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/*
* Copyright (C) 2006 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.browser;
import android.view.KeyEvent;
import android.view.ViewConfiguration;
class KeyTracker {
public enum Stage {
DOWN, //!< the key has just been pressed
SHORT_REPEAT, //!< repeated key, but duration is under the long-press threshold
LONG_REPEAT, //!< repeated key, but duration is over the long-press threshold
UP //!< the key is being released
}
public enum State {
KEEP_TRACKING, //!< return this to continue to track the key
DONE_TRACKING, //!< return this if you handled the key, but need not track it anymore
NOT_TRACKING //!< return this if you will not handle this key
}
public interface OnKeyTracker {
/** Called whenever there is a key event [down, short/long repeat, up]
@param keyCode The current keyCode (see KeyEvent class)
@param msg The message associated with the keyCode
@maram stage The state the key press is in [down, short/long repeat, up]
@param duration The number of milliseconds since this key was initially pressed
@return your state after seeing the key. If you return DONE_TRACKING or NOT_TRACKING,
you will not be called again for the lifetime of this key event.
*/
public State onKeyTracker(int keyCode, KeyEvent event, Stage stage, int duration);
}
public KeyTracker(OnKeyTracker tracker) {
mTracker = tracker;
}
public boolean doKeyDown(int keyCode, KeyEvent event) {
long now = System.currentTimeMillis();
Stage stage = null;
// check if its a new/different key
if (mKeyCode != keyCode || event.getRepeatCount() == 0) {
mKeyCode = keyCode;
mStartMS = now;
stage = Stage.DOWN;
}
else if (mState == State.KEEP_TRACKING) {
stage = (now - mStartMS) >= LONG_PRESS_DURATION_MS ? Stage.LONG_REPEAT : Stage.SHORT_REPEAT;
}
if (stage != null) {
mEvent = event;
callTracker(stage, now);
}
return mState != State.NOT_TRACKING;
}
public boolean doKeyUp(int keyCode, KeyEvent event) {
boolean handled = false;
if (mState == State.KEEP_TRACKING && mKeyCode == keyCode) {
mEvent = event;
callTracker(Stage.UP, System.currentTimeMillis());
handled = mState != State.NOT_TRACKING;
}
mKeyCode = NOT_A_KEYCODE;
return handled;
}
private void callTracker(Stage stage, long now) {
mState = mTracker.onKeyTracker(mKeyCode, mEvent, stage, (int)(now - mStartMS));
}
private void dump() {
System.out.println(" key=" + mKeyCode + " dur=" + (System.currentTimeMillis() - mStartMS) +
" state=" + mState);
}
private int mKeyCode = NOT_A_KEYCODE;
private KeyEvent mEvent;
private long mStartMS;
private State mState;
private OnKeyTracker mTracker;
private static final int LONG_PRESS_DURATION_MS =
ViewConfiguration.getLongPressTimeout();
private static final int NOT_A_KEYCODE = -123456;
}
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