package com.gzgd.myapplication4;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Build;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.FocusFinder;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityNodeInfo;
import android.view.animation.AnimationUtils;
import android.widget.EdgeEffect;
import android.widget.FrameLayout;
import android.widget.OverScroller;
import android.widget.ScrollView;

import java.util.List;

/**
*翻页有反弹效果

• Created by runrun on 2018/4/4.
  */

public class MScrollView extends FrameLayout {
static final int ANIMATED_SCROLL_GAP = 200;

static final float MAX_SCROLL_FACTOR = 0.5f;

private static final String TAG = "MScrollView";

private long mLastScroll;

protected final Rect mTempRect = new Rect();
private OverScroller mScroller;
private EdgeEffect mEdgeGlowTop;
private EdgeEffect mEdgeGlowBottom;

/**
 * True when the layout has changed but the traversal has not come through yet.
 * Ideally the view hierarchy would keep track of this for us.
 */
private boolean mIsLayoutDirty = true;

/**
 * The child to give focus to in the event that a child has requested focus while the
 * layout is dirty. This prevents the scroll from being wrong if the child has not been
 * laid out before requesting focus.
 */
private View mChildToScrollTo = null;

/**
 * Determines speed during touch scrolling
 */
private VelocityTracker mVelocityTracker;

/**
 * When set to true, the scroll view measure its child to make it fill the currently
 * visible area.
 */
@ViewDebug.ExportedProperty(category = "layout")
private boolean mFillViewport;

/**
 * Whether arrow scrolling is animated.
 */
private boolean mSmoothScrollingEnabled = true;

private int mOverflingDistance;

/**
 * ID of the active pointer. This is used to retain consistency during
 * drags/flings if multiple pointers are used.
 */
private int mActivePointerId = INVALID_POINTER;

/**
 * Sentinel value for no current active pointer.
 * Used by {@link #mActivePointerId}.
 */
private static final int INVALID_POINTER = -1;

private MScrollView.SavedState mSavedState;

private Context mContext;

public MScrollView(Context context) {
    this(context, null);
}

public MScrollView(Context context, AttributeSet attrs) {
    this(context, attrs, com.android.internal.R.attr.scrollViewStyle);
}

public MScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
    this(context, attrs, defStyleAttr, 0);
}

public MScrollView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
    mContext = context;
    initScrollView();

    final TypedArray a = context.obtainStyledAttributes(
            attrs, com.android.internal.R.styleable.ScrollView, defStyleAttr, defStyleRes);

    setFillViewport(a.getBoolean(com.android.internal.R.styleable.ScrollView_fillViewport, false));

    a.recycle();
}

@Override
public boolean shouldDelayChildPressedState() {
    return true;
}

@Override
protected float getTopFadingEdgeStrength() {
    if (getChildCount() == 0) {
        return 0.0f;
    }

    final int length = getVerticalFadingEdgeLength();
    if (getScrollY() < length) {
        return getScrollY() / (float) length;
    }

    return 1.0f;
}

@Override
protected float getBottomFadingEdgeStrength() {
    if (getChildCount() == 0) {
        return 0.0f;
    }

    final int length = getVerticalFadingEdgeLength();
    final int bottomEdge = getHeight() - getPaddingBottom();
    final int span = getChildAt(0).getBottom() - getScrollY() - bottomEdge;
    if (span < length) {
        return span / (float) length;
    }

    return 1.0f;
}

/**
 * @return The maximum amount this scroll view will scroll in response to
 * an arrow event.
 */
public int getMaxScrollAmount() {
    return (int) (MAX_SCROLL_FACTOR * (getBottom() - getTop()));
}


private void initScrollView() {
    mScroller = new OverScroller(getContext());
    setFocusable(true);
    setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
    setWillNotDraw(false);
    final ViewConfiguration configuration = ViewConfiguration.get(mContext);
    mOverflingDistance = configuration.getScaledOverflingDistance();
}

@Override
public void addView(View child) {
    if (getChildCount() > 0) {
        throw new IllegalStateException("ScrollView can host only one direct child");
    }
    super.addView(child);
}

@Override
public void addView(View child, int index) {
    if (getChildCount() > 0) {
        throw new IllegalStateException("ScrollView can host only one direct child");
    }

    super.addView(child, index);
}

@Override
public void addView(View child, ViewGroup.LayoutParams params) {
    if (getChildCount() > 0) {
        throw new IllegalStateException("ScrollView can host only one direct child");
    }

    super.addView(child, params);
}

@Override
public void addView(View child, int index, ViewGroup.LayoutParams params) {
    if (getChildCount() > 0) {
        throw new IllegalStateException("ScrollView can host only one direct child");
    }

    super.addView(child, index, params);
}

/**
 * @return Returns true this ScrollView can be scrolled
 */
protected boolean canScroll() {
    View child = getChildAt(0);
    if (child != null) {
        int childHeight = child.getHeight();
        return getHeight() < childHeight + getPaddingTop() + getPaddingBottom();
    }
    return false;
}

/**
 * Indicates whether this ScrollView's content is stretched to fill the viewport.
 *
 * @return True if the content fills the viewport, false otherwise.
 * @attr ref android.R.styleable#ScrollView_fillViewport
 */
public boolean isFillViewport() {
    return mFillViewport;
}

/**
 * Indicates this ScrollView whether it should stretch its content height to fill
 * the viewport or not.
 *
 * @param fillViewport True to stretch the content's height to the viewport's
 *                     boundaries, false otherwise.
 * @attr ref android.R.styleable#ScrollView_fillViewport
 */
public void setFillViewport(boolean fillViewport) {
    if (fillViewport != mFillViewport) {
        mFillViewport = fillViewport;
        requestLayout();
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    if (!mFillViewport) {
        return;
    }

    final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    if (heightMode == MeasureSpec.UNSPECIFIED) {
        return;
    }

    if (getChildCount() > 0) {
        final View child = getChildAt(0);
        int height = getMeasuredHeight();
        if (child.getMeasuredHeight() < height) {
            final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams();

            int childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
                    getPaddingLeft() + getPaddingRight(), lp.width);
            height -= getPaddingTop();
            height -= getPaddingBottom();
            int childHeightMeasureSpec =
                    MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);

            child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
        }
    }
}

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
    // Let the focused view and/or our descendants get the key first
    boolean isdis = super.dispatchKeyEvent(event);
    Log.i(TAG, "---------- dispatchKeyEvent : " + isdis);
    return isdis || executeKeyEvent(event);
}

/**
 * You can call this function yourself to have the scroll view perform
 * scrolling from a key event, just as if the event had been dispatched to
 * it by the view hierarchy.
 *
 * @param event The key event to execute.
 * @return Return true if the event was handled, else false.
 */
public boolean executeKeyEvent(KeyEvent event) {
    mTempRect.setEmpty();

    if (!canScroll()) {
        if (isFocused() && event.getKeyCode() != KeyEvent.KEYCODE_BACK) {
            View currentFocused = findFocus();
            if (currentFocused == this) currentFocused = null;
            View nextFocused = FocusFinder.getInstance().findNextFocus(this,
                    currentFocused, View.FOCUS_DOWN);
            return nextFocused != null
                    && nextFocused != this
                    && nextFocused.requestFocus(View.FOCUS_DOWN);
        }
        return false;
    }

    boolean handled = false;
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        switch (event.getKeyCode()) {
            case KeyEvent.KEYCODE_DPAD_UP:
                if (!event.isAltPressed()) {
                    handled = arrowScroll(View.FOCUS_UP);
                } else {
                    handled = fullScroll(View.FOCUS_UP);
                }
                break;
            case KeyEvent.KEYCODE_DPAD_DOWN:
                if (!event.isAltPressed()) {
                    handled = arrowScroll(View.FOCUS_DOWN);
                } else {
                    handled = fullScroll(View.FOCUS_DOWN);
                }
                break;
            case KeyEvent.KEYCODE_SPACE:
                pageScroll(event.isShiftPressed() ? View.FOCUS_UP : View.FOCUS_DOWN);
                break;
        }
    }

    return handled;
}

private boolean inChild(int x, int y) {
    if (getChildCount() > 0) {
        final int scrollY = getScrollY();
        final View child = getChildAt(0);
        return !(y < child.getTop() - scrollY
                || y >= child.getBottom() - scrollY
                || x < child.getLeft()
                || x >= child.getRight());
    }
    return false;
}

private void recycleVelocityTracker() {
    if (mVelocityTracker != null) {
        mVelocityTracker.recycle();
        mVelocityTracker = null;
    }
}

@Override
public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
    if (disallowIntercept) {
        recycleVelocityTracker();
    }
    super.requestDisallowInterceptTouchEvent(disallowIntercept);
}


@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
    return true;
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    return true;
}

@Override
public boolean onGenericMotionEvent(MotionEvent event) {
    return super.onGenericMotionEvent(event);
}

@Override
protected void onOverScrolled(int scrollX, int scrollY,
                              boolean clampedX, boolean clampedY) {
    // Treat animating scrolls differently; see #computeScroll() for why.
    if (!mScroller.isFinished()) {
        final int oldX = getScrollX();
        final int oldY = getScrollY();
        setScrollX(scrollX);
        setScrollY(scrollY);
        invalidateParentIfNeeded();
        onScrollChanged(getScrollX(), getScrollY(), oldX, oldY);
        if (clampedY) {
            mScroller.springBack(getScrollX(), getScrollY(), 0, 0, 0, getScrollRange());
        }
    } else {
        super.scrollTo(scrollX, scrollY);
    }

// awakenScrollBars();
}

protected void invalidateParentIfNeeded() {
    if (isHardwareAccelerated() && getParent() instanceof View) {
        ((View) getParent()).invalidate();
    }
}

@Override
public boolean performAccessibilityAction(int action, Bundle arguments) {
    if (super.performAccessibilityAction(action, arguments)) {
        return true;
    }
    if (!isEnabled()) {
        return false;
    }
    switch (action) {
        case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: {
            final int viewportHeight = getHeight() - getPaddingBottom() - getPaddingTop();
            final int targetScrollY = Math.min(getScrollY() + viewportHeight, getScrollRange());
            if (targetScrollY != getScrollY()) {
                smoothScrollTo(0, targetScrollY);
                return true;
            }
        }
        return false;
        case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: {
            final int viewportHeight = getHeight() - getPaddingBottom() - getPaddingTop();
            final int targetScrollY = Math.max(getScrollY() - viewportHeight, 0);
            if (targetScrollY != getScrollY()) {
                smoothScrollTo(0, targetScrollY);
                return true;
            }
        }
        return false;
    }
    return false;
}

@Override
public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
    super.onInitializeAccessibilityNodeInfo(info);
    info.setClassName(ScrollView.class.getName());
    if (isEnabled()) {
        final int scrollRange = getScrollRange();
        if (scrollRange > 0) {
            info.setScrollable(true);
            if (getScrollY() > 0) {
                info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD);
            }
            if (getScrollY() < scrollRange) {
                info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD);
            }
        }
    }
}

@Override
public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
    super.onInitializeAccessibilityEvent(event);
    event.setClassName(ScrollView.class.getName());
    final boolean scrollable = getScrollRange() > 0;
    event.setScrollable(scrollable);
    event.setScrollX(getScrollX());
    event.setScrollY(getScrollY());
    event.setMaxScrollX(getScrollX());
    event.setMaxScrollY(getScrollRange());
}

private int getScrollRange() {
    int scrollRange = 0;
    if (getChildCount() > 0) {
        View child = getChildAt(0);
        scrollRange = Math.max(0,
                child.getHeight() - (getHeight() - getPaddingBottom() - getPaddingTop()));
    }
    return scrollRange;
}

/**
 * <p>
 * Finds the next focusable component that fits in the specified bounds.
 * </p>
 *
 * @param topFocus look for a candidate is the one at the top of the bounds
 *                 if topFocus is true, or at the bottom of the bounds if topFocus is
 *                 false
 * @param top      the top offset of the bounds in which a focusable must be
 *                 found
 * @param bottom   the bottom offset of the bounds in which a focusable must
 *                 be found
 * @return the next focusable component in the bounds or null if none can
 * be found
 */
private View findFocusableViewInBounds(boolean topFocus, int top, int bottom) {

    List<View> focusables = getFocusables(View.FOCUS_FORWARD);
    View focusCandidate = null;

    /*
     * A fully contained focusable is one where its top is below the bound's
     * top, and its bottom is above the bound's bottom. A partially
     * contained focusable is one where some part of it is within the
     * bounds, but it also has some part that is not within bounds.  A fully contained
     * focusable is preferred to a partially contained focusable.
     */
    boolean foundFullyContainedFocusable = false;

    int count = focusables.size();
    for (int i = 0; i < count; i++) {
        View view = focusables.get(i);
        int viewTop = view.getTop();
        int viewBottom = view.getBottom();

        if (top < viewBottom && viewTop < bottom) {
            /*
             * the focusable is in the target area, it is a candidate for
             * focusing
             */

            final boolean viewIsFullyContained = (top < viewTop) &&
                    (viewBottom < bottom);

            if (focusCandidate == null) {
                /* No candidate, take this one */
                focusCandidate = view;
                foundFullyContainedFocusable = viewIsFullyContained;
            } else {
                final boolean viewIsCloserToBoundary =
                        (topFocus && viewTop < focusCandidate.getTop()) ||
                                (!topFocus && viewBottom > focusCandidate
                                        .getBottom());

                if (foundFullyContainedFocusable) {
                    if (viewIsFullyContained && viewIsCloserToBoundary) {
                        /*
                         * We're dealing with only fully contained views, so
                         * it has to be closer to the boundary to beat our
                         * candidate
                         */
                        focusCandidate = view;
                    }
                } else {
                    if (viewIsFullyContained) {
                        /* Any fully contained view beats a partially contained view */
                        focusCandidate = view;
                        foundFullyContainedFocusable = true;
                    } else if (viewIsCloserToBoundary) {
                        /*
                         * Partially contained view beats another partially
                         * contained view if it's closer
                         */
                        focusCandidate = view;
                    }
                }
            }
        }
    }

    return focusCandidate;
}

/**
 * <p>Handles scrolling in response to a "page up/down" shortcut press. This
 * method will scroll the view by one page up or down and give the focus
 * to the topmost/bottommost component in the new visible area. If no
 * component is a good candidate for focus, this scrollview reclaims the
 * focus.</p>
 *
 * @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
 *                  to go one page up or
 *                  {@link android.view.View#FOCUS_DOWN} to go one page down
 * @return true if the key event is consumed by this method, false otherwise
 */
public boolean pageScroll(int direction) {
    boolean down = direction == View.FOCUS_DOWN;
    int height = getHeight();

    if (down) {
        mTempRect.top = getScrollY() + height;
        int count = getChildCount();
        if (count > 0) {
            View view = getChildAt(count - 1);
            if (mTempRect.top + height > view.getBottom()) {
                mTempRect.top = view.getBottom() - height;
            }
        }
    } else {
        mTempRect.top = getScrollY() - height;
        if (mTempRect.top < 0) {
            mTempRect.top = 0;
        }
    }
    mTempRect.bottom = mTempRect.top + height;

    return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom);
}

/**
 * <p>Handles scrolling in response to a "home/end" shortcut press. This
 * method will scroll the view to the top or bottom and give the focus
 * to the topmost/bottommost component in the new visible area. If no
 * component is a good candidate for focus, this scrollview reclaims the
 * focus.</p>
 *
 * @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
 *                  to go the top of the view or
 *                  {@link android.view.View#FOCUS_DOWN} to go the bottom
 * @return true if the key event is consumed by this method, false otherwise
 */
public boolean fullScroll(int direction) {
    boolean down = direction == View.FOCUS_DOWN;
    int height = getHeight();

    mTempRect.top = 0;
    mTempRect.bottom = height;

    if (down) {
        int count = getChildCount();
        if (count > 0) {
            View view = getChildAt(count - 1);
            mTempRect.bottom = view.getBottom() + getPaddingBottom();
            mTempRect.top = mTempRect.bottom - height;
        }
    }

    return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom);
}

/**
 * <p>Scrolls the view to make the area defined by <code>top</code> and
 * <code>bottom</code> visible. This method attempts to give the focus
 * to a component visible in this area. If no component can be focused in
 * the new visible area, the focus is reclaimed by this ScrollView.</p>
 *
 * @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
 *                  to go upward, {@link android.view.View#FOCUS_DOWN} to downward
 * @param top       the top offset of the new area to be made visible
 * @param bottom    the bottom offset of the new area to be made visible
 * @return true if the key event is consumed by this method, false otherwise
 */
private boolean scrollAndFocus(int direction, int top, int bottom) {
    boolean handled = true;

    int height = getHeight();
    int containerTop = getScrollY();
    int containerBottom = containerTop + height;
    boolean up = direction == View.FOCUS_UP;

    View newFocused = findFocusableViewInBounds(up, top, bottom);
    if (newFocused == null) {
        newFocused = this;
    }

    if (top >= containerTop && bottom <= containerBottom) {
        handled = false;
    } else {
        int delta = up ? (top - containerTop) : (bottom - containerBottom);
        doScrollY(delta);
    }

    if (newFocused != findFocus()) newFocused.requestFocus(direction);

    return handled;
}

/**
 * Handle scrolling in response to an up or down arrow click.
 *
 * @param direction The direction corresponding to the arrow key that was
 *                  pressed
 * @return True if we consumed the event, false otherwise
 */
protected boolean arrowScroll(int direction) {

    View currentFocused = findFocus();
    if (currentFocused == this) currentFocused = null;

    View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction);

    final int maxJump = getMaxScrollAmount();
    if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump, getHeight())) {
        nextFocused.getDrawingRect(mTempRect);
        offsetDescendantRectToMyCoords(nextFocused, mTempRect);
        int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);
        doScrollY(scrollDelta);
        nextFocused.requestFocus(direction);
    } else {
        // no new focus
        int scrollDelta = maxJump;

        if (direction == View.FOCUS_UP && getScrollY() < scrollDelta) {
            scrollDelta = getScrollY();
        } else if (direction == View.FOCUS_DOWN) {
            if (getChildCount() > 0) {
                int daBottom = getChildAt(0).getBottom();
                int screenBottom = getScrollY() + getHeight() - getPaddingBottom();
                if (daBottom - screenBottom < maxJump) {
                    scrollDelta = daBottom - screenBottom;
                }
            }
        }
        if (scrollDelta == 0) {
            return false;
        }
        doScrollY(direction == View.FOCUS_DOWN ? scrollDelta : -scrollDelta);
    }

    if (currentFocused != null && currentFocused.isFocused()
            && isOffScreen(currentFocused)) {
        // previously focused item still has focus and is off screen, give
        // it up (take it back to ourselves)
        // (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are
        // sure to
        // get it)
        final int descendantFocusability = getDescendantFocusability();  // save
        setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
        requestFocus();
        setDescendantFocusability(descendantFocusability);  // restore
    }
    return true;
}

/**
 * @return whether the descendant of this scroll view is scrolled off
 * screen.
 */
protected boolean isOffScreen(View descendant) {
    return !isWithinDeltaOfScreen(descendant, 0, getHeight());
}

/**
 * @return whether the descendant of this scroll view is within delta
 * pixels of being on the screen.
 */
protected boolean isWithinDeltaOfScreen(View descendant, int delta, int height) {
    descendant.getDrawingRect(mTempRect);
    offsetDescendantRectToMyCoords(descendant, mTempRect);

    return (mTempRect.bottom + delta) >= getScrollY()
            && (mTempRect.top - delta) <= (getScrollY() + height);
}

/**
 * Smooth scroll by a Y delta
 *
 * @param delta the number of pixels to scroll by on the Y axis
 */
protected void doScrollY(int delta) {
    if (delta != 0) {
        if (mSmoothScrollingEnabled) {
            smoothScrollBy(0, delta);
        } else {
            scrollBy(0, delta);
        }
    }
}

/**
 * Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
 *
 * @param dx the number of pixels to scroll by on the X axis
 * @param dy the number of pixels to scroll by on the Y axis
 */
public final void smoothScrollBy(int dx, int dy) {
    if (getChildCount() == 0) {
        return;
    }
    if (!mScroller.isFinished()) {
        mScroller.abortAnimation();
    }
    final int height = getHeight() - getPaddingBottom() - getPaddingTop();
    final int bottom = getChildAt(0).getHeight();
    final int maxY = Math.max(0, bottom - height);
    final int scrollY = getScrollY();
    dy = Math.max(0, Math.min(scrollY + dy, maxY)) - scrollY;
    mScroller.startScroll(getScrollX(), scrollY, dx, dy, computeTime(dy));
    postInvalidateOnAnimation();
}

private int computeTime(int d) {
    int time = Math.abs(d);
    if (time < ANIMATED_SCROLL_GAP) {
        time = ANIMATED_SCROLL_GAP;
    } else {
        double index = 1 + Math.pow(((float) ANIMATED_SCROLL_GAP / time), time / ANIMATED_SCROLL_GAP);
        time = (int) (ANIMATED_SCROLL_GAP * index);
    }
    return time;
}

/**
 * Like {@link #scrollTo}, but scroll smoothly instead of immediately.
 *
 * @param x the position where to scroll on the X axis
 * @param y the position where to scroll on the Y axis
 */
public final void smoothScrollTo(int x, int y) {
    smoothScrollBy(x - getScrollX(), y - getScrollY());
}

/**
 * <p>The scroll range of a scroll view is the overall height of all of its
 * children.</p>
 */
@Override
protected int computeVerticalScrollRange() {
    final int count = getChildCount();
    final int contentHeight = getHeight() - getPaddingBottom() - getPaddingTop();
    if (count == 0) {
        return contentHeight;
    }

    int scrollRange = getChildAt(0).getBottom();
    final int scrollY = getScrollY();
    final int overscrollBottom = Math.max(0, scrollRange - contentHeight);
    if (scrollY < 0) {
        scrollRange -= scrollY;
    } else if (scrollY > overscrollBottom) {
        scrollRange += scrollY - overscrollBottom;
    }

    return scrollRange;
}

@Override
protected int computeVerticalScrollOffset() {
    return Math.max(0, super.computeVerticalScrollOffset());
}

@Override
protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) {
    ViewGroup.LayoutParams lp = child.getLayoutParams();

    int childWidthMeasureSpec;
    int childHeightMeasureSpec;

    childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec, getPaddingLeft()
            + getPaddingRight(), lp.width);

    childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);

    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}

@Override
protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed,
                                       int parentHeightMeasureSpec, int heightUsed) {
    final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

    final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
            getPaddingLeft() + getPaddingRight() + lp.leftMargin + lp.rightMargin
                    + widthUsed, lp.width);
    final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
            lp.topMargin + lp.bottomMargin, MeasureSpec.UNSPECIFIED);

    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}

@Override
public void computeScroll() {
    if (mScroller.computeScrollOffset()) {
        int oldX = getScrollX();
        int oldY = getScrollY();
        int x = mScroller.getCurrX();
        int y = mScroller.getCurrY();
        if (oldX != x || oldY != y) {
            final int range = getScrollRange();
            final int overscrollMode = getOverScrollMode();
            final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS ||
                    (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0);

            overScrollBy(x - oldX, y - oldY, oldX, oldY, 0, range,
                    0, mOverflingDistance, false);

// onScrollChanged(getScrollX(), getScrollY(), oldX, oldY);

// if (canOverscroll) {
// if (y < 0 && oldY >= 0) {
// mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity());
// } else if (y > range && oldY <= range) {
// mEdgeGlowBottom.onAbsorb((int) mScroller.getCurrVelocity());
// }
// }
}

// if (!awakenScrollBars()) {
// Keep on drawing until the animation has finished.
// postInvalidateOnAnimation();
// }
} else

    {
    }
}

/**
 * Scrolls the view to the given child.
 *
 * @param child the View to scroll to
 */
private void scrollToChild(View child) {
    child.getDrawingRect(mTempRect);

    /* Offset from child's local coordinates to ScrollView coordinates */
    offsetDescendantRectToMyCoords(child, mTempRect);

    int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);

    if (scrollDelta != 0) {
        scrollBy(0, scrollDelta);
    }
}

/**
 * If rect is off screen, scroll just enough to get it (or at least the
 * first screen size chunk of it) on screen.
 *
 * @param rect      The rectangle.
 * @param immediate True to scroll immediately without animation
 * @return true if scrolling was performed
 */
private boolean scrollToChildRect(Rect rect, boolean immediate) {
    final int delta = computeScrollDeltaToGetChildRectOnScreen(rect);
    final boolean scroll = delta != 0;
    if (scroll) {
        if (immediate) {
            scrollBy(0, delta);
        } else {
            smoothScrollBy(0, delta);
        }
    }
    return scroll;
}

/**
 * Compute the amount to scroll in the Y direction in order to get
 * a rectangle completely on the screen (or, if taller than the screen,
 * at least the first screen size chunk of it).
 *
 * @param rect The rect.
 * @return The scroll delta.
 */
protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) {
    if (getChildCount() == 0) return 0;

    int height = getHeight();
    int screenTop = getScrollY();
    int screenBottom = screenTop + height;

    int fadingEdge = getVerticalFadingEdgeLength();

    // leave room for top fading edge as long as rect isn't at very top
    if (rect.top > 0) {
        screenTop += fadingEdge;
    }

    // leave room for bottom fading edge as long as rect isn't at very bottom
    if (rect.bottom < getChildAt(0).getHeight()) {
        screenBottom -= fadingEdge;
    }

    int scrollYDelta = 0;

    if (rect.bottom > screenBottom && rect.top > screenTop) {
        // need to move down to get it in view: move down just enough so
        // that the entire rectangle is in view (or at least the first
        // screen size chunk).

        if (rect.height() > height) {
            // just enough to get screen size chunk on
            scrollYDelta += (rect.top - screenTop);
        } else {
            // get entire rect at bottom of screen
            scrollYDelta += (rect.bottom - screenBottom);
        }

        // make sure we aren't scrolling beyond the end of our content
        int bottom = getChildAt(0).getBottom();
        int distanceToBottom = bottom - screenBottom;
        scrollYDelta = Math.min(scrollYDelta, distanceToBottom);

    } else if (rect.top < screenTop && rect.bottom < screenBottom) {
        // need to move up to get it in view: move up just enough so that
        // entire rectangle is in view (or at least the first screen
        // size chunk of it).

        if (rect.height() > height) {
            // screen size chunk
            scrollYDelta -= (screenBottom - rect.bottom);
        } else {
            // entire rect at top
            scrollYDelta -= (screenTop - rect.top);
        }

        // make sure we aren't scrolling any further than the top our content
        scrollYDelta = Math.max(scrollYDelta, -getScrollY());
    }
    return scrollYDelta;
}

@Override
public void requestChildFocus(View child, View focused) {
    if (!mIsLayoutDirty) {
        scrollToChild(focused);
    } else {
        // The child may not be laid out yet, we can't compute the scroll yet
        mChildToScrollTo = focused;
    }
    super.requestChildFocus(child, focused);
}


/**
 * When looking for focus in children of a scroll view, need to be a little
 * more careful not to give focus to something that is scrolled off screen.
 * <p>
 * This is more expensive than the default {@link android.view.ViewGroup}
 * implementation, otherwise this behavior might have been made the default.
 */
@Override
protected boolean onRequestFocusInDescendants(int direction,
                                              Rect previouslyFocusedRect) {

    // convert from forward / backward notation to up / down / left / right
    // (ugh).
    if (direction == View.FOCUS_FORWARD) {
        direction = View.FOCUS_DOWN;
    } else if (direction == View.FOCUS_BACKWARD) {
        direction = View.FOCUS_UP;
    }

    final View nextFocus = previouslyFocusedRect == null ?
            FocusFinder.getInstance().findNextFocus(this, null, direction) :
            FocusFinder.getInstance().findNextFocusFromRect(this,
                    previouslyFocusedRect, direction);

    if (nextFocus == null) {
        return false;
    }

    if (isOffScreen(nextFocus)) {
        return false;
    }

    return nextFocus.requestFocus(direction, previouslyFocusedRect);
}

@Override
public boolean requestChildRectangleOnScreen(View child, Rect rectangle,
                                             boolean immediate) {
    // offset into coordinate space of this scroll view
    rectangle.offset(child.getLeft() - child.getScrollX(),
            child.getTop() - child.getScrollY());

    return scrollToChildRect(rectangle, immediate);
}

@Override
public void requestLayout() {
    mIsLayoutDirty = true;
    super.requestLayout();
}

@Override
protected void onDetachedFromWindow() {
    super.onDetachedFromWindow();
}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    super.onLayout(changed, l, t, r, b);
    if (!changed) {
        return;
    }
    mIsLayoutDirty = false;
    // Give a child focus if it needs it
    if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) {
        scrollToChild(mChildToScrollTo);
    }
    mChildToScrollTo = null;

    if (!isLaidOut()) {
        if (mSavedState != null) {
            setScrollY(mSavedState.scrollPosition);
            mSavedState = null;
        } // mScrollY default value is "0"

        final int childHeight = (getChildCount() > 0) ? getChildAt(0).getMeasuredHeight() : 0;
        final int scrollRange = Math.max(0,
                childHeight - (b - t - getPaddingBottom() - getPaddingTop()));

        // Don't forget to clamp
        if (getScrollY() > scrollRange) {
            setScrollY(scrollRange);
        } else if (getScrollY() < 0) {
            setScrollY(0);
        }
    }

    // Calling this with the present values causes it to re-claim them
    scrollTo(getScrollX(), getScrollY());
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);

    View currentFocused = findFocus();
    if (null == currentFocused || this == currentFocused)
        return;

    // If the currently-focused view was visible on the screen when the
    // screen was at the old height, then scroll the screen to make that
    // view visible with the new screen height.
    if (isWithinDeltaOfScreen(currentFocused, 0, oldh)) {
        currentFocused.getDrawingRect(mTempRect);
        offsetDescendantRectToMyCoords(currentFocused, mTempRect);
        int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);
        doScrollY(scrollDelta);
    }
}

/**
 * Return true if child is a descendant of parent, (or equal to the parent).
 */
private static boolean isViewDescendantOf(View child, View parent) {
    if (child == parent) {
        return true;
    }

    final ViewParent theParent = child.getParent();
    return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent);
}

/**
 * Fling the scroll view
 *
 * @param velocityY The initial velocity in the Y direction. Positive
 *                  numbers mean that the finger/cursor is moving down the screen,
 *                  which means we want to scroll towards the top.
 */
public void fling(int velocityY) {
    if (getChildCount() > 0) {
        int height = getHeight() - getPaddingBottom() - getPaddingTop();
        int bottom = getChildAt(0).getHeight();

        mScroller.fling(getScrollX(), getScrollY(), 0, velocityY, 0, 0, 0,
                Math.max(0, bottom - height), 0, height / 2);

        postInvalidateOnAnimation();
    }
}

private void flingWithNestedDispatch(int velocityY) {
    final boolean canFling = (getScrollY() > 0 || velocityY > 0) &&
            (getScrollY() < getScrollRange() || velocityY < 0);
    if (!dispatchNestedPreFling(0, velocityY)) {
        dispatchNestedFling(0, velocityY, canFling);
        if (canFling) {
            fling(velocityY);
        }
    }
}

/**
 * {@inheritDoc}
 * <p>
 * <p>This version also clamps the scrolling to the bounds of our child.
 */
@Override
public void scrollTo(int x, int y) {
    // we rely on the fact the View.scrollBy calls scrollTo.
    if (getChildCount() > 0) {
        View child = getChildAt(0);
        x = clamp(x, getWidth() - getPaddingRight() - getPaddingLeft(), child.getWidth());
        y = clamp(y, getHeight() - getPaddingBottom() - getPaddingTop(), child.getHeight());
        if (x != getScrollX() || y != getScrollY()) {
            super.scrollTo(x, y);
        }
    }
}

@Override
public void setOverScrollMode(int mode) {
    if (mode != OVER_SCROLL_NEVER) {
        if (mEdgeGlowTop == null) {
            Context context = getContext();
            mEdgeGlowTop = new EdgeEffect(context);
            mEdgeGlowBottom = new EdgeEffect(context);
        }
    } else {
        mEdgeGlowTop = null;
        mEdgeGlowBottom = null;
    }
    super.setOverScrollMode(mode);
}

@Override
public boolean onStartNestedScroll(View child, View target, int nestedScrollAxes) {
    return (nestedScrollAxes & SCROLL_AXIS_VERTICAL) != 0;
}

@Override
public void onNestedScrollAccepted(View child, View target, int axes) {
    super.onNestedScrollAccepted(child, target, axes);
    startNestedScroll(SCROLL_AXIS_VERTICAL);
}

/**
 * @inheritDoc
 */
@Override
public void onStopNestedScroll(View target) {
    super.onStopNestedScroll(target);
}

@Override
public void onNestedScroll(View target, int dxConsumed, int dyConsumed,
                           int dxUnconsumed, int dyUnconsumed) {
    final int oldScrollY = getScrollY();
    scrollBy(0, dyUnconsumed);
    final int myConsumed = getScrollY() - oldScrollY;
    final int myUnconsumed = dyUnconsumed - myConsumed;
    dispatchNestedScroll(0, myConsumed, 0, myUnconsumed, null);
}

/**
 * @inheritDoc
 */
@Override
public boolean onNestedFling(View target, float velocityX, float velocityY, boolean consumed) {
    if (!consumed) {
        flingWithNestedDispatch((int) velocityY);
        return true;
    }
    return false;
}

//    float time = 0;

// float currentTime = 0;
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
if (mEdgeGlowTop != null) {
final int scrollY = getScrollY();
if (!mEdgeGlowTop.isFinished()) {
final int restoreCount = canvas.save();
final int width = getWidth() - getPaddingLeft() - getPaddingRight();

            canvas.translate(getPaddingLeft(), Math.min(0, scrollY));
            mEdgeGlowTop.setSize(width, getHeight());
            if (mEdgeGlowTop.draw(canvas)) {
                postInvalidateOnAnimation();
            }
            canvas.restoreToCount(restoreCount);
        }
        if (!mEdgeGlowBottom.isFinished()) {
            final int restoreCount = canvas.save();
            final int width = getWidth() - getPaddingLeft() - getPaddingRight();
            final int height = getHeight();

            canvas.translate(-width + getPaddingLeft(),
                    Math.max(getScrollRange(), scrollY) + height);
            canvas.rotate(180, width, 0);
            mEdgeGlowBottom.setSize(width, height);
            if (mEdgeGlowBottom.draw(canvas)) {
                postInvalidateOnAnimation();
            }
            canvas.restoreToCount(restoreCount);
        }
    }

// currentTime = System.currentTimeMillis();
// if (0 != time) {
// LogUtils.i(TAG, "onDraw: time : " + (currentTime - time));
// }
// time = currentTime;
}

private static int clamp(int n, int my, int child) {
    if (my >= child || n < 0) {
        /* my >= child is this case:
         *                    |--------------- me ---------------|
         *     |------ child ------|
         * or
         *     |--------------- me ---------------|
         *            |------ child ------|
         * or
         *     |--------------- me ---------------|
         *                                  |------ child ------|
         *
         * n < 0 is this case:
         *     |------ me ------|
         *                    |-------- child --------|
         *     |-- mScrollX --|
         */
        return 0;
    }
    if ((my + n) > child) {
        /* this case:
         *                    |------ me ------|
         *     |------ child ------|
         *     |-- mScrollX --|
         */
        return child - my;
    }
    return n;
}

@Override
protected void onRestoreInstanceState(Parcelable state) {
    if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) {
        // Some old apps reused IDs in ways they shouldn't have.
        // Don't break them, but they don't get scroll state restoration.
        super.onRestoreInstanceState(state);
        return;
    }
    MScrollView.SavedState ss = (MScrollView.SavedState) state;
    super.onRestoreInstanceState(ss.getSuperState());
    mSavedState = ss;
    requestLayout();
}

@Override
protected Parcelable onSaveInstanceState() {
    if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) {
        // Some old apps reused IDs in ways they shouldn't have.
        // Don't break them, but they don't get scroll state restoration.
        return super.onSaveInstanceState();
    }
    Parcelable superState = super.onSaveInstanceState();
    MScrollView.SavedState ss = new MScrollView.SavedState(superState);
    ss.scrollPosition = getScrollY();
    return ss;
}

static class SavedState extends BaseSavedState {
    public int scrollPosition;

    SavedState(Parcelable superState) {
        super(superState);
    }

    public SavedState(Parcel source) {
        super(source);
        scrollPosition = source.readInt();
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        super.writeToParcel(dest, flags);
        dest.writeInt(scrollPosition);
    }

    @Override
    public String toString() {
        return "HorizontalScrollView.SavedState{"
                + Integer.toHexString(System.identityHashCode(this))
                + " scrollPosition=" + scrollPosition + "}";
    }

    public static final Parcelable.Creator<MScrollView.SavedState> CREATOR
            = new Parcelable.Creator<MScrollView.SavedState>() {
        public MScrollView.SavedState createFromParcel(Parcel in) {
            return new MScrollView.SavedState(in);
        }

        public MScrollView.SavedState[] newArray(int size) {
            return new MScrollView.SavedState[size];
        }
    };
}

}