Question

这是我第一次与 Gson 面对面。我的问题将是一个很长的问题，希望你能理解，我还有更多的问题让我被困了大约一个星期。

所以，我有ListView，我从另一个Activtity获取了所选项目。在此ListView下，我有Button，卖家将商品保存到FireBase，由客户购买。

现在的问题是，每当卖家将购买的商品保存到FireBase时，我想枚举（如增量）每个客户并提供客户编号。并在页面顶部显示TextView中的客户数量，其中数字1位于图片中。但是第二天的枚举必须从1开始。所以每天必须从1开始。在这个ListView中，我计算所选项目并计算价格总和。

但第二个问题是我不知道如何将客户编号，计数项和项目总和发送到另一个{{1}卡片视图。我想把它放在Gson里面。我尝试了一些东西，但我完全迷失了。而且我的代码在这一刻看起来非常混乱。希望你能理解。

以下是我获取所选项目并使用Toast显示计算的项目和项目总和的代码：

ListView

客户编号，计算项目和项目总和的对象类：

int totalPrice = 0;
            for(VanzatorProduse v : Util.getInstance().getVanzatorProduse())
            {
                int vPrice = Integer.parseInt(v.getPret());
                totalPrice = totalPrice + vPrice;
            }

            Toast.makeText(getApplicationContext(), "Selected products : " + listaProdusePreview.getAdapter().getCount() +"\n"+"Total sum : " + totalPrice , Toast.LENGTH_LONG).show();

            Intent sumaProduse = new Intent(FormCumparareActivity.this, VanzatorActivity.class);
            sumaProduse.putExtra("sumaProduse", totalPrice);
            startActivity(sumaProduse);

            String produseSelectate = String.valueOf(listaProdusePreview.getAdapter().getCount());
            Intent intent = new Intent(FormCumparareActivity.this, VanzatorActivity.class);
            intent.putExtra("produseSelectate", produseSelectate);
            startActivity(intent);

            Util.getInstance().getVanzatorProduse().removeAll(Util.getInstance().getVanzatorProduse());

以下是listview适配器的代码：

public class Card {
private Integer numarCumparator;
private String listaProduse;
private Integer sumaProduse;

public Card(Integer numarCumparator, String listaProduse, Integer sumaProduse) {
    this.numarCumparator = numarCumparator;
    this.listaProduse = listaProduse;
    this.sumaProduse = sumaProduse;
}

public Integer getNumarCumparator() {
    return numarCumparator;
}

public void setNumarCumparator(Integer numarCumparator) {
    this.numarCumparator = numarCumparator;
}

public String getListaProduse() {
    return listaProduse;
}

public void setListaProduse(String listaProduse) {
    this.listaProduse = listaProduse;
}

public Integer getSumaProduse() {
    return sumaProduse;
}

public void setSumaProduse(Integer sumaProduse) {
    this.sumaProduse = sumaProduse;
}

卡片视图的布局：

public class CardArrayAdapter  extends ArrayAdapter<Card> {
private static final String TAG = "CardArrayAdapter";
private List<Card> cardList = new ArrayList<Card>();

static class CardViewHolder {
    TextView line1;
    TextView line2;
    TextView line3;
}

public CardArrayAdapter(Context context, int textViewResourceId) {
    super(context, textViewResourceId);
}

@Override
public void add(Card object) {
    cardList.add(object);
    super.add(object);
}

@Override
public int getCount() {
    return this.cardList.size();
}

@Override
public Card getItem(int index) {
    return this.cardList.get(index);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    CardViewHolder viewHolder;
    if (row == null) {
        LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        row = inflater.inflate(R.layout.list_item_card, parent, false);
        viewHolder = new CardViewHolder();
        viewHolder.line1 = (TextView) row.findViewById(R.id.txtViewNumarCumparator);
        viewHolder.line2 = (TextView) row.findViewById(R.id.listaProduse);
        viewHolder.line3 = (TextView) row.findViewById(R.id.sumaProduse);
        row.setTag(viewHolder);
    } else {
        viewHolder = (CardViewHolder)row.getTag();
    }
    Card card = getItem(position);

        viewHolder.line1.setText(card.getNumarCumparator());
        viewHolder.line2.setText(card.getListaProduse());
        viewHolder.line3.setText(card.getSumaProduse());

    return row;
}

这是我对Gson的尝试，我将它放在JSONManager类中：

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:descendantFocusability="afterDescendants"
    android:orientation="vertical"
    android:paddingBottom="15dp"
    android:paddingLeft="15dp"
    android:paddingRight="15dp"
    android:paddingTop="15dp">

    <TextView
        android:id="@+id/txtViewNumarCumparator"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="NumarCumparator" />

    <TextView
        android:id="@+id/listaProduse"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/txtViewNumarCumparator"
        android:layout_marginTop="10dp"
        android:text="NumarProduse" />

    <TextView
        android:id="@+id/sumaProduse"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="15dp"
        android:text="SumaProdsue" />

我试图从Gson获取数据的活动代码。

    public class JSONManager {

private static JSONManager instance = null;



protected JSONManager() {
    // Exists only to defeat instantiation.
}

public static JSONManager getInstance() {
    if (instance == null) {
        instance = new JSONManager();
    }
    return instance;
}


//Create list of Cards because we need to show list for date selected
public List<Card> readJSON(String dateFromCalendar) throws JSONException {

    String JSON = SharedPreference.getString(Util.get(), SharedPreference.APP_DATA, SharedPreference.JSON_DATA, "");
    String numeVanzator = SharedPreference.getString(Util.get(), SharedPreference.USER_DATA, SharedPreference.NUME_VANZATOR,"");

    JSONObject jsonObj = new JSONObject(JSON);

    JSONArray contacts = jsonObj.getJSONArray("jsonData");
    List<Card> listCard = null;
    Card card = null;

    listCard = new ArrayList<>();


    for (int i =0; i< contacts.length();i++) {

        JSONObject c = contacts.getJSONObject(i);
        String data = c.getString("data");

        if (data.equals(dateFromCalendar)){
            String numeVanzato = c.getString("numeVanzator");
            if (numeVanzato.equals(numeVanzator)){

                Integer numarClient = c.getInt("numarClient");

                JSONObject detaliiCos = c.getJSONObject("detaliiCos");
                Integer sumaProduse = detaliiCos.getInt("sumaProduse");
                String produseselectate = c.getString("produseSelectate");

                card = new Card(numarClient, produseselectate, sumaProduse);
                listCard.add(card);
            }
        }
    }
    return listCard;
}  }

目前，一切工作都很完美，但点击保存@Override protected void onResume() { super.onResume(); c = Calendar.getInstance(); String numeVanzator = SharedPreference.getString(this, SharedPreference.USER_DATA, SharedPreference.NUME_VANZATOR, ""); if (!numeVanzator.equals("")) { textViewNumeVanzator.setText(numeVanzator); } String jsonData = SharedPreference.getString(getApplicationContext(), SharedPreference.APP_DATA, SharedPreference.JSON_DATA, ""); System.out.println("JSON data" + jsonData); textViewDataCurenta.setText(getDate(c.getTimeInMillis())); cardArrayAdapter = new CardArrayAdapter(this, R.layout.list_item_card); Card card = null; List<Card> listCard = new ArrayList<Card>(); c = Calendar.getInstance(); try { String date = getDate(c.getTimeInMillis()); listCard = JSONManager.getInstance().readJSON(date); } catch (JSONException e) { e.printStackTrace(); } for (int i = 0; i <= listCard.size()-1; i++) { card = listCard.get(i); cardArrayAdapter.add(card); } listViewVanzatorActivity.setAdapter(cardArrayAdapter); }下次活动中没有任何内容，也没有错误。

希望，你了解我的问题，我真的需要你的帮助。谢谢!!

Answer 1

在您的代码中，您为调用活动创建了两次Intent，这不是一个好方法。只需删除此

中的第二个意图

 Intent sumaProduse = new Intent(FormCumparareActivity.this, VanzatorActivity.class);
 sumaProduse.putExtra("sumaProduse", totalPrice);
 startActivity(sumaProduse);


 Intent intent = new Intent(FormCumparareActivity.this, VanzatorActivity.class);
 intent.putExtra("produseSelectate", produseSelectate);
 startActivity(intent);

现在创建新的bundle并使用这样的键添加pass：

 Intent intent = new Intent(FormCumparareActivity.this, VanzatorActivity.class);
 Bundle bundle = new Bundle();
 bundle.put("key",totalPrice);
 bundle.put("key",produseSelectate);
 intent .putExtras(bundle)
 startActivity(intent);

您从JSON获取的列表未存储在共享首选项中。希望你明白我的观点。

将数据放入Gson并将其显示在列表视图中

1 个答案:

将数据放入Gson并将其显​​示在列表视图中

1 个答案:

将数据放入Gson并将其显示在列表视图中