Develop Reference

How to approach this fade transition

I am building an app using Android Studio, and I cannot figure out how to approach this issue I am facing.
I have a recyclerview that takes up about two-thirds of the lower half of the screen. Above it are three other elements. I need those elements to disappear when the recyclerview gets scrolled, and I need the recyclerview to scale up to fill the entire screen. I have found ways to do this, but they all cause the items inside of the recyclerview to scale up as well, distorting them.

Use this implementation:-
recyclerview.addOnScrollListener(new HidingScrollListener()
{
#Override
public void onHide()
{
tabss.animate().translationY(tabss.getHeight())
.setInterpolator(new AccelerateInterpolator(2)).start();
filtershow.animate().translationY(-filtershow.getHeight())
.setInterpolator(new AccelerateInterpolator(1));
}
#Override
public void onShow()
{
tabss.animate().translationY(0).setInterpolator(new
DecelerateInterpolator(2)).start();
filtershow.animate().translationY(0).setInterpolator
(new DecelerateInterpolator(1)).start();
}
});

scrollView.scrollTo() speed control?

I would like to programmatically scroll to a specific point in a
scrollView...which I can do just fine...
Except I land there instantly.
Is there a way to control the speed of the scroll so it looks smoother?
Could somebody point me to an animation with a scrollview?

You can use object animator to scroll:
ObjectAnimator.ofInt(scrollView, "scrollY", scrollTo).setDuration(duration).start();
or you can use ContDownTimer:
new CountDownTimer(2000, 20) {
public void onTick(long millisUntilFinished) {
scrollView.scrollTo((int) (2000 - millisUntilFinished), 0);
}
public void onFinish() {
}
}.start();

There is method for that if you want to scroll it smoothly smoothScrollTo()
use it Like
scrollView.smoothScrollTo(xPos, yPos);

Android - Scrollview start at the bottom

Is there anyway I can make a Scrollview start on bottom? I tried to:
post(new Runnable() {
#Override
public void run() {
fullScroll(ScrollView.FOCUS_DOWN);
}
});
And also setting the android:focusableInTouchMode="true" on the lowest element in the layout.
But I can see it scrolling to the bottom sometimes. The idea is to make it imperceptible to the user.
Thanks a lot.

try with scrollView.fullScroll(View.FOCUS_DOWN)

Try this
scrollView.scrollTo(0, scrollView.getBottom());

Since I was adding Views dynamically, I also had to allow Android to complete the layout on the content view inside the ScrollView. I just added a post at the end of the View's queue, that will run after it has completed its layout. Otherwise, Android was trying to use the old size of the content view, and wasn't scrolling all the way down.
mMessagesLayout.addView(messageLayout);
mMessagesLayout.requestLayout();
mMessagesLayout.post(new Runnable() {
#Override
public void run() {
mScrollView.scrollTo(0, mScrollView.getBottom());
}
});

Android smoothScrollToPosition up top

I have set up smoothScrollToPosition on a listview and it works perfect! However... I would rather it put the position at the top of the listview rather than just on the screen (mostly on the bottom if its needed to scroll down). Any ideas how i can accomplish this?

Use smoothScrollToPositionFromTop(). It places the item at the specified position a specified number of pixels from the top of the ListView (if possible). You should simply supply a small offset.
Note: requires API level 11+.

recycleviewlist.post(new Runnable() {
#Override
public void run() {
new CountDownTimer(totalScrollTime, scrollPeriod) {
public void onTick(long millisUntilFinished) {
recycleviewlist.smoothScrollBy( widthToScroll,0);
}
public void onFinish() {
// gridlayoutmanager
// recycleviewlist.scrollToPosition(0);
gridlayoutmanager1
.scrollToPosition(Integer.MAX_VALUE / 2);
}
}.start();
}
});

Android: Hiding a view off the top edge of the screen

Would it be possible to hide a view off the top edge of the screen, and only have it appear if the user scrolls upwards?
My first attempt used a scrollview, but it seems that scrollTo() doesn't work unless I used postDelayed (it doesn't even work with Post()). I tried adding it to the scrollview's view tree observer onPreDraw() event and it still doesn't work unless I delay it, so there is an ugly glitch when the activity is first launched.
The second issue is that if the onscreen keyboard is minimized, the view no longer needs to scroll so hiding things by using a scroll offset no longer works. I thought about manipulating the height in code, but this seems pretty hackish.
Is there a better way to do this than by using a scrollview? Alternatively, Does anyone have any tips on the best place to place the scrollTo (the end of onCreate does not work nor the other places I have tried) so I don't need to use postDelayed? That would at least eliminate one glitch.
Thanks!
This is the code I'm using right now, which is the least glitchy but I don't understand why it doesn't work until the third time onPreDraw() is called.
mScrollView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener()
{
#Override
public boolean onPreDraw()
{
final int fieldYStart = mFieldIWantAtTheTop.getTop();
if (mFieldIWantAtTheTopYStart != fieldYStart
|| mScrollView.getScrollY() < 10)
{
mFieldIWantAtTheTopYStart = fieldYStart;
mScrollView.post(new Runnable()
{
#Override
public void run()
{
Log.v("Testing", "scrolling!");
mScrollView.scrollTo(0, mFieldIWantAtTheTopYStart);
Log.v("Testing", "scroll is now=" + mScrollView.getScrollY());
}
});
}
return true;
}
});
I also tried using a custom scrollview as mentioned below, but this does not solve the issue of the graphical glitch:
#Override
public void onMeasure(int measureWidthSpec, int measureHeightSpec) {
super.onMeasure(measureWidthSpec, measureHeightSpec);
Log.v("Testing", "Scrolling");
post(
new Runnable()
{
public void run()
{
scrollTo(0, 100);
Log.v("Testing", "ScrollY = " + getScrollY());
}
});
}
This code works as does the onPreDraw() code above but there is still a glitch when the activity is launched because the activity is first drawn with the scroll at 0.

I haven't tried this, but you may want to create a custom ScrollView and override onMeasure:
ScrollView scroll = new ScrollView(this) {
#Override
public void onMeasure(int measureWidthSpec, int measureHeightSpec) {
super.onMeasure(measureWidthSpec, measureHeightSpec);
scrollTo(...);
}
};
It seems like this would be the earliest point that scrollTo would be valid.
Edit - I found this answer, which apparently worked for the asker. Is this the method you tried?