Drop down refresh conflicts with recyclerview sliding (swiperefreshlayout conflicts with recyclerview sliding)

SwipeRefreshLayout nesting  RecyclerView When sliding down and up , Sometimes they conflict with each other .
First of all, the online solution is ：

to  RecyclerView Add slide monitor （addOnScrollListener）, stay onScrolled Get the first one in item Of top, When sliding up and down top Only negative , When the first one item When fully displayed top by 0.

When top by 0 when . It means that it slides to the end , And then SwipeRefreshLayout Of Enabled Set to true......

RecyclerView Of id yes  home_recyclerView,SwipeRefreshLayout  Of id yes  home_refresh

home_recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
    override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
        LogUtils.e("onScrollStateChanged = ")
   }

    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        LogUtils.e("onScrolled = ")

        if (recyclerView != null && recyclerView.getChildCount() > 0) {
            val firstChild = recyclerView.getChildAt(0)
            val firstChildPosition = if(firstChild == null) 0 else firstChild.top
            LogUtils.e("onScrolled = "+ firstChild.top)
            // If firstChild At the first position in the list , And top>=0, Then the drop-down refresh control is available 
            home_refresh.setEnabled(firstChildPosition >= 0)
        }

    }
})

The disadvantage is ：

But this is the case RecyclerView It works only when the height of is relatively fixed , If RecyclerView Height is wrap_content The above method does not work .....recyclerView.getChildAt(0).top by 0 Whether it is the first item, Will trigger the pull-down refresh .....

My solution is ：
Let's look at the layout first ：

In the project SwipeRefreshLayout nesting ScrollView,ScrollView Inside RecyclerView,RecyclerView Height is wrap_content.

Above is the head of the layout ( green ), Next is the scrolling message view（ Light green ）,banner, And blank padding, At the bottom is RecyclerView.

The effect to be achieved is , Except for the head of the layout , The rest should be able to slide , When the news view Show them all and then make SwipeRefreshLayout start-up .

The solution is ：
When RecyclerView After drawing, calculate the first item To the head of the layout （ Dark green ） Distance of y, When RecyclerView so One of the first item by 0 when , And visible first item The distance from the head is greater than or equal to the previous y when , Set again if yes SwipeRefreshLayout You can use ~

（ Coordinates are used to calculate the distance ）

Specific code ：

var rvFirstItemDistanceHomeHead: Int = 0 // Record view When finished, the first item  distance home_head  Distance from the bottom 

home_recyclerView.viewTreeObserver.addOnGlobalLayoutListener {
    LogUtils.e("addOnGlobalLayoutListener = ")
    //RecyclerView Finish drawing . Measure the first visible item  distance home_head  Distance from the bottom 
    if(rvFirstItemDistanceHomeHead == 0){
        val distanceFirstItem = getDistanceFirstItem(refuseMarket)
        val firstChildY = distanceFirstItem.get(0)
        val headLocationY = distanceFirstItem.get(1)

        if ((firstChildY - headLocationY) > 0) rvFirstItemDistanceHomeHead =
            (firstChildY - headLocationY)
        LogUtils.e("rvFirstItemDistanceHomeHead = " + rvFirstItemDistanceHomeHead)
    }

}


home_recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
    override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
        //LogUtils.e("onScrollStateChanged = " + if (newState == 0) " No scrolling " else if (newState == 1) " Dragged by the outside " else " Auto scroll ")
        LogUtils.e("onScrollStateChanged = ")
        // Judge the first visible item Is it the first item
        val layoutManager = recyclerView.layoutManager as LinearLayoutManager
        val firstCompletelyVisibleItemPosition =
            layoutManager!!.findFirstCompletelyVisibleItemPosition()
        LogUtils.e("onScrollStateChanged = " + firstCompletelyVisibleItemPosition)

        // Judge the first visible in real time item  distance home_head  Distance from the bottom 
        val distanceFirstItem = getDistanceFirstItem(recyclerView)
        val firstChildY = distanceFirstItem.get(0)
        val headLocationY = distanceFirstItem.get(1)
        LogUtils.e("onScrolled = " + (firstChildY - headLocationY))

        // When RecyclerView  so   One of the first item  by  0( by RecyclerView  The first data of ) when , And visible first item  The distance from the head is greater than or equal to the previous y when , Set to available 
        home_refresh.setEnabled((firstCompletelyVisibleItemPosition == 0) && (firstChildY - headLocationY >= rvFirstItemDistanceHomeHead))
    }

    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        LogUtils.e("onScrolled = ")
    }
})

Among them getDistanceFirstItem Method is ：
 

private fun getDistanceFirstItem(recyclerView: RecyclerView): ArrayList {
    val distanceList = ArrayList()// Used to store recycleView The first is visible item  At the top of the Y coordinate 、  Head view Under   Of Y coordinate 
    if (recyclerView != null && recyclerView.getChildCount() > 0) {
        val layoutManager = recyclerView.layoutManager as LinearLayoutManager
        val firstCompletelyVisibleItemPosition =
            layoutManager!!.findFirstCompletelyVisibleItemPosition()
        val firstChild =
            layoutManager.findViewByPosition(firstCompletelyVisibleItemPosition)

        var firstChildY = 0//recycleView The first is visible item  At the top of the Y coordinate 
        var headLocationY = 0// Head view Under   Of Y coordinate 
        if (firstChild != null) {
            // Get coordinates 
            val firstChildLocation = IntArray(2)
            firstChild.getLocationInWindow(firstChildLocation)
            //                firstChildLocation[0]//x coordinate 
            firstChildY = firstChildLocation[1] // y  coordinate 
        }

        // Get coordinates 
        val headLocation = IntArray(2)
        home_head.getLocationInWindow(headLocation)
        //                firstChildLocation[0]//x coordinate 
        headLocationY = headLocation[1] // y  coordinate 

        distanceList.add(firstChildY)
        distanceList.add(headLocationY)
    }
    return distanceList
}

The main code is done . This is in recycleView It is also effective when the height is fixed .

in addition ：

control SwipeRefreshLayout Whether it is available is in onScrollStateChanged（） Method , because recycleView Height is wrap_content Of , And nested ScrollView, It won't walk when sliding onScrolled（） Of .

Even if recycleView Fixed height , Only when the data display slides more than one screen onScrolled（）, It can be displayed on one screen, and the sliding will not be adjusted onScrolled（）, It should be like this ....

If there is something wrong, please give me some advice ~