Example usage for android.util MathUtils constrain

Introduction

In this page you can find the example usage for android.util MathUtils constrain.

Prototype

@UnsupportedAppUsage
    public static float constrain(float amount, float low, float high) 

Source Link

Usage

From source file:com.android.internal.widget.ViewPager.java

boolean setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) {
    if (mAdapter == null || mAdapter.getCount() <= 0) {
        setScrollingCacheEnabled(false);
        return false;
    }//from   ww  w . j  a v a 2 s .c  o m

    item = MathUtils.constrain(item, 0, mAdapter.getCount() - 1);
    if (!always && mCurItem == item && mItems.size() != 0) {
        setScrollingCacheEnabled(false);
        return false;
    }

    final int pageLimit = mOffscreenPageLimit;
    if (item > (mCurItem + pageLimit) || item < (mCurItem - pageLimit)) {
        // We are doing a jump by more than one page.  To avoid
        // glitches, we want to keep all current pages in the view
        // until the scroll ends.
        for (int i = 0; i < mItems.size(); i++) {
            mItems.get(i).scrolling = true;
        }
    }

    final boolean dispatchSelected = mCurItem != item;
    if (mFirstLayout) {
        // We don't have any idea how big we are yet and shouldn't have any pages either.
        // Just set things up and let the pending layout handle things.
        mCurItem = item;
        if (dispatchSelected && mOnPageChangeListener != null) {
            mOnPageChangeListener.onPageSelected(item);
        }
        if (dispatchSelected && mInternalPageChangeListener != null) {
            mInternalPageChangeListener.onPageSelected(item);
        }
        requestLayout();
    } else {
        populate(item);
        scrollToItem(item, smoothScroll, velocity, dispatchSelected);
    }

    return true;
}

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From source file:com.android.internal.widget.ViewPager.java

private int getLeftEdgeForItem(int position) {
    final ItemInfo info = infoForPosition(position);
    if (info == null) {
        return 0;
    }/*  w  w w  .  j a v a  2 s.c o m*/

    final int width = getPaddedWidth();
    final int scaledOffset = (int) (width * MathUtils.constrain(info.offset, mFirstOffset, mLastOffset));

    if (isLayoutRtl()) {
        final int itemWidth = (int) (width * info.widthFactor + 0.5f);
        return MAX_SCROLL_X - itemWidth - scaledOffset;
    } else {
        return scaledOffset;
    }
}

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From source file:com.android.systemui.statusbar.phone.NotificationPanelView.java

/**
 * @return the alpha to be used to fade out the contents on Keyguard (status bar, bottom area)
 *         during swiping up//from  w w w .  ja  va 2 s . c o m
 */
private float getKeyguardContentsAlpha() {
    float alpha;
    if (mStatusBar.getBarState() == StatusBarState.KEYGUARD) {

        // When on Keyguard, we hide the header as soon as the top card of the notification
        // stack scroller is close enough (collision distance) to the bottom of the header.
        alpha = getNotificationsTopY() / (mKeyguardStatusBar.getHeight() + mNotificationsHeaderCollideDistance);
    } else {

        // In SHADE_LOCKED, the top card is already really close to the header. Hide it as
        // soon as we start translating the stack.
        alpha = getNotificationsTopY() / mKeyguardStatusBar.getHeight();
    }
    alpha = MathUtils.constrain(alpha, 0, 1);
    alpha = (float) Math.pow(alpha, 0.75);
    return alpha;
}

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From source file:com.android.internal.widget.ViewPager.java

/**
 * @param currentPage the position of the page with the first visible starting edge
 * @param pageOffset the fraction of the right-hand page that's visible
 * @param velocity the velocity of the touch event stream
 * @param deltaX the distance of the touch event stream
 * @return the position of the target page
 *//*from  w w  w . ja va 2s  .co  m*/
private int determineTargetPage(int currentPage, float pageOffset, int velocity, int deltaX) {
    int targetPage;
    if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) {
        targetPage = currentPage - (velocity < 0 ? mLeftIncr : 0);
    } else {
        final float truncator = currentPage >= mCurItem ? 0.4f : 0.6f;
        targetPage = (int) (currentPage - mLeftIncr * (pageOffset + truncator));
    }

    if (mItems.size() > 0) {
        final ItemInfo firstItem = mItems.get(0);
        final ItemInfo lastItem = mItems.get(mItems.size() - 1);

        // Only let the user target pages we have items for
        targetPage = MathUtils.constrain(targetPage, firstItem.position, lastItem.position);
    }

    return targetPage;
}

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