Как использовать onItemSelectedListener внутри onClickListener?

Question

Я делаю простой калькулятор, но с помощью счетчика как способа выбора оператора, поэтому всякий раз, когда я нажимаю "Рассчитать", он никогда не вычисляет его, но когда я изменяю элемент, выбранный на счетчике, он вычисляет x и y с их соответствующими операторами. Как правильно использовать /code onItemSelectedListener внутри onClickListener?

Вот мой код

package com.example.leks.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity  implements View.OnClickListener 
{

    private TextView tvResult;
    private EditText etFirstnumber, etSecondnumber;
    private Button btnCalculate;
    private Spinner spnOperators;
    private int result;

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


    }

    private void init()
    {
        etFirstnumber = (EditText) findViewById(R.id.etFirstnumber);
        etSecondnumber = (EditText) findViewById(R.id.etSecondnumber);

        spnOperators = (Spinner) findViewById(R.id.spnOperators);

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

        btnCalculate = (Button) findViewById(R.id.btnCalculate);

        btnCalculate.setOnClickListener(this);
    }


    @Override
    public void onClick(View view)
    {


        try {
            switch (view.getId()) {
                case R.id.btnCalculate:
                    spnOperators.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
                    {
                        @Override

                        public void onItemSelected(AdapterView<?> parent, View view, int position, long l)
                        {
                            String num1 = etFirstnumber.getText().toString();
                            String num2 = etSecondnumber.getText().toString();
                            int x = Integer.parseInt(num1);
                            int y = Integer.parseInt(num2);

                            String SelectedItem = parent.getItemAtPosition(position).toString();
                            if (SelectedItem.equals("+"))
                            {
                                result = x + y;
                                tvResult.setText(String.valueOf(result));
                            }
                            if (SelectedItem.equals("-"))
                            {
                                result = x - y;
                                tvResult.setText(String.valueOf(result));
                            }
                            if (SelectedItem.equals("*"))
                            {
                                result = x * y;
                                tvResult.setText(String.valueOf(result));
                            }
                            if (SelectedItem.equals("/"))
                            {
                                result = x/y;
                                tvResult.setText(String.valueOf(result));
                            }

                        }

                        @Override
                        public void onNothingSelected(AdapterView<?> adapterView)
                        {

                        }
                    });
                    break;
            }
        }catch(Exception e)
        {
            tvResult.setText("Error");
        }
    }
}

Answer 1

Попробуйте код ниже:

public class MainActivity extends AppCompatActivity  implements View.OnClickListener 
{

String num1="",num2="";
int x=0,y=0;
String SelectedItem ;

private TextView tvResult;
private EditText etFirstnumber, etSecondnumber;
private Button btnCalculate;
private Spinner spnOperators;
private int result;

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


}

private void init()
{
    etFirstnumber = (EditText) findViewById(R.id.etFirstnumber);
    etSecondnumber = (EditText) findViewById(R.id.etSecondnumber);

    spnOperators = (Spinner) findViewById(R.id.spnOperators);

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

    btnCalculate = (Button) findViewById(R.id.btnCalculate);

    btnCalculate.setOnClickListener(this);

    num1 = etFirstnumber.getText().toString();
    num2 = etSecondnumber.getText().toString();
    x = Integer.parseInt(num1);
    y = Integer.parseInt(num2);


    spnOperators.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
                {
                    @Override

                    public void onItemSelected(AdapterView<?> parent, View view, int position, long l)
                    {

                        SelectedItem = parent.getItemAtPosition(position).toString();

                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> adapterView)
                    {

                    }
                });
}


@Override
public void onClick(View view)
{


    try {
        switch (view.getId()) {
            case R.id.btnCalculate:
                calculate();
                break;
        }
    }catch(Exception e)
    {
        tvResult.setText("Error");
    }
}

public void calculate(){
     if (SelectedItem.equals("+"))
                        {
                            result = x + y;
                            tvResult.setText(String.valueOf(result));
                        }
                        if (SelectedItem.equals("-"))
                        {
                            result = x - y;
                            tvResult.setText(String.valueOf(result));
                        }
                        if (SelectedItem.equals("*"))
                        {
                            result = x * y;
                            tvResult.setText(String.valueOf(result));
                        }
                        if (SelectedItem.equals("/"))
                        {
                            result = x/y;
                            tvResult.setText(String.valueOf(result));
                        }

}
}

Answer 2

Пожалуйста, поместите ваш onItemSelectedListener в методе init.

Вам не нужно ставить его методом onClick.

private void init()
{
    etFirstnumber = (EditText) findViewById(R.id.etFirstnumber);
    etSecondnumber = (EditText) findViewById(R.id.etSecondnumber);

    spnOperators = (Spinner) findViewById(R.id.spnOperators);

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

    btnCalculate = (Button) findViewById(R.id.btnCalculate);

    btnCalculate.setOnClickListener(this);



spnOperators.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
                {
                    @Override

                    public void onItemSelected(AdapterView<?> parent, View view, int position, long l)
                    {
                        String num1 = etFirstnumber.getText().toString();
                        String num2 = etSecondnumber.getText().toString();
                        int x = Integer.parseInt(num1);
                        int y = Integer.parseInt(num2);

                        String SelectedItem = parent.getItemAtPosition(position).toString();
                        if (SelectedItem.equals("+"))
                        {
                            result = x + y;
                            tvResult.setText(String.valueOf(result));
                        }
                        if (SelectedItem.equals("-"))
                        {
                            result = x - y;
                            tvResult.setText(String.valueOf(result));
                        }
                        if (SelectedItem.equals("*"))
                        {
                            result = x * y;
                            tvResult.setText(String.valueOf(result));
                        }
                        if (SelectedItem.equals("/"))
                        {
                            result = x/y;
                            tvResult.setText(String.valueOf(result));
                        }

                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> adapterView)
                    {

                    }
                });
}