RecyclerView选中Item滚动到屏幕中间 / 指定位置

重写 LinearLayoutManager 原文链接

package com.pingan.aftercarmarket.view;

import android.content.Context;

import android.support.v7.widget.LinearLayoutManager;

import android.support.v7.widget.LinearSmoothScroller;

import android.support.v7.widget.RecyclerView;

import android.util.AttributeSet;

import android.util.DisplayMetrics;

/**

* @Author: ex-xuxiaopeng002

* @CreateDate: 2019-09-20 16:31

* @Description: java类作用描述

*/

public class CenterLayoutManager extends LinearLayoutManager {

public CenterLayoutManager(Context context) {

super(context);

    }

public CenterLayoutManager(Context context, int orientation, boolean reverseLayout) {

super(context, orientation, reverseLayout);

    }

public CenterLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {

super(context, attrs, defStyleAttr, defStyleRes);

    }

@Override

    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {

RecyclerView.SmoothScrollersmoothScroller =new CenterSmoothScroller(recyclerView.getContext());

        smoothScroller.setTargetPosition(position);

        startSmoothScroll(smoothScroller);

    }

private static class CenterSmoothScrollerextends LinearSmoothScroller {

public CenterSmoothScroller(Context context) {

super(context);

        }

@Override

        public int calculateDtToFit(int viewStart, int viewEnd, int boxStart, int boxEnd, int snapPreference) {

return (boxStart + (boxEnd - boxStart) /2) - (viewStart + (viewEnd - viewStart) /2);

        }

@Override

        protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {

return 100f / displayMetrics.densityDpi;

        }

}

}