CODEWITHSUNDEEP
androidformsvalidationvalidatingvalidating-event
RodrigoKrz
RodrigoKrz

Reputation: 1

Android app shutting if form blank - Need a validation form

I have a app for convert km/h for mph. If the form is blank and press button convert, the app simply closes. I understand that i need a function thats validade if the form is blank and show a message informating users that form cannot be blank but i cannot found a code for my problem.

My onClick code is:

        buttonConverter.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            double Value1 = Double.valueOf(txtKmhUser.getText().toString());
            double Value2 = Value1 / 1.60;
            Result.setText(String.valueOf(Value2));

        }


    });

Upvotes: -1

Views: 63

Answers (4)

Marcus
Marcus

Reputation: 6717

You can show a toast, if the EditText is empty.

    @Override
    public void onClick(View arg0) {
        String yourString = txtKmhUser.getText().toString();
        if(!yourString.equals("")){
            double Value1 = Double.valueOf(yourString);
            double Value2 = Value1 / 1.60;
            Result.setText(String.valueOf(Value2));
        }else{
            Toast.makeText(this, "Form can not be blank", Toast.LENGTH_SHORT).show();
        }
    }

Upvotes: 1

thestrongenough
thestrongenough

Reputation: 225

Check your edit text has value null before converting it

if(!value1.equals(null))

Upvotes: 0

Adam W
Adam W

Reputation: 1012

The reason your app is crashing is because Double.valueOf("") throws a number format exception. So you need to validate your form ahead of processing or use a try/catch for the exception. 

buttonConverter.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View arg0) {
        if(txtQuilometros.getText().toString().length() > 0) {
             double Value1 = Double.valueOf(txtQuilometros.getText().toString());
             double Value2 = Value1 / 1.60;
             Result.setText(String.valueOf(Value2));
         } else {
          txtQuilometros.setError("Please enter a value");
    }
});

Upvotes: 0

MDMalik
MDMalik

Reputation: 4001

Just do validation before converting

  buttonConverter.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
        String str=txtQuilometros.getText().toString();
        if(str.length()>0)
        {
             double Value1 = Double.valueOf(str);
             double Value2 = Value1 / 1.60;
             Result.setText(String.valueOf(Value2));
         }

    }


});

Upvotes: 0

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