直接上代码。
1 首先需要一个显示的界面MainActivity;xml文件如下,其中ShoppingCartBottomView是简单自定义的一个底部控件，下面会讲到
<com.oman.shoppingcart.customview.ShoppingCartBottomView android:id="@+id/shoppingcart_bottom" android:layout_width="match_parent" android:layout_height="60dp" android:layout_alignParentBottom="true"/>
然后MainActivity.ava的代码如下，不要着急有些类没有讲到，后面会详细讲解，淡定。。。
public class MainActivity extends BaseActivity {
protected ShoppingCartBottomView mBottomView;
protected ListView mListView; protected ShoppingCartListAdapter mAdapter; protected ArrayList mData = new ArrayList<>();
@Override protected int getLayoutId() { return R.layout.activity_main; }
@Override protected void initView() { CartCommodityModel model = new CartCommodityModel(); model.setId(1); model.setName("测试商品1"); model.setPrice("100"); model.setOriginalPrice("120"); model.setVipPrice("80"); model.setBuyNum("2"); mData.add(model);
CartCommodityModel model2 = new CartCommodityModel();
model2.setId(1);
model2.setName("测试商品2");
model2.setPrice("200");
model2.setOriginalPrice("220");
model2.setVipPrice("160");
model2.setBuyNum("3");
mData.add(model2);
CartCommodityModel model3 = new CartCommodityModel();
model3.setId(1);
model3.setName("测试商品3");
model3.setPrice("300");
model3.setOriginalPrice("340");
model3.setVipPrice("280");
model3.setBuyNum("4");
mData.add(model3);
mBottomView = (ShoppingCartBottomView) findViewById(R.id.shoppingcart_bottom);
mAdapter = new ShoppingCartListAdapter(this, mData, mBottomView);
mBottomView.setData(mData);
mBottomView.setBinderAdapter(mAdapter);
mListView= (ListView) findViewById(R.id.listview);
mListView.setAdapter(mAdapter);
mBottomView.setOnConfirmListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(MainActivity.this,PaymentActivity.class));
}
});
}
}
2 这里面用到了几个类 ShoppingCartBottomView（底部的一些操作按钮） ShoppingCartListAdapter（填充商品的适配器） CartCommodityModel（商品的model）
ShoppingCartViewHolder（这个就不用说了吧。。。你懂的）
在hoppingCartViewHolder中我写了一个接口，用来监听商品的数量变化的接口，当点击加减号的时候就会回调；
addView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (listener != null) { listener.onAmountAddClick(getAdapterPosition()); } } }); minusView.setOnClickListener(new View.OnClickListener() { @Override public vo 67C0 id onClick(View view) { if (listener != null) { listener.onAmountMinusClick(getAdapterPosition()); } } });
}
public interface OnViewClickListener {
void onAmountAddClick(int position);
void onAmountMinusClick(int position);
}
3 当然了，在ShoppingCartListAdapter中需要实现这个接口，那么就要实现他的方法，点击加号或者减号的时候要将商品的数量相应的加减1（当商品的数量是大于等于1的时候 才能减），当点击小计前面的CheckBox按钮时候需要监听中实现该model是否选中该商品，然后更新一下适配器（不过这里我自己重写了一下notifyDataSetChanged()方法，见 下面代码）；我还封装了两个抽象类，一个是适配器继承的类TemplateListAdapter，还有一个是Activity继承的类BaseActivity，在项目中挺实用的；
public class ShoppingCartListAdapter extends TemplateListAdapter<CartCommodityModel, ShoppingCartViewHolder> implements ShoppingCartViewHolder.OnViewClickListener {
private DecimalFormat mDecimalFormat = new DecimalFormat("##0.00");
private ShoppingCartBottomView mBottomView;
public ShoppingCartListAdapter(Context context, List data, ShoppingCartBottomView mBottomView) { super(context, data); this.mBottomView = mBottomView; }
@Override public void notifyDataSetChanged() { super.notifyDataSetChanged(); mBottomView.notifyDataSetChanged(); }
@Override public int getLayoutId() { return R.layout.item_shopping_cart; }
@Override public ShoppingCartViewHolder getViewHolder(View convertView) { return new ShoppingCartViewHolder(convertView, this); }
@Override public void bindData(int position, ShoppingCartViewHolder holder) { final CartCommodityModel model = getItem(position); holder.sumPriceView.setText(getSumPrice(model)); holder.checkBox.setChecked(model.isSelected()); holder.amountView.setText(model.getBuyNum()); Picasso.with(mContext).load(R.mipmap.ic_launcher).into(holder.imageView); holder.nameView.setText(model.getName()); holder.priceView.setText(model.getPrice()); holder.originPriceView.setText(model.getOriginalPrice()); holder.vipPriceView.setText(model.getVipPrice()); holder.rootView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Toast.makeText(mContext, "点击了" + model.getName(), Toast.LENGTH_SHORT).show(); } }); holder.checkBox.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { model.setSelected(!model.isSelected()); mBottomView.notifyDataSetChanged(); } }); }
private String getSumPrice(CartCommodityModel model) { if (Integer.valueOf(model.getBuyNum()) != 0) { return "小计:" + (Integer.valueOf(model.getBuyNum())) * (Integer.valueOf(model.getPrice())); } else { return "小计：¥0.00"; }
}
@Override public void onAmountAddClick(int position) { CartCommodityModel model = getItem(position); model.setBuyNum(String.valueOf(Integer.valueOf(model.getBuyNum()) + 1)); notifyDataSetChanged(); }
@Override public void onAmountMinusClick(int position) { CartCommodityModel model = getItem(position); if (Integer.valueOf(model.getBuyNum()) > 1) { model.setBuyNum(String.valueOf(Integer.valueOf(model.getBuyNum()) - 1)); notifyDataSetChanged(); } }
}
4 我认为这里面最主要的就属于ShoppingCartBottomView这个类了，下面详细讲解一下
当点击全选按钮时候，需要将每一个model的选中状态和全选按钮一致，然后更新一下各个控件的显示（需要写几个方法用来在notifyDataSetChanged()中调用即可）
当点击去结算按钮时候就会跳转到付款页面
有没有被我的详细讲解惊艳到，哈哈，是不是很简单
public class ShoppingCartBottomView extends LinearLayout {
protected AppCompatCheckBox mCheckBox; protected TextView mSelectedNumberView; protected TextView mSumPriceView; protected TextView mDiscountPriceView;
protected List mData; protected ShoppingCartListAdapter mBinderAdapter;
protected OnClickListener mListener;
private DecimalFormat mDecimalFormat = new DecimalFormat("##0.00");
public ShoppingCartBottomView(Context context) { super(context); initView(); }
public ShoppingCartBottomView(Context context, AttributeSet attrs) { super(context, attrs); initView(); }
public ShoppingCartBottomView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initView(); }
public void setData(List data) { mData = data; }
public void setBinderAdapter(ShoppingCartListAdapter adapter) { mBinderAdapter = adapter; }
protected void initView() { View view = View.inflate(getContext(), R.layout.view_shoppingcart_bottom, null); mCheckBox = (AppCompatCheckBox) view.findViewById(R.id.shoppingcart_bottom_checkbox); mSelectedNumberView = (TextView) view.findViewById(R.id.shoppingcart_bottom_selected_number); mSumPriceView = (TextView) view.findViewById(R.id.shoppingcart_bottom_sum_price); mDiscountPriceView = (TextView) view.findViewById(R.id.shoppingcart_bottom_discount_price); mCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) { for (CartCommodityModel model : mData) { model.setSelected(isChecked); } if (mBinderAdapter != null) { mBinderAdapter.notifyDataSetChanged(); } } }); view.findViewById(R.id.shoppingcart_bottom_confirm).setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if (mListener != null) { mListener.onClick(v); } } }); RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); view.setLayoutParams(layoutParams); addView(view); }
@Override protected void onAttachedToWindow() { super.onAttachedToWindow(); }
@Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); }
private void updateNumberView(int number) { mSelectedNumberView.setText("(" + number + ")"); }
private void updateSumPriceView(float sumPrice) { mSumPriceView.setText("合计: " + mDecimalFormat.format(sumPrice) + "元"); }
private void updateDiscountView(float discount) { mDiscountPriceView.setText("已优惠: " + mDecimalFormat.format(discount) + "元"); }
public void setOnConfirmListener(OnClickListener listener) { mListener = listener; }
public void notifyDataSetChanged() { if (mData != null) { float sumPrice = 0; float originalPrice = 0; int sumCount = 0; for (CartCommodityModel model : mData) { if (model.isSelected()) { sumPrice += Float.valueOf(model.getPrice()) * Integer.valueOf(model.getBuyNum()); originalPrice += Float.valueOf(model.getOriginalPrice()) * Integer.valueOf(model.getBuyNum()); sumCount += Integer.valueOf(model.getBuyNum()); } } updateNumberView(sumCount); updateSumPriceView(sumPrice); updateDiscountView(originalPrice - sumPrice); } }
}
这样的话这个完整的小购物车项目基本上就结束了