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？
[英]I'm getting a NaN value when pressing the button in my app, could someone point out why?
问题描述
This is my Java code: 
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;
}
}
This will be my first app so excuse me for messy code. 这将是我的第一个应用程序，请原谅我的代码混乱。 What it basically does is as follows: the app has 10 input fields where you can enter a number and 10 fields to enter the weight of that number. 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。 If you click on the bottom button, it will calculate the average of the entered numbers + weight. 如果单击底部按钮，它将计算输入数字+重量的平均值。 Currently, when I click on the button, the following gets appended to "textGemiddelde" (which is Dutch for average): NaN. 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。 I'd really appreciate it if someone could point out to me why I get this code and not the average of the given numbers + weight. 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，我将非常感激。
3 个解决方案
解决方案1
0 2018-08-14 16:01:33
您不调用sum()方法，并且变量counter未初始化。
解决方案2
0 已采纳 2018-08-14 16:07:33
NaN occurred because you were trying to compute 0/0. 发生NaN，因为您尝试计算0/0。 Also, counter is not initialized. 此外，计数器未初始化。 I have corrected it. 我已经改正了。 Tell if it works or not. 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;
}
}
解决方案3
0 2018-08-14 16:20:29
You need to call sum() method so that the sum and counter variables have the values. 您需要调用sum（）方法，以便sum和counter变量具有值。 In the current code, they are 0 as the sum() method is not called. 在当前代码中，它们为0，因为未调用sum（）方法。 So, 0/0 returns NaN. 因此，0/0返回NaN。 Also, you need to reset the values of sum and counter every time the button is clicked. 另外，每次单击按钮时，您都需要重置总和和计数器的值。 Or else these values will get added up every time as these are the field variables. 否则，这些值将每次都加起来，因为它们是字段变量。 Also, you don't have to use findViewById every time in the sum() method. 另外，您不必每次在sum（）方法中都使用findViewById。 Just initialize it once in the onCreate and it will serve the purpose, as this operation is the heavy one. 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。 For quick fix change the average methods by: 要快速修复，请通过以下方法更改平均方法：
public double average() {
sum = 0;
counter = 0;
sum();
return sum / counter;
}
This will work. 这将起作用。
But to make the code neat and good, you can write the class as: 但是，为了使代码整洁美观，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;
}
} }
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