Example usage for android.view Gravity CENTER

Introduction

In this page you can find the example usage for android.view Gravity CENTER_VERTICAL.

Prototype

int CENTER_VERTICAL

To view the source code for android.view Gravity CENTER_VERTICAL.

Click Source Link

Document

Place object in the vertical center of its container, not changing its size.

Usage

From source file:com.example.view.VerticalViewPager.java

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mInLayout = true;/*from  www .jav  a 2  s  . c  o  m*/
    populate();
    mInLayout = false;

    final int count = getChildCount();
    int width = r - l;
    int height = b - t;
    int paddingLeft = getPaddingLeft();
    int paddingTop = getPaddingTop();
    int paddingRight = getPaddingRight();
    int paddingBottom = getPaddingBottom();
    final int scrollY = getScrollY();

    int decorCount = 0;

    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            ItemInfo ii;
            int childLeft = 0;
            int childTop = 0;
            if (lp.isDecor) {
                // XXX isDecoralse??
                final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
                final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
                switch (hgrav) {
                default:
                    childLeft = paddingLeft;
                    break;
                case Gravity.LEFT:
                    childLeft = paddingLeft;
                    paddingLeft += child.getMeasuredWidth();
                    break;
                case Gravity.CENTER_HORIZONTAL:
                    childLeft = Math.max((width - child.getMeasuredWidth()) / 2, paddingLeft);
                    break;
                case Gravity.RIGHT:
                    childLeft = width - paddingRight - child.getMeasuredWidth();
                    paddingRight += child.getMeasuredWidth();
                    break;
                } /* end of switch */
                switch (vgrav) {
                default:
                    childTop = paddingTop;
                    break;
                case Gravity.TOP:
                    childTop = paddingTop;
                    paddingTop += child.getMeasuredHeight();
                    break;
                case Gravity.CENTER_VERTICAL:
                    childTop = Math.max((height - child.getMeasuredHeight()) / 2, paddingTop);
                    break;
                case Gravity.BOTTOM:
                    childTop = height - paddingBottom - child.getMeasuredHeight();
                    paddingBottom += child.getMeasuredHeight();
                    break;
                } /* end of switch */

                // XXX ????
                childTop += scrollY;
                decorCount++;
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
            } else if ((ii = infoForChild(child)) != null) {
                // XXX ???iewPager??
                int toff = (height + mPageMargin) * ii.position;
                childLeft = paddingLeft;
                childTop = paddingTop + toff;

                if (DEBUG)
                    Log.v(TAG, "Positioning #" + i + " " + child + " f=" + ii.object + ":" + childLeft + ","
                            + childTop + " " + child.getMeasuredWidth() + "x" + child.getMeasuredHeight());
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
            } /* end of if */
        } /* end of if */
    } /* end of for */

    // XXX ?????
    mLeftPageBounds = paddingLeft;
    mRightPageBounds = width - paddingRight;
    mDecorChildCount = decorCount;
    mFirstLayout = false;
}

From source file:com.actionbarsherlock.internal.widget.ActionBarView.java

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int x = getPaddingLeft();
    final int y = getPaddingTop();
    final int contentHeight = b - t - getPaddingTop() - getPaddingBottom();

    if (contentHeight <= 0) {
        // Nothing to do if we can't see anything.
        return;// w w w  .j av  a 2 s  .c o m
    }

    HomeView homeLayout = mExpandedActionView != null ? mExpandedHomeLayout : mHomeLayout;
    if (homeLayout.getVisibility() != GONE) {
        final int leftOffset = homeLayout.getLeftOffset();
        x += positionChild(homeLayout, x + leftOffset, y, contentHeight) + leftOffset;
    }

    if (mExpandedActionView == null) {
        final boolean showTitle = mTitleLayout != null && mTitleLayout.getVisibility() != GONE
                && (mDisplayOptions & ActionBar.DISPLAY_SHOW_TITLE) != 0;
        if (showTitle) {
            x += positionChild(mTitleLayout, x, y, contentHeight);
        }

        switch (mNavigationMode) {
        case ActionBar.NAVIGATION_MODE_STANDARD:
            break;
        case ActionBar.NAVIGATION_MODE_LIST:
            if (mListNavLayout != null) {
                if (showTitle)
                    x += mItemPadding;
                x += positionChild(mListNavLayout, x, y, contentHeight) + mItemPadding;
            }
            break;
        case ActionBar.NAVIGATION_MODE_TABS:
            if (mTabScrollView != null) {
                if (showTitle)
                    x += mItemPadding;
                x += positionChild(mTabScrollView, x, y, contentHeight) + mItemPadding;
            }
            break;
        }
    }

    int menuLeft = r - l - getPaddingRight();
    if (mMenuView != null && mMenuView.getParent() == this) {
        positionChildInverse(mMenuView, menuLeft, y, contentHeight);
        menuLeft -= mMenuView.getMeasuredWidth();
    }

    if (mIndeterminateProgressView != null && mIndeterminateProgressView.getVisibility() != GONE) {
        positionChildInverse(mIndeterminateProgressView, menuLeft, y, contentHeight);
        menuLeft -= mIndeterminateProgressView.getMeasuredWidth();
    }

    View customView = null;
    if (mExpandedActionView != null) {
        customView = mExpandedActionView;
    } else if ((mDisplayOptions & ActionBar.DISPLAY_SHOW_CUSTOM) != 0 && mCustomNavView != null) {
        customView = mCustomNavView;
    }
    if (customView != null) {
        ViewGroup.LayoutParams lp = customView.getLayoutParams();
        final ActionBar.LayoutParams ablp = lp instanceof ActionBar.LayoutParams ? (ActionBar.LayoutParams) lp
                : null;

        final int gravity = ablp != null ? ablp.gravity : DEFAULT_CUSTOM_GRAVITY;
        final int navWidth = customView.getMeasuredWidth();

        int topMargin = 0;
        int bottomMargin = 0;
        if (ablp != null) {
            x += ablp.leftMargin;
            menuLeft -= ablp.rightMargin;
            topMargin = ablp.topMargin;
            bottomMargin = ablp.bottomMargin;
        }

        int hgravity = gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
        // See if we actually have room to truly center; if not push against left or right.
        if (hgravity == Gravity.CENTER_HORIZONTAL) {
            final int centeredLeft = ((getRight() - getLeft()) - navWidth) / 2;
            if (centeredLeft < x) {
                hgravity = Gravity.LEFT;
            } else if (centeredLeft + navWidth > menuLeft) {
                hgravity = Gravity.RIGHT;
            }
        } else if (gravity == -1) {
            hgravity = Gravity.LEFT;
        }

        int xpos = 0;
        switch (hgravity) {
        case Gravity.CENTER_HORIZONTAL:
            xpos = ((getRight() - getLeft()) - navWidth) / 2;
            break;
        case Gravity.LEFT:
            xpos = x;
            break;
        case Gravity.RIGHT:
            xpos = menuLeft - navWidth;
            break;
        }

        int vgravity = gravity & Gravity.VERTICAL_GRAVITY_MASK;

        if (gravity == -1) {
            vgravity = Gravity.CENTER_VERTICAL;
        }

        int ypos = 0;
        switch (vgravity) {
        case Gravity.CENTER_VERTICAL:
            final int paddedTop = getPaddingTop();
            final int paddedBottom = getBottom() - getTop() - getPaddingBottom();
            ypos = ((paddedBottom - paddedTop) - customView.getMeasuredHeight()) / 2;
            break;
        case Gravity.TOP:
            ypos = getPaddingTop() + topMargin;
            break;
        case Gravity.BOTTOM:
            ypos = getHeight() - getPaddingBottom() - customView.getMeasuredHeight() - bottomMargin;
            break;
        }
        final int customWidth = customView.getMeasuredWidth();
        customView.layout(xpos, ypos, xpos + customWidth, ypos + customView.getMeasuredHeight());
        x += customWidth;
    }

    if (mProgressView != null) {
        mProgressView.bringToFront();
        final int halfProgressHeight = mProgressView.getMeasuredHeight() / 2;
        mProgressView.layout(mProgressBarPadding, -halfProgressHeight,
                mProgressBarPadding + mProgressView.getMeasuredWidth(), halfProgressHeight);
    }
}

From source file:interactive.view.pagereader.VerticalViewPager.java

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mInLayout = true;//w  w w.j  a v  a 2 s  . co  m
    populate();
    mInLayout = false;

    final int count = getChildCount();
    int width = r - l;
    int height = b - t;
    int paddingLeft = getPaddingLeft();
    int paddingTop = getPaddingTop();
    int paddingRight = getPaddingRight();
    int paddingBottom = getPaddingBottom();
    final int scrollY = getScrollY();

    int decorCount = 0;

    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            ItemInfo ii;
            int childLeft = 0;
            int childTop = 0;
            if (lp.isDecor) {
                // XXX isDecoralse?
                final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
                final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
                switch (hgrav) {
                default:
                    childLeft = paddingLeft;
                    break;
                case Gravity.LEFT:
                    childLeft = paddingLeft;
                    paddingLeft += child.getMeasuredWidth();
                    break;
                case Gravity.CENTER_HORIZONTAL:
                    childLeft = Math.max((width - child.getMeasuredWidth()) / 2, paddingLeft);
                    break;
                case Gravity.RIGHT:
                    childLeft = width - paddingRight - child.getMeasuredWidth();
                    paddingRight += child.getMeasuredWidth();
                    break;
                } /* end of switch */
                switch (vgrav) {
                default:
                    childTop = paddingTop;
                    break;
                case Gravity.TOP:
                    childTop = paddingTop;
                    paddingTop += child.getMeasuredHeight();
                    break;
                case Gravity.CENTER_VERTICAL:
                    childTop = Math.max((height - child.getMeasuredHeight()) / 2, paddingTop);
                    break;
                case Gravity.BOTTOM:
                    childTop = height - paddingBottom - child.getMeasuredHeight();
                    paddingBottom += child.getMeasuredHeight();
                    break;
                } /* end of switch */

                // XXX ??y?
                childTop += scrollY;
                decorCount++;
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
            } else if ((ii = infoForChild(child)) != null) {
                // XXX ViewPager?
                int toff = (height + mPageMargin) * ii.position;
                childLeft = paddingLeft;
                childTop = paddingTop + toff;

                if (DEBUG)
                    Log.v(TAG, "Positioning #" + i + " " + child + " f=" + ii.object + ":" + childLeft + ","
                            + childTop + " " + child.getMeasuredWidth() + "x" + child.getMeasuredHeight());
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
            } /* end of if */
        } /* end of if */
    } /* end of for */

    // XXX ?
    mLeftPageBounds = paddingLeft;
    mRightPageBounds = width - paddingRight;
    mDecorChildCount = decorCount;
    mFirstLayout = false;
}

From source file:javalibrary.android.ui.VerticalViewPager.java

/**
 * This method will be invoked when the current page is scrolled, either as part
 * of a programmatically initiated smooth scroll or a user initiated touch scroll.
 * If you override this method you must call through to the superclass implementation
 * (e.g. super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled
 * returns.//from www.  j av  a  2s  . co  m
 *
 * @param position Position index of the first page currently being displayed.
 *                 Page position+1 will be visible if positionOffset is nonzero.
 * @param offset Value from [0, 1) indicating the offset from the page at position.
 * @param offsetPixels Value in pixels indicating the offset from position.
 */
protected void onPageScrolled(int position, float offset, int offsetPixels) {
    // Offset any decor views if needed - keep them on-screen at all times.
    if (mDecorChildCount > 0) {
        /*final int scrollX = getScrollX();
        int paddingLeft = getPaddingLeft();
        int paddingRight = getPaddingRight();
        final int width = getWidth();
        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
        final View child = getChildAt(i);
        final LayoutParams lp = (LayoutParams) child.getLayoutParams();
        if (!lp.isDecor) continue;
                
        final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
        int childLeft = 0;
        switch (hgrav) {
            default:
                childLeft = paddingLeft;
                break;
            case Gravity.LEFT:
                childLeft = paddingLeft;
                paddingLeft += child.getWidth();
                break;
            case Gravity.CENTER_HORIZONTAL:
                childLeft = Math.max((width - child.getMeasuredWidth()) / 2,
                        paddingLeft);
                break;
            case Gravity.RIGHT:
                childLeft = width - paddingRight - child.getMeasuredWidth();
                paddingRight += child.getMeasuredWidth();
                break;
        }
        childLeft += scrollX;
                
        final int childOffset = childLeft - child.getLeft();
        if (childOffset != 0) {
            child.offsetLeftAndRight(childOffset);
        }
        }*/
        final int scrollY = getScrollY();
        int paddingTop = getPaddingTop();
        int paddingBottom = getPaddingBottom();
        final int height = getHeight();
        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = getChildAt(i);
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            if (!lp.isDecor)
                continue;

            final int hgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
            int childLeft = 0;
            switch (hgrav) {
            default:
                childLeft = paddingTop;
                break;
            case Gravity.LEFT:
                childLeft = paddingTop;
                paddingTop += child.getHeight();
                break;
            case Gravity.CENTER_VERTICAL:
                childLeft = Math.max((height - child.getMeasuredWidth()) / 2, paddingTop);
                break;
            case Gravity.BOTTOM:
                childLeft = height - paddingBottom - child.getMeasuredWidth();
                paddingBottom += child.getMeasuredWidth();
                break;
            }
            childLeft += scrollY;

            final int childOffset = childLeft - child.getTop();
            if (childOffset != 0) {
                //                    child.offsetLeftAndRight(childOffset);
                child.offsetTopAndBottom(childOffset);
            }
        }
    }

    if (mOnPageChangeListener != null) {
        mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels);
    }
    if (mInternalPageChangeListener != null) {
        mInternalPageChangeListener.onPageScrolled(position, offset, offsetPixels);
    }
    mCalledSuper = true;
}

From source file:org.drrickorang.loopback.LoopbackActivity.java

public void showToast(String msg) {
    if (mToast == null) {
        mToast = Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_SHORT);
    } else {/*from  w w  w.j a v  a 2  s . c o m*/
        mToast.setText(msg);
    }

    {
        mToast.setGravity(Gravity.CENTER_VERTICAL | Gravity.CENTER_HORIZONTAL, 10, 10);
        mToast.show();
    }
}

From source file:lewa.support.v7.widget.Toolbar.java

private void ensureNavButtonView() {
    if (mNavButtonView == null) {
        mNavButtonView = new ImageButton(getContext(), null, R.attr.toolbarNavigationButtonStyle);
        final LayoutParams lp = generateDefaultLayoutParams();
        //      lp.gravity = GravityCompat.START | (mButtonGravity & Gravity.VERTICAL_GRAVITY_MASK);
        lp.gravity = Gravity.CENTER_VERTICAL;
        mNavButtonView.setLayoutParams(lp);
    }/*from  w w  w.  j  a  v a 2s.c  o m*/
}

From source file:org.androfarsh.widget.DragGridLayout.java

private int resolveOffset(int size, int cellSize, int cellCount, int gravity) {
    switch (gravity) {
    case Gravity.LEFT:
    case Gravity.TOP:
        return 0;
    case Gravity.RIGHT:
    case Gravity.BOTTOM:
        return Math.max(0, size - (cellCount * cellSize));
    case Gravity.CENTER_HORIZONTAL:
    case Gravity.CENTER_VERTICAL:
    default:// w  w  w.  j  a  va 2 s.  c o m
        return Math.max(0, (size - (cellCount * cellSize)) / 2);
    }
}

From source file:com.jecelyin.editor.v2.widget.AnyDrawerLayout.java

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mInLayout = true;/*  w  w w.  j  av a2  s. c  o  m*/
    final int width = r - l;
    final int height = b - t;
    final int childCount = getChildCount();
    for (int i = 0; i < childCount; i++) {
        final View child = getChildAt(i);

        if (child.getVisibility() == GONE) {
            continue;
        }

        final LayoutParams lp = (LayoutParams) child.getLayoutParams();

        if (isContentView(child)) {
            child.layout(lp.leftMargin, lp.topMargin, lp.leftMargin + child.getMeasuredWidth(),
                    lp.topMargin + child.getMeasuredHeight());
        } else { // Drawer, if it wasn't onMeasure would have thrown an exception.
            final int childWidth = child.getMeasuredWidth();
            final int childHeight = child.getMeasuredHeight();
            int childLeft, childTop = 0;

            float newOffset;
            if (checkDrawerViewAbsoluteGravity(child, Gravity.BOTTOM)) {
                float offset = lp.onScreen == 0 ? (Math.abs(lp.topMargin) / (float) childHeight) : lp.onScreen;
                childTop = height - (int) (childHeight * offset);
                newOffset = (float) (height - childTop) / childHeight;
                childLeft = child.getLeft();
            } else if (checkDrawerViewAbsoluteGravity(child, Gravity.LEFT)) {
                childLeft = -childWidth + (int) (childWidth * lp.onScreen);
                newOffset = (float) (childWidth + childLeft) / childWidth;
            } else { // Right; onMeasure checked for us.
                childLeft = width - (int) (childWidth * lp.onScreen);
                newOffset = (float) (width - childLeft) / childWidth;
            }

            final boolean changeOffset = newOffset != lp.onScreen;

            final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;

            switch (vgrav) {
            default:
            case Gravity.TOP: {
                child.layout(childLeft, lp.topMargin, childLeft + childWidth, lp.topMargin + childHeight);
                break;
            }

            case Gravity.BOTTOM: {
                child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
                break;
            }

            case Gravity.CENTER_VERTICAL: {
                childTop = (height - childHeight) / 2;

                // Offset for margins. If things don't fit right because of
                // bad measurement before, oh well.
                if (childTop < lp.topMargin) {
                    childTop = lp.topMargin;
                } else if (childTop + childHeight > height - lp.bottomMargin) {
                    childTop = height - lp.bottomMargin - childHeight;
                }
                child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
                break;
            }
            }

            if (changeOffset) {
                setDrawerViewOffset(child, newOffset);
            }

            int newVisibility = lp.onScreen > 0 ? VISIBLE : INVISIBLE;
            //??
            if (vgrav == Gravity.BOTTOM && mHideBottomDrawer)
                newVisibility = INVISIBLE;
            if (child.getVisibility() != newVisibility) {
                child.setVisibility(newVisibility);
            }
        }
    }
    mInLayout = false;
    mFirstLayout = false;
}

From source file:com.gome.ecmall.custom.VerticalViewPager.java

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mInLayout = true;/*from w w  w .  j a v  a2s.  co m*/
    populate();
    mInLayout = false;

    final int count = getChildCount();
    int width = r - l;
    int height = b - t;
    int paddingLeft = getPaddingLeft();
    int paddingTop = getPaddingTop();
    int paddingRight = getPaddingRight();
    int paddingBottom = getPaddingBottom();
    final int scrollY = getScrollY();

    int decorCount = 0;

    // First pass - decor views. We need to do this in two passes so that
    // we have the proper offsets for non-decor views later.
    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            int childLeft = 0;
            int childTop = 0;
            if (lp.isDecor) {
                final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
                final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
                switch (hgrav) {
                default:
                    childLeft = paddingLeft;
                    break;
                case Gravity.LEFT:
                    childLeft = paddingLeft;
                    paddingLeft += child.getMeasuredWidth();
                    break;
                case Gravity.CENTER_HORIZONTAL:
                    childLeft = Math.max((width - child.getMeasuredWidth()) / 2, paddingLeft);
                    break;
                case Gravity.RIGHT:
                    childLeft = width - paddingRight - child.getMeasuredWidth();
                    paddingRight += child.getMeasuredWidth();
                    break;
                }
                switch (vgrav) {
                default:
                    childTop = paddingTop;
                    break;
                case Gravity.TOP:
                    childTop = paddingTop;
                    paddingTop += child.getMeasuredHeight();
                    break;
                case Gravity.CENTER_VERTICAL:
                    childTop = Math.max((height - child.getMeasuredHeight()) / 2, paddingTop);
                    break;
                case Gravity.BOTTOM:
                    childTop = height - paddingBottom - child.getMeasuredHeight();
                    paddingBottom += child.getMeasuredHeight();
                    break;
                }
                childTop += scrollY;
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
                decorCount++;
            }
        }
    }

    // Page views. Do this once we have the right padding offsets from
    // above.
    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            ItemInfo ii;
            if (!lp.isDecor && (ii = infoForChild(child)) != null) {
                int loff = (int) (height * ii.offset);
                int childTop = paddingTop + loff;
                int childLeft = paddingLeft;
                if (lp.needsMeasure) {
                    // This was added during layout and needs measurement.
                    // Do it now that we know what we're working with.
                    lp.needsMeasure = false;

                    final int widthSpec = MeasureSpec.makeMeasureSpec(width - paddingLeft - paddingRight,
                            MeasureSpec.EXACTLY);
                    final int heightSpec = MeasureSpec.makeMeasureSpec(
                            (height - paddingTop - paddingBottom) * lp.height, MeasureSpec.EXACTLY);
                    child.measure(widthSpec, heightSpec);
                }
                if (DEBUG)
                    Log.v(TAG, "Positioning #" + i + " " + child + " f=" + ii.object + ":" + childLeft + ","
                            + childTop + " " + child.getMeasuredWidth() + "x" + child.getMeasuredHeight());
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
            }
        }
    }
    mLeftPageBounds = paddingLeft;
    mRightPageBounds = width - paddingRight;
    mDecorChildCount = decorCount;
    mFirstLayout = false;
}

From source file:org.bangbang.support.v4.widget.VerticalViewPager.java

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mInLayout = true;//w  w  w. j  a  va 2 s. co m
    populate();
    mInLayout = false;

    final int count = getChildCount();
    int width = r - l;
    int height = b - t;
    int paddingLeft = getPaddingLeft();
    int paddingTop = getPaddingTop();
    int paddingRight = getPaddingRight();
    int paddingBottom = getPaddingBottom();
    final int scrollX = getScrollX();

    int decorCount = 0;

    // First pass - decor views. We need to do this in two passes so that
    // we have the proper offsets for non-decor views later.
    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            int childLeft = 0;
            int childTop = 0;
            if (lp.isDecor) {
                final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
                final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
                switch (hgrav) {
                default:
                    childLeft = paddingLeft;
                    break;
                case Gravity.LEFT:
                    childLeft = paddingLeft;
                    paddingLeft += child.getMeasuredWidth();
                    break;
                case Gravity.CENTER_HORIZONTAL:
                    childLeft = Math.max((width - child.getMeasuredWidth()) / 2, paddingLeft);
                    break;
                case Gravity.RIGHT:
                    childLeft = width - paddingRight - child.getMeasuredWidth();
                    paddingRight += child.getMeasuredWidth();
                    break;
                }
                switch (vgrav) {
                default:
                    childTop = paddingTop;
                    break;
                case Gravity.TOP:
                    childTop = paddingTop;
                    paddingTop += child.getMeasuredHeight();
                    break;
                case Gravity.CENTER_VERTICAL:
                    childTop = Math.max((height - child.getMeasuredHeight()) / 2, paddingTop);
                    break;
                case Gravity.BOTTOM:
                    childTop = height - paddingBottom - child.getMeasuredHeight();
                    paddingBottom += child.getMeasuredHeight();
                    break;
                }
                childLeft += scrollX;
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
                decorCount++;
            }
        }
    }

    // Page views. Do this once we have the right padding offsets from above.
    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            ItemInfo ii;
            if (!lp.isDecor && (ii = infoForChild(child)) != null) {
                int loff = (int) (height * ii.offset);
                int childLeft = paddingLeft;
                int childTop = paddingBottom + loff;
                if (lp.needsMeasure) {
                    // This was added during layout and needs measurement.
                    // Do it now that we know what we're working with.
                    lp.needsMeasure = false;
                    final int widthSpec = MeasureSpec
                            .makeMeasureSpec((int) ((width - paddingLeft - paddingRight)), MeasureSpec.EXACTLY);
                    final int heightSpec = MeasureSpec.makeMeasureSpec(
                            (int) ((height - paddingTop - paddingBottom) * lp.widthFactor),
                            MeasureSpec.EXACTLY);
                    child.measure(widthSpec, heightSpec);
                }
                if (DEBUG)
                    Log.v(TAG, "Positioning #" + i + " " + child + " f=" + ii.object + ":" + childLeft + ","
                            + childTop + " " + child.getMeasuredWidth() + "x" + child.getMeasuredHeight());
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());
            }
        }
    }
    mTopPageBounds = paddingTop;
    mBottomPageBounds = height - paddingBottom;
    mDecorChildCount = decorCount;
    mFirstLayout = false;
}

Example usage for android.view Gravity CENTER_VERTICAL

Introduction

Prototype

Document

Usage