矽谷商城5--購物車商品選中和商品總價計算

1_商品總價格計算

①在GovaffairPager類中設置

adapter = new GovaffairPagerAdapter(context,datas,checkbox_all,tv_total_price);

②GovaffairPagerAdapter　　

/**
 * 顯示總商品價格
 */
private void showTotalPrice(){
    tv_total_price.setText("合計￥"+getTotalPrice());
}

/**
 * 計算購物車裡面所選商品總架構
 * @return
 */
private double getTotalPrice(){
    double num = 0;
    if(datas != null && datas.size() >0){
        for(int i=0;i<datas.size();i++){
            ShoppingCart cart = datas.get(i);
            //判斷是否選中的商品
            if(cart.isChecked()){
                num = num + cart.getPrice()*cart.getCount();
            }
        }
    }
    return num;
}

//在構造方法中調用
 public GovaffairPagerAdapter(final Context context, final List<ShopingCart> datas) {
        this.context = context;
        this.datas = datas;
        cartProvider = new CartProvider(context);
        showTotalPrice();
}

2_增加商品或者減少商品的時候計算總價格

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    final ShoppingCart cart = datas.get(position);
    ......

    holder.numberAddSubView.setOnButtonClickListenter(new NumberAddSubView.OnButtonClickListenter() {

        @Override
        public void onButtonAddClick(View view, int value) {
            cart.setCount(value);
            cartProvider.update(cart);
            showTotalPrice();
        }
        @Override
        public void onButtonSubClick(View view, int value) {
            cart.setCount(value);
            cartProvider.update(cart);
            showTotalPrice();
        }
    });

}

3_設置點擊某一條item

1_先定義介面和調用

//設置點擊某個item的監聽
public interface OnItemClickListener{
    void onItemClick(View view,int position);
}

private OnItemClickListener onItemClickListener;
/**
 * 設置某條的監聽
 * @param onItemClickListener
 */
public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
    this.onItemClickListener = onItemClickListener;
}

2_調用介面

class ViewHolder extends RecyclerView.ViewHolder {
    private CheckBox checkbox;
     .................
    public ViewHolder(View itemView) {
        super(itemView);
        checkbox = (CheckBox) itemView.findViewById(R.id.checkbox);
        iv_icon = (ImageView) itemView.findViewById(R.id.iv_icon);
        ......
        itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(onItemClickListener != null){
                    onItemClickListener.onItemClick(v,getLayoutPosition());
                }
            }
        });
    }
}

3_在構造方法中設置監聽

 public GovaffairPagerAdapter(final Context context, final List<ShopingCart> datas) {
        this.context = context;
        this.datas = datas;
        cartProvider = new CartProvider(context);
        showTotalPrice();
        setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {

                //1.設置點擊item的狀態
                ShoppingCart ShoppingCart = datas.get(position);
                shopingCart.setIsChecked(!shopingCart.isChecked());
                notifyItemChanged(position);
                //2.設置全選和非全選
                checkListener();
                //3.顯示總價格
                showTotalPrice();
                // Toast.makeText(context,"選中了"+position,Toast.LENGTH_SHORT).show();
            }
        });
    }

 /**
 * 全選的監聽
 */
private void checkListener() {
    int num = 0;
    if(datas != null && datas.size()>0){
        for(int i=0;i<datas.size();i++){
            ShoppingCart cart = datas.get(i);
            //只要有一個沒有被選中就把全選設置為未勾選
            if(!cart.isChecked()){
                checkbox_all.setChecked(false);
            }else{
                num += 1;
            }
        }
        if(datas.size()==num){
            checkbox_all.setChecked(true);
        }
    }
}

4_全選和反選

   //把CheckBox  和 TextView 傳入到適配器中
    private final CheckBox checkbox_all;
    private final TextView tv_total_price;
    private CartProvider cartProvider;

    public GovaffairPagerAdapter(final Context context, final List<ShopingCart> datas, final CheckBox checkbox_all, TextView tv_total_price) {
        this.context = context;
        this.datas = datas;
        this.checkbox_all = checkbox_all;
        this.tv_total_price = tv_total_price;
         ..........................
        checkbox_all.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //全選和反選
                checkAll_none(checkbox_all.isChecked());

                showTotalPrice();
            }
        });
    }

 /**
 * 全選和反選
 * @param ischeck
 */
private void checkAll_none(boolean ischeck){
    if(datas != null && datas.size() >0){
        for(int i=0;i<datas.size();i++){
            ShoppingCart cart = datas.get(i);
            cart.setIsChecked(ischeck);
            notifyItemChanged(i);
        }
    }
}

//在GovaffairPager類中設置

adapter = new GovaffairPagerAdapter(context,datas,checkbox_all,tv_total_price);