Question

我有一个应用程序，其中有ListView三列。 ListView Adapter填充了来自Firebase的数据（产品名称，价格，数量）。 firebase的数据来自另一个activity

但在我的ListView我希望第三列（即数量）添加NumberPicker来选择每种产品的数量。我还想要，例如，如果在firebase中有可用的quantity : 3并且用户选择4，则会显示一条错误消息，显示类似quantity not available的内容。

对象类代码：

public class Produse {

public String produsId;
public String produs;
public String pret;
public String cantitate;

public Produse(){

}

public Produse(String produsId, String produs, String pret, String cantitate) {
    this.produsId = produsId;
    this.produs = produs;
    this.pret = pret;
    this.cantitate = cantitate;
}

public String getProdusId() {
    return produsId;
}

public String getProdus() {
    return produs;
}

public String getPret() {
    return pret;
}

public String getCantitate() {
    return cantitate;
}
}

ListView适配器代码

public class ProduseList extends ArrayAdapter<Produse> {

private Activity context;
private List<Produse> produseList;


public ProduseList(Activity context, List<Produse> produseList) {
    super(context, R.layout.list_layout, produseList);
    this.context = context;
    this.produseList = produseList;
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    LayoutInflater inflater = context.getLayoutInflater();

    View listViewItem = inflater.inflate(R.layout.list_layout, null, true);

    TextView textViewProdus = (TextView) listViewItem.findViewById(R.id.textViewProdus);
    TextView textViewPret = (TextView) listViewItem.findViewById(R.id.textViewPret);
    TextView textViewCantitate = (TextView) listViewItem.findViewById(R.id.textViewCantitate);

    Produse produse = produseList.get(position);

    textViewProdus.setText(produse.getProdus());
    textViewPret.setText(produse.getPret());
    textViewCantitate.setText(produse.getCantitate());


    return listViewItem;
}
}

列的布局：

  <TextView
    android:id="@+id/textViewProdus"
    android:layout_width="115dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="2.5dp"
    android:gravity="center_horizontal"
    android:descendantFocusability="blocksDescendants"
    android:text="Produs"
    android:textAppearance="@style/Base.TextAppearance.AppCompat.Body1"
    android:textSize="14.5dp"
    android:padding="7dp"
    android:layout_weight="1" />

<TextView
    android:id="@+id/textViewPret"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="40dp"
    android:layout_marginTop="2.5dp"
    android:gravity="center_horizontal"
    android:descendantFocusability="blocksDescendants"
    android:text="Suma"
    android:textAppearance="@style/Base.TextAppearance.AppCompat.Headline"
    android:textSize="14dp"
    android:layout_weight="1"/>



<TextView
    android:id="@+id/textViewCantitate"
    android:layout_width="80dp"
    android:layout_height="wrap_content"
    android:layout_marginLeft="50dp"
    android:layout_marginTop="2.5dp"
    android:gravity="center_horizontal"
    android:descendantFocusability="blocksDescendants"
    android:text="0"
    android:textAppearance="@style/Base.TextAppearance.AppCompat.Headline"
    android:textSize="14dp"
    android:padding="7dp"
    android:layout_weight="1"/>

在我的代码中产品名称= produs，price = pret和quantity = cantitate 。

希望你明白的人我真的相信你。

Answer 1

尝试以下代码，您应该编辑类似＆＃34;密钥数量产品＆＃34;你存放在firebase上。

    public class ProduseList extends ArrayAdapter<Produse> {

    private Activity context;
    private List<Produse> produseList;


    public ProduseList(Activity context, List<Produse> produseList) {
        super(context, R.layout.list_layout, produseList);
        this.context = context;
        this.produseList = produseList;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();

        View listViewItem = inflater.inflate(R.layout.list_layout, null, true);

        TextView textViewProdus = (TextView) listViewItem.findViewById(R.id.textViewProdus);
        TextView textViewPret = (TextView) listViewItem.findViewById(R.id.textViewPret);
        final NumberPicker numCantitate = (NumberPicker) listViewItem.findViewById(R.id.textViewCantitate);

        Produse produse = produseList.get(position);

        textViewProdus.setText(produse.getProdus());
        textViewPret.setText(produse.getPret());
        numCantitate.setMaxValue(100);
        numCantitate.setMinValue(0);
        numCantitate.setWrapSelectorWheel(true);
        //Set a value change listener for NumberPicker
        numCantitate.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
            @Override
            public void onValueChange(NumberPicker picker, final int oldVal, final int newVal){
                //get your valid quantity from firebase server 
                // Get a reference to our posts
                final FirebaseDatabase database = FirebaseDatabase.getInstance();
                DatabaseReference ref = database.getReference("server/saving-data/quantity/product");

                // Attach a listener to read the data at our posts reference
                ref.addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        int validQuantity = dataSnapshot.getValue(Integer.class);
                        if(newVal <= validQuantity){
                            //Display the newly selected number from picker
                            numCantitate.setValue(newVal); 
                        }else {
                            numCantitate.setValue(oldVal);
                            Toast.makeText(getContext(), "Wrong quantity.....", Toast.LENGTH_SHORT).show();
                        }
                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {
                        System.out.println("The read failed: " + databaseError.getCode());
                    }
                });
            }
        });
        return listViewItem;
    }
}

更改产品数量

1 个答案: