Increase a char value by one

Question

I have an app with an EditText and a button named "forward". All I want is just when I type "a" in the EditText and click the button, the word "b" to be typed in the EditText, "c" if pressed again and so on. I have tried:

value = edt.getText();
edt.setText(value + 1);

But that of course will print the initial string followed by the number "1". Any ideas? Thanks a lot

Answer 1

Tested and works

All letters can be represented by their ASCII values.

If you cast the letters to an int, add 1, and then cast back to a char, the letter will increase by 1 ASCII value (the next letter).

For example:

'a' is 97
'b' is 98

So if the input was 'a' and you casted that to an int, you would get 97. Then add 1 and get 98, and then finally cast it back to a char again and get 'b'.

Here is an example of casting:

System.out.println( (int)('a') ); // 97
System.out.println( (int)('b') ); // 98
System.out.println( (char)(97) ); // a
System.out.println( (char)(98) ); // b

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So, your final code might be this:

// get first char in the input string
char value = et.getText().toString().charAt(0);

int nextValue = (int)value + 1; // find the int value plus 1

char c = (char)nextValue; // convert that to back to a char

et.setText( String.valueOf(c) ); // print the char as a string

Of course this will only work properly if there is one single character as an input.

Answer 2

A simpler way would be:

char value = edt.getText().toString().charAt(0);
edt.setText(Character.toString ((char) value+1));

Here the value + 1 adds the decimal equivalent of the character and increments it by one.. Here is a small chart:

Whats happens after 'z'? ... it wont crash.. see here for the full chart..