Rxjava，使用.zip合并两个livedata对象

Question

我试图使用rxjava .zip合并两个livedata对象。这就是我到目前为止所拥有的。

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.util.Consumer;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;


import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.example.myapplication.API.model.OrderRows;
import com.example.myapplication.API.model.Orders;


import java.util.function.BiFunction;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button myButt;
    private MainViewModel mvw;
    private TextView myView;


    @RequiresApi(api = Build.VERSION_CODES.N)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        mvw = new ViewModelProvider(this).get(MainViewModel.class);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myButt = findViewById(R.id.button);
        myView = findViewById(R.id.textview);
        myButt.setOnClickListener(this);
        final Observer<Orders> obsOrders = new Observer<Orders>() {
            @Override
            public void onChanged(Orders orders) {
                Log.i("order obs", "order obs");
            }
        };
        final Observer<OrderRows> obsOrderRow = new Observer<OrderRows>() {
            @Override
            public void onChanged(OrderRows orders) {
                Log.i("orderRows obs", "orderRow obs");
            }
        };
        mvw.getAllOrders().observe(this,obsOrders);
        mvw.getAllOrderRows().observe(this,obsOrderRow);

        Observable.zip(obsOrderRow,obsOrders,mergeItems())
                .subscribe(printer());


    }
@RequiresApi(api = Build.VERSION_CODES.N)
@NonNull
private BiFunction<OrderRows, Orders, String> mergeItems() {
    return new BiFunction<OrderRows, Orders, String>() {
        @Override
        public String apply(OrderRows orderRows, Orders orders) {
            return "asd";
        }
    };
}
@NonNull
private Consumer<String> printer() {
    return new Consumer<String>() {
        @Override
        public void accept(String s) {
            Log.i("merged",s);
        }
    };
}


    @Override
    public void onClick(View view) {
        switch(view.getId()){
            case R.id.button:
                Log.i("button","clicked");
                mvw.updateOrderData(); // calls for new values to be fetched
                mvw.updateOrderRowData();
        }
    }
}

问题在于，当我尝试运行.zip函数时，我会得到以下错误。

错误:没有找到适合于zip(观察者、观察者、BiFunction) Observable.zip(obsOrderRow，obsOrders，mergeItems())的方法^^

增加了进口，这样你们就可以看到了。

Answer 1

你使用错误的BiFunction。

你有：

import java.util.function.BiFunction;

而zip则选择io.reactivex.functions.BiFunction。