// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.chrome.browser.customtabs.features.partialcustomtab;
import static org.chromium.chrome.browser.customtabs.features.partialcustomtab.PartialCustomTabHandleStrategy.FLING_VELOCITY_PIXELS_PER_MS;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import androidx.annotation.IntDef;
import org.chromium.base.supplier.Supplier;
import org.chromium.chrome.browser.customtabs.features.partialcustomtab.PartialCustomTabHandleStrategy.DragEventCallback;
import org.chromium.chrome.browser.tab.Tab;
import org.chromium.content_public.browser.RenderCoordinates;
import org.chromium.content_public.browser.WebContents;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.function.BooleanSupplier;
/**
* Class responsible for detecting swipe and scroll events on the partial custom tab's content view,
* and setting the event target appropriately to the tab window or the content view.
*/
class ContentGestureListener extends GestureDetector.SimpleOnGestureListener {
/**
* The base duration of the settling animation of the sheet. 218 ms is a spec for material
* design (this is the minimum time a user is guaranteed to pay attention to something).
*/
private static final long BASE_ANIMATION_DURATION_MS = 218;
static final float MIN_VERTICAL_SCROLL_SLOPE = 2.0f;
/** The targets that can handle MotionEvents. */
@IntDef({GestureState.NONE, GestureState.DRAG_TAB, GestureState.SCROLL_CONTENT})
@Retention(RetentionPolicy.SOURCE)
public @interface GestureState {
int NONE = 0;
int DRAG_TAB = 1;
int SCROLL_CONTENT = 2;
}
private @GestureState int mState;
private VelocityTracker mVelocityTracker;
private DragEventCallback mCallback;
private Supplier<Tab> mTab;
private BooleanSupplier mIsFullyExpanded;
private int mPrevRawY;
/**
* Constructor.
*
* @param tab Supplier of the current custom tab.
* @param callback Callback invoked at each tab resizing phase (start/move/end).
* @param isFullyExpanded Supplier of the flag whether the tab is in fully expanded state.
*/
public ContentGestureListener(
Supplier<Tab> tab, DragEventCallback callback, BooleanSupplier isFullyExpanded) {
mTab = tab;
mCallback = callback;
mIsFullyExpanded = isFullyExpanded;
mVelocityTracker = VelocityTracker.obtain();
mState = GestureState.NONE;
}
/** Returns the current {@link GestureState} */
public @GestureState int getState() {
return mState;
}
/** Perform non-fling release. */
public void doNonFlingRelease() {
mVelocityTracker.computeCurrentVelocity(FLING_VELOCITY_PIXELS_PER_MS);
mCallback.onDragEnd(getFlingDistance(mVelocityTracker.getYVelocity()));
mState = GestureState.NONE;
}
@Override
public boolean onDown(MotionEvent e) {
mState = GestureState.NONE;
return e != null;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
if (e1 == null) return false;
// Mutable local flags for readability. Needs updating when |mState| changes.
boolean isScrollingContent = mState == GestureState.SCROLL_CONTENT;
boolean isMovingTab = mState == GestureState.DRAG_TAB;
final boolean contentReachedTop = isContentScrolledToTop();
final boolean draggingUp = distanceY > 0; // == scrolling down
final boolean draggingDown = distanceY < 0; // == scrolling up
// Content scrolling should stop when the content reaches the top while dragging down.
// Reset the state as we may need to switch to the tab dragging instead.
if (isScrollingContent && draggingDown && contentReachedTop) {
mState = GestureState.NONE;
isScrollingContent = false;
isMovingTab = false;
}
// Stop if the scroll is not vertical, except when the tab was already being dragged.
float slope =
Math.abs(distanceX) > 0f
? Math.abs(distanceY) / Math.abs(distanceX)
: MIN_VERTICAL_SCROLL_SLOPE;
if (!isMovingTab && slope < MIN_VERTICAL_SCROLL_SLOPE) {
mVelocityTracker.clear();
return false;
}
mVelocityTracker.addMovement(e2);
if (mIsFullyExpanded.getAsBoolean()) {
// 1) Sheet fully expands but keep dragging up -> switch to SCROLL_CONTENT.
// 2) Start dragging up/down at expanded state -> state gets set to DRAG_TAB first,
// and then immediately switched to SCROLL_CONTENT here.
if ((draggingUp || !contentReachedTop) && isMovingTab) startContentScrolling(e2);
} else if (draggingDown && mState == GestureState.NONE) {
// Drag down at peeked state -> SCROLL_CONTENT, but unlike in |startContentScrolling|,
// no need to inject an additional ACTION_DOWN in this case.
mState = GestureState.SCROLL_CONTENT;
// State changed. Update |isScrollingContent/isMovingTab| if they're to be used below.
}
switch (mState) {
case GestureState.NONE:
startTabDragging(e2); // Start dragging tab if not set to scroll content above.
break;
case GestureState.DRAG_TAB:
mCallback.onDragMove((int) e2.getRawY());
break;
case GestureState.SCROLL_CONTENT:
// Events from now on are routed to content view for scroll in
// BottomSheetStrategy#onTouchEvent.
break;
}
return true;
}
private void startTabDragging(MotionEvent e) {
mCallback.onDragStart((int) e.getRawY());
mState = GestureState.DRAG_TAB;
}
private void startContentScrolling(MotionEvent e) {
// Inject an ACTION_DOWN to content view to make it initiate the content scroll.
MotionEvent down = MotionEvent.obtain(e);
down.setAction(MotionEvent.ACTION_DOWN);
mState = GestureState.SCROLL_CONTENT;
mTab.get().getContentView().onTouchEvent(down);
}
private boolean isContentScrolledToTop() {
WebContents webContents = mTab.get().getWebContents();
return RenderCoordinates.fromWebContents(webContents).getScrollYPixInt() == 0;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if (e1 == null || mState != GestureState.DRAG_TAB) return false;
mCallback.onDragEnd(getFlingDistance(velocityY));
mState = GestureState.NONE;
return true;
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
return false; // Let the content view consume single taps.
}
private int getFlingDistance(float velocity) {
// This includes conversion from seconds to ms.
return (int) (velocity * BASE_ANIMATION_DURATION_MS / 2000f);
}
int getStateForTesting() {
return mState;
}
}
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