Question

I am a newbie Android Developer. I am trying to get a text input from user using and Edittext box and then convert that text into string and then into a char array of size 4. i have an array already stored that is of size 4 and it contains values. i want to compare both the arrays and perform a task based on the result.

I don’t know why am i getting the ArrayIndexOutOfBoundsExecption

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.newgame);

    Button submit = (Button) findViewById(R.id.guess);



    EditText guess = (EditText) findViewById(R.id.editText1);


    boolean c=false;

    char[] guessword;
    char[] appword = {'T', 'R', 'U', 'E'};
    guessword = guess.getText().toString().toCharArray();


    for(int i=0;i<appword.length;i++)
    {
        if(guessword[i]==appword[i])
        {
            c=true;
        }
        else
        {
            c=false;
        }
    }

    final boolean correct=c;        


    submit.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {

            if(correct){
                startActivity(new Intent(Newgame.this, Win.class));
            }
            else{
                startActivity(new Intent(Newgame.this, Loose.class));
            }

        }
    });



}

}

Answer 1

The problem is that guessword may have fewer than four characters, and your code does not check for that condition.

Change your code as follows to account for this condition:

for(int i=0;i<appword.length;i++)
{
    if((i < guessword.length) && (guessword[i]==appword[i]))
    {
        c=true;
    }
    else
    {
        c=false;
        break; // <<<=== Add this to end the loop
    }
}

Also note that your code as written does not “lock in” the false when characters are not equal to each other: for example, {'A','B','Z'} and {'X', 'Y', 'Z'} will compare equal under your old algorithm. Add break to exit the loop as soon as you see a false.