Java NumberFormatException：空字符串；双人，双人

我的应用程序不断崩溃，给了我一个：

 java.lang.NumberFormatException: empty String

也这么说

 FATAL EXCEPTION: main
              Process: com.example.ayyan.jellybeanestimator, PID: 2966
              java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ayyan.jellybeanestimator/com.example.ayyan.jellybeanestimator.MainActivity}: java.lang.NumberFormatException: empty String

所有编辑文本都以空开头。在

onCreate

中不能

getText（）

，必须在

onClick中执行

calculate.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {

        jellybeantall = Double.parseDouble(jellyBeanLength.getText().toString());
        jellybeanfat = Double.parseDouble(jellyBeanDiameter.getText().toString());
        jellybeanspace = Double.parseDouble(jarSizeVolume.getText().toString());

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

注意：当
volumeOfOneJellyBean==0
时，您将得到一个被零除的错误

jellybeantall = Double.parseDouble(jellyBeanLength.getText().toString());
jellybeanfat = Double.parseDouble(jellyBeanDiameter.getText().toString());
jellybeanspace = Double.parseDouble(jarSizeVolume.getText().toString());

calculate.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {

        jellybeantall = Double.parseDouble(jellyBeanLength.getText().toString());
        jellybeanfat = Double.parseDouble(jellyBeanDiameter.getText().toString());
        jellybeanspace = Double.parseDouble(jarSizeVolume.getText().toString());

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