Question

为学生出勤率创建一个Android应用程序。当我运行我的应用程序时，我得到的结果为NaN。我将两个浮点值从主活动传递给活动A1。但在我的应用程序中，“e2”字段显示值“NaN”。直到现在我找不到我的错误。它必须在划分浮点值。

我的代码中有什么错误？

MainActivity.java

package shafir.arraytest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {

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

    public void sort(View v) {
        EditText e1, e2, e3, e4, e5;
        char ch = 0;
        e1 = (EditText) findViewById(R.id.text1);
        e2 = (EditText) findViewById(R.id.text2);
        e3 = (EditText) findViewById(R.id.text3);
        e4 = (EditText) findViewById(R.id.text4);
        e5 = (EditText) findViewById(R.id.text5);
        Button b1;
        b1 = (Button) findViewById(R.id.sort);
        int i1, i2, i3,c1 = 0, c2 = 0;
        float tot,att;
        i1 = Integer.parseInt(e1.getText().toString());
        i2 = Integer.parseInt(e2.getText().toString());
        i3 = Integer.parseInt(e3.getText().toString());
        tot=Float.parseFloat(e4.getText().toString());
        att=Float.parseFloat(e5.getText().toString());
        if ((i1 == i2) && (i1 == i3)) {
            c1 = i1;
            c2 = i1;
        }
        if ((i1 == i2) || (i1 > i2) && (i1 == i3) || (i1 > i3)) {
            c1 = i1;
            ch = '1';
        }
        if ((i2 == i1) || (i2 > i1) && (i2 == i3) || (i2 > i3)) {
            c1 = i2;
            ch = '2';
        }
        if ((i3 == i1) || (i3 > i1) && (i3 == i2) || (i3 > i2)) {
            c1 = i3;
            ch = '3';
        }
        switch (ch) {
        case '1':
            if (i2 > i3) {
                c2 = i2;
            } else {
                c2 = i3;
            }
            break;
        case '2':
            if (i1 > i3) {
                c2 = i1;
            } else {
                c2 = i3;
            }
            break;
        case '3':
            if (i1 > i2) {
                c2 = i1;
            } else {
                c2 = i2;
            }
            break;
        }
        Intent in1 = new Intent(this, A1.class);
        in1.putExtra("c1", c1);
        in1.putExtra("c2", c2);
        in1.putExtra("tot", c1);
        in1.putExtra("att", c2);
        startActivity(in1);
    }
}


`


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`
**This is my Activity A1:**

package shafir.arraytest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.EditText;

public class A1 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_a1);
        edit();
    }

    public void edit() {
        EditText e1, e2, e3;
        float ex, patt, internal,tempp,tot1,att1;
        int g1, g2,tempsum, matt = 0;
        e1 = (EditText) findViewById(R.id.great1);
        e2 = (EditText) findViewById(R.id.great2);
        e3 = (EditText) findViewById(R.id.inter);
        Intent in2 = getIntent();
        g1 = in2.getIntExtra("c1", 0);
        g2 = in2.getIntExtra("c2", 0);
        tot1 = in2.getFloatExtra("tot", 0);
        att1 = in2.getFloatExtra("att", 0);
        tempsum=g1+g2;
        ex = (float) (tempsum*0.075);
        tempp=att1/tot1;
        patt = (float)(att1 / tot1) * 100;
        if ((patt > 90) && (patt <= 100)) {
            matt = 5;
        } else if ((patt > 80) && (patt <= 90)) {
            matt = 4;
        } else if ((patt > 70) && (patt <= 80)) {
            matt = 3;
        } else if ((patt > 60) && (patt <= 70)) {
            matt = 2;
        } else if ((patt >= 50) && (patt <= 60)) {
            matt = 1;
        } else {
            matt = 0;
        }
        internal = ex + matt;
        e1.setText(Float.toString(ex));
        e2.setText(Float.toString(tempp));
        e3.setText(Float.toString(internal));
    }
}

Answer 1

我的猜测是tot1为0然后你得到NaN，因为你不能除以0。如果不是这样，请添加一些打印语句，看看tempp转向NaN的位置。

Answer 2

我发现了我的错误：我在传递主要活动的值时犯了一个错误。我为float使用了相同的变量名c1和c2。现在它已经清除，我的应用程序运行正常。

android中的NaN错误

2 个答案: