Android input method improvements

Use the new inputmethod query API. and get rid of the hack where
we would move the cursor back and forwards to make sure that the
Android software keyboard noticed that the cursor had moved.

The android plugin now uses absolute positions instead of
position within the paragraph for all cursor handling (provided
that the control supports the new API).

Task-number: QTBUG-37511
Change-Id: I03463dbbcb4acbfa41e2eab06889d021d50da01f
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

1 files changed, 70 insertions, 16 deletions

diff --git a/src/plugins/platforms/android/qandroidinputcontext.cpp b/src/plugins/platforms/android/qandroidinputcontext.cpp
index 326972e71e..bfb13811e3 100644
--- a/src/plugins/platforms/android/qandroidinputcontext.cpp
+++ b/src/plugins/platforms/android/qandroidinputcontext.cpp
@@ -81,7 +81,7 @@ static jboolean commitText(JNIEnv *env, jobject /*thiz*/, jstring text, jint new
     env->ReleaseStringChars(text, jstr);
 
 #ifdef QT_DEBUG_ANDROID_IM_PROTOCOL
-    qDebug() << "@@@ COMMIT" << str;
+    qDebug() << "@@@ COMMIT" << str << newCursorPosition;
 #endif
     return m_androidInputContext->commitText(str, newCursorPosition);
 }
@@ -160,7 +160,7 @@ static jstring getTextAfterCursor(JNIEnv *env, jobject /*thiz*/, jint length, ji
 
     const QString &text = m_androidInputContext->getTextAfterCursor(length, flags);
 #ifdef QT_DEBUG_ANDROID_IM_PROTOCOL
-    qDebug() << "@@@ GET" << length << text;
+    qDebug() << "@@@ GETA" << length << text;
 #endif
     return env->NewString(reinterpret_cast<const jchar *>(text.constData()), jsize(text.length()));
 }
@@ -172,7 +172,7 @@ static jstring getTextBeforeCursor(JNIEnv *env, jobject /*thiz*/, jint length, j
 
     const QString &text = m_androidInputContext->getTextBeforeCursor(length, flags);
 #ifdef QT_DEBUG_ANDROID_IM_PROTOCOL
-    qDebug() << "@@@ GET" << length << text;
+    qDebug() << "@@@ GETB" << length << text;
 #endif
     return env->NewString(reinterpret_cast<const jchar *>(text.constData()), jsize(text.length()));
 }
@@ -188,7 +188,7 @@ static jboolean setComposingText(JNIEnv *env, jobject /*thiz*/, jstring text, ji
     env->ReleaseStringChars(text, jstr);
 
 #ifdef QT_DEBUG_ANDROID_IM_PROTOCOL
-    qDebug() << "@@@ SET" << str;
+    qDebug() << "@@@ SET" << str << newCursorPosition;
 #endif
     return m_androidInputContext->setComposingText(str, newCursorPosition);
 }
@@ -271,6 +271,18 @@ static jboolean paste(JNIEnv */*env*/, jobject /*thiz*/)
     return m_androidInputContext->paste();
 }
 
+static jboolean updateCursorPosition(JNIEnv */*env*/, jobject /*thiz*/)
+{
+    if (!m_androidInputContext)
+        return JNI_FALSE;
+
+#ifdef QT_DEBUG_ANDROID_IM_PROTOCOL
+    qDebug() << "@@@ UPDATECURSORPOS";
+#endif
+    m_androidInputContext->updateCursorPosition();
+    return true;
+}
+
 
 static JNINativeMethod methods[] = {
     {"commitText", "(Ljava/lang/String;I)Z", (void *)commitText},
@@ -288,7 +300,8 @@ static JNINativeMethod methods[] = {
     {"cut", "()Z", (void *)cut},
     {"copy", "()Z", (void *)copy},
     {"copyURL", "()Z", (void *)copyURL},
-    {"paste", "()Z", (void *)paste}
+    {"paste", "()Z", (void *)paste},
+    {"updateCursorPosition", "()Z", (void *)updateCursorPosition}
 };
 
 
@@ -404,7 +417,9 @@ void QAndroidInputContext::updateCursorPosition()
 {
     QSharedPointer<QInputMethodQueryEvent> query = focusObjectInputMethodQuery();
     if (!query.isNull() && !m_blockUpdateSelection) {
-        const int cursorPos = query->value(Qt::ImCursorPosition).toInt();
+        // make sure it also works with editors that have not been updated to the new API
+        QVariant absolutePos = query->value(Qt::ImAbsolutePosition);
+        const int cursorPos = absolutePos.isValid() ? absolutePos.toInt() : query->value(Qt::ImCursorPosition).toInt();
         QtAndroidInput::updateSelection(cursorPos, cursorPos, -1, -1); //selection empty and no pre-edit text
     }
 }
@@ -422,9 +437,9 @@ void QAndroidInputContext::invokeAction(QInputMethod::Action action, int cursorP
 #warning TODO Handle at least QInputMethod::ContextMenu action
     Q_UNUSED(action)
     Q_UNUSED(cursorPosition)
-
-    if (action == QInputMethod::Click)
-        commit();
+    //### click should be passed to the IM, but in the meantime it's better to ignore it than to do something wrong
+    // if (action == QInputMethod::Click)
+    //     commit();
 }
 
 QRectF QAndroidInputContext::keyboardRect() const
@@ -573,6 +588,12 @@ QString QAndroidInputContext::getSelectedText(jint /*flags*/)
 
 QString QAndroidInputContext::getTextAfterCursor(jint length, jint /*flags*/)
 {
+    QVariant textAfter = queryFocusObjectThreadSafe(Qt::ImTextAfterCursor, QVariant(length));
+    if (textAfter.isValid()) {
+        return textAfter.toString().left(length);
+    }
+
+    //compatibility code for old controls that do not implement the new API
     QSharedPointer<QInputMethodQueryEvent> query = focusObjectInputMethodQuery();
     if (query.isNull())
         return QString();
@@ -587,15 +608,21 @@ QString QAndroidInputContext::getTextAfterCursor(jint length, jint /*flags*/)
 
 QString QAndroidInputContext::getTextBeforeCursor(jint length, jint /*flags*/)
 {
+    QVariant textBefore = queryFocusObjectThreadSafe(Qt::ImTextBeforeCursor, QVariant(length));
+    if (textBefore.isValid()) {
+        return textBefore.toString().left(length);
+    }
+
+    //compatibility code for old controls that do not implement the new API
     QSharedPointer<QInputMethodQueryEvent> query = focusObjectInputMethodQuery();
     if (query.isNull())
         return QString();
 
+    int cursorPos = query->value(Qt::ImCursorPosition).toInt();
     QString text = query->value(Qt::ImSurroundingText).toString();
     if (!text.length())
         return text;
 
-    int cursorPos = query->value(Qt::ImCursorPosition).toInt();
     const int wordLeftPos = cursorPos - length;
     return text.mid(wordLeftPos > 0 ? wordLeftPos : 0, cursorPos);
 }
@@ -621,8 +648,9 @@ jboolean QAndroidInputContext::setComposingText(const QString &text, jint newCur
 
     QSharedPointer<QInputMethodQueryEvent> query = focusObjectInputMethodQuery();
     if (!query.isNull() && !m_blockUpdateSelection) {
-        int cursorPos = query->value(Qt::ImCursorPosition).toInt();
-        int preeditLength = text.length();
+        QVariant absolutePos = query->value(Qt::ImAbsolutePosition);
+        const int cursorPos = absolutePos.isValid() ? absolutePos.toInt() : query->value(Qt::ImCursorPosition).toInt();
+        const int preeditLength = text.length();
         QtAndroidInput::updateSelection(cursorPos+preeditLength, cursorPos+preeditLength, cursorPos, cursorPos+preeditLength);
     }
 
@@ -650,16 +678,19 @@ jboolean QAndroidInputContext::setComposingRegion(jint start, jint end)
       Therefore, the length of the region is end - start
      */
     int length = end - start;
+    int localPos = query->value(Qt::ImCursorPosition).toInt();
+    QVariant absolutePos = query->value(Qt::ImAbsolutePosition);
+    int blockPosition = absolutePos.isValid() ? absolutePos.toInt() - localPos : 0;
+    int localStart = start - blockPosition; // Qt uses position inside block
 
     bool updateSelectionWasBlocked = m_blockUpdateSelection;
     m_blockUpdateSelection = true;
 
     QString text = query->value(Qt::ImSurroundingText).toString();
-    m_composingText = text.mid(start, length);
+    m_composingText = text.mid(localStart, length);
 
-    //in the Qt text controls, cursor pos is the start of the preedit
-    int cursorPos = query->value(Qt::ImCursorPosition).toInt();
-    int relativeStart = start - cursorPos;
+    //in the Qt text controls, the cursor position is the start of the preedit
+    int relativeStart = localStart - localPos;
 
     QList<QInputMethodEvent::Attribute> attributes;
 
@@ -669,6 +700,9 @@ jboolean QAndroidInputContext::setComposingRegion(jint start, jint end)
     attributes.append(QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat,0, length,
                                                    QVariant(underlined)));
 
+    // Keep the cursor position unchanged (don't move to end of preedit)
+    attributes.append(QInputMethodEvent::Attribute(QInputMethodEvent::Cursor, localPos - localStart, length, QVariant()));
+
     QInputMethodEvent event(m_composingText, attributes);
     event.setCommitString(QString(), relativeStart, length);
     sendInputMethodEvent(&event);
@@ -720,6 +754,26 @@ jboolean QAndroidInputContext::paste()
     return JNI_FALSE;
 }
 
+
+Q_INVOKABLE QVariant QAndroidInputContext::queryFocusObjectUnsafe(Qt::InputMethodQuery query, QVariant argument)
+{
+    return QInputMethod::queryFocusObject(query, argument);
+}
+
+QVariant QAndroidInputContext::queryFocusObjectThreadSafe(Qt::InputMethodQuery query, QVariant argument)
+{
+    bool inMainThread = qGuiApp->thread() == QThread::currentThread();
+    QVariant retval;
+
+    QMetaObject::invokeMethod(this, "queryFocusObjectUnsafe",
+                              inMainThread ? Qt::DirectConnection : Qt::BlockingQueuedConnection,
+                              Q_RETURN_ARG(QVariant, retval),
+                              Q_ARG(Qt::InputMethodQuery, query),
+                              Q_ARG(QVariant, argument));
+
+    return retval;
+}
+
 QSharedPointer<QInputMethodQueryEvent> QAndroidInputContext::focusObjectInputMethodQuery(Qt::InputMethodQueries queries)
 {
 #warning TODO make qGuiApp->focusObject() thread safe !!!