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/*
* Copyright (C) 2019 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.launcher3.touch;
import android.content.Context;
import android.graphics.PointF;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
import androidx.annotation.NonNull;
import androidx.annotation.VisibleForTesting;
import com.android.launcher3.Utilities;
/**
* Two dimensional scroll/drag/swipe gesture detector that reports x and y displacement/velocity.
*/
public class BothAxesSwipeDetector extends BaseSwipeDetector {
public static final int DIRECTION_UP = 1 << 0;
// Note that this will track left instead of right in RTL.
public static final int DIRECTION_RIGHT = 1 << 1;
public static final int DIRECTION_DOWN = 1 << 2;
// Note that this will track right instead of left in RTL.
public static final int DIRECTION_LEFT = 1 << 3;
/* Client of this gesture detector can register a callback. */
private final Listener mListener;
private int mScrollDirections;
public BothAxesSwipeDetector(@NonNull Context context, @NonNull Listener l) {
this(ViewConfiguration.get(context), l, Utilities.isRtl(context.getResources()));
}
@VisibleForTesting
protected BothAxesSwipeDetector(@NonNull ViewConfiguration config, @NonNull Listener l,
boolean isRtl) {
super(config, isRtl);
mListener = l;
}
public void setDetectableScrollConditions(int scrollDirectionFlags, boolean ignoreSlop) {
mScrollDirections = scrollDirectionFlags;
mIgnoreSlopWhenSettling = ignoreSlop;
}
@Override
protected boolean shouldScrollStart(PointF displacement) {
// Check if the client is interested in scroll in current direction.
boolean canScrollUp = (mScrollDirections & DIRECTION_UP) > 0
&& displacement.y <= -mTouchSlop;
boolean canScrollRight = (mScrollDirections & DIRECTION_RIGHT) > 0
&& displacement.x >= mTouchSlop;
boolean canScrollDown = (mScrollDirections & DIRECTION_DOWN) > 0
&& displacement.y >= mTouchSlop;
boolean canScrollLeft = (mScrollDirections & DIRECTION_LEFT) > 0
&& displacement.x <= -mTouchSlop;
return canScrollUp || canScrollRight || canScrollDown || canScrollLeft;
}
@Override
protected void reportDragStartInternal(boolean recatch) {
mListener.onDragStart(!recatch);
}
@Override
protected void reportDraggingInternal(PointF displacement, MotionEvent event) {
mListener.onDrag(displacement, event);
}
@Override
protected void reportDragEndInternal(PointF velocity) {
mListener.onDragEnd(velocity);
}
/** Listener to receive updates on the swipe. */
public interface Listener {
/** @param start whether this was the original drag start, as opposed to a recatch. */
void onDragStart(boolean start);
boolean onDrag(PointF displacement, MotionEvent motionEvent);
void onDragEnd(PointF velocity);
}
}
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