Question

在我的页面上，用户可以选择多个项目。我使用复选框并遍历用户的所有项目。现在，我想向用户显示他在该页面上选择的所有项目的总价。可以这么说，购物车的总价。

如何在用户单击它们的同一页面上访问我的商品的ID？我知道在控制器中我可以通过

访问它们

Item.find(params[:items])

非常感谢：）

Answer 1

您需要通过Javascript完成此操作。

一种方法是将ID存储在html元素的this标签中（在这种情况下为Activity）

然后您可以在Javascript回调中以以下方式获取该值

public class Core_Activity extends AppCompatActivity implements
View.OnClickListener, Detailed_Group_Fragment.TransitionScheduler {
private static final String TAG = "Core_Activity";
private ViewPager viewPager;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    postponeEnterTransition();
    ...
}
...

public void scheduleStartTransition(final View sharedView){
    sharedView.getViewTreeObserver().addOnPreDrawListener(
            new ViewTreeObserver.OnPreDrawListener() {
                @Override
                public boolean onPreDraw() {
                    Log.i(TAG,"The sharedView called onPreDraw.");
                    sharedView.getViewTreeObserver()
                        .removeOnPreDrawListener(this);
                    startPostponedEnterTransition();
                    return true;
                }
            }
    );
}

或者如果您使用的是jQuery

Fragment

现在，您将需要使用Javascript访问商品的值（具有选定ID的商品的单独价格）。您可以通过将id到price的映射存储在js变量中来实现

public class Detailed_Group_Fragment extends Fragment {
private static final String TAG = "Detailed_Group_Fragment";
private static final String TRANSITION_NAME = "transition_name";
private static final String GROUP_BASE = "group_base";

TransitionScheduler transitionScheduler;
public interface TransitionScheduler{
    void scheduleStartTransition(View sharedView);
}

public static Detailed_Group_Fragment newInstance(GroupBase groupBase, String transitionName){
    Detailed_Group_Fragment detailed_group_fragment = new Detailed_Group_Fragment();
    Bundle bundle = new Bundle();
    bundle.putParcelable(GROUP_BASE, groupBase);
    bundle.putString(TRANSITION_NAME,transitionName);
    detailed_group_fragment.setArguments(bundle);
    return detailed_group_fragment;
}
...
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    final GroupBase groupBase = getArguments().getParcelable(GROUP_BASE);
    String transitionName = getArguments().getString(TRANSITION_NAME);

    final TextView name = view.findViewById(R.id.detail_group_name_txt);

    name.setText(transitionName);
    name.setTransitionName("hungry");
    transitionScheduler.scheduleStartTransition(name);

    TextView desc = view.findViewById(R.id.group_desc_txt);
    desc.setText(groupBase.getDescription());

    final ImageView image = view.findViewById(R.id.group_image);
    if(groupBase.getImageURI()!=null && groupBase.getBytes()==null){
        Log.i(TAG,"Fetching the photo for this group.");
        mGroupViewModel.getImage(groupBase.getImageURI())
                .addOnSuccessListener(new OnSuccessListener<byte[]>() {
                    @Override
                    public void onSuccess(byte[] bytes) {
                        groupBase.setBytes(bytes);
                        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes,0,bytes.length);
                        image.setImageBitmap(bitmap);

                    }
                });
    }
    if(groupBase.getBytes()!=null){
        Bitmap bitmap = BitmapFactory.decodeByteArray(groupBase.getBytes(),0,groupBase.getBytes().length);
        image.setImageBitmap(bitmap);
    }
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    try{
        //We need to get an instance of the Class that will execute our interface method.
        transitionScheduler = (TransitionScheduler) getActivity();
    } catch (ClassCastException e) {
        Log.e(TAG,"Class cast exception." + e.getMessage());
    }
}

或者，您也可以将价格存储在每个复选框的数据属性中，并使用该值更新所选总价。

复选框显示在页面上选择了哪些项目

1 个答案: