仿IOS回弹效果支持任何控件

效果图:

导入依赖:

dependencies {
    // ...

    compile 'me.everything:overscroll-decor-android:1.0.4'
}

RecyclerView
支持线性布局和网格布局管理器（即所有原生Android布局）。可以轻松适应支持自定义布局管理器。

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);

// Horizontal
OverScrollDecoratorHelper.setUpOverScroll(recyclerView, OverScrollDecoratorHelper.ORIENTATION_HORIZONTAL);
// Vertical
OverScrollDecoratorHelper.setUpOverScroll(recyclerView, OverScrollDecoratorHelper.ORIENTATION_VERTICAL);

ListView

ListView listView = (ListView) findViewById(R.id.list_view);
OverScrollDecoratorHelper.setUpOverScroll(listView);

GridView

GridView gridView = (GridView) findViewById(R.id.grid_view);
OverScrollDecoratorHelper.setUpOverScroll(gridView);

ViewPager

ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
OverScrollDecoratorHelper.setUpOverScroll(viewPager);

ScrollView, HorizontalScrollView

ScrollView scrollView = (ScrollView) findViewById(R.id.scroll_view);
OverScrollDecoratorHelper.setUpOverScroll(scrollView);
HorizontalScrollView horizontalScrollView = (HorizontalScrollView) findViewById(R.id.horizontal_scroll_view);
OverScrollDecoratorHelper.setUpOverScroll(horizontalScrollView);

Any View - Text, Image…

View view = findViewById(R.id.demo_view);    
// Horizontal
OverScrollDecoratorHelper.setUpStaticOverScroll(view, OverScrollDecoratorHelper.ORIENTATION_HORIZONTAL);
// Vertical
OverScrollDecoratorHelper.setUpStaticOverScroll(view, OverScrollDecoratorHelper.ORIENTATION_VERTICAL);

高级用法

// Horizontal RecyclerView
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
new HorizontalOverScrollBounceEffectDecorator(new RecyclerViewOverScrollDecorAdapter(recyclerView));

// ListView (vertical)
ListView listView = (ListView) findViewById(R.id.list_view);
new VerticalOverScrollBounceEffectDecorator(new AbsListViewOverScrollDecorAdapter(listView));

// GridView (vertical)
GridView gridView = (GridView) findViewById(R.id.grid_view);
new VerticalOverScrollBounceEffectDecorator(new AbsListViewOverScrollDecorAdapter(gridView));

// ViewPager
ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
new HorizontalOverScrollBounceEffectDecorator(new ViewPagerOverScrollDecorAdapter(viewPager));

// A simple TextView - horizontal
View textView = findViewById(R.id.title);
new HorizontalOverScrollBounceEffectDecorator(new StaticOverScrollDecorAdapter(view));

RecyclerView 使用 ItemTouchHelper 进行拖动
从版本1.0.1起，效果可以与RecyclerView内置的滑动机制（基于ItemTouchHelper）平滑运行。但是，还需要一些很少显式的配置工作：

// Normally you would attach an ItemTouchHelper & a callback to a RecyclerView, this way:
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
ItemTouchHelper.Callback myCallback = new ItemTouchHelper.Callback() {
    ...
};
ItemTouchHelper myHelper = new ItemTouchHelper(myCallback);
myHelper.attachToRecyclerView(recyclerView);

// INSTEAD of attaching the helper yourself, simply use the dedicated adapter
new VerticalOverScrollBounceEffectDecorator(new RecyclerViewOverScrollDecorAdapter(recyclerView, myCallback));

滚动状态改变回调

// Note: over-scroll is set-up using the helper method.
IOverScrollDecor decor = OverScrollDecoratorHelper.setUpOverScroll(recyclerView, OverScrollDecoratorHelper.ORIENTATION_HORIZONTAL);

decor.setOverScrollStateListener(new IOverScrollStateListener() {
    @Override
    public void onOverScrollStateChange(IOverScrollDecor decor, int oldState, int newState) {
        switch (newState) {
            case STATE_IDLE:
                // No over-scroll is in effect.
                break;
            case STATE_DRAG_START_SIDE:
                // Dragging started at the left-end.
                break;
            case STATE_DRAG_END_SIDE:
                // Dragging started at the right-end.
                break;
            case STATE_BOUNCE_BACK:
                if (oldState == STATE_DRAG_START_SIDE) {
                    // Dragging stopped -- view is starting to bounce back from the *left-end* onto natural position.
                } else { // i.e. (oldState == STATE_DRAG_END_SIDE)
                    // View is starting to bounce back from the *right-end*.
                }
                break;
        }
    }
}

拖拽出View原本范围时回调
当前拖拽的强度（偏移量）

// Note: over-scroll is set-up by explicity instantiating a decorator rather than using the helper; The two methods can be used interchangeably for registering listeners.
VerticalOverScrollBounceEffectDecorator decor = new VerticalOverScrollBounceEffectDecorator(new RecyclerViewOverScrollDecorAdapter(recyclerView, itemTouchHelperCallback));
decor.setOverScrollUpdateListener(new IOverScrollUpdateListener() {
    @Override
    public void onOverScrollUpdate(IOverScrollDecor decor, int state, float offset) {
        final View view = decor.getView();
        if (offset > 0) {
            // 'view' is currently being over-scrolled from the top.
        } else if (offset < 0) {
            // 'view' is currently being over-scrolled from the bottom.
        } else {
            // No over-scroll is in-effect.
            // This is synonymous with having (state == STATE_IDLE).
        }
    }
});

自定义控件

public class CustomView extends View {
    // ...
}

final CustomView view = (CustomView) findViewById(R.id.custom_view);
new VerticalOverScrollBounceEffectDecorator(new IOverScrollDecoratorAdapter() {

    @Override
    public View getView() {
        return view;
    }

    @Override
    public boolean isInAbsoluteStart() {
        // canScrollUp() is an example of a method you must implement
        return !view.canScrollUp();
    }

    @Override
    public boolean isInAbsoluteEnd() {
         // canScrollDown() is an example of a method you must implement
        return !view.canScrollDown();
    }
});

拖拽强度和回弹效果配置

/// Make over-scroll applied over a list-view feel more 'stiff'
new VerticalOverScrollBounceEffectDecorator(new AbsListViewOverScrollDecorAdapter(view),
        5f, // Default is 3
        VerticalOverScrollBounceEffectDecorator.DEFAULT_TOUCH_DRAG_MOVE_RATIO_BCK,
        VerticalOverScrollBounceEffectDecorator.DEFAULT_DECELERATE_FACTOR);

// Make over-scroll applied over a list-view bounce-back more softly
new VerticalOverScrollBounceEffectDecorator(new AbsListViewOverScrollDecorAdapter(view),
        VerticalOverScrollBounceEffectDecorator.DEFAULT_TOUCH_DRAG_MOVE_RATIO_FWD,
        VerticalOverScrollBounceEffectDecorator.DEFAULT_TOUCH_DRAG_MOVE_RATIO_BCK,
        -1f // Default is -2
        );

禁用回弹效果和开启回弹效果

IOverScrollDecor decor = OverScrollDecoratorHelper.setUpOverScroll(view);

// Detach. You are strongly encouraged to only call this when overscroll isn't
// in-effect: Either add getCurrentState()==STATE_IDLE as a precondition,
// or use a state-change listener.
decor.detach();
// Attach.
decor.attach();

源码地址：https://github.com/overscroll-decor