,7 +1448,19 @@ public class InputMethodService extends AbstractInputMethodService {
mWindowWasVisible = mWindowVisible;
mInShowWindow = true;
showWindowInner(showInput);
} catch (BadTokenException e) {
// BadTokenException is a normal consequence in certain situations, e.g., swapping IMEs
// while there is a DO_SHOW_SOFT_INPUT message in the IIMethodWrapper queue.
if (DEBUG) Log.v(TAG, "BadTokenException: IME is done.");
mWindowVisible = false;
mWindowAdded = false;
// Rethrow the exception to preserve the existing behavior. Some IMEs may have directly
// called this method and relied on this exception for some clean-up tasks.
// TODO: Give developers a clear guideline of whether it's OK to call this method or
// InputMethodManager#showSoftInputFromInputMethod() should always be used instead.
throw e;
} finally {
// TODO: Is it OK to set true when we get BadTokenException?
mWindowWasVisible = true;
mInShowWindow = false;
}