Question

I’m working on a disk space calculator and i need to dynamically calculate some values according to user input. I have an EditText element in my application that receives numbers. I want to call my function calculate() that will calculate other values automatically when user inputs a value in the text field. Here’s my code for it

//fps is my EditText element
this.fps.addTextChangedListener(new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count)  
           {
    // TODO Auto-generated method stub
        calculate();
    }
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
    // TODO Auto-generated method stub
    }
    @Override
    public void afterTextChanged(Editable s) {
    // TODO Auto-generated method stub

    }
    });     

My calculate() function uses the text input, converts it into float and calculates other values like bandwidth. It works fine but the problem comes when I want to delete all numbers in EditText to add another one. The moment there’s nothing in the editText it gives an exception. Which I understand, it’s because there’s nothing to convert into float so parsing exception etc.
I tried putting a default value

if(fps.getText().length==0)
    fps.setText("1");

But it doesn’t work. How can I solve this problem?

Answer 1

Just try to surround your calculate() with try/catch block and catch the exception thrown..

try { 
  calculate();
} catch {NumberFormatException nfe) { //or whatever exception you get
      //do some handling if you need to
}