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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
package org.mozilla.focus.webview;
import android.content.Context;
import androidx.core.view.NestedScrollingChild;
import androidx.core.view.NestedScrollingChildHelper;
import androidx.core.view.ViewCompat;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.webkit.WebView;
/**
* WebView that supports nested scrolls (for using in a CoordinatorLayout).
*
* This code is a simplified version of the NestedScrollView implementation
* which can be found in the support library:
* {@link androidx.core.widget.NestedScrollView}
*
* Based on:
*/
public class NestedWebView extends WebView implements NestedScrollingChild {
private int mLastY;
private final int[] mScrollOffset = new int[2];
private final int[] mScrollConsumed = new int[2];
private int mNestedOffsetY;
private NestedScrollingChildHelper mChildHelper;
public NestedWebView(Context context, AttributeSet attrs) {
super(context, attrs);
mChildHelper = new NestedScrollingChildHelper(this);
setNestedScrollingEnabled(true);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
final MotionEvent event = MotionEvent.obtain(ev);
final int action = ev.getActionMasked();
if (action == MotionEvent.ACTION_DOWN) {
mNestedOffsetY = 0;
}
final int eventY = (int) event.getY();
event.offsetLocation(0, mNestedOffsetY);
switch (action) {
case MotionEvent.ACTION_MOVE:
int deltaY = mLastY - eventY;
if (dispatchNestedPreScroll(0, deltaY, mScrollConsumed, mScrollOffset)) {
deltaY -= mScrollConsumed[1];
event.offsetLocation(0, -mScrollOffset[1]);
mNestedOffsetY += mScrollOffset[1];
}
mLastY = eventY - mScrollOffset[1];
if (dispatchNestedScroll(0, mScrollOffset[1], 0, deltaY, mScrollOffset)) {
mLastY -= mScrollOffset[1];
event.offsetLocation(0, mScrollOffset[1]);
mNestedOffsetY += mScrollOffset[1];
}
break;
case MotionEvent.ACTION_DOWN:
mLastY = eventY;
startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
stopNestedScroll();
break;
default:
// We don't care about other touch events
}
// Execute event handler from parent class in all cases
boolean eventHandled = super.onTouchEvent(event);
// Recycle previously obtained event
event.recycle();
return eventHandled;
}
// NestedScrollingChild
@Override
public void setNestedScrollingEnabled(boolean enabled) {
mChildHelper.setNestedScrollingEnabled(enabled);
}
@Override
public boolean isNestedScrollingEnabled() {
return mChildHelper.isNestedScrollingEnabled();
}
@Override
public boolean startNestedScroll(int axes) {
return mChildHelper.startNestedScroll(axes);
}
@Override
public void stopNestedScroll() {
mChildHelper.stopNestedScroll();
}
@Override
public boolean hasNestedScrollingParent() {
return mChildHelper.hasNestedScrollingParent();
}
@Override
public boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int[] offsetInWindow) {
return mChildHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, offsetInWindow);
}
@Override
public boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow) {
return mChildHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow);
}
@Override
public boolean dispatchNestedFling(float velocityX, float velocityY, boolean consumed) {
return mChildHelper.dispatchNestedFling(velocityX, velocityY, consumed);
}
@Override
public boolean dispatchNestedPreFling(float velocityX, float velocityY) {
return mChildHelper.dispatchNestedPreFling(velocityX, velocityY);
}
}