Question

我正在制作一个可以维持所有销售额的应用程序。我在firebase中有一个库存数据库，其中包含所有重要信息，例如名称，价格，说明等。我已经用所有产品的名称填充了微调器。现在，我想单击微调器中的特定商品名称，以获取相应产品的价格。搜索了很多东西，没发现有用的东西

到目前为止，我的代码是

        @Override
        public void onDataChange(final DataSnapshot dataSnapshot) {

            final List<String> items = new ArrayList<String>();


            for (final DataSnapshot itemSnapshot: dataSnapshot.getChildren()) {
                final String itemName = itemSnapshot.child("name").getValue(String.class);

                items.add(itemName);
            }
                java.util.Collections.sort(items);
                ArrayAdapter<String> itemAdapter = new ArrayAdapter<String>(Sale.this, android.R.layout.simple_spinner_item, items);
                itemAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                itemSpinner.setAdapter(itemAdapter);

                itemSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {


                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> adapterView) {

                    }
                });

                }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    });

Answer 1

将pojo创建为-

public class Inventory
{
    private String name;
    private int qty;
    private String price;
    private String desc;

    public Inventory()
    {

    }

    public Inventory(String name, int qty, String price, String desc) {
        this.name = name;
        this.qty = qty;
        this.price = price;
        this.desc = desc;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getQty() {
        return qty;
    }

    public void setQty(int qty) {
        this.qty = qty;
    }

    public String getPrice() {
        return price;
    }

    public void setPrice(String price) {
        this.price = price;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    @Override
    public String toString() {
        return "Inventory [name=" + name + ", qty=" + qty + ", price=" + price
                + ", desc=" + desc + "]";
    }
}

然后做-

final ArrayList<Inventory> items = new ArrayList<Inventory>();
ArrayList<String> listname = new ArrayList<String>();

@Override
public void onDataChange(final DataSnapshot dataSnapshot) {

for (final DataSnapshot itemSnapshot: dataSnapshot.getChildren()) {
    Inventory inv= itemSnapshot.getValue(String.class);
    listname.add(inv.getName());

    items.add(inv);
}

ArrayAdapter<String> itemAdapter = new ArrayAdapter<String>(Sale.this, android.R.layout.simple_spinner_item, listname);
            itemAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
itemSpinner.setAdapter(itemAdapter);

itemSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
        String price = items.get(i).getPrice();

     }

     @Override
     public void onNothingSelected(AdapterView<?> adapterView) {

     }
 });

Answer 2

在onItemSelected()内部添加此元素以获得每个元素

String selected = items.getItemAtPosition(i).toString();

您还可以创建日志以查看您单击的元素

Log.e("Clicked:",""+selected);

如果要在微调器中显示用户ID，则应在onItemSelected()中获取该用户ID，然后使用所选的用户ID对数据库进行另一个查询，并查询该产品的价格

例如，在获得所选项目后，可以说是您的用户ID

 mDatabase.child("inventory").child(selected)..addValueEventListener(new ValueEventListener() {
                                        @Override
                                        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

//Get your price from that element

...

所有完成的操作都应这样

    itemSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                        @Override
                        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                          String selected = items.getItemAtPosition(i).toString();
                          Log.e("Clicked:",""+selected);

                         mDatabase.child("inventory").child(selected).addValueEventListener(new ValueEventListener() {
       @Override
       public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

        //Get your price from that element

        ...
     }

           @Override
          public void onNothingSelected(AdapterView<?> adapterView){

                        }
                    });

.....

在Android中单击微调器项目时从Firebase检索相应的数据

2 个答案: