>由于之前發了篇「[BaseRecyclerAdapter之添加不同布局（頭部尾部）](http://www.jianshu.com/p/9d75c22f0964)」收到了以下反饋，在此非常感謝，寶貴建議！希望加群多多提建議，讓這個項目更加好用，幫助到更多人。
>>目前已優化：「[GitHub源碼地址](https://github.com/CymChad/BaseRecyclerViewAdapterHelper)」
#效果如何？
優化前：
```
public class MultipleItemAdapter extends BaseQuickAdapter<String> {
private final int TEXT_TYPE = 1;
private int mTextLayoutResId;
public MultipleItemAdapter(Context context, List data, int... layoutResId) {
super(context, layoutResId[0], data);
mTextLayoutResId = layoutResId[1];
}
@Override
protected int getDefItemViewType(int position) {
if (position % 2 == 0)
return TEXT_TYPE;
return super.getDefItemViewType(position);
}
@Override
protected BaseViewHolder onCreateDefViewHolder(ViewGroup parent, int viewType) {
if (viewType == TEXT_TYPE)
return new TextViewHolder(getItemView(mTextLayoutResId, parent));
return super.onCreateDefViewHolder(parent, viewType);
}
@Override
protected void onBindDefViewHolder(BaseViewHolder holder, String item) {
if (holder instanceof TextViewHolder)
holder.setText(R.id.tv, item);
}
@Override
protected void convert(BaseViewHolder helper, String item) {
helper.setImageUrl(R.id.iv, item);
}
public class TextViewHolder extends BaseViewHolder {
public TextViewHolder(View itemView) {
super(itemView.getContext(), itemView);
}
}
}
```
優化后(瘦身二分之一)：
```
public class MultipleItemQuickAdapter extends BaseMultiItemQuickAdapter<MultipleItem> {
public MultipleItemQuickAdapter(Context context, List data) {
super(context, data);
addItmeType(MultipleItem.TEXT, R.layout.text_view);
addItmeType(MultipleItem.IMG, R.layout.image_view);
}
@Override
protected void convert(BaseViewHolder helper, MultipleItem item) {
switch (helper.getItemViewType()) {
case MultipleItem.TEXT:
helper.setImageUrl(R.id.tv, item.getContent());
break;
case MultipleItem.IMG:
helper.setImageUrl(R.id.iv, item.getContent());
break;
}
}
}
```
#原理分析
由于上篇說了寫多個不同類型的布局一定會用到```getItemViewType```和```onCreateViewHolder```方法，但是在優化后的代碼中沒看到，怎么做的到呢？
優化前：```getDefItemViewType```
```
protected int getDefItemViewType(int position) {
if (position % 2 == 0) return TEXT_TYPE;
return super.getDefItemViewType(position);
}
```
優化后不用寫：```getDefItemViewType```，看看基類的處理
```
@Overrideprotected int getDefItemViewType(int position) {
return mData.get(position).getItemType();
}
```
原理分析：**在填充數據的時候就把view type給添加進去了。**
---
優化前：```onCreateDefViewHolder```
```
@Override
protected BaseViewHolder onCreateDefViewHolder(ViewGroup parent, int viewType) {
if (viewType == TEXT_TYPE)
return new TextViewHolder(getItemView(mTextLayoutResId, parent));
return super.onCreateDefViewHolder(parent, viewType);
}
```
優化后不用寫：```onCreateDefViewHolder```，看看基類的處理
```
private SparseArray<Integer> layouts;
protected BaseViewHolder onCreateDefViewHolder(ViewGroup parent, int viewType) {
int layoutId = getLayoutId(viewType);
View view = LayoutInflater.from(parent.getContext()).inflate(layoutId, parent, false);
return new BaseViewHolder(mContext, view);
}
private int getLayoutId(int viewType) { return layouts.get(viewType);}
protected void addItmeType(int type, int layoutResId) {
if (layouts == null) {
layouts = new SparseArray<>();
}
layouts.put(type, layoutResId);
}
```
原理分析：**```addItmeType```以type為鍵以layoutResId為值存儲到的SparseArray里面，在```onCreateDefViewHolder```根據viewType來獲取相應的layoutResId。**
>每次收獲一點點，后續還會擴展更多功能，供大家使用及學習「[BaseRecyclerViewAdapterHelper](http://blog.csdn.net/cym492224103/article/details/51171802)」。
