scroll parallel
that mean different layer view scroll in different speed
some basic knowledge:
use onScrolled(RecyclerView recyclerView, int dx, int dy) in OnScrollListener can easily get the amount of y and x that scrolled.
getHeight get the view height
setTranslationY can set the y location of the view
the different between setY and setTranslationY
getY and getTranslationY a all get the location of Y,but
getY:the location is rlative his father
getTranslationY:the location is is relative itself,so if the view dont move,getTranslationY must be 0
now,talk about the concept of moving the app bar
in onScrolled,we can’t get how much Y we moved
up is +,down is -
if we scroll up
the bat move app together
parallax_bar.getTranslationY() - dy / 2,dy/2 because we want the bar move more low the we scroll,adn we need to limit the bar move,the location of the bar conden’t<the -(bar height),because we want the bar come down fast when we just scroll down a little.
if we scroll down
same (parallax_bar.getTranslationY() - dy / 2,could not move do more tha its orginal location 0.
here is the answer code:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
Log.d("onScrolled", "dy: " + dy + "");
if (parallax_bar != null) {
int maxH = parallax_bar.getHeight();
Log.d("onScrolled", "maxh: " + maxH + "");
if (dy > 0) {
//scroll up
parallax_bar.setTranslationY(Math.max(parallax_bar.getTranslationY() - dy / 2, -maxH));
} else {
//scroll down
parallax_bar.setTranslationY(Math.min(parallax_bar.getTranslationY() - dy / 2, 0));
}
}
}
});
}
only can do in when the device android version is > HONEYCOMB and using recycle view.
that mean different layer view scroll in different speed
some basic knowledge:
use onScrolled(RecyclerView recyclerView, int dx, int dy) in OnScrollListener can easily get the amount of y and x that scrolled.
getHeight get the view height
setTranslationY can set the y location of the view
the different between setY and setTranslationY
getY and getTranslationY a all get the location of Y,but
getY:the location is rlative his father
getTranslationY:the location is is relative itself,so if the view dont move,getTranslationY must be 0
now,talk about the concept of moving the app bar
in onScrolled,we can’t get how much Y we moved
up is +,down is -
if we scroll up
the bat move app together
parallax_bar.getTranslationY() - dy / 2,dy/2 because we want the bar move more low the we scroll,adn we need to limit the bar move,the location of the bar conden’t<the -(bar height),because we want the bar come down fast when we just scroll down a little.
if we scroll down
same (parallax_bar.getTranslationY() - dy / 2,could not move do more tha its orginal location 0.
here is the answer code:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
Log.d("onScrolled", "dy: " + dy + "");
if (parallax_bar != null) {
int maxH = parallax_bar.getHeight();
Log.d("onScrolled", "maxh: " + maxH + "");
if (dy > 0) {
//scroll up
parallax_bar.setTranslationY(Math.max(parallax_bar.getTranslationY() - dy / 2, -maxH));
} else {
//scroll down
parallax_bar.setTranslationY(Math.min(parallax_bar.getTranslationY() - dy / 2, 0));
}
}
}
});
}
only can do in when the device android version is > HONEYCOMB and using recycle view.
