所以这是我的逻辑：
public void onScrollChanged(ScrollViewExt scrollView, int x, int y,
int oldx, int oldy) {
if (y < 200)
// the footer is still visible
{
if(y > oldy) {
// scrolling down, need to hide footer
TranslateAnimation slide = new TranslateAnimation(0, 0, y, 0);
slide.setDuration(1);
slide.setFillAfter(true);
footerOffer.startAnimation(slide);
} else {
// scrolling up, need to show footer
TranslateAnimation slide = new TranslateAnimation(0, 0, -y, 0);
slide.setDuration(1);
slide.setFillAfter(true);
footerOffer.startAnimation(slide);
}
} else if (y == 0) {
// scrolled to top
} }
});
问题是它在滚动期间闪烁，然后当我向上滚动时，它会奇怪地向上移动。
所以，我想在向下滚动时缓慢地隐藏页脚，并在向上滚动时慢慢显示它。有人可以帮忙解决这里的逻辑吗？
答案 0 :(得分：1)
看看我在下面的代码中是如何解决这个问题的。这是OnScrollListener的自定义RecyclerView。
您可以在此处查看更多示例：https://github.com/lawloretienne/QuickReturn
public class QuickReturnRecyclerViewOnScrollListener extends RecyclerView.OnScrollListener {
// region Member Variables
private final QuickReturnViewType mQuickReturnViewType;
private final View mHeader;
private final int mMinHeaderTranslation;
private final View mFooter;
private final int mMinFooterTranslation;
private final int mColumnCount;
private final boolean mIsSnappable; // Can Quick Return view snap into place?
private int mPrevScrollY = 0;
private int mHeaderDiffTotal = 0;
private int mFooterDiffTotal = 0;
private List < RecyclerView.OnScrollListener > mExtraOnScrollListenerList = new ArrayList < > ();
// endregion
// region Constructors
private QuickReturnRecyclerViewOnScrollListener(Builder builder) {
mQuickReturnViewType = builder.mQuickReturnViewType;
mHeader = builder.mHeader;
mMinHeaderTranslation = builder.mMinHeaderTranslation;
mFooter = builder.mFooter;
mMinFooterTranslation = builder.mMinFooterTranslation;
mColumnCount = builder.mColumnCount;
mIsSnappable = builder.mIsSnappable;
}
// endregion
@
Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
// apply another list' s on scroll listener
for (RecyclerView.OnScrollListener listener: mExtraOnScrollListenerList) {
listener.onScrollStateChanged(recyclerView, newState);
}
if (newState == RecyclerView.SCROLL_STATE_IDLE && mIsSnappable) {
int midHeader = -mMinHeaderTranslation / 2;
int midFooter = mMinFooterTranslation / 2;
switch (mQuickReturnViewType) {
case HEADER:
if (-mHeaderDiffTotal > 0 && -mHeaderDiffTotal < midHeader) {
ObjectAnimator anim = ObjectAnimator.ofFloat(mHeader, "translationY", mHeader.getTranslationY(), 0);
anim.setDuration(100);
anim.start();
mHeaderDiffTotal = 0;
} else if (-mHeaderDiffTotal < -mMinHeaderTranslation && -mHeaderDiffTotal >= midHeader) {
ObjectAnimator anim = ObjectAnimator.ofFloat(mHeader, "translationY", mHeader.getTranslationY(), mMinHeaderTranslation);
anim.setDuration(100);
anim.start();
mHeaderDiffTotal = mMinHeaderTranslation;
}
break;
case FOOTER:
if (-mFooterDiffTotal > 0 && -mFooterDiffTotal < midFooter) { // slide up
ObjectAnimator anim = ObjectAnimator.ofFloat(mFooter, "translationY", mFooter.getTranslationY(), 0);
anim.setDuration(100);
anim.start();
mFooterDiffTotal = 0;
} else if (-mFooterDiffTotal < mMinFooterTranslation && -mFooterDiffTotal >= midFooter) { // slide down
ObjectAnimator anim = ObjectAnimator.ofFloat(mFooter, "translationY", mFooter.getTranslationY(), mMinFooterTranslation);
anim.setDuration(100);
anim.start();
mFooterDiffTotal = -mMinFooterTranslation;
}
break;
case BOTH:
if (-mHeaderDiffTotal > 0 && -mHeaderDiffTotal < midHeader) {
ObjectAnimator anim = ObjectAnimator.ofFloat(mHeader, "translationY", mHeader.getTranslationY(), 0);
anim.setDuration(100);
anim.start();
mHeaderDiffTotal = 0;
} else if (-mHeaderDiffTotal < -mMinHeaderTranslation && -mHeaderDiffTotal >= midHeader) {
ObjectAnimator anim = ObjectAnimator.ofFloat(mHeader, "translationY", mHeader.getTranslationY(), mMinHeaderTranslation);
anim.setDuration(100);
anim.start();
mHeaderDiffTotal = mMinHeaderTranslation;
}
if (-mFooterDiffTotal > 0 && -mFooterDiffTotal < midFooter) { // slide up
ObjectAnimator anim = ObjectAnimator.ofFloat(mFooter, "translationY", mFooter.getTranslationY(), 0);
anim.setDuration(100);
anim.start();
mFooterDiffTotal = 0;
} else if (-mFooterDiffTotal < mMinFooterTranslation && -mFooterDiffTotal >= midFooter) { // slide down
ObjectAnimator anim = ObjectAnimator.ofFloat(mFooter, "translationY", mFooter.getTranslationY(), mMinFooterTranslation);
anim.setDuration(100);
anim.start();
mFooterDiffTotal = -mMinFooterTranslation;
}
break;
case TWITTER:
if (-mHeaderDiffTotal > 0 && -mHeaderDiffTotal < midHeader) {
ObjectAnimator anim = ObjectAnimator.ofFloat(mHeader, "translationY", mHeader.getTranslationY(), 0);
anim.setDuration(100);
anim.start();
mHeaderDiffTotal = 0;
} else if (-mHeaderDiffTotal < -mMinHeaderTranslation && -mHeaderDiffTotal >= midHeader) {
ObjectAnimator anim = ObjectAnimator.ofFloat(mHeader, "translationY", mHeader.getTranslationY(), mMinHeaderTranslation);
anim.setDuration(100);
anim.start();
mHeaderDiffTotal = mMinHeaderTranslation;
}
if (-mFooterDiffTotal > 0 && -mFooterDiffTotal < midFooter) { // slide up
ObjectAnimator anim = ObjectAnimator.ofFloat(mFooter, "translationY", mFooter.getTranslationY(), 0);
anim.setDuration(100);
anim.start();
mFooterDiffTotal = 0;
} else if (-mFooterDiffTotal < mMinFooterTranslation && -mFooterDiffTotal >= midFooter) { // slide down
ObjectAnimator anim = ObjectAnimator.ofFloat(mFooter, "translationY", mFooter.getTranslationY(), mMinFooterTranslation);
anim.setDuration(100);
anim.start();
mFooterDiffTotal = -mMinFooterTranslation;
}
break;
}
}
}@
Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
// apply extra on scroll listener
for (RecyclerView.OnScrollListener listener: mExtraOnScrollListenerList) {
listener.onScrolled(recyclerView, dx, dy);
}
int scrollY = QuickReturnUtils.getScrollY(recyclerView, mColumnCount);
// Log.d("", "onScrolled() : scrollY - "+scrollY);
int diff = mPrevScrollY - scrollY;
// Log.d("", "onScrolled() : diff - "+diff);
if (diff != 0) {
switch (mQuickReturnViewType) {
case HEADER:
if (diff < 0) { // scrolling down
mHeaderDiffTotal = Math.max(mHeaderDiffTotal + diff, mMinHeaderTranslation);
} else { // scrolling up
mHeaderDiffTotal = Math.min(Math.max(mHeaderDiffTotal + diff, mMinHeaderTranslation), 0);
}
mHeader.setTranslationY(mHeaderDiffTotal);
break;
case FOOTER:
if (diff < 0) { // scrolling down
mFooterDiffTotal = Math.max(mFooterDiffTotal + diff, -mMinFooterTranslation);
} else { // scrolling up
mFooterDiffTotal = Math.min(Math.max(mFooterDiffTotal + diff, -mMinFooterTranslation), 0);
}
mFooter.setTranslationY(-mFooterDiffTotal);
break;
case BOTH:
if (diff < 0) { // scrolling down
mHeaderDiffTotal = Math.max(mHeaderDiffTotal + diff, mMinHeaderTranslation);
mFooterDiffTotal = Math.max(mFooterDiffTotal + diff, -mMinFooterTranslation);
} else { // scrolling up
mHeaderDiffTotal = Math.min(Math.max(mHeaderDiffTotal + diff, mMinHeaderTranslation), 0);
mFooterDiffTotal = Math.min(Math.max(mFooterDiffTotal + diff, -mMinFooterTranslation), 0);
}
mHeader.setTranslationY(mHeaderDiffTotal);
mFooter.setTranslationY(-mFooterDiffTotal);
break;
case TWITTER:
if (diff < 0) { // scrolling down
if (scrollY > -mMinHeaderTranslation)
mHeaderDiffTotal = Math.max(mHeaderDiffTotal + diff, mMinHeaderTranslation);
if (scrollY > mMinFooterTranslation)
mFooterDiffTotal = Math.max(mFooterDiffTotal + diff, -mMinFooterTranslation);
} else { // scrolling up
mHeaderDiffTotal = Math.min(Math.max(mHeaderDiffTotal + diff, mMinHeaderTranslation), 0);
mFooterDiffTotal = Math.min(Math.max(mFooterDiffTotal + diff, -mMinFooterTranslation), 0);
}
mHeader.setTranslationY(mHeaderDiffTotal);
mFooter.setTranslationY(-mFooterDiffTotal);
default:
break;
}
}
mPrevScrollY = scrollY;
}
// region Helper Methods
public void registerExtraOnScrollListener(RecyclerView.OnScrollListener listener) {
mExtraOnScrollListenerList.add(listener);
}
// endregion
// region Inner Classes
public static class Builder {
// Required parameters
private final QuickReturnViewType mQuickReturnViewType;
// Optional parameters - initialized to default values
private View mHeader = null;
private int mMinHeaderTranslation = 0;
private View mFooter = null;
private int mMinFooterTranslation = 0;
private int mColumnCount = 1;
private boolean mIsSnappable = false;
public Builder(QuickReturnViewType quickReturnViewType) {
mQuickReturnViewType = quickReturnViewType;
}
public Builder header(View header) {
mHeader = header;
return this;
}
public Builder minHeaderTranslation(int minHeaderTranslation) {
mMinHeaderTranslation = minHeaderTranslation;
return this;
}
public Builder footer(View footer) {
mFooter = footer;
return this;
}
public Builder minFooterTranslation(int minFooterTranslation) {
mMinFooterTranslation = minFooterTranslation;
return this;
}
public Builder columnCount(int columnCount) {
mColumnCount = columnCount;
return this;
}
public Builder isSnappable(boolean isSnappable) {
mIsSnappable = isSnappable;
return this;
}
public QuickReturnRecyclerViewOnScrollListener build() {
return new QuickReturnRecyclerViewOnScrollListener(this);
}
}
// endregion
}