你對比下我的


import?android.graphics.Rect;
import?android.support.annotation.NonNull;
import?android.support.v7.widget.RecyclerView;
import?android.view.View;
import?android.widget.LinearLayout;

public?class?GridSpaceltemDecoration?extends?RecyclerView.ItemDecoration?{
????private?int?mSpace;
????public?GridSpaceltemDecoration(int?space,RecyclerView?parent)
????{
????????mSpace=space;
????????getRecyclerViewOffsets(parent);
????}

????/**
?????*
?????*?@param?outRect?Item的矩形邊界
?????*?@param?view?ItemView
?????*?@param?parent?RecyclerView
?????*?@param?state?RecyclerView的狀態
?????*/
????@Override
????public?void?getItemOffsets(@NonNull?Rect?outRect,?@NonNull?View?view,?@NonNull?RecyclerView?parent,?@NonNull?RecyclerView.State?state)?{
????????super.getItemOffsets(outRect,?view,?parent,?state);
????????outRect.left=mSpace;
????}
????private?void?getRecyclerViewOffsets(RecyclerView?parent)
????{
//????????View?margin,
//????????margin?為正,則View?會距離邊界產生一個距離
//????????margin?為負,則View?會超出邊界產生一個距離
????????LinearLayout.LayoutParams?layoutParams=(LinearLayout.LayoutParams)parent.getLayoutParams();
????????layoutParams.leftMargin=-mSpace;
????????parent.setLayoutParams(layoutParams);
????}

}