按下应用程序中的按钮时，我得到的是NaN值，有人可以指出原因吗？

Question

这是我的Java代码：

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

import org.w3c.dom.Text;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
private double counter;
private double sum = 0;
private String value;

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

    Button button = (Button) findViewById(R.id.Button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // handle click
            TextView textGemiddelde = (TextView) 
findViewById(R.id.Gemiddelde);
            textGemiddelde.append(calculate());
        }
    });
}

public double sum() {

    EditText EditText1 = (EditText) findViewById(R.id.EditText1);
    double cijfer1 = Double.valueOf(EditText1.getText().toString());

    EditText EditText2 = (EditText) findViewById(R.id.EditText2);
    double cijfer2 = Double.valueOf(EditText2.getText().toString());

    EditText EditText3 = (EditText) findViewById(R.id.EditText3);
    double cijfer3 = Double.valueOf(EditText3.getText().toString());

    EditText EditText4 = (EditText) findViewById(R.id.EditText4);
    double cijfer4 = Double.valueOf(EditText4.getText().toString());

    EditText EditText5 = (EditText) findViewById(R.id.EditText5);
    double cijfer5 = Double.valueOf(EditText5.getText().toString());

    EditText EditText6 = (EditText) findViewById(R.id.EditText6);
    double cijfer6 = Double.valueOf(EditText6.getText().toString());

    EditText EditText7 = (EditText) findViewById(R.id.EditText7);
    double cijfer7 = Double.valueOf(EditText7.getText().toString());

    EditText EditText8 = (EditText) findViewById(R.id.EditText8);
    double cijfer8 = Double.valueOf(EditText8.getText().toString());

    EditText EditText9 = (EditText) findViewById(R.id.EditText9);
    double cijfer9 = Double.valueOf(EditText9.getText().toString());

    EditText EditText10 = (EditText) findViewById(R.id.EditText10);
    double cijfer10 = Double.valueOf(EditText10.getText().toString());


    EditText EditText_1 = (EditText) findViewById(R.id.EditText_1);
    double weging1 = Double.valueOf(EditText_1.getText().toString());

    EditText EditText_2 = (EditText) findViewById(R.id.EditText_2);
    double weging2 = Double.valueOf(EditText_2.getText().toString());

    EditText EditText_3 = (EditText) findViewById(R.id.EditText_3);
    double weging3 = Double.valueOf(EditText_3.getText().toString());

    EditText EditText_4 = (EditText) findViewById(R.id.EditText_4);
    double weging4 = Double.valueOf(EditText_4.getText().toString());

    EditText EditText_5 = (EditText) findViewById(R.id.EditText_5);
    double weging5 = Double.valueOf(EditText_5.getText().toString());

    EditText EditText_6 = (EditText) findViewById(R.id.EditText_6);
    double weging6 = Double.valueOf(EditText_6.getText().toString());

    EditText EditText_7 = (EditText) findViewById(R.id.EditText_7);
    double weging7 = Double.valueOf(EditText_7.getText().toString());

    EditText EditText_8 = (EditText) findViewById(R.id.EditText_8);
    double weging8 = Double.valueOf(EditText_8.getText().toString());

    EditText EditText_9 = (EditText) findViewById(R.id.EditText_9);
    double weging9 = Double.valueOf(EditText_9.getText().toString());

    EditText EditText_10 = (EditText) findViewById(R.id.EditText_10);
    double weging10 = Double.valueOf(EditText_10.getText().toString());


    if(!TextUtils.isEmpty(EditText1.getText().toString()) && 
!TextUtils.isEmpty(EditText_1.getText().toString())) {
        this.sum += cijfer1 * weging1;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText2.getText().toString()) && 
!TextUtils.isEmpty(EditText_2.getText().toString())) {
        this.sum += cijfer2 * weging2;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText3.getText().toString()) && 
!TextUtils.isEmpty(EditText_3.getText().toString())) {
        this.sum += cijfer3 * weging3;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText4.getText().toString()) && 
!TextUtils.isEmpty(EditText_4.getText().toString())) {
        this.sum += cijfer4 * weging4;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText5.getText().toString()) && 
!TextUtils.isEmpty(EditText_5.getText().toString())) {
        this.sum += cijfer5 * weging5;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText6.getText().toString()) && 
!TextUtils.isEmpty(EditText_6.getText().toString())) {
        this.sum += cijfer6 * weging6;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText7.getText().toString()) && 
!TextUtils.isEmpty(EditText_7.getText().toString())) {
        this.sum += cijfer7 * weging7;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText8.getText().toString()) && 
!TextUtils.isEmpty(EditText_8.getText().toString())) {
        this.sum += cijfer8 * weging8;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText9.getText().toString()) && 
!TextUtils.isEmpty(EditText_9.getText().toString())) {
        this.sum += cijfer9 * weging9;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText10.getText().toString()) && !TextUtils.isEmpty(EditText_10.getText().toString())) {
        this.sum += cijfer10 * weging10;
        this.counter++;
    } else {

    }

    return sum;
}

public double average() {
    return sum / counter;
}

public String calculate() {
    value = String.valueOf(average());
    return value;
}

}

这将是我的第一个应用程序，因此请输入乱码。它的基本作用如下：该应用程序有10个输入字段，您可以在其中输入数字，还有10个字段输入该数字的权重。如果单击底部按钮，它将计算输入数字+重量的平均值。当前，当我单击按钮时，以下内容将附加到“ textGemiddelde”（平均为荷兰语）：NaN。如果有人能指出为什么我得到此代码，而不是给出的数字+权重的平均值，我将不胜感激。

Answer 1

您不会调用<int-aws:request-handler-advice-chain>方法，并且变量sum()未初始化。

Answer 2

发生NaN，因为您尝试计算0/0。此外，计数器未初始化。我已经改正了。告诉它是否有效。

public class MainActivity extends AppCompatActivity {
private double counter = 0;
private double sum = 0;
private String value;
TextView textGemiddelde;
EditText EditText1;
EditText EditText2;
EditText EditText3;
EditText EditText4;
EditText EditText5;
EditText EditText6;
EditText EditText7;
EditText EditText8;
EditText EditText9;
EditText EditText10;
EditText EditText_1;
EditText EditText_2;
EditText EditText_3;
EditText EditText_4;
EditText EditText_5;
EditText EditText_6;
EditText EditText_7;
EditText EditText_8;
EditText EditText_9;
EditText EditText_10;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    EditText1 = (EditText) findViewById(R.id.EditText1);

    EditText2 = (EditText) findViewById(R.id.EditText2);

    EditText3 = (EditText) findViewById(R.id.EditText3);

    EditText4 = (EditText) findViewById(R.id.EditText4);

    EditText5 = (EditText) findViewById(R.id.EditText5);

    EditText6 = (EditText) findViewById(R.id.EditText6);

    EditText7 = (EditText) findViewById(R.id.EditText7);

    EditText8 = (EditText) findViewById(R.id.EditText8);

    EditText9 = (EditText) findViewById(R.id.EditText9);

    EditText10 = (EditText) findViewById(R.id.EditText10);

    EditText_1 = (EditText) findViewById(R.id.EditText_1);

    EditText_2 = (EditText) findViewById(R.id.EditText_2);

    EditText_3 = (EditText) findViewById(R.id.EditText_3);

    EditText_4 = (EditText) findViewById(R.id.EditText_4);

    EditText_5 = (EditText) findViewById(R.id.EditText_5);

    EditText_6 = (EditText) findViewById(R.id.EditText_6);

    EditText_7 = (EditText) findViewById(R.id.EditText_7);

    EditText_8 = (EditText) findViewById(R.id.EditText_8);

    EditText_9 = (EditText) findViewById(R.id.EditText_9);

    EditText_10 = (EditText) findViewById(R.id.EditText_10);

    textGemiddelde = (TextView)
            findViewById(R.id.Gemiddelde);
    Button button = (Button) findViewById(R.id.Button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // handle click
           sum = sum();
            textGemiddelde.append(calculate());
        }
    });
}

public double sum() {

    sum = 0;
    counter = 0;
    double cijfer1 = ParseDouble(EditText1.getText().toString());


    double cijfer2 = ParseDouble(EditText2.getText().toString());


    double cijfer3 = ParseDouble(EditText3.getText().toString());


    double cijfer4 = ParseDouble(EditText4.getText().toString());


    double cijfer5 = ParseDouble(EditText5.getText().toString());


    double cijfer6 = ParseDouble(EditText6.getText().toString());


    double cijfer7 = ParseDouble(EditText7.getText().toString());


    double cijfer8 = ParseDouble(EditText8.getText().toString());


    double cijfer9 = ParseDouble(EditText9.getText().toString());


    double cijfer10 = ParseDouble(EditText10.getText().toString());


    double weging1 = ParseDouble(EditText_1.getText().toString());


    double weging2 = ParseDouble(EditText_2.getText().toString());

    double weging3 = ParseDouble(EditText_3.getText().toString());

    double weging4 = ParseDouble(EditText_4.getText().toString());

    double weging5 = ParseDouble(EditText_5.getText().toString());

    double weging6 = ParseDouble(EditText_6.getText().toString());

    double weging7 = ParseDouble(EditText_7.getText().toString());

    double weging8 = ParseDouble(EditText_8.getText().toString());

    double weging9 = ParseDouble(EditText_9.getText().toString());

    double weging10 = ParseDouble(EditText_10.getText().toString());


    if(!TextUtils.isEmpty(EditText1.getText().toString()) &&
            !TextUtils.isEmpty(EditText_1.getText().toString())) {
        this.sum += cijfer1 * weging1;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText2.getText().toString()) &&
            !TextUtils.isEmpty(EditText_2.getText().toString())) {
        this.sum += cijfer2 * weging2;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText3.getText().toString()) &&
            !TextUtils.isEmpty(EditText_3.getText().toString())) {
        this.sum += cijfer3 * weging3;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText4.getText().toString()) &&
            !TextUtils.isEmpty(EditText_4.getText().toString())) {
        this.sum += cijfer4 * weging4;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText5.getText().toString()) &&
            !TextUtils.isEmpty(EditText_5.getText().toString())) {
        this.sum += cijfer5 * weging5;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText6.getText().toString()) &&
            !TextUtils.isEmpty(EditText_6.getText().toString())) {
        this.sum += cijfer6 * weging6;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText7.getText().toString()) &&
            !TextUtils.isEmpty(EditText_7.getText().toString())) {
        this.sum += cijfer7 * weging7;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText8.getText().toString()) &&
            !TextUtils.isEmpty(EditText_8.getText().toString())) {
        this.sum += cijfer8 * weging8;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText9.getText().toString()) &&
            !TextUtils.isEmpty(EditText_9.getText().toString())) {
        this.sum += cijfer9 * weging9;
        this.counter++;
    } else {

    }

    if(!TextUtils.isEmpty(EditText10.getText().toString()) && !TextUtils.isEmpty(EditText_10.getText().toString())) {
        this.sum += cijfer10 * weging10;
        this.counter++;
    } else {

    }

    return sum;
}

public double average() {
    if(couter == 0) return -1;
    return sum / counter;
}

public String calculate() {
    value = String.valueOf(average());
    return value;
}
double ParseDouble(String strNumber) {
    if (strNumber != null && strNumber.length() > 0) {
        try {
            return Double.parseDouble(strNumber);
        } catch(Exception e) {
            return -1;   // or some value to mark this field is wrong. or make a function validates field first ...
        }
    }
    else return 0;
}

}

Answer 3

您需要调用sum（）方法，以便sum和counter变量具有值。在当前代码中，它们为0，因为未调用sum（）方法。因此，0/0返回NaN。 另外，每次单击按钮时，您都需要重置总和和计数器的值。否则，这些值将每次都加起来，因为它们是字段变量。 另外，您不必每次在sum（）方法中都使用findViewById。 只需在onCreate中将其初始化一次即可，这将达到目的，因为此操作很繁琐。 要快速修复，请通过以下方式更改平均方法：

public double average() {
    sum = 0;
    counter = 0;
    sum();
    return sum / counter;
}

这将起作用。

但是，为了使代码更简洁明了，可以将类编写为：

class MainActivity extends AppCompatActivity {

private double counter;
private double sum = 0;
private String value;
private EditText mEditText1;
private EditText mEditText2;
private EditText mEditText3;
private EditText mEditText4;
private EditText mEditText5;
private EditText mEditText6;
private EditText mEditText7;
private EditText mEditText8;
private EditText mEditText9;
private EditText mEditText10;
private EditText mEditText_1;
private EditText mEditText_2;
private EditText mEditText_3;
private EditText mEditText_4;
private EditText mEditText_5;
private EditText mEditText_6;
private EditText mEditText_7;
private EditText mEditText_8;
private EditText mEditText_9;
private EditText mEditText_10;

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

    Button button = (Button) findViewById(R.id.Button);
    mEditText1 = (EditText) findViewById(R.id.EditText1);
    mEditText2 = (EditText) findViewById(R.id.EditText2);
    mEditText3 = (EditText) findViewById(R.id.EditText3);
    mEditText4 = (EditText) findViewById(R.id.EditText4);
    mEditText5 = (EditText) findViewById(R.id.EditText5);
    mEditText6 = (EditText) findViewById(R.id.EditText6);
    mEditText7 = (EditText) findViewById(R.id.EditText7);
    mEditText8 = (EditText) findViewById(R.id.EditText8);
    mEditText9 = (EditText) findViewById(R.id.EditText9);
    mEditText10 = (EditText) findViewById(R.id.EditText10);

    mEditText_1 = (EditText) findViewById(R.id.EditText_1);
    mEditText_2 = (EditText) findViewById(R.id.EditText_2);
    mEditText_3 = (EditText) findViewById(R.id.EditText_3);
    mEditText_4 = (EditText) findViewById(R.id.EditText_4);
    mEditText_5 = (EditText) findViewById(R.id.EditText_5);
    mEditText_6 = (EditText) findViewById(R.id.EditText_6);
    mEditText_7 = (EditText) findViewById(R.id.EditText_7);
    mEditText_8 = (EditText) findViewById(R.id.EditText_8);
    mEditText_9 = (EditText) findViewById(R.id.EditText_9);
    mEditText_10 = (EditText) findViewById(R.id.EditText_10);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // handle click
            TextView textGemiddelde = (TextView)
                    findViewById(R.id.Gemiddelde);
            textGemiddelde.append(calculate());
        }
    });
}

public double sum() {

    sum = 0;
    counter = 0;

    double cijfer1 = Double.valueOf(mEditText1.getText().toString());
    double cijfer2 = Double.valueOf(mEditText2.getText().toString());
    double cijfer3 = Double.valueOf(mEditText3.getText().toString());
    double cijfer4 = Double.valueOf(mEditText4.getText().toString());
    double cijfer5 = Double.valueOf(mEditText5.getText().toString());
    double cijfer6 = Double.valueOf(mEditText6.getText().toString());
    double cijfer7 = Double.valueOf(mEditText7.getText().toString());
    double cijfer8 = Double.valueOf(mEditText8.getText().toString());
    double cijfer9 = Double.valueOf(mEditText9.getText().toString());
    double cijfer10 = Double.valueOf(mEditText10.getText().toString());

    double weging1 = Double.valueOf(mEditText_1.getText().toString());
    double weging2 = Double.valueOf(mEditText_2.getText().toString());
    double weging3 = Double.valueOf(mEditText_3.getText().toString());
    double weging4 = Double.valueOf(mEditText_4.getText().toString());
    double weging5 = Double.valueOf(mEditText_5.getText().toString());
    double weging6 = Double.valueOf(mEditText_6.getText().toString());
    double weging7 = Double.valueOf(mEditText_7.getText().toString());
    double weging8 = Double.valueOf(mEditText_8.getText().toString());
    double weging9 = Double.valueOf(mEditText_9.getText().toString());
    double weging10 = Double.valueOf(mEditText_10.getText().toString());


    if (cijfer1 != 0 && weging1 != 0) {
        this.sum += cijfer1 * weging1;
        this.counter++;
    }

    if (cijfer2 != 0 && weging2 != 0) {
        this.sum += cijfer2 * weging2;
        this.counter++;
    }

    if (cijfer3 != 0 && weging3 != 0) {
        this.sum += cijfer3 * weging3;
        this.counter++;
    }

    if (cijfer4 != 0 && weging4 != 0) {
        this.sum += cijfer4 * weging4;
        this.counter++;
    }

    if (cijfer5 != 0 && weging5 != 0) {
        this.sum += cijfer5 * weging5;
        this.counter++;
    }

    if (cijfer6 != 0 && weging6 != 0) {
        this.sum += cijfer6 * weging6;
        this.counter++;
    }

    if (cijfer7 != 0 && weging7 != 0) {
        this.sum += cijfer7 * weging7;
        this.counter++;
    }

    if (cijfer8 != 0 && weging8 != 0) {
        this.sum += cijfer8 * weging8;
        this.counter++;
    }

    if (cijfer9 != 0 && weging9 != 0) {
        this.sum += cijfer9 * weging9;
        this.counter++;
    }

    if (cijfer10 != 0 && weging10 != 0) {
        this.sum += cijfer10 * weging10;
        this.counter++;
    }
    return sum;
}

public String calculate() {
    sum = 0;
    counter = 0;
    sum();
    if (counter != 0)
        value = String.valueOf(sum / counter);
    else
        value = "Invalid Input";
    return value;
}

}