file - My objects in my array are going to null (java)

Question

I have this while loop that is pulling information from a file and making new objects and then placing the objects into an array and for some reason the while loop iterates once for each if statement and then exits so all the other lines are made null. Here is my while loop

// open file and create array
        File file = new File("Adventures.txt");
        Scanner myReader = new Scanner(file);
        Adventure[] array = new Adventure[myReader.nextInt()];
        int i = 0;
        // reading file
        while (myReader.hasNext()) {
            if ("Zipline".equals(myReader.next())) {
                array[i] = new Zipline(myReader.nextDouble(), myReader.nextDouble());
                i++;
            }
            if ("Snorkel".equals(myReader.next())) {
                array[i] = new Snorkel(myReader.nextDouble(), myReader.nextDouble());
                i++;
            }
            if ("Helicopter".equals(myReader.next())) {
                array[i] = new Helicopter(myReader.nextDouble(), myReader.nextDouble());
                i++;
            }
        } // while loop
    ```

question from:https://stackoverflow.com/questions/66059348/my-objects-in-my-array-are-going-to-null-java

Answer 1

Each iteration of the loop is using too many values, because each call to myReader.next() is consuming another token. Store the token in a variable, so you can check it multiple times.

while (myReader.hasNext()) {
    String token = myReader.next();
    if ("Zipline".equals(token)) {
        array[i++] = new Zipline(myReader.nextDouble(), myReader.nextDouble());
    }
    if ("Snorkel".equals(token)) {
        array[i++] = new Snorkel(myReader.nextDouble(), myReader.nextDouble());
    }
    if ("Helicopter".equals(token)) {
        array[i++] = new Helicopter(myReader.nextDouble(), myReader.nextDouble());
    }
} // while loop

Or use a switch statement:

while (myReader.hasNext()) {
    switch (myReader.next()) {
        case "Zipline":
            array[i++] = new Zipline(myReader.nextDouble(), myReader.nextDouble());
            break;
        case "Snorkel":
            array[i++] = new Snorkel(myReader.nextDouble(), myReader.nextDouble());
            break;
        case "Helicopter":
            array[i++] = new Helicopter(myReader.nextDouble(), myReader.nextDouble());
            break;
    }
} // while loop