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Android仿外卖购物车的实现

2016-10-08 12:38 281 查看
又两周没写博客了,不是不想写而是不知道该写点什么，总不能为了写博客而写博客，前两天项目里要加个购物车功能，看了下别人APP的效果觉得不错，虽然我项目里没用上不过毕竟还算是个常用的功能，于是决定写个博客分享下！

效果图



知识点分析

效果图来看不复杂内容并没多少，值得介绍一下的知识点也就下面几个吧

- 列表标题悬停

- 左右列表滑动时联动

- 添加商品时的抛物线动画

- 底部弹出购物车清单

- 数据的同步

另外就是实现效果的时候可能会遇到的几个坑。。。

布局很简单直接进入代码

列表标题悬停

现在做项目列表什么的基本抛弃了ListView改用RecyclerView，上篇博客中的标题悬停也是使用了一个RecyclerView的开源项目
sticky-headers-recyclerview
,不过写这个demo的时候遇到了两个坑

sticky-headers-recyclerview做悬停标题的时候scrollToPosition(int position)方法滚动的位置不准确。
当布局复杂点的时候 如果RecyclerView的宽度自适应或者使用权重百分比之类可能会导致header显示空白。
并且该开源项目作者已经停止维护，所以这次又换回了
StickyListHeadersListView
。

需要购物车Demo的很多都是新手，这里简单介绍下StickyListHeadersListView的使用

AS引用 gradle文件dependencies内添加
<code class="hljs bash has-numbering">    compile <span class="hljs-string">'se.emilsjolander:stickylistheaders:2.7.0'</span></code><ul class="pre-numbering" style=""><li>1</li></ul><ul class="pre-numbering" style=""><li>1</li></ul>

xml文件中使用StickyListHeadersListView代替ListView
<code class="hljs avrasm has-numbering">    <se<span class="hljs-preprocessor">.emilsjolander</span><span class="hljs-preprocessor">.stickylistheaders</span><span class="hljs-preprocessor">.StickyListHeadersListView</span>
android:layout_width=<span class="hljs-string">"match_parent"</span>
android:background=<span class="hljs-string">"#fff"</span>
android:id=<span class="hljs-string">"@+id/itemListView"</span>
android:layout_height=<span class="hljs-string">"match_parent"</span>>
</se<span class="hljs-preprocessor">.emilsjolander</span><span class="hljs-preprocessor">.stickylistheaders</span><span class="hljs-preprocessor">.StickyListHeadersListView</span>></code>

Adapter继承BaseAdapter和接口StickyListHeadersAdapter
StickyListHeadersAdapter接口包括两个方法

<code class="hljs cs has-numbering">    View getHeaderView(<span class="hljs-keyword">int</span> position, View convertView, ViewGroup parent);

<span class="hljs-keyword">long</span> getHeaderId(<span class="hljs-keyword">int</span> position);
</code>

代码中使用和ListView一样，下面是几个特有的方法,看方法名也很容易理解用途

<code class="hljs java has-numbering"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">setAreHeadersSticky</span>(<span class="hljs-keyword">boolean</span> areHeadersSticky);
<span class="hljs-keyword">public</span> <span class="hljs-keyword">boolean</span> <span class="hljs-title">areHeadersSticky</span>();

<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">setOnHeaderClickListener</span>(OnHeaderClickListener listener);

<span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">interface</span> <span class="hljs-title">OnHeaderClickListener</span> {</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onHeaderClick</span>(StickyListHeadersListView l, View header, <span class="hljs-keyword">int</span> itemPosition, <span class="hljs-keyword">long</span> headerId, <span class="hljs-keyword">boolean</span> currentlySticky);
}

<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">setOnStickyHeaderChangedListener</span>(OnStickyHeaderChangedListener listener);

<span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">interface</span> <span class="hljs-title">OnStickyHeaderChangedListener</span> {</span>
<span class="hljs-keyword">void</span> onStickyHeaderChanged(StickyListHeadersListView l, View header, <span class="hljs-keyword">int</span> itemPosition, <span class="hljs-keyword">long</span> headerId);
}

<span class="hljs-keyword">public</span> View <span class="hljs-title">getListChildAt</span>(<span class="hljs-keyword">int</span> index);
<span class="hljs-keyword">public</span> <span class="hljs-keyword">int</span> <span class="hljs-title">getListChildCount</span>();</code>

左右列表联动

联动主要有两个效果

- 左侧列表点击选择分类，右侧列表滑动到对应分类

- 右侧列表滑动过程中左侧列表高亮的分类跟随变化

第一个效果简单，左侧列表item添加点击事件，事件中调用右侧列表的setSelection(int positon) 方法。

第二个效果要给右侧列表添加ScrollListener，根据列表中显示的第一条数据设置左侧选中的分类

<code class="hljs java has-numbering">    listView.setOnScrollListener(<span class="hljs-keyword">new</span> AbsListView.OnScrollListener() {
<span class="hljs-annotation">@Override</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onScrollStateChanged</span>(AbsListView view, <span class="hljs-keyword">int</span> scrollState) {

}

<span class="hljs-annotation">@Override</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onScroll</span>(AbsListView view, <span class="hljs-keyword">int</span> firstVisibleItem, <span class="hljs-keyword">int</span> visibleItemCount, <span class="hljs-keyword">int</span> totalItemCount) {
<span class="hljs-comment">//根据firstVisibleItem获取分类ID，根据分类id获取左侧要选中的位置</span>
GoodsItem item = dataList.get(firstVisibleItem);
<span class="hljs-keyword">if</span>(typeAdapter.selectTypeId != item.typeId) {
typeAdapter.selectTypeId = item.typeId;
typeAdapter.notifyDataSetChanged();
<span class="hljs-comment">//左侧列表是个RecyclerView 所以使用smoothScrollToPosition(int position) 使当对应position的item可以滚动显示出来</span>
rvType.smoothScrollToPosition(<span class="hljs-keyword">int</span> position)(getSelectedGroupPosition(item.typeId));
}
}
});</code>

添加商品的动画

添加商品一共有三个动画

- 当商品从0到1 旋转左移显示出减号按钮

- 当商品从1到0 减号按钮旋转右移消失

- 添加商品时抛物线动画添加到购物车图标

前两个动画很简单可以分解成三个补间动画 旋转、平移、透明度。

可以用xml完成，也可以代码设置，不过有个小坑要注意一下 旋转动画一定要在平移动画前面，否则就不是滚动平移了,而是乱跳。。。

这里贴一下动画的代码设置方法

<code class="hljs avrasm has-numbering">    //显示减号的动画
private Animation getShowAnimation(){
AnimationSet <span class="hljs-keyword">set</span> = new AnimationSet(true)<span class="hljs-comment">;</span>
RotateAnimation rotate = new RotateAnimation(<span class="hljs-number">0</span>,<span class="hljs-number">720</span>,RotateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0.5</span>f,RotateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0.5</span>f)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.addAnimation</span>(rotate)<span class="hljs-comment">;</span>
TranslateAnimation translate = new TranslateAnimation(
TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">2</span>f
,TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0</span>
,TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0</span>
,TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0</span>)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.addAnimation</span>(translate)<span class="hljs-comment">;</span>
AlphaAnimation alpha = new AlphaAnimation(<span class="hljs-number">0</span>,<span class="hljs-number">1</span>)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.addAnimation</span>(alpha)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.setDuration</span>(<span class="hljs-number">500</span>)<span class="hljs-comment">;</span>
return <span class="hljs-keyword">set</span><span class="hljs-comment">;</span>
}
//隐藏减号的动画
private Animation getHiddenAnimation(){
AnimationSet <span class="hljs-keyword">set</span> = new AnimationSet(true)<span class="hljs-comment">;</span>
RotateAnimation rotate = new RotateAnimation(<span class="hljs-number">0</span>,<span class="hljs-number">720</span>,RotateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0.5</span>f,RotateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0.5</span>f)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.addAnimation</span>(rotate)<span class="hljs-comment">;</span>
TranslateAnimation translate = new TranslateAnimation(
TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0</span>
,TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">2</span>f
,TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0</span>
,TranslateAnimation<span class="hljs-preprocessor">.RELATIVE</span>_TO_SELF,<span class="hljs-number">0</span>)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.addAnimation</span>(translate)<span class="hljs-comment">;</span>
AlphaAnimation alpha = new AlphaAnimation(<span class="hljs-number">1</span>,<span class="hljs-number">0</span>)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.addAnimation</span>(alpha)<span class="hljs-comment">;</span>
<span class="hljs-keyword">set</span><span class="hljs-preprocessor">.setDuration</span>(<span class="hljs-number">500</span>)<span class="hljs-comment">;</span>
return <span class="hljs-keyword">set</span><span class="hljs-comment">;</span>
}

//执行动画 只需给对应控件setAnimation然后调用setVisibility方法即可
{
....
tvMinus<span class="hljs-preprocessor">.setAnimation</span>(getHiddenAnimation())<span class="hljs-comment">;</span>
tvMinus<span class="hljs-preprocessor">.setVisibility</span>(View<span class="hljs-preprocessor">.GONE</span>)<span class="hljs-comment">;</span>
}</code>

抛物线动画和上面的差不多可以分解成两个平移动画,不过两个平移动画的差值器一个线性一个加速而已，因为动画界面跨度比较大所以需要在根部局内写，不能写在列表的item中(这样会显示不全)。

代码中的anim_mask_layout 即为整个布局文件的根布局，这里是一个RelativeLayout

实现过程

1、首先点击加号图标，拿到控件在屏幕上的绝对坐标，回调activity显示动画

<code class="hljs cs has-numbering">    <span class="hljs-keyword">int</span>[] loc = <span class="hljs-keyword">new</span> <span class="hljs-keyword">int</span>[<span class="hljs-number">2</span>];
v.getLocationInWindow(loc);
activity.playAnimation(loc);</code>

2、创建动画的控件并添加到根部局并在动画结束后移除动画view

<code class="hljs cs has-numbering">    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">playAnimation</span>(<span class="hljs-keyword">int</span>[] start_location){
ImageView img = <span class="hljs-keyword">new</span> ImageView(<span class="hljs-keyword">this</span>);
img.setImageResource(R.drawable.button_add);
setAnim(img,start_location);
}
<span class="hljs-comment">//创建动画 平移动画直接传递偏移量 </span>
<span class="hljs-keyword">private</span> Animation <span class="hljs-title">createAnim</span>(<span class="hljs-keyword">int</span> startX,<span class="hljs-keyword">int</span> startY){
<span class="hljs-keyword">int</span>[] des = <span class="hljs-keyword">new</span> <span class="hljs-keyword">int</span>[<span class="hljs-number">2</span>];
imgCart.getLocationInWindow(des);

AnimationSet <span class="hljs-keyword">set</span> = <span class="hljs-keyword">new</span> AnimationSet(<span class="hljs-keyword">false</span>);

Animation translationX = <span class="hljs-keyword">new</span> TranslateAnimation(<span class="hljs-number">0</span>, des[<span class="hljs-number">0</span>]-startX, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>);
<span class="hljs-comment">//线性插值器 默认就是线性</span>
translationX.setInterpolator(<span class="hljs-keyword">new</span> LinearInterpolator());
Animation translationY = <span class="hljs-keyword">new</span> TranslateAnimation(<span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>, des[<span class="hljs-number">1</span>]-startY);
<span class="hljs-comment">//设置加速插值器</span>
translationY.setInterpolator(<span class="hljs-keyword">new</span> AccelerateInterpolator());
Animation alpha = <span class="hljs-keyword">new</span> AlphaAnimation(<span class="hljs-number">1</span>,<span class="hljs-number">0.5</span>f);
<span class="hljs-keyword">set</span>.addAnimation(translationX);
<span class="hljs-keyword">set</span>.addAnimation(translationY);
<span class="hljs-keyword">set</span>.addAnimation(alpha);
<span class="hljs-keyword">set</span>.setDuration(<span class="hljs-number">500</span>);

<span class="hljs-keyword">return</span> <span class="hljs-keyword">set</span>;
}
<span class="hljs-comment">//计算动画view在根部局中的坐标 添加到根部局中</span>
<span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">addViewToAnimLayout</span>(final ViewGroup vg, final View view,
<span class="hljs-keyword">int</span>[] location) {

<span class="hljs-keyword">int</span> x = location[<span class="hljs-number">0</span>];
<span class="hljs-keyword">int</span> y = location[<span class="hljs-number">1</span>];
<span class="hljs-keyword">int</span>[] loc = <span class="hljs-keyword">new</span> <span class="hljs-keyword">int</span>[<span class="hljs-number">2</span>];
vg.getLocationInWindow(loc);
view.setX(x);
view.setY(y-loc[<span class="hljs-number">1</span>]);
vg.addView(view);
}
<span class="hljs-comment">//设置动画结束移除动画view </span>
<span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">setAnim</span>(final View v, <span class="hljs-keyword">int</span>[] start_location) {

addViewToAnimLayout(anim_mask_layout, v, start_location);
Animation <span class="hljs-keyword">set</span> = createAnim(start_location[<span class="hljs-number">0</span>],start_location[<span class="hljs-number">1</span>]);
<span class="hljs-keyword">set</span>.setAnimationListener(<span class="hljs-keyword">new</span> Animation.AnimationListener() {
@Override
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onAnimationStart</span>(Animation animation) {

}

@Override
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onAnimationEnd</span>(final Animation animation) {
<span class="hljs-comment">//直接remove可能会因为界面仍在绘制中成而报错</span>
mHanlder.postDelayed(<span class="hljs-keyword">new</span> Runnable() {
@Override
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">run</span>() {
anim_mask_layout.removeView(v);
}
},<span class="hljs-number">100</span>);
}

@Override
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onAnimationRepeat</span>(Animation animation) {

}
});
v.startAnimation(<span class="hljs-keyword">set</span>);
}</code>

底部弹出购物车清单

底部弹出的效果大家一定都很熟悉了，几回每个项目中都会用的到，官方没有提供简单的控件实现，一般都需要自己写，不过要做到简单流畅，便于移植推荐使用第三方库，这里向大家推荐一个

bottomsheet

集成简单，效果多样这里简单介绍一下使用方法

集成
<code class="hljs bash has-numbering">    compile <span class="hljs-string">'com.flipboard:bottomsheet-core:1.5.1'</span></code><ul class="pre-numbering" style=""><li>1</li></ul><ul class="pre-numbering" style=""><li>1</li></ul>

使用
xml中使用BottomSheetLayout包裹弹出view时候的背景布局，BottomSheetLayout继承自帧布局

<code class="hljs avrasm has-numbering"><<span class="hljs-keyword">com</span><span class="hljs-preprocessor">.flipboard</span><span class="hljs-preprocessor">.bottomsheet</span><span class="hljs-preprocessor">.BottomSheetLayout</span>
xmlns:android=<span class="hljs-string">"http://schemas.android.com/apk/res/android"</span>
android:id=<span class="hljs-string">"@+id/bottomSheetLayout"</span>
android:layout_width=<span class="hljs-string">"match_parent"</span>
android:layout_height=<span class="hljs-string">"match_parent"</span>>
<LinearLayout
android:orientation=<span class="hljs-string">"horizontal"</span>
android:layout_width=<span class="hljs-string">"match_parent"</span>
android:layout_height=<span class="hljs-string">"match_parent"</span>>

<android<span class="hljs-preprocessor">.support</span><span class="hljs-preprocessor">.v</span>7<span class="hljs-preprocessor">.widget</span><span class="hljs-preprocessor">.RecyclerView</span>
android:layout_width=<span class="hljs-string">"100dp"</span>
android:id=<span class="hljs-string">"@+id/typeRecyclerView"</span>
android:layout_height=<span class="hljs-string">"match_parent"</span>>
</android<span class="hljs-preprocessor">.support</span><span class="hljs-preprocessor">.v</span>7<span class="hljs-preprocessor">.widget</span><span class="hljs-preprocessor">.RecyclerView</span>>

<se<span class="hljs-preprocessor">.emilsjolander</span><span class="hljs-preprocessor">.stickylistheaders</span><span class="hljs-preprocessor">.StickyListHeadersListView</span>
android:layout_width=<span class="hljs-string">"match_parent"</span>
android:background=<span class="hljs-string">"#fff"</span>
android:id=<span class="hljs-string">"@+id/itemListView"</span>
android:layout_height=<span class="hljs-string">"match_parent"</span>>
</se<span class="hljs-preprocessor">.emilsjolander</span><span class="hljs-preprocessor">.stickylistheaders</span><span class="hljs-preprocessor">.StickyListHeadersListView</span>>
</LinearLayout>
</<span class="hljs-keyword">com</span><span class="hljs-preprocessor">.flipboard</span><span class="hljs-preprocessor">.bottomsheet</span><span class="hljs-preprocessor">.BottomSheetLayout</span>></code>

代码中使用很简单

<code class="hljs cs has-numbering">    <span class="hljs-comment">//弹出View  bottomSheet即是要弹出的view</span>
bottomSheetLayout.showWithSheetView(bottomSheet);

<span class="hljs-comment">//代码隐藏view (点击弹出view以外的地方可以隐藏弹出的view，向下滑动也可以）</span>
bottomSheetLayout.dismissSheet();
</code>

数据的同步

同步数据，控制界面刷新应该是新手最容易绕弯的地方了，其实只要仔细一点也不难，这里简单提供一种思路(并不一定适合你的项目).

<code class="hljs cs has-numbering">    <span class="hljs-comment">//商品列表</span>
<span class="hljs-keyword">private</span> ArrayList<GoodsItem> dataList;
<span class="hljs-comment">//分类列表</span>
<span class="hljs-keyword">private</span> ArrayList<GoodsItem> typeList;
<span class="hljs-comment">//已选择的商品</span>
<span class="hljs-keyword">private</span> SparseArray<GoodsItem> selectedList;
<span class="hljs-comment">//用于记录每个分组选择的数目</span>
<span class="hljs-keyword">private</span> SparseIntArray groupSelect;</code>

SparseArray这个类其实就是 HashMap< Integer,Object >

不过SparseArray既可以根据key查找Value，也可以根据位置查找value，性能比HashMap高，是官方推荐的替代类，

同样SparseIntArray 其实是HashMap< Integer,Integer> 的替代者。

Activity里实现了下面几个方法,用于数据统一管理

列表中显示的商品购买数量统一从activity获取,商品的加减统一调用Activity的方法然后notifiDatasetChanged，由于代码不少具体的还是看源码吧

<code class="hljs java has-numbering"> <span class="hljs-javadoc">/**
* Item代表商品的购买数量加一
*<span class="hljs-javadoctag"> @param</span> item
*<span class="hljs-javadoctag"> @param</span> refreshGoodList 是否刷新商品list
*/</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">add</span>(GoodsItem item,<span class="hljs-keyword">boolean</span> refreshGoodList){

<span class="hljs-keyword">int</span> groupCount = groupSelect.get(item.typeId);
<span class="hljs-keyword">if</span>(groupCount==<span class="hljs-number">0</span>){
groupSelect.append(item.typeId,<span class="hljs-number">1</span>);
}<span class="hljs-keyword">else</span>{
groupSelect.append(item.typeId,++groupCount);
}

GoodsItem temp = selectedList.get(item.id);
<span class="hljs-keyword">if</span>(temp==<span class="hljs-keyword">null</span>){
item.count=<span class="hljs-number">1</span>;
selectedList.append(item.id,item);
}<span class="hljs-keyword">else</span>{
temp.count++;
}
update(refreshGoodList);
}
<span class="hljs-javadoc">/**
* Item商品的购买数量减一
*<span class="hljs-javadoctag"> @param</span> item
*<span class="hljs-javadoctag"> @param</span> refreshGoodList 是否刷新商品list
*/</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">remove</span>(GoodsItem item,<span class="hljs-keyword">boolean</span> refreshGoodList){

<span class="hljs-keyword">int</span> groupCount = groupSelect.get(item.typeId);
<span class="hljs-keyword">if</span>(groupCount==<span class="hljs-number">1</span>){
groupSelect.delete(item.typeId);
}<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(groupCount><span class="hljs-number">1</span>){
groupSelect.append(item.typeId,--groupCount);
}

GoodsItem temp = selectedList.get(item.id);
<span class="hljs-keyword">if</span>(temp!=<span class="hljs-keyword">null</span>){
<span class="hljs-keyword">if</span>(temp.count<<span class="hljs-number">2</span>){
selectedList.remove(item.id);
}<span class="hljs-keyword">else</span>{
item.count--;
}
}
update(refreshGoodList);
}

<span class="hljs-javadoc">/**
* 刷新界面 总价、购买数量等
*<span class="hljs-javadoctag"> @param</span> refreshGoodList 是否刷新商品list
*/</span>
<span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">update</span>(<span class="hljs-keyword">boolean</span> refreshGoodList){
...
}

<span class="hljs-comment">//根据商品id获取当前商品的采购数量</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">int</span> <span class="hljs-title">getSelectedItemCountById</span>(<span class="hljs-keyword">int</span> id){
GoodsItem temp = selectedList.get(id);
<span class="hljs-keyword">if</span>(temp==<span class="hljs-keyword">null</span>){
<span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
}
<span class="hljs-keyword">return</span> temp.count;
}
<span class="hljs-comment">//根据类别Id获取属于当前类别的数量</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">int</span> <span class="hljs-title">getSelectedGroupCountByTypeId</span>(<span class="hljs-keyword">int</span> typeId){
<span class="hljs-keyword">return</span> groupSelect.get(typeId);
}</code>

具体逻辑还是看代码吧，也许有更简单的实现。。。

Demo下载地址，下载到的文件是个AS module，你可以在自己新建的工程中Import Module.
http://download.csdn.net/detail/w804518214/9539602
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标签：  android 饿了么 购物车 底部弹出动画 抛物线动画
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