一個iOS風格的邊緣滾動效果：overscroll

核心效果類是安卓view的松耦合的－-decorators ，因此它和和具體的View是解耦了的。這讓開發者在實現效果的同時盡可能像黑盒那樣不受干擾。

Gradle 依賴

添加如下到module的build.gradle 文件:

dependencies {
    // ...

    compile 'me.everything:overscroll-decor-android:1.0.0'
}

RecyclerView

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);

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);

任意view   (Always Over-Scroll Ready)

View view = fragmentView.findViewById(R.id.demo_view);

// Horizontal
OverScrollDecoratorHelper.setUpStaticOverScroll(view, OverScrollDecoratorHelper.ORIENTATION_HORIZONTAL);
// Vertical
OverScrollDecoratorHelper.setUpStaticOverScroll(view, OverScrollDecoratorHelper.ORIENTATION_VERTICAL);

高級用法

// 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));

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

自定義 View

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();
    }
});

效果與行為配置

/// 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
        );