回收器项目视图未正确显示数据

Question

当我按下后退按钮时，这个ShoppingActivity会被破坏，当我再次访问该activity时，我发现我的回收器视图项目被替换了两次。我该如何解决这个问题？

ShoppingActivity.java这里编写的所有代码和volley类也在这里调用，当我按下后退键并再次访问该活动时，我发现我的回收器视图项被替换了
@override protected void onCreate（Bundle savedInstanceState）{super.onCreate（savedInstanceState）；setContentView(r.layout.activity_shopping)；

    recyclerView = (RecyclerView) findViewById(R.id.rv_recycler_view);
    layoutManager = new LinearLayoutManager(this);

    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(layoutManager);

    btn_sort_name = (Button) findViewById(R.id.btn_name);
    btn_sort_price = (Button) findViewById(R.id.btn_price);

    tv_total_products = (TextView) findViewById(R.id.totalproduct);
    tv_apihits = (TextView) findViewById(R.id.apihits);

    tv_total_products.setText(null);

    if(savedInstanceState==null){
    final JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET,
            BaseUrl,
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    int index = 0;
                    arrayList.clear();
                    while (index < response.length()) {
                        try {
                            JSONObject jsonObject = response.getJSONObject(index);
                            arrayList.add(new Items(jsonObject.getString("name"),
                                    jsonObject.getString("description"),
                                    jsonObject.getString("category"),
                                    jsonObject.getDouble("price"),
                                    jsonObject.getInt("quantity"),
                                    jsonObject.getString("shipping"),
                                    jsonObject.getString("location"),
                                    jsonObject.getString("color"),
                                    jsonObject.getString("link")));
                            da = jsonObject.getString("name");
                            Log.d(TAG, da);
                            index++;
                            total_products = index;
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }

                    recyclerViewAdapter = new RecyclerViewAdapter(arrayList, ShoppingActivity.this);
                    recyclerView.setAdapter(recyclerViewAdapter);
                    tv_total_products.append(String.valueOf(total_products));

                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Log.d(TAG, "Error");
                }
            });

    RequestQueue requestQueue = Volley.newRequestQueue(this);
    requestQueue.add(jsonArrayRequest);
}

    recyclerView.addOnItemTouchListener(new RecyclerViewAdapter.ViewItemClick(getApplicationContext(), recyclerView,
            new RecyclerViewAdapter.ItemClickListener() {
                @Override
                public void clickedItem(View view, int position) {

                    name = arrayList.get(position).getName();
                    description = arrayList.get(position).getDescription();
                    category = arrayList.get(position).getCategory();
                    shipping = arrayList.get(position).getShipping();
                    location = arrayList.get(position).getLocation();
                    color = arrayList.get(position).getColor();
                    link = arrayList.get(position).getLink();
                    price = arrayList.get(position).getPrice();
                    quantity = arrayList.get(position).getQuantity();
                    DataParcel dataParcel = new DataParcel(name, description, category, shipping, location, color, link, price, quantity);

                    Intent intent = new Intent(ShoppingActivity.this, DetailsViewActivity.class);
                    intent.putExtra("data", dataParcel);
                    startActivity(intent);

                }
            }));

}

@Override
public void onBackPressed() {

    super.onBackPressed();
    finish();
}

这是我的DetailsViewActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_details_view);

    btn_back= (Button) findViewById(R.id.btn_back);
    btn_link= (Button) findViewById(R.id.btn_link);
    btn_share= (Button) findViewById(R.id.btn_share);
    btn_sms= (Button) findViewById(R.id.btn_sms);
    tv_description= (TextView) findViewById(R.id.tv_description);

    tv_app_name= (TextView) findViewById(R.id.tv_app_name);

    category= (Button) findViewById(R.id.category);
    price= (Button) findViewById(R.id.price);
    location= (Button) findViewById(R.id.location);
    quantity= (Button) findViewById(R.id.quantity);
    shipping= (Button) findViewById(R.id.shipping);

    iv_star1= (ImageView) findViewById(R.id.star1);
    iv_star2= (ImageView) findViewById(R.id.star2);
    iv_star3= (ImageView) findViewById(R.id.star3);
    iv_star4= (ImageView) findViewById(R.id.star4);
    iv_item_image= (ImageView) findViewById(R.id.item_image);

    Bundle bundle= getIntent().getExtras();
    dataParcel= bundle.getParcelable("data");
    category.setText(dataParcel.getCategory());
    price.setText(String .valueOf(dataParcel.getPrice()));
    quantity.setText("Avilable"+String.valueOf(    dataParcel.getQuantity() ));
    location.setText(dataParcel.getLocation());
    shipping.setText("Shipping: "+dataParcel.getShipping());
    tv_app_name.setText(dataParcel.getName());
    tv_description.setText(dataParcel.getDescription());


}

@Override
protected void onStart() {
    super.onStart();

    btn_back.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            finish();
        }
    });
}

@Override
public void onBackPressed() {
    super.onBackPressed();
    finish();
}

Answer 1

问题在于活动的生命周期，您可以在从另一个活动返回时检查第一个活动的实例是否还在。对于快速修复，您可以在使用数据填充arraylist之前清除它，这将在从另一个活动返回时清除先前添加的数据，您可以这样做

arrayList.clear();

之前

 while(index<response.length())

在响应块上。但这只是一个快速的解决方案，而不是实际的解决方案，所以更好的方法是检查类的实例。