Question

I am using a Java switch statement to assign different values to a variable based on the id of the button that called it.

The problem is that it always evaluates to the detail.

I think the error might be in how I am getting the Id (the R.java bit), but I have done some internet research, and can’t find the ‘proper’ way of doing it.

This is my code (the -99 and 23 are there so it was obvious if it wasn’t working)

public void rootMe(View v){

 /* I got rid of some code here so it was shorter */

    int mult = -99;

    int buttonId = v.getId();

    switch(buttonId)
    {
    case R.id.root2:
        mult = 1/2;
    case R.id.root3:
        mult = 1/3;
    case R.id.root4:
        mult = 1/4;
    case R.id.root5:
        mult = 1/5;
    case R.id.root6:
        mult = 1/6;
    default:
        mult = 23;
    }

Answer 1

With a swicth construct, once a case has been reached, the code below that case will be executed — even if there is another case statement.

If you want the execution to stop (to exit the switch construct), you must use a break statement ; most probably at the end of each one of your case blocks :

switch(buttonId)
{
    case R.id.root2:
        mult = 1/2;
        break;
    case R.id.root3:
        mult = 1/3;
        break;
    case R.id.root4:
        mult = 1/4;
        break;
    case R.id.root5:
        mult = 1/5;
        break;
    case R.id.root6:
        mult = 1/6;
        break;
    default:
        mult = 23;
        break;
}

This way, when the code that corresponds to a case statement is executed, it will no longer execute the code that corresponds to the following cases statements, and exit the switch construct.

Note that this is not android-specific : it’s just the way the switch statement works in JAVA ; see for exemple : The switch Statement