我有这个奇怪的周期性错误，当我启动应用程序时，onCreate被调用，但CardView没有显示任何内容。其他时候，我做同样的事情，启动应用程序，CardView正好显示它应该是什么。
我似乎无法找到错误..
主要课程：
package lassebjoerklund.easyfridge;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
import android.widget.ImageButton;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
public class BootActivity extends Activity {
//TODO Make get method for table with barcode.
//TODO Update postRequest so that it macthes the barcode to the database, and getting a json object. object -> toString
private ArrayList<Products> productsToDisplayInlist;
private String TAG = BootActivity.class.getSimpleName();
private String getDataurl = "http://XXX.XXX.XXX.XXX/selectAll.php";
private static String insertDataUrl = "http://XXX.XXX.XXX.XXX/insertAll.php";
private JsonArrayRequest jsonArrayRequest;
private RecyclerView.Adapter mAdapter;
private String jsonRespons = "";
private static RequestQueue rQueue;
@Override
protected void onCreate(Bundle savedInstanceState) {
//Layout
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_boot_layout);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.cardList);
recyclerView.setHasFixedSize(false);
recyclerView.setLayoutManager(linearLayoutManager);
//RequestQueue
rQueue = Volley.newRequestQueue(this);
productsToDisplayInlist = new ArrayList<>();
getRequest();
Log.d(TAG, productsToDisplayInlist.toString());
mAdapter = new ProductCardAdapter(productsToDisplayInlist);
recyclerView.setAdapter(mAdapter);
//Intent to switch to activity
//final Intent dispalyProductsIntent = new Intent(BootActivity.this, ProductViewController.class);
//final Intent scanBarcodeIntent = new Intent(BootActivity.this, BarcodeTracking.class);
//final ImageButton updateViewButton = (ImageButton) findViewById(R.id.bViewProducts);
/*updateViewButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startActivity(dispalyProductsIntent);
}
});*/
/* final ImageButton addNewEntry = (ImageButton) findViewById(R.id.addEntry);
addNewEntry.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
startActivity(scanBarcodeIntent);
}
});*/
}
@Override
protected void onResume() {
Log.d("onResume", "onResume");
/*Toast toast = Toast.makeText(this, "onResume", Toast.LENGTH_LONG);
toast.show();*/
super.onResume();
}
@Override
protected void onRestart() {
Log.d("onRestart", "onRestart");
/*Toast toast = Toast.makeText(this, "onRestart", Toast.LENGTH_SHORT);
toast.show();*/
super.onRestart();
}
@Override
protected void onStop() {
Log.d("onStop", "onStop");
// productsToDisplayInlist.clear();
super.onStop();
}
@Override
protected void onPause() {
Log.d("onPause", "onPause");
super.onPause();
}
//TODO make error msg if there is no connection.
public void getRequest() {
productsToDisplayInlist.clear();
jsonArrayRequest = new JsonArrayRequest(Request.Method.GET, getDataurl, null, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
//Log.d(TAG, response.toString());
try {
for (int i = 0; i < response.length(); i++) {
JSONObject productToBuild = (JSONObject) response.get(i);
jsonRespons = productToBuild.toString();
String barcode = productToBuild.getString("code");
String name = productToBuild.getString("name");
String type = productToBuild.getString("type");
int id = productToBuild.optInt("id");
String rmDate = productToBuild.getString("rm_date");
String exDate = productToBuild.getString("ex_date");
String placementDate = productToBuild.getString("add_date");
Products product = new Products(barcode, name, placementDate, exDate, rmDate, type);
productsToDisplayInlist.add(product);
Log.d("Product", product.toString());
}
} catch (Exception e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Volly", "Error");
error.printStackTrace();
}
});
rQueue.add(jsonArrayRequest);
}
public static void postRequest(final Products product) {
try {
StringRequest stringRequest = new StringRequest(Request.Method.POST, insertDataUrl, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
VolleyLog.d("onResponse", response);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Volley insertData", "ERROR");
Log.d("error: ", error.getCause().toString());
error.printStackTrace();
}
}) {
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> perameters = new HashMap<>();
perameters.put("barcode", product.getBarcode());
perameters.put("addDate", product.getDayOfadd());
perameters.put("exDate", product.getExDate());
return perameters;
}
};
rQueue.add(stringRequest);
} catch (Exception e) {
e.printStackTrace();
}
}
}
这里我初始化布局并为RecycleView添加适配器。 productsToDisplayInList方法中填充了getRequest()。但不知何故，它只是定期填充......
适配器类：
package lassebjoerklund.easyfridge;
import android.graphics.Color;
import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
public class ProductCardAdapter extends RecyclerView.Adapter<ProductHolder> {
private CardView cardView;
private List<Products> productses;
private Calendar c;
public ProductCardAdapter(ArrayList<Products> items) {
productses = items;
}
@Override
public int getItemCount() {
return productses.size();
}
@Override
public void onBindViewHolder(ProductHolder holder, int position) {
Products product = productses.get(position);
Date returnDate = Util.parseDateString(product.getExDate());
if (Util.getCurrentDate().after(returnDate)) {
cardView.setCardBackgroundColor(Color.parseColor("#FF000D"));
holder.cardName.setText(product.getName());
holder.cardAddDate.setText(product.getDayOfadd());
holder.cardExDate.setText(product.getExDate());
holder.cardType.setText(product.getType());
Log.d("Product Card", product.toString());
} else {
holder.cardName.setText(product.getName());
holder.cardAddDate.setText(product.getDayOfadd());
holder.cardExDate.setText(product.getExDate());
holder.cardType.setText(product.getType());
Log.d("Product Card", product.toString());
}
}
@Override
public ProductHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardlayout, parent, false);
cardView = new CardView(parent.getContext());
return new ProductHolder(itemView);
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
}
持有人类：
package lassebjoerklund.easyfridge;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.TextView;
public class ProductHolder extends RecyclerView.ViewHolder {
protected TextView cardName;
protected TextView cardAddDate;
protected TextView cardExDate;
protected TextView cardType;
public ProductHolder(View itemView) {
super(itemView);
cardName = (TextView) itemView.findViewById(R.id.cardName);
cardAddDate = (TextView) itemView.findViewById(R.id.cardAddDate);
cardExDate = (TextView) itemView.findViewById(R.id.cardExDate);
cardType = (TextView) itemView.findViewById(R.id.cardType);
}
}