com.smoothsync.smoothsetup.utils.CoordinatorWebView.java Source code

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Here is the source code for com.smoothsync.smoothsetup.utils.CoordinatorWebView.java

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/*
 * Copyright (c) 2017 dmfs GmbH
 *
 * 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.smoothsync.smoothsetup.utils;

import android.content.Context;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.NestedScrollingChild;
import android.support.v4.view.NestedScrollingChildHelper;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.webkit.WebView;

/**
 * A {@link WebView} that works with a {@link CollapsingToolbarLayout} inside of a {@link CoordinatorLayout}.
 *
 * @author Marten Gajda
 */
public final class CoordinatorWebView extends WebView implements NestedScrollingChild {
    private int mLastY;
    private NestedScrollingChildHelper mNestedScrollingChildHelper;

    public CoordinatorWebView(Context context) {
        super(context);
        mNestedScrollingChildHelper = new NestedScrollingChildHelper(this);
        setNestedScrollingEnabled(true);
    }

    public CoordinatorWebView(Context context, AttributeSet attributeSet) {
        super(context, attributeSet);
        mNestedScrollingChildHelper = new NestedScrollingChildHelper(this);
        setNestedScrollingEnabled(true);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        MotionEvent event = MotionEvent.obtain(ev);
        switch (MotionEventCompat.getActionMasked(ev)) {
        case MotionEvent.ACTION_DOWN: {
            startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL);
            mLastY = (int) ev.getY();
            return super.onTouchEvent(event);
        }
        case MotionEvent.ACTION_MOVE: {
            int[] offsetInWindow = new int[2];
            int[] consumed = new int[2];
            int deltaY = (int) (mLastY - ev.getY() + 0.5 /* round properly */);
            if (dispatchNestedPreScroll(0, deltaY, consumed, offsetInWindow)) {
                deltaY -= consumed[1];
            }

            boolean result = super.onTouchEvent(event);
            dispatchNestedScroll(0, deltaY, 0, 0, offsetInWindow);
            return result;
        }
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL: {
            stopNestedScroll();
            return super.onTouchEvent(event);
        }
        default: {
            return super.onTouchEvent(event);
        }
        }
    }

    @Override
    public boolean isNestedScrollingEnabled() {
        return mNestedScrollingChildHelper.isNestedScrollingEnabled();
    }

    @Override
    public void setNestedScrollingEnabled(boolean enabled) {
        mNestedScrollingChildHelper.setNestedScrollingEnabled(enabled);
    }

    @Override
    public boolean startNestedScroll(int axes) {
        return mNestedScrollingChildHelper.startNestedScroll(axes);
    }

    @Override
    public void stopNestedScroll() {
        mNestedScrollingChildHelper.stopNestedScroll();
    }

    @Override
    public boolean hasNestedScrollingParent() {
        return mNestedScrollingChildHelper.hasNestedScrollingParent();
    }

    @Override
    public boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed,
            int[] offsetInWindow) {
        return mNestedScrollingChildHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed,
                offsetInWindow);
    }

    @Override
    public boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow) {
        return mNestedScrollingChildHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow);
    }

    @Override
    public boolean dispatchNestedFling(float velocityX, float velocityY, boolean consumed) {
        return mNestedScrollingChildHelper.dispatchNestedFling(velocityX, velocityY, consumed);
    }

    @Override
    public boolean dispatchNestedPreFling(float velocityX, float velocityY) {
        return mNestedScrollingChildHelper.dispatchNestedPreFling(velocityX, velocityY);
    }
}