单击按钮时 Java 中不重复单词 - Android App

Question

I'm trying to create an android app that randomizes fruits but does not repeat them. Something fun for my kids to do since we're all at home right now. However, I'm still very new at programming and had some questions I was hoping you Pro's can help answer.

Here I go:

How can I not repeat the array when I click on the button in Java? I'm trying to generate fruits without them repeating. Can I sort the string that way it runs through all the fruits one by one? It doesn't have to be randomized. I just want each word to show only once when I click the button and show the last array "There aren't any fruit options left"

I tried to randomize the string but that repeats the fruits. I just want it to go one by one. When I press the button on my screen the output on the image label should give me each fruit one at a time.

ie. Button pressed" Output: "Apple"

button pressed again Output: "Banana"

and so on until the last string shows "There aren't any fruit options left"

Can someone also help me go back to the previous array? For example if I clicked the buttons and Apple, Banana, Orange showed but I wanted to go back to see banana. How would I do that?

Thank you for your help!

public class Fruit extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fruit);

        final View.OnClickListener myFamQ = new View.OnClickListener() {
            public void onClick(View v) {


                final TextView Fruittext = (TextView) findViewById(R.id.fruitFamilyText);
                final Button next = (Button) findViewById(R.id.nextQuestion);


                final String[] Fruit = new String [] {"Apple", "Banana", "Orange", "Cherry", "Grapes"};
                final int nextQ = 0;

                if (nextQ < Fruittext.length) {
                    Fruittext.setText(Fruittext[nextQ]);

                } else familyText.setText("There is no more left");



            next.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {

                }

Answer 1

If you edit your code to this it should work without repeating your array.

public class Fruit extends AppCompatActivity {

Button next;
TextView Fruittext;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fruit);

        next = findViewByID(R.id.nextQuestion);
        String[] fruit = new String [] {"Apple", "Banana", "Orange", "Cherry", "Grapes"};

        next.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int nextQ = 0;

                if (nextQ < Fruittext.length) {
                    Fruittext.setText(fruit[nextQ]);
                    nextQ++;
                } else {
                    Fruittext.setText("There is no more available");
                }
            }
        });

If you want to show up a random Fruit in the TextView, just let me know, I'll help you!

Answer 2

You could use an ArrayList and shuffle that easier, but you want to move the logic outside of your OnClickListener .

final String[] Fruit = new String [] {"Apple", "Banana", "Orange", "Cherry", "Grapes"};

// Create a new ArrayList to store the Fruits
final ArrayList<String> list = new ArrayList<String>();
// Add the entire Fruit Array to the list
Collections.addAll(list, Fruit);

// Shuffle the ArrayList to randomize the order
Collections.shuffle(list);
// Our index to keep track of what fruit we want next.
int index = 0;

final View.OnClickListener myFamQ = new View.OnClickListener() {
    public void onClick(View v) {
        final TextView Fruittext = (TextView) findViewById(R.id.fruitFamilyText);
        final Button next = (Button) findViewById(R.id.nextQuestion);

        // You can use the list's size as a max, and just get the next item each click.
        if (index < list.size()) {
            // Grab the next fruit and set the TextView.
            String fruit = list.get(index);
            Fruittext.setText(fruit );

            // Increase our index by 1.
            index = index + 1;
        } else {
            familyText.setText("There is no more left");
        }
    }
}