ViewPager-Layout-Manager

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A view pager like layout manager with custom ability.

It will handle the recycling under the hood. All you need to concern about is which the property you want to change and how it change accroding to the scroll offset.

Usage

Gradle

RecyclerView is required so:

compile 'com.android.support:recyclerview-v7:[your version code]'

if you want custom your own layout manager please add code below:

compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-core:1.3.1'

or if you want use the effect above please import(No need to import core):

compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-support:1.3.1'

Attention!!!

Make sure that your item view has the same width and height

Enable springback

recyclerView.addOnScrollListener(new CenterScrollListener());

OnPageChangeListener

Only wrok when enabling springback or you need to implement your own OnScrollListene.

mLayoutManager.setOnPageChangeListener(new ViewPagerLayoutManager.OnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

Enable scrollbars

same as recyclerView

 <android.support.v7.widget.RecyclerView
        android:scrollbars="horizontal"
        android:id="@+id/recycler"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

Endless Scroll

viewPagerLayoutManager.setEnableEndlessScroll(true);

Customize

Default Properties

protected Context context;

// Size of each items
protected int mDecoratedChildWidth;
protected int mDecoratedChildHeight;

protected int startLeft; //position x of first item
protected int startTop; // position y of first item
protected float offset; //The delta of property which will change when scroll

protected float interval; //the interval between each items

Consturct

By default there are two constructs.mShouldReverseLayout determine the way how each items align

//Default pass mShouldReverseLayout true
public CustomLayoutManager(){
    this(true);
}

public CustomLayoutManager(boolean mShouldReverseLayout) {
    this.mShouldReverseLayout = mShouldReverseLayout;
}

Methods must be implemented.

It will set the interval of each items. Once it was set you can use the variable interval directly

protected abstract float setInterval();

You can set up your own properties or change the default properties like startLeft and startTop here

protected abstract void setUp();

You can set item's properties which is determined by target offset here

protected abstract void setItemViewProperty(View itemView,float targetOffset);

Methods you can override.

The max offset value of which the view should be removed

protected float maxRemoveOffset(){
    return getHorizontalSpace() - startLeft;
}

The min offset value of which the view should be removed

protected abstract minRemoveOffset(){
    return -mDecoratedChildWidth-getPaddingLeft() - startLeft;
}

You can calculate and set the postion x of each items here

protected int calItemLeftPosition(float targetOffset){
    return targetOffset;
}

You can calculate and set the postion y of each items here

protected int calItemTopPosition(float targetOffset){
    return 0;
}

Return the property which you want to change while scrolling

protected float propertyChangeWhenScroll(View itemView){
    return itemView.getLeft()-startLeft;
}

It return the (scroll dx / offset);

protected float getDistanceRatio(){
   return 1f;
}

Change Logs

1.1.0

Spliting single library into core and support
Fixing jumping back to first item when loading image with universal-image-loader
Supporting using scrollToPosition before view inflated
Optimizing performance

1.2.0

Supporting endless scroll
Fixing scrollbar does not show when shouldReverseLayout is true
Fixing scrollToPosition scrolls to wrong position when shouldReverseLayout is true

1.3.0

Fixing crash which caused by wrong position calculation when enabling endless scroll
Add ElevateScaleLayoutManager

1.3.1

Fixing onPageSelected does not trigger when scrolling back distance equals zero
Add RotateLayoutManager

Things to do

~~support infinite scroll~~
optimize performance
support indicator
support item view with different size
support other effects (long term subject)

License

Copyright 2016 shenruochuan
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.

babogoos/ViewPagerLayoutManager