Example usage for android.support.v4.view PagerAdapter POSITION_UNCHANGED

Introduction

In this page you can find the example usage for android.support.v4.view PagerAdapter POSITION_UNCHANGED.

Prototype

int POSITION_UNCHANGED

To view the source code for android.support.v4.view PagerAdapter POSITION_UNCHANGED.

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Usage

From source file:comm.custom.CustomViewPager.java

void dataSetChanged() {
    // This method only gets called if our observer is attached, so mAdapter is non-null.

    final int adapterCount = mAdapter.getCount();
    mExpectedAdapterCount = adapterCount;
    boolean needPopulate = mItems.size() < mOffscreenPageLimit * 2 + 1 && mItems.size() < adapterCount;
    int newCurrItem = mCurItem;

    boolean isUpdating = false;
    for (int i = 0; i < mItems.size(); i++) {
        final ItemInfo ii = mItems.get(i);
        final int newPos = mAdapter.getItemPosition(ii.object);

        if (newPos == PagerAdapter.POSITION_UNCHANGED) {
            continue;
        }/*from  w ww  . jav a 2 s. c  o m*/

        if (newPos == PagerAdapter.POSITION_NONE) {
            mItems.remove(i);
            i--;

            if (!isUpdating) {
                mAdapter.startUpdate(this);
                isUpdating = true;
            }

            mAdapter.destroyItem(this, ii.position, ii.object);
            needPopulate = true;

            if (mCurItem == ii.position) {
                // Keep the current item in the valid range
                newCurrItem = Math.max(0, Math.min(mCurItem, adapterCount - 1));
                needPopulate = true;
            }
            continue;
        }

        if (ii.position != newPos) {
            if (ii.position == mCurItem) {
                // Our current item changed position. Follow it.
                newCurrItem = newPos;
            }

            ii.position = newPos;
            needPopulate = true;
        }
    }

    if (isUpdating) {
        mAdapter.finishUpdate(this);
    }
    Collections.sort(mItems, COMPARATOR);
    if (needPopulate) {
        // Reset our known page widths; populate will recompute them.
        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) {
                lp.widthFactor = 0.f;
            }
        }

        setCurrentItemInternal(newCurrItem, false, true);
        requestLayout();
    }
}

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From source file:com.example.sky.test.view.ViewPager.java

void dataSetChanged() {
    // This method only gets called if our observer is attached, so mAdapter is non-null.

    final int adapterCount = mAdapter.getCount();
    mExpectedAdapterCount = adapterCount;
    boolean needPopulate = mItems.size() < mOffscreenPageLimit * 2 + 1 && mItems.size() < adapterCount;
    int newCurrItem = mCurItem;

    boolean isUpdating = false;
    for (int i = 0; i < mItems.size(); i++) {
        final ItemInfo ii = mItems.get(i);
        final int newPos = mAdapter.getItemPosition(ii.object);

        if (newPos == PagerAdapter.POSITION_UNCHANGED) {
            continue;
        }/*from w w w .jav  a  2 s.c  o  m*/

        if (newPos == PagerAdapter.POSITION_NONE) {
            mItems.remove(i);
            i--;

            if (!isUpdating) {
                mAdapter.startUpdate(this);
                isUpdating = true;
            }

            mAdapter.destroyItem(this, ii.position, ii.object);
            needPopulate = true;

            if (mCurItem == ii.position) {
                // Keep the current item in the valid range
                newCurrItem = Math.max(0, Math.min(mCurItem, adapterCount - 1));
                needPopulate = true;
            }
            continue;
        }

        if (ii.position != newPos) {
            if (ii.position == mCurItem) {
                // Our current item changed position. Follow it.
                newCurrItem = newPos;
            }

            ii.position = newPos;
            needPopulate = true;
        }
    }

    if (isUpdating) {
        mAdapter.finishUpdate(this);
    }

    Collections.sort(mItems, COMPARATOR);

    if (needPopulate) {
        // Reset our known page widths; populate will recompute them.
        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = getChildAt(i);
            final ViewPager.LayoutParams lp = (ViewPager.LayoutParams) child.getLayoutParams();
            if (!lp.isDecor) {
                lp.widthFactor = 0.f;
            }
        }

        setCurrentItemInternal(newCurrItem, false, true);
        requestLayout();
    }
}

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