浅谈Android RecyclerView 间距全适配

import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;
/**
 * Created by anonymous on 2016/9/9 0009.
 * <p>
 * SpacesItemDecoration
 * <p>
 * mRecyclerView.addItemDecoration(new SpacesItemDecoration(5));
 */
public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
  private int space;
  public SpacesItemDecoration(int space) {
    this.space = space;
  }

  @Override
  public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
    outRect.left = space;
    outRect.right = space;
    outRect.bottom = space;
    // Add top margin only for the first item to avoid double space between items
    if (parent.getChildLayoutPosition(view) == 0) {
      outRect.top = space;
    } else {
      outRect.top = 0;
    }
  }
}

mRecyclerView.addItemDecoration(new SpacesItemDecoration(5));

import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;
/**
 * Created by anonymous on 2016/9/9 0009.
 * <p>
 * GridSpacingItemDecoration
 * <p>
 * int spanCount = 3; // 3 columns
 * int spacing = 50; // 50px
 * boolean includeEdge = false;
 * recyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));
 */
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {
  private int spanCount;
  private int spacing;
  private boolean includeEdge;

  public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {
    this.spanCount = spanCount;
    this.spacing = spacing;
    this.includeEdge = includeEdge;
  }

  @Override
  public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
    int position = parent.getChildAdapterPosition(view); // item position
    int column = position % spanCount; // item column
    if (includeEdge) {
      outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
      outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)
      if (position < spanCount) { // top edge
        outRect.top = spacing;
      }
      outRect.bottom = spacing; // item bottom
    } else {
      outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
      outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f /  spanCount) * spacing)
      if (position >= spanCount) {
        outRect.top = spacing; // item top
      }
    }
  }
}

    int spanCount = 3; // 3 columns
    int spacing = 50; // 50px
    boolean includeEdge = false;
    mRecyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));