This library encapsulates scrolling logic when implementing scrolling tabs (hot topic nowadays in Android development). It saves us from unpleasant routine aka addHeader
, addFooter
for every scrolling content which appears in tabs and synchronising it with our real headers. It also works good for a single scrolling widget, for e.g. RecyclerView which has it's own issues with headers (at least parallaxing them). Also check out the ScrollableDialog
in sample application it mimics new Android Lollipop Intent chooser behavior.
compile 'ru.noties:scrollable:x.x.x'
- Bundled with own Scroller implementation to be independent of device's Scroller
- Using ScrollableLayout with Toolbar fix
- Improved interception of ghost touches when
ScrollableLayout.getScrollY()
> 0 && < max scroll y - Added
Close-up logic
(turned off by default)
Simply wrap your views in ru.noties.scrollable.ScrollableLayout
. The final xml might be looking something like that (don't copy, it's not valid):
<ru.noties.scrollable.ScrollableLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/scrollable_layout"
app:scrollable_maxScroll="@dimen/header_height"> --!(1)
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="@dimen/header_height" --!(2)
android:background="@color/header_background"
android:textColor="@color/white"
android:textSize="30sp"
android:text="Header"
android:id="@+id/header"
android:gravity="center"/>
<ru.noties.scrollable.sample.TabsLayout
android:layout_width="match_parent"
android:layout_height="@dimen/tabs_height" --!(3)
android:background="@color/tabs_background"
android:id="@+id/tabs" />
</LinearLayout>
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="match_parent" --!(4)
android:layout_marginTop="@dimen/tabs_height" --!(5)
android:id="@+id/view_pager" />
</ru.noties.scrollable.ScrollableLayout>
The most imprortant things here are:
app:scrollable_maxScroll="@dimen/header_height"
- it's the value of header height aka the max scroll distance for a ScrollableLayout- It's what will be a header
- It you wish to create sticky behavior to a certain View, you should indicate it's heigth here & in step 5
- Out main content should have
match_parent
as it's layout_height attribute - Crucial for a sticky behavior
Then we should init out logic in code (copied from sample application):
final View header = findViewById(R.id.header);
final TabsLayout tabs = findView(this, R.id.tabs);
mScrollableLayout = findView(this, R.id.scrollable_layout);
mScrollableLayout.setDraggableView(tabs);
final ViewPager viewPager = findView(this, R.id.view_pager);
final ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager(), getResources(), getFragments());
viewPager.setAdapter(adapter);
tabs.setViewPager(viewPager);
// Note this bit, it's very important
mScrollableLayout.setCanScrollVerticallyDelegate(new CanScrollVerticallyDelegate() {
@Override
public boolean canScrollVertically(int direction) {
return adapter.canScrollVertically(viewPager.getCurrentItem(), direction);
}
});
mScrollableLayout.setOnScrollChangedListener(new OnScrollChangedListener() {
@Override
public void onScrollChanged(int y, int oldY, int maxY) {
// Sticky behavior
final float tabsTranslationY;
if (y < maxY) {
tabsTranslationY = .0F;
} else {
tabsTranslationY = y - maxY;
}
tabs.setTranslationY(tabsTranslationY);
header.setTranslationY(y / 2);
}
});
In order to start rolling we should pass to our ScrollableLayout a ru.noties.scrollable.CanScrollVerticallyDelegate
. For e.g. PagerAdapter implements it what way:
boolean canScrollVertically(int position, int direction) {
return getItem(position).canScrollVertically(direction);
}
And fragments implements it that way:
@Override
public boolean canScrollVertically(int direction) {
return mView != null && mView.canScrollVertically(direction);
}
Additionally you could provide a ScrollableLayout with a ru.noties.scrollable.OnScrollChangedListener
and implement where your own logic. It's the place to implement parallax and all other possible stuff.
Since 1.1.0
it's possible to evaluate custom close-up logic. For a simple close-up (with only two states of ScrollableLayout - collapsed & expanded) use ru.noties.scrollable.DefaultCloseUpAlgorithm
. For more fancy stuff create your own by implementing ru.noties.scrollable.CloseUpAlgorithm
.
Might be set with ScrollableLayout.setCloseUpAlgorithm()
or (if default implementation is desired) via xml definition app:scrollable_defaultCloseUp="true"
ru.noties.scrollable.CloseUpIdleAnimationTime
is used to compute the duration of the close-up animation. For a simple case when duration for all close-ups is constant ru.noties.scrollable.SimpleCloseUpIdleAnimationTime
might be used via ScrollableLayout.setCloseUpIdleAnimationTime()
or via xml definition app:scrollable_closeUpAnimationMillis="200"
.
Default value is 200
ms.
Value in milliseconds after which scroll state of a ScrollableLayout is considered idle and thus close-up logic is evaluated. Might be set via ScrollableLayout.setConsiderIdleMillis()
or via xml definition app:scrollable_considerIdleMillis="100"
.
Default value is 100
ms.
ru.noties.scrollable.CloseUpAnimatorConfigurator
is used to configure an ObjectAnimator
of a pending close-up animation. If the only configurable value is an Interpolator
then ru.noties.scrollable.InterpolatorCloseUpAnimatorConfigurator
might be used via ScrollableLayout.setCloseUpAnimatorConfigurator()
or via xml definition app:scrollable_closeUpAnimatorInterpolator="@android:anim/bounce_interpolator"
.
Default value is null
app:scrollable_maxScroll="@dimen/header_height"
app:scrollable_considerIdleMillis="100"
app:scrollable_friction="0.075"
app:scrollable_closeUpAnimationMillis="200"
app:scrollable_defaultCloseUp="true"
app:scrollable_scrollerFlywheel="false"
app:scrollable_closeUpAnimatorInterpolator="@android:anim/bounce_interpolator"
Copyright 2015 Dimitry Ivanov (mail@dimitryivanov.ru)
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.