NumberFormatException while converting string to Integer

Question

I'm getting integers of two EditText and on one of them textWatch is applied, multiplying them and setting text to another EditText. it normally works fine but when one of edit field become empty while hitting backspace app crashes.

protected final TextWatcher getValueWatcher = new TextWatcher() {
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        int qty = Integer.parseInt(s.toString());
        int unitPrice = Integer.parseInt(unitPriceEdit.getText().toString());
        if (s.length() > 0)
        totalPriceEdit.setText(String.valueOf(qty * unitPrice));
    }
    public void afterTextChanged(Editable s) {
    }
};

Logcat

java.lang.NumberFormatException: Invalid int: "" at 
java.lang.Integer.invalidInt(Integer.java:138) at 
java.lang.Integer.parseInt(Integer.java:358) at 
java.lang.Integer.parseInt(Integer.java:334) at 
com.example.fani.project.MainActivity$2.onTextChanged(MainActivity.java:90) 
at android.widget.TextView.sendOnTextChanged(TextView.java:7679) at 
android.widget.TextView.handleTextChanged(TextView.java:7739)

what kind of exception do you get? probably a NumberFormatException? — Manuel Jain
– Manuel Jain, Commented Aug 7, 2015 at 10:44
java.lang.NumberFormatException: Invalid int: "" at java.lang.Integer.invalidInt(Integer.java:138) at java.lang.Integer.parseInt(Integer.java:358) at java.lang.Integer.parseInt(Integer.java:334) at com.example.fani.project.MainActivity$2.onTextChanged(MainActivity.java:90) at android.widget.TextView.sendOnTextChanged(TextView.java:7679) at android.widget.TextView.handleTextChanged(TextView.java:7739) — Farhan ALi
– Farhan ALi, Commented Aug 7, 2015 at 10:49
I think you should check the length of string before converting it to integer...because if u try to convert an empty string....it will raise NumberFormatException..😊 — EEJ
– EEJ, Commented Aug 7, 2015 at 10:50

Lal · Accepted Answer · 2015-08-07 10:51:21Z

3

Replace your code as below

protected final TextWatcher getValueWatcher = new TextWatcher() {
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }
    public void onTextChanged(CharSequence s, int start, int before, int count) {
      if (s.length() > 0){
        int qty = Integer.parseInt(s.toString());
        int unitPrice = Integer.parseInt(unitPriceEdit.getText().toString());
        totalPriceEdit.setText(String.valueOf(qty * unitPrice));
      }
    }
    public void afterTextChanged(Editable s) {
    }
};

Check the length of your string before parsing it..

answered Aug 7, 2015 at 10:51

Lal

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2 Comments

Farhan ALi Over a year ago

works like a charm Thank you So much and sorry for posting a silly question but I'm a beginner

Lal Over a year ago

Glad that it helped.. :)

zkminusck · Accepted Answer · 2015-08-07 11:07:59Z

1

Modify your onTextChanged():

public void onTextChanged(CharSequence s, int start, int before, int count) {
    if (s.length() > 0){
        int qty = Integer.parseInt(s.toString());
        int unitPrice = Integer.parseInt(unitPriceEdit.getText().toString());
        totalPriceEdit.setText(String.valueOf(qty * unitPrice));
    }
}

edited Aug 7, 2015 at 11:07

answered Aug 7, 2015 at 10:50

zkminusck

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2 Comments

Farhan ALi Over a year ago

works like a charm Thank you So much and sorry for posting a silly question but I'm a beginner

zkminusck Over a year ago

Good to know, can you please accept it as an answer?

mahesh · Accepted Answer · 2015-08-07 10:52:08Z

0

null pointer error occurs due to s.length > 0 Change this in your code.

 if (s.length() > 0)
    totalPriceEdit.setText(String.valueOf(qty * unitPrice));
 }

TO

if(s != null){

   if (s.length() > 0)
    totalPriceEdit.setText(String.valueOf(qty * unitPrice));
  }
}

answered Aug 7, 2015 at 10:52

mahesh

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