# AutoScrollRecyclerView

**Repository Path**: zhangguangchao/AutoScrollRecyclerView

## Basic Information

- **Project Name**: AutoScrollRecyclerView
- **Description**: RecyclerView实现垂直自动无限滚动，类似于中奖信息，跑马灯
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2020-12-02
- **Last Updated**: 2022-08-25

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

## RecyclerView实现垂直自动无限滚动，类似于中奖信息，跑马灯

[java版源码](https://github.com/yebook/AutoScrollRecyclerView/blob/master/AutoScrollQua(JAVA%E7%89%88).zip)


> 实现RecyclerView中的效果有两种：
>
> 一种为以item为单体，每隔多少秒进行滚动一次
>
> 一种为整体流形式进行缓慢滚动



![效果图](https://github.com/yebook/AutoScrollRecyclerView/blob/master/autoscrollrecyclerview.gif)


#### 实现无限滚动

> 这里实现无限滚动的方式为在adpater中设置itemCount为 Integer.MAX_VALUE
>
> 注意：此处基于BaseQuickAdapter的库进行的，也可直接使用原生

```kotlin
class MainAdatper(data: List<String>) : BaseQuickAdapter<String, BaseViewHolder>(R.layout.item_txt, data) {

    override fun convert(helper: BaseViewHolder?, item: String?) {
        helper?.setText(R.id.mTv, item)
    }


    override fun getItem(position: Int): String? {
        val newPosition = position % data.size
        return getData().get(newPosition)
    }

    override fun getItemViewType(position: Int): Int {
        var count = getHeaderLayoutCount() + getData().size
        //刚开始进入包含该类的activity时,count为0。就会出现0%0的情况，这会抛出异常，所以我们要在下面做一下判断
        if (count <= 0) {
            count = 1
        }
        var newPosition = position % count;
        return super.getItemViewType(newPosition);
    }

    override fun getItemCount(): Int {
        return Integer.MAX_VALUE
    }

}
```







#### item为单位，每隔n秒滚动一个item

> 这边主要是使用recyclerView中的**smoothScrollToPosition()** 方法实现，然后再配合自定义layoutManager 控制速度达到目的效果



```kotlin
var layoutManager = object : LinearLayoutManager(this) {
    override fun smoothScrollToPosition(recyclerView: RecyclerView?, state: RecyclerView.State?, position: Int) {
        var linearSmoothScroller = object : LinearSmoothScroller(recyclerView?.context) {

            //返回滑动一个pixel需要多少毫秒
            override fun calculateSpeedPerPixel(displayMetrics: DisplayMetrics?): Float {
                //这边可以自定义进行控制速度
                return 3f / (displayMetrics?.density ?: 1f)
            }
        }
        linearSmoothScroller.setTargetPosition(position)
        startSmoothScroll(linearSmoothScroller)
    }
}

mRv.layoutManager = layoutManager
mRv.addItemDecoration(DividerItemDecoration(this, DividerItemDecoration.VERTICAL))
mRv.adapter = MainAdatper(data)



==============================================================
fun startAuto() {
    if (mAutoTask != null && (mAutoTask?.isDisposed ?: true))
        mAutoTask?.dispose()
	
    //此处的4为当前显示的最后一个item
    mAutoTask = Observable.interval(1, 2, TimeUnit.SECONDS).subscribe {
        mRv.smoothScrollToPosition((4 + it).toInt())
    }
}

fun stopAuto() {
    if (mAutoTask != null && (mAutoTask?.isDisposed ?: true)) {
        mAutoTask?.dispose()
        mAutoTask = null
    }
}


override fun onStart() {
    super.onStart()
    //开始滚动
    startAuto()
}

override fun onStop() {
    super.onStop()
    //停止滚动
    stopAuto()
}

```



#### 流式滚动

> 流式滚动是使用recyclerView中的 **smoothScrollBy(x, y)** 方法来实现的
>
> 此处是通过自定义recyclerView来进行实现，也可直接在activity中进行实现。



```kotlin
class AutoScrollRecyclerView(mContext: Context, attrs: AttributeSet?) : RecyclerView(mContext, attrs) {

    private var mAutoTask: Disposable? = null

    //禁止手动滑动
    override fun dispatchTouchEvent(ev: MotionEvent?): Boolean {
        return true
    }

    fun start() {
        if (mAutoTask != null && !mAutoTask!!.isDisposed) {
            mAutoTask!!.dispose()
        }
        mAutoTask = Observable.interval(1000, 100, TimeUnit.MILLISECONDS).observeOn(AndroidSchedulers.mainThread()).subscribe { smoothScrollBy(0, 20) }
    }

    fun stop() {
        if (mAutoTask != null && !mAutoTask!!.isDisposed) {
            mAutoTask!!.dispose()
            mAutoTask = null
        }
    }

}

==================================================
//在activity中调用开始滚动与停止滚动
override fun onStart() {
    super.onStart()
    mRvTwo.start()
}

override fun onStop() {
    super.onStop()
    mRvTwo.stop()
}
    
```