1 files changed, 93 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/latin/EmojiAltPhysicalKeyDetector.java b/java/src/com/android/inputmethod/latin/EmojiAltPhysicalKeyDetector.java
new file mode 100644
index 000000000..8116a4983
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+++ b/java/src/com/android/inputmethod/latin/EmojiAltPhysicalKeyDetector.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.latin;
+
+import android.view.KeyEvent;
+
+import com.android.inputmethod.keyboard.KeyboardSwitcher;
+import com.android.inputmethod.latin.settings.Settings;
+
+/**
+ * A class for detecting Emoji-Alt physical key.
+ */
+final class EmojiAltPhysicalKeyDetector {
+    // True if the Alt key has been used as a modifier. In this case the Alt key up isn't
+    // recognized as an emoji key.
+    private boolean mAltHasBeenUsedAsAModifier;
+
+    /**
+     * Record a down key event.
+     * @param keyEvent a down key event.
+     */
+    public void onKeyDown(final KeyEvent keyEvent) {
+        if (isAltKey(keyEvent)) {
+            mAltHasBeenUsedAsAModifier = false;
+        }
+        if (containsAltModifier(keyEvent)) {
+            mAltHasBeenUsedAsAModifier = true;
+        }
+    }
+
+    /**
+     * Determine whether an up key event is a special key up or not.
+     * @param keyEvent an up key event.
+     */
+    public void onKeyUp(final KeyEvent keyEvent) {
+        if (keyEvent.isCanceled()) {
+            // This key up event was a part of key combinations and should be ignored.
+            return;
+        }
+        if (!isAltKey(keyEvent)) {
+            mAltHasBeenUsedAsAModifier |= containsAltModifier(keyEvent);
+            return;
+        }
+        if (containsAltModifier(keyEvent)) {
+            mAltHasBeenUsedAsAModifier = true;
+            return;
+        }
+        if (!Settings.getInstance().getCurrent().mEnableEmojiAltPhysicalKey) {
+            return;
+        }
+        if (!mAltHasBeenUsedAsAModifier) {
+            onEmojiAltKeyDetected();
+        }
+    }
+
+    private static void onEmojiAltKeyDetected() {
+        KeyboardSwitcher.getInstance().onToggleEmojiKeyboard();
+    }
+
+    private static boolean isAltKey(final KeyEvent keyEvent) {
+        final int keyCode = keyEvent.getKeyCode();
+        return keyCode == KeyEvent.KEYCODE_ALT_LEFT || keyCode == KeyEvent.KEYCODE_ALT_RIGHT;
+    }
+
+    private static boolean containsAltModifier(final KeyEvent keyEvent) {
+        final int metaState = keyEvent.getMetaState();
+        // TODO: Support multiple keyboards. Take device id into account.
+        switch (keyEvent.getKeyCode()) {
+        case KeyEvent.KEYCODE_ALT_LEFT:
+            // Return true if Left-Alt is pressed with Right-Alt pressed.
+            return (metaState & KeyEvent.META_ALT_RIGHT_ON) != 0;
+        case KeyEvent.KEYCODE_ALT_RIGHT:
+            // Return true if Right-Alt is pressed with Left-Alt pressed.
+            return (metaState & KeyEvent.META_ALT_LEFT_ON) != 0;
+        default:
+            return (metaState & (KeyEvent.META_ALT_LEFT_ON | KeyEvent.META_ALT_RIGHT_ON)) != 0;
+        }
+    }
+}