我在ProductListAdapter类中实现了一个接口，它是一个列表适配器。此列表中的项目有三个输入字段。为了跟踪这些值，我实现了一个扩展MyCustomEditTextListener类的类TextWatcher。该类只是创建编辑数据的数组列表。每次从包含列表视图的片段更改时，我想要引用数组列表。为此，我实施了DataChangedListener
ProductListAdapter.java
public class ProductListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private LayoutInflater inflater;
private ArrayList<Products> listData;
private ArrayList<Products> editedData;
private Context context;
private DataChangedListener dataChangedListener;
private static final int ITEM = 0;
private static final int LOADING = 1;
private static final int QUANTITY = 5;
private static final int FREE_QUANTITY = 10;
private static final int DISCOUNT = 15;
public ProductListAdapter(ArrayList<Products> listData, ArrayList<Products> editedData, Context context) {
this.listData = listData;
this.context = context;
this.editedData = editedData;
inflater = LayoutInflater.from(this.context);
}
public void updateData(ArrayList<Products> data) {
this.listData = data;
notifyDataSetChanged();
}
public void setDataChangedListener(DataChangedListener listener) {
this.dataChangedListener = listener;
}
@Override
public int getItemViewType(int position) {
return listData.get(position) == null ? LOADING : ITEM;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder = null;
switch (viewType) {
case ITEM:
viewHolder = getViewHolder(parent, inflater);
break;
case LOADING:
View v2 = inflater.inflate(R.layout.list_footer, parent, false);
viewHolder = new LoadingVH(v2);
break;
}
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
Products productObject = listData.get(position);
switch (getItemViewType(position)) {
case ITEM:
for(int i=0; i<editedData.size(); i++){
if(productObject.getProductId().equals(editedData.get(i).getProductId())){
productObject.setQuantity(editedData.get(i).getQuantity());
productObject.setFreeQuantity(editedData.get(i).getFreeQuantity());
productObject.setDiscount(editedData.get(i).getDiscount());
}
}
String productName = productObject.getProductName();
String quantityValue = productObject.getQuantity();
String freeQuantityValue = productObject.getFreeQuantity();
String discountValue = productObject.getDiscount();
String quantityInHand = productObject.getQuantityInHand();
String price = productObject.getWholeSalePrice();
ContentViewHolder movieVH = (ContentViewHolder) holder;
movieVH.productName.setText(productName);
movieVH.stock.setText(quantityInHand);
movieVH.price.setText("Rs."+price);
movieVH.quantityEditTextListener.updatePosition(movieVH.getLayoutPosition());
movieVH.quantity.setText(quantityValue);
movieVH.freeQuantityEditTextListener.updatePosition(movieVH.getLayoutPosition());
movieVH.freeQuantity.setText(freeQuantityValue);
movieVH.discountEditTextListener.updatePosition(movieVH.getLayoutPosition());
movieVH.discount.setText(discountValue);
movieVH.quantity.setOnEditorActionListener(new TextView.OnEditorActionListener() {
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
return false;
}
});
break;
case LOADING:
//Do nothing
break;
}
}
@Override
public int getItemCount() {
return listData == null ? 0 : listData.size();
}
@NonNull
private RecyclerView.ViewHolder getViewHolder(ViewGroup parent, LayoutInflater inflater) {
RecyclerView.ViewHolder viewHolder;
View view = inflater.inflate(R.layout.custom_product_list_item, parent, false);
viewHolder = new ContentViewHolder(view, new MyCustomEditTextListener()
, new MyCustomEditTextListener(), new MyCustomEditTextListener());
return viewHolder;
}
/**
* View holder for main container
*/
public class ContentViewHolder extends RecyclerView.ViewHolder{
private TextView productName;
private EditText quantity;
private EditText freeQuantity;
private EditText discount;
private TextView stock;
private TextView price;
private MyCustomEditTextListener quantityEditTextListener;
private MyCustomEditTextListener freeQuantityEditTextListener;
private MyCustomEditTextListener discountEditTextListener;
public ContentViewHolder(View itemView, MyCustomEditTextListener textListener
, MyCustomEditTextListener textListener2, MyCustomEditTextListener textListener3) {
super(itemView);
productName = (TextView) itemView.findViewById(R.id.product_name_data);
quantity = (EditText) itemView.findViewById(R.id.quantity_1_edit_text);
freeQuantity = (EditText) itemView.findViewById(R.id.quantity_2_edit_text);
discount = (EditText) itemView.findViewById(R.id.quantity_3_edit_text);
stock = (TextView) itemView.findViewById(R.id.quantity_in_hand_value);
price = (TextView) itemView.findViewById(R.id.price_value);
quantityEditTextListener = textListener;
quantityEditTextListener.setEditTextType(QUANTITY);
freeQuantityEditTextListener = textListener2;
freeQuantityEditTextListener.setEditTextType(FREE_QUANTITY);
discountEditTextListener = textListener3;
discountEditTextListener.setEditTextType(DISCOUNT);
this.quantity.addTextChangedListener(quantityEditTextListener);
this.freeQuantity.addTextChangedListener(freeQuantityEditTextListener);
this.discount.addTextChangedListener(discountEditTextListener);
}
}
/**
* View holder to display loading list item
*/
protected class LoadingVH extends RecyclerView.ViewHolder {
public LoadingVH(View itemView) {
super(itemView);
}
}
/**
* textWatcher for to keep track of changed data.
*/
private class MyCustomEditTextListener implements TextWatcher {
private int position;
private int type;
public void updatePosition(int position) {
this.position = position;
}
public void setEditTextType(int type) {
this.type = type;
}
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {
// no op
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
if (type == QUANTITY) {
listData.get(position).setQuantity(charSequence.toString());
} else if (type == FREE_QUANTITY) {
listData.get(position).setFreeQuantity(charSequence.toString());
} else if (type == DISCOUNT) {
listData.get(position).setDiscount(charSequence.toString());
}
}
@Override
public void afterTextChanged(Editable s) {
boolean matchFound = false;
if(s.toString().length()>0){
for (int i=0;i<editedData.size();i++){
if(editedData.get(i).getProductId()
.equals(listData.get(position).getProductId())){
matchFound = true;
if (type == QUANTITY) {
editedData.get(i).setQuantity(s.toString());
} else if (type == FREE_QUANTITY) {
editedData.get(i).setFreeQuantity(s.toString());
} else if (type == DISCOUNT) {
editedData.get(i).setDiscount(s.toString());
}
}
}
if(!matchFound){
editedData.add(listData.get(position));
}
if(dataChangedListener!=null){
dataChangedListener.onDataChanged(editedData);
}
}
}
}
public interface DataChangedListener{
void onDataChanged(ArrayList<Products> editedData);
}
在我的OrderEditFragment我试图实现该界面以进行必要的计算。
OrderEditFragment.java
public class OrderEditFragment extends Fragment implements ProductListAdapter.DataChangedListener {
private LinearLayoutManager layoutManager;
private RecyclerView productRecyclerView;
private static ProductListAdapter productListAdapter;
private String employeeId;
private static ArrayList<Products> editedData;
private static ArrayList<Products> productsData;
private SharedPreferences sharedpreferences;
private final static OkHttpClient client = new OkHttpClient();
public OrderEditFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View inflate = inflater.inflate(R.layout.fragment_order_edit, container, false);
initComponents(inflate);
return inflate;
}
private void initComponents(View view) {
productRecyclerView = (RecyclerView) view.findViewById(R.id.product_edit_recycler_view);
progressView = (CircularProgressView) view.findViewById(R.id.progress_view);
layoutManager = new LinearLayoutManager(getContext());
sharedpreferences = getActivity().getSharedPreferences("dgFashionPref", Context.MODE_PRIVATE);
employeeId = sharedpreferences.getString("employee_id","");
productsData = new ArrayList<>();
editedData = new ArrayList<>();
isLoading = false;
isLastPage = false;
isFirstLoad = true;
isSearch = false;
new GetProductListGetRequest(getContext(), productRecyclerView, layoutManager)
.execute(RestConnection.PRODUCT_LIST_GET
+ RestConnection.CUSTOMER_ID_FOR_NAME + employeeId);
}
@Override
public void onDataChanged(ArrayList<Products> editedData) {
Log.d(TAG,editedData.toString());
}
/**
* AsyncTask class which handel the GET request to get product list
**/
public static class GetProductListGetRequest extends AsyncTask<String, Void, String>{
private WeakReference<Context> ActivityWeakReference;
private WeakReference<RecyclerView> recyclerViewWeakReference;
private WeakReference<RecyclerView.LayoutManager> layoutManagerWeakReference;
public GetProductListGetRequest(Context activity, RecyclerView recyclerView
, RecyclerView.LayoutManager layoutManager) {
ActivityWeakReference = new WeakReference<>(activity);
recyclerViewWeakReference = new WeakReference<>(recyclerView);
layoutManagerWeakReference = new WeakReference<>(layoutManager);
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... params) {
String urlEndPoint = params[0];
Request request = new Request.Builder()
.url(RestConnection.API_BASE + urlEndPoint)
.build();
try {
Response response = client.newCall(request).execute();
return response.body().string();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String response) {
if( productsData.size()>0){
productsData.remove(productsData.size() - 1);
}
JSONArray responseBody;
try {
if (response != null && ActivityWeakReference.get() != null) {
responseBody = new JSONArray(response);
for (int i = 0; i < responseBody.length(); i++) {
JSONObject row = responseBody.getJSONObject(i);
String productId = row.getString("ProductID");
String productName = row.getString("Name");
String unit = row.getString("Unit");
String wholeSalePrice = row.getString("WSalePrice");
String packSize = row.getString("PackSize");
String retailPrice = row.getString("RetailPrice");
String costPrice = row.getString("CostPrice");
String qtyInHand = row.getString("QtyInHand");
Products productObj = new Products();
productObj.setProductName(productName);
productObj.setProductId(productId);
productObj.setUnit(unit);
productObj.setWholeSalePrice(wholeSalePrice);
productObj.setPackSize(packSize);
productObj.setRetailPrice(retailPrice);
productObj.setCostPrice(costPrice);
productObj.setQuantityInHand(qtyInHand);
productsData.add(productObj);
}
productListAdapter = new ProductListAdapter(productsData, editedData, ActivityWeakReference.get());
productListAdapter.setDataChangedListener(ActivityWeakReference.get());
recyclerViewWeakReference.get().setAdapter(productListAdapter);
recyclerViewWeakReference.get().setLayoutManager(layoutManagerWeakReference.get());
recyclerViewWeakReference.get().addItemDecoration(new RecyclerViewDivider(2));
} else {
Toast.makeText(ActivityWeakReference.get(), "Can't connect to the server", Toast.LENGTH_LONG).show();
}
} catch (JSONException e)
{
Log.d(TAG, "Get customer details onPostExecute :" + e.getLocalizedMessage());
}
}
}
/**
* A class that define space between list items
*/
private static class RecyclerViewDivider extends RecyclerView.ItemDecoration {
int space;
public RecyclerViewDivider(int space) {
this.space = space;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
outRect.bottom = space;
if (parent.getChildLayoutPosition(view) == 0) {
outRect.top = space;
}
}
}
}
正如您所看到的，我正在尝试通过调用productListAdapter方法在创建setDataChangedListener(DataChangedListener listener);对象后立即在AsyncTask类中实例化接口。但它没有将ActivityWeakReference.get()作为有效参数。我之前使用列表适配器将自定义创建的onListItemClick事件带到活动中。在这些情况下ActivityWeakReference.get()工作正常。我认为这种情况正在发生，因为我是一个片段，但我无法弄清楚我应该通过哪个对象。我需要在AsyncTask内创建适配器，因为我已经为列表视图实现了分页。我删除这些代码以缩短此帖子。请帮忙。
答案 0 :(得分：0)
找到解决方案。您需要将片段对象传递给接口而不是活动。
现在是我的片段课。
/**
* AsyncTask class which handel the GET request to get product list
**/
public static class GetProductListGetRequest extends AsyncTask<String, Void, String>{
private WeakReference<OrderEditFragment> fragmentWeakReference;
private WeakReference<RecyclerView> recyclerViewWeakReference;
private WeakReference<RecyclerView.LayoutManager> layoutManagerWeakReference;
public GetProductListGetRequest(OrderEditFragment fragment, RecyclerView recyclerView
, RecyclerView.LayoutManager layoutManager) {
fragmentWeakReference = new WeakReference<>(fragment);
recyclerViewWeakReference = new WeakReference<>(recyclerView);
layoutManagerWeakReference = new WeakReference<>(layoutManager);
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... params) {
String urlEndPoint = params[0];
Request request = new Request.Builder()
.url(RestConnection.API_BASE + urlEndPoint)
.build();
//Log.d(TAG,RestConnection.API_BASE + urlEndPoint);
try {
Response response = client.newCall(request).execute();
return response.body().string();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String response) {
if( productsData.size()>0){
productsData.remove(productsData.size() - 1);
}
JSONArray responseBody;
//Log.d(TAG,response);
try {
if (response != null && fragmentWeakReference.get() != null) {
responseBody = new JSONArray(response);
for (int i = 0; i < responseBody.length(); i++) {
JSONObject row = responseBody.getJSONObject(i);
String productId = row.getString("ProductID");
String productName = row.getString("Name");
String unit = row.getString("Unit");
String wholeSalePrice = row.getString("WSalePrice");
String packSize = row.getString("PackSize");
String retailPrice = row.getString("RetailPrice");
String costPrice = row.getString("CostPrice");
String qtyInHand = row.getString("QtyInHand");
Products productObj = new Products();
productObj.setProductName(productName);
productObj.setProductId(productId);
productObj.setUnit(unit);
productObj.setWholeSalePrice(wholeSalePrice);
productObj.setPackSize(packSize);
productObj.setRetailPrice(retailPrice);
productObj.setCostPrice(costPrice);
productObj.setQuantityInHand(qtyInHand);
productsData.add(productObj);
}
/** if lower limit and upper limit change, change responseBody.length()<10 respectively **/
if (responseBody.length() == 0 || responseBody.length() < 10) {
isLastPage = true;
}
if (isFirstLoad) {
progressView.setVisibility(View.GONE);
recyclerViewWeakReference.get().setVisibility(View.VISIBLE);
productListAdapter = new ProductListAdapter(productsData, editedData, fragmentWeakReference.get().getContext());
productListAdapter.setDataChangedListener(fragmentWeakReference.get());
recyclerViewWeakReference.get().setAdapter(productListAdapter);
recyclerViewWeakReference.get().setLayoutManager(layoutManagerWeakReference.get());
recyclerViewWeakReference.get().addItemDecoration(new RecyclerViewDivider(2));
isFirstLoad = false;
} else {
productListAdapter.updateData(productsData);
isLoading = false;
}
} else {
Toast.makeText(fragmentWeakReference.get().getContext(), "Can't connect to the server", Toast.LENGTH_LONG).show();
}
} catch (JSONException e)
{
Log.d(TAG, "Get customer details onPostExecute :" + e.getLocalizedMessage());
}
}
}
并创建AsyncTask对象，如下图。
new GetProductListGetRequest(this, productRecyclerView, layoutManager)
.execute(RestConnection.PRODUCT_LIST_GET
+ RestConnection.CUSTOMER_ID_FOR_NAME + employeeId);