RecyclerView控制元件大家肯定不陌生，已經應用有一段時間了，最近在專案中寫一個GridLayout樣式的RecyclerView時需要設定，item之間左右的間距，下面是我總結的一個設定間距的方法分享給大家。

下面是沒間距的情況

想要設定item之間的間距需要自己建立一個繼承自RecyclerView.ItemDecoration的類

public class RecyclerViewSpacesItemDecoration extends RecyclerView.ItemDecoration {

   private HashMap<String, Integer> mSpaceValueMap;

   public
 
 static final String TOP_DECORATION = "top_decoration";
   public static final String BOTTOM_DECORATION = "bottom_decoration";
   public static final String LEFT_DECORATION = "left_decoration";
   public static final String RIGHT_DECORATION = "right_decoration";
​
   public RecyclerViewSpacesItemDecoration(HashMap
 
<String, Integer> mSpaceValueMap) {
       this.mSpaceValueMap = mSpaceValueMap;
   }
​
   @Override
   public void getItemOffsets(Rect outRect, View view,
                               RecyclerView parent, RecyclerView.State state) {
       if (mSpaceValueMap.get(TOP_DECORATION) != null)
           outRect.top = mSpaceValueMap.get
 
(TOP_DECORATION);
       if (mSpaceValueMap.get(LEFT_DECORATION) != null)

           outRect.left = mSpaceValueMap.get(LEFT_DECORATION);
       if (mSpaceValueMap.get(RIGHT_DECORATION) != null)
           outRect.right = mSpaceValueMap.get(RIGHT_DECORATION);
       if (mSpaceValueMap.get(BOTTOM_DECORATION) != null)

           outRect.bottom = mSpaceValueMap.get(BOTTOM_DECORATION);

   }

}

下面是 設定RecyclerView間距的關鍵方法

HashMap<String, Integer> stringIntegerHashMap = new HashMap<>();
stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.TOP_DECORATION,50);//top間距

stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.BOTTOM_DECORATION,100);//底部間距

stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.LEFT_DECORATION,50);//左間距

stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.RIGHT_DECORATION,100);//右間距

mRecyclerView.addItemDecoration(newRecyclerViewSpacesItemDecoration(stringIntegerHashMap));

可以根據自己的實際情況去設定想要的間距，也可以去單獨設定
下面是設定間距後的效果圖