package net.osmand.plus.widgets.tools;
import android.app.ListActivity;
import android.app.ListFragment;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPropertyAnimatorListener;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.AdapterView;
import android.widget.ListView;
/**
* A {@link View.OnTouchListener} that makes any {@link View} dismissable when the
* user swipes (drags her finger) horizontally across the view.
* <p/>
* <p><em>For {@link ListView} list items that don't manage their own touch events
* (i.e. you're using
* {@link ListView#setOnItemClickListener(AdapterView.OnItemClickListener)}
* or an equivalent listener on {@link ListActivity} or
* {@link ListFragment}.</em></p>
* <p/>
* <p>Example usage:</p>
* <p/>
* <pre>
* view.setOnTouchListener(new SwipeDismissTouchListener(
* view,
* null, // Optional token/cookie object
* new SwipeDismissTouchListener.OnDismissCallback() {
* public void onDismiss(View view, Object token) {
* parent.removeView(view);
* }
* }));
* </pre>
* <p/>
* <p>This class Requires API level 12 or later due to use of {@link
* android.view.ViewPropertyAnimator}.</p>
*/
public class SwipeDismissTouchListener implements View.OnTouchListener {
private static final String TAG = "SwipeDismissTouchListener";
// Cached ViewConfiguration and system-wide constant values
private int mSlop;
private int mMinFlingVelocity;
private int mMaxFlingVelocity;
private long mAnimationTime;
// Fixed properties
private View mView;
private DismissCallbacks mCallbacks;
private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero
// Transient properties
private float mDownX;
private float mDownY;
private boolean mSwiping;
private int mSwipingSlop;
private Object mToken;
private VelocityTracker mVelocityTracker;
private float mTranslationX;
/**
* The callback interface used by {@link SwipeDismissTouchListener} to inform its client
* about a successful dismissal of the view for which it was created.
*/
public interface DismissCallbacks {
/**
* Called to determine whether the view can be dismissed.
*/
boolean canDismiss(Object token);
/**
* Called when the user has indicated they she would like to dismiss the view.
*
* @param view The originating {@link View} to be dismissed.
* @param token The optional token passed to this object's constructor.
* @param isSwipeRight Is swiping performed from right to left?
*/
void onDismiss(View view, Object token, boolean isSwipeRight);
}
/**
* Constructs a new swipe-to-dismiss touch listener for the given view.
*
* @param view The view to make dismissable.
* @param token An optional token/cookie object to be passed through to the callback.
* @param callbacks The callback to trigger when the user has indicated that she would like to
* dismiss this view.
*/
public SwipeDismissTouchListener(View view, Object token, DismissCallbacks callbacks) {
ViewConfiguration vc = ViewConfiguration.get(view.getContext());
mSlop = vc.getScaledTouchSlop();
mMinFlingVelocity = vc.getScaledMinimumFlingVelocity() * 16;
mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity();
mAnimationTime = view.getContext().getResources().getInteger(
android.R.integer.config_shortAnimTime);
mView = view;
mToken = token;
mCallbacks = callbacks;
}
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
// offset because the view is translated during swipe
motionEvent.offsetLocation(mTranslationX, 0);
if (mViewWidth < 2) {
mViewWidth = mView.getWidth();
}
switch (motionEvent.getActionMasked()) {
case MotionEvent.ACTION_DOWN: {
// TODO: ensure this is a finger, and set a flag
mDownX = motionEvent.getRawX();
mDownY = motionEvent.getRawY();
if (mCallbacks.canDismiss(mToken)) {
mVelocityTracker = VelocityTracker.obtain();
mVelocityTracker.addMovement(motionEvent);
}
return true;
}
case MotionEvent.ACTION_UP: {
if (mVelocityTracker == null) {
break;
}
float deltaX = motionEvent.getRawX() - mDownX;
mVelocityTracker.addMovement(motionEvent);
mVelocityTracker.computeCurrentVelocity(1000);
float velocityX = mVelocityTracker.getXVelocity();
float absVelocityX = Math.abs(velocityX);
float absVelocityY = Math.abs(mVelocityTracker.getYVelocity());
boolean dismiss = false;
boolean dismissRight = false;
if (Math.abs(deltaX) > mViewWidth / 2 && mSwiping) {
dismiss = true;
dismissRight = deltaX > 0;
} else if (mMinFlingVelocity <= absVelocityX && absVelocityX <= mMaxFlingVelocity
&& absVelocityY < absVelocityX
&& absVelocityY < absVelocityX && mSwiping) {
// dismiss only if flinging in the same direction as dragging
dismiss = (velocityX < 0) == (deltaX < 0);
dismissRight = mVelocityTracker.getXVelocity() > 0;
}
if (dismiss) {
// dismiss
final boolean finalDismissRight = dismissRight;
ViewCompat.animate(mView)
.translationX(dismissRight ? mViewWidth : -mViewWidth)
.alpha(0)
.setDuration(mAnimationTime)
.setListener(new ViewPropertyAnimatorListener() {
@Override
public void onAnimationStart(View view) {
}
@Override
public void onAnimationEnd(View view) {
performDismiss(finalDismissRight);
}
@Override
public void onAnimationCancel(View view) {
}
});
} else if (mSwiping) {
// cancel
ViewCompat.animate(mView)
.translationX(0)
.alpha(1)
.setDuration(mAnimationTime)
.setListener(null);
}
mVelocityTracker.recycle();
mVelocityTracker = null;
mTranslationX = 0;
mDownX = 0;
mDownY = 0;
mSwiping = false;
break;
}
case MotionEvent.ACTION_CANCEL: {
if (mVelocityTracker == null) {
break;
}
ViewCompat.animate(mView)
.translationX(0)
.alpha(1)
.setDuration(mAnimationTime)
.setListener(null);
mVelocityTracker.recycle();
mVelocityTracker = null;
mTranslationX = 0;
mDownX = 0;
mDownY = 0;
mSwiping = false;
break;
}
case MotionEvent.ACTION_MOVE: {
if (mVelocityTracker == null) {
break;
}
mVelocityTracker.addMovement(motionEvent);
float deltaX = motionEvent.getRawX() - mDownX;
float deltaY = motionEvent.getRawY() - mDownY;
if (Math.abs(deltaX) > mSlop && Math.abs(deltaY) < Math.abs(deltaX) / 2) {
mSwiping = true;
mSwipingSlop = (deltaX > 0 ? mSlop : -mSlop);
mView.getParent().requestDisallowInterceptTouchEvent(true);
// Cancel listview's touch
MotionEvent cancelEvent = MotionEvent.obtain(motionEvent);
cancelEvent.setAction(MotionEvent.ACTION_CANCEL |
(motionEvent.getActionIndex() <<
MotionEvent.ACTION_POINTER_INDEX_SHIFT));
mView.onTouchEvent(cancelEvent);
cancelEvent.recycle();
}
if (mSwiping) {
mTranslationX = deltaX;
ViewCompat.setTranslationX(mView, deltaX - mSwipingSlop);
// TODO: use an ease-out interpolator or such
ViewCompat.setAlpha(mView, Math.max(0f, Math.min(1f,
1f - 2f * Math.abs(deltaX) / mViewWidth)));
return true;
}
break;
}
}
return false;
}
private void performDismiss(boolean isSwipingRight) {
mCallbacks.onDismiss(mView, mToken, isSwipingRight);
}
}