为什么我的应用程序崩溃没有任何错误？

Question

应用程序崩溃，我会得到以下错误：

致命异常：主进程：com.example.ayyan.JellyBeanEstimator,pid：2960 java.lang.RuntimeException：无法启动活动

ComponentInfo{com.example.ayyan.JellyBeanEstimator/com.example.ayyan.JellyBeanEstimator.MainActivity}：java.lang.NumberFormatException：Android.app.ActivityThread.PerformLaunchActivity(ActivityThread.java:2646)在Android.app.ActivityThread.HandleLaunchActivity(ActivityThread.java:2707)在Android.app.ActivityThread.-Wrap12(ActivityThread.java)在Android.app.ActivityThreadYBeanEstimator.MainActivity.OnCreate（MainActivity.java:25)位于Android.app.Activity.PerformCreate（Activity.java:6662)位于Android.app.Instrumentation.CallActivityCreate（Instrumentation.java:1118)位于Android.app.ActivityThread.PerformLaunchActivity（ActivityThread.java:2599)位于Android.app.ActivityThread.HandleLaunchActivity（ActivityThread.java:2707） 在android.app.activitythread.-wrap12(activitythread.java) 在Android.app.ActivityThread$H.HandleMessage（ActivityThread.java:1460) 在android.os.handler.dispatchmessage(handler.java:102) 在android.os.looper.loop(looper.java:154) 在android.app.activityThread.main（activityThread.java:6077) 在java.lang.Reflect.Method.Invoke（原生方法） 在com.android.internal.os.zygoteInit$methodandargscaller.run（zygoteInit.java:865) 在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

检查是否在edittext中插入了任何值，然后仅在double中解析它

    @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);
            } 
        }); 
    }