CODEWITHSUNDEEP
android
Henrik Granström
Henrik Granström

Reputation: 27

How to test string for null value

Have a problem with this code!

I want to check the editText values, if it is null or not... But it gets stuck at the if segment, doesnt mather if it is a value in the editText or not. If there is a value in the editText string it should go further and calculate the values.

Second problem I have is the toast, it doesnt show the text in the string variable, it just prints the string link. 

private EditText fp;
        private EditText fC;
        private EditText drive;
        private TextView totalcost;
    public void CalcButton(View button) {
        // Converting strings to float and check if each is NULL (empty)
        if (!(fp.getText().equals(null)) || (fC.getText().equals(null)) || (drive.getText().equals(null)))
        {
            Toast.makeText(getApplicationContext(), "@string/toast", Toast.LENGTH_LONG).show();

        }else {
            String n1 = fp.getText().toString();
            float no1 = Float.parseFloat(n1);
            String n2 = fC.getText().toString();
            float no2 = Float.parseFloat(n2);
            String n3 = drive.getText().toString();
            float no3 = Float.parseFloat(n3);
            // Calculates the floats
            float calc = no1 * no2 * no3;
            // Converting and prints out the result
            String sum = Float.toString(calc);

                totalcost.setText(sum);
            }

Upvotes: 0

Views: 160

Answers (5)

Kaloglu
Kaloglu

Reputation: 1761

function isNull(int resourceId, boolean getError){
    EditText editText= (EditText) findViewById(resourceId);
    String strEditText = String.valueOf(editText.getText());

    if(TextUtils.isEmpty(strEditText)) {
        if(getError) editText.setError("this is null!");
        return true;
    }else{
        return false;
    }
}

May be this block gives you a few clues about yours

about If Conditions; In your 'IF conditions', parentheses seems less than the count it is necessary. Try to add one more after (!)

I guess it should be like this; for Negative

if (!(
    (String.valueOf(fp.getText()).equals("")) || 
    (String.valueOf(fC.getText()).equals("")) || 
    (String.valueOf(drive.getText()).equals(""))
))

for Positive

if (
    (String.valueOf(fp.getText()).equals("")) || 
    (String.valueOf(fC.getText()).equals("")) || 
    (String.valueOf(drive.getText()).equals(""))
)

Upvotes: 0

Mauker
Mauker

Reputation: 11497

Try to use TextUtils.isEmpty() instead, it checks for null and 0-length String.

On your if statement it should look like:

if (!TextUtils.isEmpty(fp.getText().toString())) {
    // Code
}

And on your Toast, change "@string/toast" to R.string.toast or getApplicationContext().getString(R.string.toast);

The code should look like:

// Converting strings to float and check if each is NULL (empty)
if (! (TextUtils.isEmpty(fp.getText().toString()) || 
        (TextUtils.isEmpty(fC.getText().toString())) || 
        (TextUtils.isEmpty(drive.getText().toString()))))
{
    Toast.makeText(getApplicationContext(), getApplicationContext().getString(R.string.toast), Toast.LENGTH_LONG).show();
}

More on the getString() method here.

EDIT: I've seen that your code also was missing a pair of parenthesis ( ). So your "not" was only applying to the first test.

Something like: 

!(test1) || test2 || test3

Instead of

!((test1) || (test2) || (test3))

Upvotes: 1

PetrS
PetrS

Reputation: 1110

To problem with Toast - use this:

  Toast.makeText(getApplicationContext(), R.string.toast, Toast.LENGTH_LONG).show();

Upvotes: 1

iTurki
iTurki

Reputation: 16398

To check if EditText is empty you do editText.getText().toString().equals("")

So, Your if-statement will look like this:

if (!(fp.getText().toString().equals("")) || 
     (fC.getText().toString().equals("")) ||
     (drive.getText().toString().equals("")))

And your Toast would be like this:

Toast.makeText(getApplicationContext(), R.string.toast, Toast.LENGTH_LONG).show();

Upvotes: 0

M0CH1R0N
M0CH1R0N

Reputation: 756

You should not do it this way, do this instead:

if (!fp.getText().toString().equals("")) {

}

Upvotes: 2

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