Я делаю заказ, принимая кассу. Использование представления переработчика для отображения очереди заказа. Однако у меня возникают проблемы при передаче значений ArrayList между классами, а также при обновлении представления переработчика. В этом случае у меня не будет большого представления о переработчике, так что производительность не будет такой большой проблемой, но высоко ценится оптимизированный способ сделать это. Я просто не знаю, как справиться с этой проблемой.
Я пытался создать метод set в классе MainActivty, я также пытался добавить намерение extra, но я не верю, что полностьюпонять еще лучше.
Класс MainActivity:
public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {
private RecyclerView recyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager layoutManager;
public ArrayList<String> orderList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// set up the RecyclerView
recyclerView = findViewById(R.id.recyle_view_activity);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
mAdapter = new MyRecyclerViewAdapter(this, orderList);
((MyRecyclerViewAdapter) mAdapter).setClickListener(this);
recyclerView.addItemDecoration(new DividerItemDecoration(this,
DividerItemDecoration.VERTICAL));
recyclerView.setAdapter(mAdapter);
}
//This is the set method I attempted:
public void setOrderAdd(ArrayList<String> data){
if (data != null){
mAdapter = new MyRecyclerViewAdapter(this,data); //Error refrences here
}
}
}
Другой класс:
public class regularCoffee extends AppCompatActivity implements AdapterView.OnItemSelectedListener, Serializable {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_regular_coffee);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
addToOrder();
}
public void addToOrder(){
//Reg Addons:
final CheckBox leaveRoomReg = findViewById(R.id.leave_room_reg);
final CheckBox cinnamonReg = findViewById(R.id.cinnamon_reg);
final CheckBox chocolateSyrupReg = findViewById(R.id.chocolate_syrup_reg);
final CheckBox whiteChocolateSyrupReg = findViewById(R.id.white_chocolate_syrup_reg);
final CheckBox caramelReg = findViewById(R.id.caramelReg);
final CheckBox hazelnutReg = findViewById(R.id.hazel_nut_reg);
final CheckBox[] RegCoffeeAddOns = {leaveRoomReg,cinnamonReg,chocolateSyrupReg,whiteChocolateSyrupReg,caramelReg,hazelnutReg};
//Decaf Addons:
final Button leaveRoomDecaf = findViewById(R.id.leave_room_decaf);
final Button cinnamonDecaf = findViewById(R.id.cinnamon_decaf);
final Button chocolateSyrupDecaf = findViewById(R.id.chocolate_syrup_decaf);
final Button whiteChocolateDecaf = findViewById(R.id.white_chocolate_syrup_decaf);
final Button caramelDecaf = findViewById(R.id.caramel_decaf);
final Button hazelnutDecaf = findViewById(R.id.hazel_nut_decaf);
final Button[] DecafCoffeeAddOns = {leaveRoomDecaf,cinnamonDecaf,caramelDecaf,chocolateSyrupDecaf,whiteChocolateDecaf,hazelnutDecaf};
Button addToOrderButton = findViewById(R.id.addToOrderReg);
addToOrderButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MainActivity addToOrderArea = new MainActivity();
String forOrder;
ArrayList<String> tempArray = new ArrayList<>();
if (regCoffeeQuantity > 0){
forOrder = "Regular Coffee (x" + regCoffeeQuantity + ") \n ";
for (int i = 0; i < RegCoffeeAddOns.length; i++){
if (RegCoffeeAddOns[i].isChecked()){
forOrder = forOrder + "| " + RegCoffeeAddOns[i].getText().toString() + " ";
System.out.println(forOrder);
}
}
addToOrderArea.setOrderAdd(tempArray); //Error refrences here
}
}
});
}
Адаптер RecyclerView:
package com.example.holygroundsapplication;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {
private List<String> mData;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
MyRecyclerViewAdapter(Context context, List<String> data) {
this.mInflater = LayoutInflater.from(context); //Error refrences here.
this.mData = data;
}
// inflates the row layout from xml when needed
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_row, parent, false);
return new ViewHolder(view);
}
// binds the data to the TextView in each row
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
String animal = mData.get(position);
holder.myTextView.setText(animal);
}
// total number of rows
@Override
public int getItemCount() {
return mData.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView myTextView;
ViewHolder(View itemView) {
super(itemView);
myTextView = itemView.findViewById(R.id.tvAnimalName);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// convenience method for getting data at click position
String getItem(int id) {
return mData.get(id);
}
// allows clicks events to be caught
void setClickListener(MainActivity itemClickListener) {
this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
}
Этоошибка:
java.lang.IllegalStateException: System services not available to Activities before onCreate()
at android.app.Activity.getSystemService(Activity.java:5774)
at android.view.LayoutInflater.from(LayoutInflater.java:233)
at com.example.holygroundsapplication.MyRecyclerViewAdapter.<init>(MyRecyclerViewAdapter.java:21)
at com.example.holygroundsapplication.MainActivity.setOrderAdd(MainActivity.java:89)
at com.example.holygroundsapplication.regularCoffee$8.onClick(regularCoffee.java:262)
...