Why does my app crash without any errors?

Question

App crashes and I am getting these errors:

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FATAL EXCEPTION: main Process: com.example.ayyan.jellybeanestimator, PID: 2960 java.lang.RuntimeException: Unable to start activity

ComponentInfo{com.example.ayyan.jellybeanestimator/com.example.ayyan.jellybeanestimator.MainActivity}: java.lang.NumberFormatException: empty String at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) Caused by: java.lang.NumberFormatException: empty String at java.lang.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1071) at java.lang.Double.parseDouble(Double.java:547) at com.example.ayyan.jell ybeanestimator.MainActivity.onCreate(MainActivity.java:25) at android.app.Activity.performCreate(Activity.java:6662) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

package com.example.ayyan.jellybeanestimator;

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

public class MainActivity extends AppCompatActivity {
EditText jellyBeanLength, jellyBeanDiameter, jarSizeVolume;
double jellybeantall, jellybeanfat, jellybeanspace;
double loadFactor = .698;
TextView answer;

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

    jellyBeanLength = (EditText) findViewById (R.id.length);
    jellyBeanDiameter = (EditText) findViewById (R.id.diameter);
    jarSizeVolume = (EditText) findViewById (R.id.jarsize);
    jellybeantall = Double.parseDouble(jellyBeanLength.getText().toString());
    jellybeanfat = Double.parseDouble(jellyBeanDiameter.getText().toString());
    jellybeanspace = Double.parseDouble(jarSizeVolume.getText().toString());
    answer = (TextView) findViewById (R.id.answer);
    Button calculate = (Button) findViewById (R.id.calculate);
    calculate.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, MainActivity.class));
        }
    });



    double volumeOfOneJellyBean =  ((3.14159265359/6)*(jellybeanfat*jellybeanfat)*jellybeantall);
    double volumeofBeans = (jellybeanspace*loadFactor);
    float numberOfBeans = (float)Math.round (volumeofBeans/volumeOfOneJellyBean);
    answer.setText("You have this amount of beans in your jar" + numberOfBeans);
}

}

Answer 1

Check if you have any value inserted in the EditText then only parse it in Double

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

        jellyBeanLength = (EditText) findViewById (R.id.length);
        jellyBeanDiameter = (EditText) findViewById (R.id.diameter);
        jarSizeVolume = (EditText) findViewById (R.id.jarsize);

        answer = (TextView) findViewById (R.id.answer);
        Button calculate = (Button) findViewById (R.id.calculate);
        calculate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

//Take out value when button pressed
        jellybeantall = Double.parseDouble(TextUtils.isEmpty(jellyBeanLength.getText().toString())?"0":jellyBeanLength.getText().toString());
        jellybeanfat = Double.parseDouble(TextUtils.isEmpty(jellyBeanDiameter.getText().toString())?"0":jellyBeanDiameter.getText().toString());
        jellybeanspace = Double.parseDouble(TextUtils.isEmpty(jarSizeVolume.getText().toString())?"0":jarSizeVolume.getText().toString());



        double volumeOfOneJellyBean =  ((3.14159265359/6)*(jellybeanfat*jellybeanfat)*jellybeantall);
        double volumeofBeans = (jellybeanspace*loadFactor);
        float numberOfBeans = (float)Math.round (volumeofBeans/volumeOfOneJellyBean);
        answer.setText("You have this amount of beans in your jar" + numberOfBeans);
            } 
        }); 
    } 

Answer 2

you should calculate onClick of button.In your code you are not entering any value and trying to calculate it.

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

    jellyBeanLength = (EditText) findViewById (R.id.length);
    jellyBeanDiameter = (EditText) findViewById (R.id.diameter);
    jarSizeVolume = (EditText) findViewById (R.id.jarsize);
    jellybeantall = Double.parseDouble(jellyBeanLength.getText().toString());
    jellybeanfat = Double.parseDouble(jellyBeanDiameter.getText().toString());
    jellybeanspace = Double.parseDouble(jarSizeVolume.getText().toString());
    answer = (TextView) findViewById (R.id.answer);
    Button calculate = (Button) findViewById (R.id.calculate);
    calculate.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
    double volumeOfOneJellyBean =  ((3.14159265359/6)*(jellybeanfat*jellybeanfat)*jellybeantall);
    double volumeofBeans = (jellybeanspace*loadFactor);
    float numberOfBeans = (float)Math.round (volumeofBeans/volumeOfOneJellyBean);
    answer.setText("You have this amount of beans in your jar" + numberOfBeans);
        }
    });
}

Answer 3

EditText字段中没有任何值，您正尝试解析该值。因此，错误java.lang.NumberFormatException：空字符串。

Answer 4

you could try changing:

answer.setText("You have this amount of beans in your jar" + numberOfBeans);

to

answer.setText("You have this amount of beans in your jar" + String.valueOf(numberOfBeans));

This should convert the double to a string.

Answer 5

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    try
    {
       jellyBeanLength = (EditText) findViewById (R.id.length);
        jellyBeanDiameter = (EditText) findViewById (R.id.diameter);
        jarSizeVolume = (EditText) findViewById (R.id.jarsize);
        jellybeantall = Double.parseDouble(jellyBeanLength.getText().toString());
        jellybeanfat = Double.parseDouble(jellyBeanDiameter.getText().toString());
        jellybeanspace = Double.parseDouble(jarSizeVolume.getText().toString());
        answer = (TextView) findViewById (R.id.answer);
        Button calculate = (Button) findViewById (R.id.calculate);
        calculate.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
        double volumeOfOneJellyBean =  ((3.14159265359/6)*(jellybeanfat*jellybeanfat)*jellybeantall);
        double volumeofBeans = (jellybeanspace*loadFactor);
        float numberOfBeans = (float)Math.round (volumeofBeans/volumeOfOneJellyBean);
        answer.setText("You have this amount of beans in your jar" + numberOfBeans);
        }
        });
    } 
    catch (Exception e) 
    {
       e.printStackTrace();
    }
}