我正在尝试同步两个ViewPager,显然有很多人在我面前,我已经有这么远：
private ViewPager mNavPager;
private ViewPager mMainPager;
private final OnPageChangeListener mNavPagerListener = new OnPageChangeListener() {
private boolean mNavDragging;
private int mScrollPosition;
@Override
public void onPageSelected(int position) {
mScrollPosition = position;
}
@Override
public void onPageScrolled(int position,float positionOffset,int positionOffsetPixels) {
if(mNavDragging)
mMainPager.scrollTo(positionOffsetPixels,0);
}
@Override
public void onPageScrollStateChanged(int state) {
switch(state) {
case ViewPager.SCROLL_STATE_DRAGGING:
case ViewPager.SCROLL_STATE_SETTLING:
mNavDragging = true;
break;
case ViewPager.SCROLL_STATE_IDLE:
mNavDragging = false;
break;
}
}
};
private OnPageChangeListener mMainPagerListener = new OnPageChangeListener() {
private boolean mMainDragging;
private int mScrollPosition;
@Override
public void onPageSelected(int position) {
mScrollPosition = position;
}
@Override
public void onPageScrolled(int position,int positionOffsetPixels) {
if(mMainDragging)
mNavPager.scrollTo(positionOffsetPixels,0);
}
@Override
public void onPageScrollStateChanged(int state) {
switch(state) {
case ViewPager.SCROLL_STATE_DRAGGING:
case ViewPager.SCROLL_STATE_SETTLING:
mMainDragging = true;
break;
case ViewPager.SCROLL_STATE_IDLE:
mMainDragging = false;
break;
}
}
};
如果任一个手动滚动,另一个则使用scroll state属性从属于它.它的工作很好,直到物品达到最后的位置;在这一点上,从来的寻呼机立即弹回到先前选择的项目,就像滚动没有发生.
我尝试使用各种不同的逻辑约束调用ViewPager#setCurrentItem(mScrolledPosition),但它也不起作用,尽管它偶尔会变得更糟.我觉得有一些东西可以做,但我不知道什么.
我如何让奴隶寻呼机保持在正确的位置？
解决方法
我使用OnPageChangeListener以更简单(更清洁)的方式解决了这个问题：
mViewPager1.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
private int mScrollState = ViewPager.SCROLL_STATE_IDLE;
@Override
public void onPageScrolled(final int position,final float positionOffset,final int positionOffsetPixels) {
if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
return;
}
mViewPager2.scrollTo(mViewPager1.getScrollX(),mViewPager2.getScrollY());
}
@Override
public void onPageSelected(final int position) {
}
@Override
public void onPageScrollStateChanged(final int state) {
mScrollState = state;
if (state == ViewPager.SCROLL_STATE_IDLE) {
mViewPager2.setCurrentItem(mViewPager1.getCurrentItem(),false);
}
}
});
mViewPager2.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
private int mScrollState = ViewPager.SCROLL_STATE_IDLE;
@Override
public void onPageScrolled(final int position,final int positionOffsetPixels) {
if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
return;
}
mViewPager1.scrollTo(mViewPager2.getScrollX(),mViewPager1.getScrollY());
}
@Override
public void onPageSelected(final int position) {
}
@Override
public void onPageScrollStateChanged(final int state) {
mScrollState = state;
if (state == ViewPager.SCROLL_STATE_IDLE) {
mViewPager1.setCurrentItem(mViewPager2.getCurrentItem(),false);
}
}
});
