package com.poi.poiandroid;
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.support.v4.view.MotionEventCompat;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
/**
* Detects various gestures and events using the supplied {@link MotionEvent}s.
* The {@link OnGestureListener} callback will notify users when a particular
* motion event has occurred. This class should only be used with
* {@link MotionEvent}s reported via touch (don't use for trackball events).
*
* To use this class:
* <ul>
* <li>Create an instance of the {@code GestureDetector} for your {@link View}
* <li>In the {@link View#onTouchEvent(MotionEvent)} method ensure you call
* {@link #onTouchEvent(MotionEvent)}. The methods defined in your callback will
* be executed when the events occur.
* </ul>
*/
public class GestureDetector {
public static final String TAG = GestureDetector.class.getSimpleName();
/**
* The listener that is used to notify when gestures occur. If you want to
* listen for all the different gestures then implement this interface. If
* you only want to listen for a subset it might be easier to extend
* {@link SimpleOnGestureListener}.
*/
public interface OnGestureListener {
/**
* Notified when a tap occurs with the down {@link MotionEvent} that
* triggered it. This will be triggered immediately for every down
* event. All other events should be preceded by this.
*
* @param e
* The down motion event.
*/
boolean onDown(MotionEvent e);
boolean onUp(MotionEvent e);
/**
* The user has performed a down {@link MotionEvent} and not performed a
* move or up yet. This event is commonly used to provide visual
* feedback to the user to let them know that their action has been
* recognized i.e. highlight an element.
*
* @param e
* The down motion event
*/
void onShowPress(MotionEvent e);
/**
* Notified when a tap occurs with the up {@link MotionEvent} that
* triggered it.
*
* @param e
* The up motion event that completed the first tap
* @return true if the event is consumed, else false
*/
boolean onSingleTapUp(MotionEvent e);
/**
* Notified when a scroll occurs with the initial on down
* {@link MotionEvent} and the current move {@link MotionEvent}. The
* distance in x and y is also supplied for convenience.
*
* @param e1
* The first down motion event that started the scrolling.
* @param e2
* The move motion event that triggered the current onScroll.
* @param distanceX
* The distance along the X axis that has been scrolled since
* the last call to onScroll. This is NOT the distance
* between {@code e1} and {@code e2}.
* @param distanceY
* The distance along the Y axis that has been scrolled since
* the last call to onScroll. This is NOT the distance
* between {@code e1} and {@code e2}.
* @return true if the event is consumed, else false
*/
boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY);
/**
* Notified when a long press occurs with the initial on down
* {@link MotionEvent} that trigged it.
*
* @param e
* The initial on down motion event that started the
* longpress.
*/
void onLongPress(MotionEvent e);
/**
* Notified of a fling event when it occurs with the initial on down
* {@link MotionEvent} and the matching up {@link MotionEvent}. The
* calculated velocity is supplied along the x and y axis in pixels per
* second.
*
* @param e1
* The first down motion event that started the fling.
* @param e2
* The move motion event that triggered the current onFling.
* @param velocityX
* The velocity of this fling measured in pixels per second
* along the x axis.
* @param velocityY
* The velocity of this fling measured in pixels per second
* along the y axis.
* @return true if the event is consumed, else false
*/
boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY);
}
/**
* The listener that is used to notify when a double-tap or a confirmed
* single-tap occur.
*/
public interface OnDoubleTapListener {
/**
* Notified when a single-tap occurs.
* <p>
* Unlike {@link OnGestureListener#onSingleTapUp(MotionEvent)}, this
* will only be called after the detector is confident that the user's
* first tap is not followed by a second tap leading to a double-tap
* gesture.
*
* @param e
* The down motion event of the single-tap.
* @return true if the event is consumed, else false
*/
boolean onSingleTapConfirmed(MotionEvent e);
/**
* Notified when a double-tap occurs.
*
* @param e
* The down motion event of the first tap of the double-tap.
* @return true if the event is consumed, else false
*/
boolean onDoubleTap(MotionEvent e);
/**
* Notified when an event within a double-tap gesture occurs, including
* the down, move, and up events.
*
* @param e
* The motion event that occurred during the double-tap
* gesture.
* @return true if the event is consumed, else false
*/
boolean onDoubleTapEvent(MotionEvent e);
}
/**
* A convenience class to extend when you only want to listen for a subset
* of all the gestures. This implements all methods in the
* {@link OnGestureListener} and {@link OnDoubleTapListener} but does
* nothing and return {@code false} for all applicable methods.
*/
public static class SimpleOnGestureListener implements OnGestureListener,
OnDoubleTapListener {
public boolean onSingleTapUp(MotionEvent e) {
return false;
}
public void onLongPress(MotionEvent e) {
}
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
return false;
}
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
return false;
}
public void onShowPress(MotionEvent e) {
}
public boolean onDown(MotionEvent e) {
return false;
}
public boolean onUp(MotionEvent e) {
return false;
}
public boolean onDoubleTap(MotionEvent e) {
return false;
}
public boolean onDoubleTapEvent(MotionEvent e) {
return false;
}
public boolean onSingleTapConfirmed(MotionEvent e) {
return false;
}
}
private int mTouchSlopSquare;
private int mLargeTouchSlopSquare;
private int mDoubleTapSlopSquare;
private int mMinimumFlingVelocity;
private int mMaximumFlingVelocity;
private static final int LONGPRESS_TIMEOUT = ViewConfiguration
.getLongPressTimeout();
private static final int TAP_TIMEOUT = ViewConfiguration.getTapTimeout();
private static final int DOUBLE_TAP_TIMEOUT = ViewConfiguration
.getDoubleTapTimeout();
// constants for Message.what used by GestureHandler below
private static final int SHOW_PRESS = 1;
private static final int LONG_PRESS = 2;
private static final int TAP = 3;
private final Handler mHandler;
private final OnGestureListener mListener;
private OnDoubleTapListener mDoubleTapListener;
private boolean mStillDown;
private boolean mInLongPress;
private boolean mAlwaysInTapRegion;
private boolean mAlwaysInBiggerTapRegion;
private MotionEvent mCurrentDownEvent;
private MotionEvent mPreviousUpEvent;
/**
* True when the user is still touching for the second tap (down, move, and
* up events). Can only be true if there is a double tap listener attached.
*/
private boolean mIsDoubleTapping;
private float mLastMotionY;
private float mLastMotionX;
private boolean mIsLongpressEnabled;
/**
* True if we are at a target API level of >= Froyo or the developer can
* explicitly set it. If true, input events with > 1 pointer will be ignored
* so we can work side by side with multitouch gesture detectors.
*/
private boolean mIgnoreMultitouch;
/**
* Determines speed during touch scrolling
*/
private VelocityTracker mVelocityTracker;
private class GestureHandler extends Handler {
GestureHandler() {
super();
}
GestureHandler(Handler handler) {
super(handler.getLooper());
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SHOW_PRESS:
mListener.onShowPress(mCurrentDownEvent);
break;
case LONG_PRESS:
dispatchLongPress();
break;
case TAP:
// If the user's finger is still down, do not count it as a tap
if (mDoubleTapListener != null && !mStillDown) {
mDoubleTapListener.onSingleTapConfirmed(mCurrentDownEvent);
}
break;
default:
throw new RuntimeException("Unknown message " + msg); // never
}
}
}
/**
* Creates a GestureDetector with the supplied listener. This variant of the
* constructor should be used from a non-UI thread (as it allows specifying
* the Handler).
*
* @param listener
* the listener invoked for all the callbacks, this must not be
* null.
* @param handler
* the handler to use
*
* @throws NullPointerException
* if either {@code listener} or {@code handler} is null.
*
* @deprecated Use
* {@link #GestureDetector(android.content.Context, android.view.GestureDetector.OnGestureListener, android.os.Handler)}
* instead.
*/
@Deprecated
public GestureDetector(OnGestureListener listener, Handler handler) {
this(null, listener, handler);
}
/**
* Creates a GestureDetector with the supplied listener. You may only use
* this constructor from a UI thread (this is the usual situation).
*
* @see android.os.Handler#Handler()
*
* @param listener
* the listener invoked for all the callbacks, this must not be
* null.
*
* @throws NullPointerException
* if {@code listener} is null.
*
* @deprecated Use
* {@link #GestureDetector(android.content.Context, android.view.GestureDetector.OnGestureListener)}
* instead.
*/
@Deprecated
public GestureDetector(OnGestureListener listener) {
this(null, listener, null);
}
/**
* Creates a GestureDetector with the supplied listener. You may only use
* this constructor from a UI thread (this is the usual situation).
*
* @see android.os.Handler#Handler()
*
* @param context
* the application's context
* @param listener
* the listener invoked for all the callbacks, this must not be
* null.
*
* @throws NullPointerException
* if {@code listener} is null.
*/
public GestureDetector(Context context, OnGestureListener listener) {
this(context, listener, null);
}
/**
* Creates a GestureDetector with the supplied listener. You may only use
* this constructor from a UI thread (this is the usual situation).
*
* @see android.os.Handler#Handler()
*
* @param context
* the application's context
* @param listener
* the listener invoked for all the callbacks, this must not be
* null.
* @param handler
* the handler to use
*
* @throws NullPointerException
* if {@code listener} is null.
*/
public GestureDetector(Context context, OnGestureListener listener,
Handler handler) {
this(context, listener, handler, true);
}
/**
* Creates a GestureDetector with the supplied listener. You may only use
* this constructor from a UI thread (this is the usual situation).
*
* @see android.os.Handler#Handler()
*
* @param context
* the application's context
* @param listener
* the listener invoked for all the callbacks, this must not be
* null.
* @param handler
* the handler to use
* @param ignoreMultitouch
* whether events involving more than one pointer should be
* ignored.
*
* @throws NullPointerException
* if {@code listener} is null.
*/
public GestureDetector(Context context, OnGestureListener listener,
Handler handler, boolean ignoreMultitouch) {
if (handler != null) {
mHandler = new GestureHandler(handler);
} else {
mHandler = new GestureHandler();
}
mListener = listener;
if (listener instanceof OnDoubleTapListener) {
setOnDoubleTapListener((OnDoubleTapListener) listener);
}
init(context, ignoreMultitouch);
}
private void init(Context context, boolean ignoreMultitouch) {
if (mListener == null) {
throw new NullPointerException("OnGestureListener must not be null");
}
mIsLongpressEnabled = true;
mIgnoreMultitouch = ignoreMultitouch;
// Fallback to support pre-donuts releases
int touchSlop, largeTouchSlop, doubleTapSlop;
if (context == null) {
// noinspection deprecation
touchSlop = ViewConfiguration.getTouchSlop();
largeTouchSlop = touchSlop + 2;
// doubleTapSlop = ViewConfiguration.getDoubleTapSlop();
doubleTapSlop = 100;
// noinspection deprecation
mMinimumFlingVelocity = ViewConfiguration.getMinimumFlingVelocity();
mMaximumFlingVelocity = ViewConfiguration.getMaximumFlingVelocity();
} else {
final ViewConfiguration configuration = ViewConfiguration
.get(context);
touchSlop = configuration.getScaledTouchSlop();
// largeTouchSlop = configuration.getScaledLargeTouchSlop();
largeTouchSlop = 18;
doubleTapSlop = configuration.getScaledDoubleTapSlop();
mMinimumFlingVelocity = configuration
.getScaledMinimumFlingVelocity();
mMaximumFlingVelocity = configuration
.getScaledMaximumFlingVelocity();
}
mTouchSlopSquare = touchSlop * touchSlop;
mLargeTouchSlopSquare = largeTouchSlop * largeTouchSlop;
mDoubleTapSlopSquare = doubleTapSlop * doubleTapSlop;
}
/**
* Sets the listener which will be called for double-tap and related
* gestures.
*
* @param onDoubleTapListener
* the listener invoked for all the callbacks, or null to stop
* listening for double-tap gestures.
*/
public void setOnDoubleTapListener(OnDoubleTapListener onDoubleTapListener) {
mDoubleTapListener = onDoubleTapListener;
}
/**
* Set whether longpress is enabled, if this is enabled when a user presses
* and holds down you get a longpress event and nothing further. If it's
* disabled the user can press and hold down and then later moved their
* finger and you will get scroll events. By default longpress is enabled.
*
* @param isLongpressEnabled
* whether longpress should be enabled.
*/
public void setIsLongpressEnabled(boolean isLongpressEnabled) {
mIsLongpressEnabled = isLongpressEnabled;
}
/**
* @return true if longpress is enabled, else false.
*/
public boolean isLongpressEnabled() {
return mIsLongpressEnabled;
}
/**
* Analyzes the given motion event and if applicable triggers the
* appropriate callbacks on the {@link OnGestureListener} supplied.
*
* @param ev
* The current motion event.
* @return true if the {@link OnGestureListener} consumed the event, else
* false.
*/
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
final float y = ev.getY();
final float x = ev.getX();
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
boolean handled = false;
switch (action & MotionEventCompat.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
if (mDoubleTapListener != null) {
boolean hadTapMessage = mHandler.hasMessages(TAP);
if (hadTapMessage)
mHandler.removeMessages(TAP);
if ((mCurrentDownEvent != null)
&& (mPreviousUpEvent != null)
&& hadTapMessage
&& isConsideredDoubleTap(mCurrentDownEvent,
mPreviousUpEvent, ev)) {
// This is a second tap
mIsDoubleTapping = true;
// Give a callback with the first tap of the double-tap
handled |= mDoubleTapListener
.onDoubleTap(mCurrentDownEvent);
// Give a callback with down event of the double-tap
handled |= mDoubleTapListener.onDoubleTapEvent(ev);
} else {
// This is a first tap
mHandler.sendEmptyMessageDelayed(TAP, DOUBLE_TAP_TIMEOUT);
}
}
mLastMotionX = x;
mLastMotionY = y;
if (mCurrentDownEvent != null) {
mCurrentDownEvent.recycle();
}
mCurrentDownEvent = MotionEvent.obtain(ev);
mAlwaysInTapRegion = true;
mAlwaysInBiggerTapRegion = true;
mStillDown = true;
mInLongPress = false;
if (mIsLongpressEnabled) {
mHandler.removeMessages(LONG_PRESS);
mHandler.sendEmptyMessageAtTime(LONG_PRESS,
mCurrentDownEvent.getDownTime() + TAP_TIMEOUT
+ LONGPRESS_TIMEOUT);
}
mHandler.sendEmptyMessageAtTime(SHOW_PRESS,
mCurrentDownEvent.getDownTime() + TAP_TIMEOUT);
handled |= mListener.onDown(ev);
break;
case MotionEvent.ACTION_MOVE:
// Logger.d(TAG, "gesture move");
if (mInLongPress) {
// Logger.d(TAG, "gesture move break");
break;
}
final float scrollX = mLastMotionX - x;
final float scrollY = mLastMotionY - y;
if (mIsDoubleTapping) {
// Give the move events of the double-tap
handled |= mDoubleTapListener.onDoubleTapEvent(ev);
} else if (mAlwaysInTapRegion) {
final int deltaX = (int) (x - mCurrentDownEvent.getX());
final int deltaY = (int) (y - mCurrentDownEvent.getY());
int distance = (deltaX * deltaX) + (deltaY * deltaY);
if (distance > mTouchSlopSquare) {
try {
handled = mListener.onScroll(mCurrentDownEvent, ev,
scrollX, scrollY);
mLastMotionX = x;
mLastMotionY = y;
mAlwaysInTapRegion = false;
mHandler.removeMessages(TAP);
mHandler.removeMessages(SHOW_PRESS);
mHandler.removeMessages(LONG_PRESS);
} catch (Exception e) {
e.printStackTrace();
}
}
if (distance > mLargeTouchSlopSquare) {
mAlwaysInBiggerTapRegion = false;
}
} else if ((Math.abs(scrollX) >= 1) || (Math.abs(scrollY) >= 1)) {
handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX,
scrollY);
mLastMotionX = x;
mLastMotionY = y;
}
break;
case MotionEvent.ACTION_UP:
mStillDown = false;
MotionEvent currentUpEvent = MotionEvent.obtain(ev);
if (mIsDoubleTapping) {
// Finally, give the up event of the double-tap
handled |= mDoubleTapListener.onDoubleTapEvent(ev);
} else if (mInLongPress) {
mHandler.removeMessages(TAP);
mInLongPress = false;
} else if (mAlwaysInTapRegion) {
handled = mListener.onSingleTapUp(ev);
} else {
// A fling must travel the minimum tap distance
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000,
mMaximumFlingVelocity);
final float velocityY = velocityTracker.getYVelocity();
final float velocityX = velocityTracker.getXVelocity();
if ((Math.abs(velocityY) > mMinimumFlingVelocity)
|| (Math.abs(velocityX) > mMinimumFlingVelocity)) {
handled = mListener.onFling(mCurrentDownEvent, ev,
velocityX, velocityY);
}
}
mListener.onUp(mCurrentDownEvent);
if (mPreviousUpEvent != null) {
mPreviousUpEvent.recycle();
}
// Hold the event we obtained above - listeners may have changed the
// original.
mPreviousUpEvent = currentUpEvent;
mVelocityTracker.recycle();
mVelocityTracker = null;
mIsDoubleTapping = false;
mHandler.removeMessages(SHOW_PRESS);
mHandler.removeMessages(LONG_PRESS);
break;
case MotionEvent.ACTION_CANCEL:
cancel();
}
return handled;
}
private void cancel() {
mHandler.removeMessages(SHOW_PRESS);
mHandler.removeMessages(LONG_PRESS);
mHandler.removeMessages(TAP);
mVelocityTracker.recycle();
mVelocityTracker = null;
mIsDoubleTapping = false;
mStillDown = false;
if (mInLongPress) {
mInLongPress = false;
}
}
private boolean isConsideredDoubleTap(MotionEvent firstDown,
MotionEvent firstUp, MotionEvent secondDown) {
if (!mAlwaysInBiggerTapRegion) {
return false;
}
if (secondDown.getEventTime() - firstUp.getEventTime() > DOUBLE_TAP_TIMEOUT) {
return false;
}
int deltaX = (int) firstDown.getX() - (int) secondDown.getX();
int deltaY = (int) firstDown.getY() - (int) secondDown.getY();
return (deltaX * deltaX + deltaY * deltaY < mDoubleTapSlopSquare);
}
private void dispatchLongPress() {
mHandler.removeMessages(TAP);
mInLongPress = true;
mListener.onLongPress(mCurrentDownEvent);
}
}