CODEWITHSUNDEEP
javaandroid
Israel Pelayo
Israel Pelayo

Reputation: 13

How Can I put a error msg if there is a blank field on Java?

I am trying to make a unit converter and it seems its working i just need to give them an error if they don't put any number on the first field and other error if they put a number on the second field (so they cant convert it backwards)

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final EditText editCentimeters = (EditText) findViewById(R.id.editCentimeters);

        final EditText editInches = (EditText) findViewById(R.id.editInches);

        Button buttonConvert = (Button)findViewById(R.id.buttonConvert);

        buttonConvert.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {

                double centimeters = Double.valueOf( editCentimeters.getText().toString());

                double inches = centimeters *  0.393700787 ;

                editInches.setText(String.valueOf(inches));

            }
        });



    }

}

Upvotes: 0

Views: 86

Answers (5)

Psypher
Psypher

Reputation: 10829

editinches should b a textview so that user can't edit or add any value... Next use should do a check if editcentimeter is empty, if yes you display an error... Can be Alertdialog, toast to show the error message.

if(editcentimeter.isEmpty(){
AlertDialog.Builder alertDialogBuilder = new    AlertDialog.Builder(context);

        // set title
        alertDialogBuilder.setTitle("Missing value");

        // set dialog message
        alertDialogBuilder
            .setMessage("Please enter a value");

        // set title
        alertDialogBuilder.setTitle("Your Title");

        // set dialog message
        alertDialogBuilder
            .setMessage("Please enter a numbert!")
            .setCancelable(false)
            .setPositiveButton("Yes",new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog,int id) {
                    dismiss();
                }
              });
        }
}

Upvotes: 0

Saqib Rezwan
Saqib Rezwan

Reputation: 1408

You can use Toast to give a error message. But I use EditText.setError() method. So user will be able see exactly which field is responsible for validation problem Click HERE for a tutorial and Here for another solid tutorial.

This is a sample code (I do not have ADT in here, so forgive me if it needs some correction):

        final EditText editCentimeters = (EditText) findViewById(R.id.editCentimeters);
        final EditText editInches = (EditText) findViewById(R.id.editInches);




        @Override
        public void onClick(View arg0) {

        boolean isValid = true;
        if (editCentimeters.getText().toString().isEmpty())
        {
            editCentimeters.setError("This input cannot be null");
            isValid = false;
        }
        if (editInches.getText().toString().isEmpty())
        {
            editInches.setError("This input cannot be null");
            isValid = false;
        }

        if (isValid) 
        {           
            double centimeters = Double.valueOf( editCentimeters.getText().toString());

            double inches = centimeters *  0.393700787 ;

            editInches.setText(String.valueOf(inches));
        }

    }

Upvotes: 1

Hadi Satrio
Hadi Satrio

Reputation: 4292

You must check the value inside each EditText yourself, and notify the user if its empty:

buttonConvert.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
        if(!"".equals(editCentimeters.getText().toString())) {
            // If the field is not empty, proceed to calculation
            double centimeters = Double.valueOf( editCentimeters.getText().toString());
            double inches = centimeters *  0.393700787 ;
            editInches.setText(String.valueOf(inches));
        } else {
            // If it's empty, show a message to the user)
            editCentimeters.setError("This field can not be empty");
        }
    }
};

Upvotes: 0

Priyank
Priyank

Reputation: 83

The Toast class will be suitable for this purpose as:-

if(editText.getText().toString().equals(""))
   Toast.makeText(this,"Your Error msg",Toast.LENGTH_LONG).show();

The first argument is the Context of your Activity
Second is the CharSequence
And third is the duration of the Toast.

Upvotes: 0

Qadir Hussain
Qadir Hussain

Reputation: 8856

use setError() method for this. do somthing like this

buttonConvert.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {

            if(editCentimeters.getText().toString().equals("")){

                 editCentimeters.setError("*Field Required");

             }else{

            double centimeters = Double.valueOf( editCentimeters.getText().toString());

            double inches = centimeters *  0.393700787 ;

            editInches.setText(String.valueOf(inches));

           }

        }
    });

Upvotes: 0

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