Android for Beginners : Negative Number of Cups of Coffee Extra Challenge Solution

Code snippet from MainActivity.java

    /**
     * This method is called when the plus button is clicked.
     */
    public void increment(View view) {
        if (quantity == 100) {
            // Show an error message as a toast 
            Toast.makeText(this, "You cannot have more than 100 coffees", Toast.LENGTH_SHORT).show();
            // Exit this method early because there's nothing left to do
            return;
        }
        quantity = quantity + 1;
        displayQuantity(quantity);
    }

    /**
     * This method is called when the minus button is clicked.
     */
    public void decrement(View view) {
        if (quantity == 1) {
            // Show an error message as a toast 
            Toast.makeText(this, "You cannot have less than 1 coffee", Toast.LENGTH_SHORT).show();
            // Exit this method early because there's nothing left to do
            return;
        }
        quantity = quantity - 1;
        displayQuantity(quantity);
    }

here is another method ( I start with quantity=2)
public void increment (View view) {
if (quantity<100){
quantity++;
display(quantity);
} else {
Toast.makeText(this, "You cannot have more than 100 coffees", Toast.LENGTH_SHORT).show();
return;
}
}
public void decrement (View view) {

    if (quantity>=2){
        quantity--;
        display(quantity);
    } else {
        Toast.makeText(this, "You cannot have less than 1 coffee", Toast.LENGTH_SHORT).show();
        return;
    }
}

to solve this I preferred to use this code...

 if (quantity > 0) {
           quantity = quantity - 1;
        } else {
            Toast.makeText(this, "You cannot have less than 1 coffee", Toast.LENGTH_SHORT).show();
        }
        displayQuantity(quantity);

this way solves the problem @tompad2, but as Katherine said, there are many ways of solving these issues

to solve this I preferred to use this code...

 if (quantity > 0) {
           quantity = quantity - 1;
        } else {
            Toast.makeText(this, "You cannot have less than 1 coffee", Toast.LENGTH_SHORT).show();
        }
        displayQuantity(quantity);

this way solves the problem @tompad2, but as Katherine said, there are many ways of solving these issues

i also solved this way:

if(quantity == 0){
Toast.makeText(MainActivity.this, "You can not have less than 1 cup of coffee", Toast.LENGTH_SHORT).show();
return;
}

instead of 1 i used 0 ===> Happy Coding

i also solved this way:

if(quantity == 0){
Toast.makeText(MainActivity.this, "You can not have less than 1 cup of coffee", Toast.LENGTH_SHORT).show();
return;
}

instead of 1 i used 0 ===> Happy Coding

Hi ...
@RandomYogi has been noticed that quantity become "0" when rotate the phone ... seems that the class MainActivity re-create... can anyone explain the reason.. to try to avoid that

thanx

Isnt quantity set to 0?? If so... if you start to click decrement when app is just started it would be doing -1....or?

Hi, I think that will work well
//AS quantity =2
// increase quantity by 1
public void increment(View view) {

    if (quantity == 100) {
        quantity = 100;
        Toast toast = Toast.makeText(context, "It isn't available, Try again", Toast.LENGTH_SHORT);
        toast.show();
             } else {
        quantity = quantity + 1;
    }
    display(quantity);
}

// decrease quantity by 1
public void decrement(View view) {


    if (quantity == 1) {
        quantity = 1;
        Toast.makeText(this, "You cannot have less than 1 coffee", Toast.LENGTH_SHORT).show();
    } else {
        quantity -= 1;
    }
    display(quantity);
}

nice code

nice this is nice lecture