Why this is so(see the below two code samples)?

Question

Code 1:

public void displayQuantity(int number) {
    TextView quantityTV = (TextView) findViewById(R.id.quantity_tv);
    quantityTV.setText( " "+ number);
      }

Code 2:

 public void displayQuantity(int number) {
            TextView quantityTV = (TextView) findViewById(R.id.quantity_tv);
            quantityTV.setText(number);
         }

Why Code 2 gives error while code 1 doesn't?? There is a difference of - " __ " in b/w code 1 & 2

Code 2 gives error because textview need CharSequence so can't support int value and code 1 not gives an error because + operator automatically converts it into String — Mahesh Vayak, Dec 22 '18 at 06:14
It is because in code 1 you are saying setText( " " + number) which means you are passing string and in code 2 you are saying setText(number) which means you are passing int instead of string. — , Dec 22 '18 at 06:14

score 1 · Answer 1 · answered Dec 22 '18 at 06:14

According to the documentation

Code 1 uses the method setText(CharSequence text) which "sets the text to be displayed".

Code 2 uses the method setText(int resid) which "Sets the text to be displayed using a string resource identifier". Your number most likely is not a valid string resource identifier which gives you an error. Even if it was, the displayed string would have nothing to do with the quantity you want to display.

score 0 · Answer 2 · answered Dec 22 '18 at 06:13

0

In TextView you can set only String(CharSequence) value and your number data type is in int if you do like this it will not show any error :

          public void displayQuantity(int number) {
            TextView quantityTV = (TextView) findViewById(R.id.quantity_tv);
            quantityTV.setText(String.valueOf(number));
         }

answered Dec 22 '18 at 06:13

Abhinav Gupta

2,225
1
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30

Not quite- setText has an int version- but it takes a resourceID to a string resource. And if the id passed doesn't match a string resource, it will throw an exception. That's what's happening here. – Gabe Sechan Dec 22 '18 at 06:27
@GabeSechan Yes I wrote this in short way.... – Abhinav Gupta Dec 22 '18 at 06:32

score 0 · Answer 3 · answered Dec 22 '18 at 06:16

0

number is int type and + operator automatically converts it into String.("" is empty String)

+ operator for String in Java

answered Dec 22 '18 at 06:16

Dhaval Goti

447
2
10
25

score 0 · Answer 4 · answered Dec 22 '18 at 06:17

0

Try number.toString() in code 2 because you are doing string concatenation with an int in the

answered Dec 22 '18 at 06:17

Sterben

9
2

Why this is so(see the below two code samples)?

4 Answers4