How do I display a Random number generated in a TextView?

Question

I am generating random flashes of a button and I want to know what exact number is being chosen each time so I can eventually add them to an ArrayList for a project I am undergoing.

TextView randomTextView;
Random r = new Random();

private void sequenceFunction() {
    //Change Alpha from Fully Visible to Invisible
    final Animation animation = new AlphaAnimation(1, 0);
    //Duration - A Second
    animation.setDuration(1000);
    //Animation Rate
    animation.setInterpolator(new LinearInterpolator());
    animation.setStartOffset(250);
    animation.setDuration(250);
    //Repeat Animation
    animation.setRepeatCount(r.nextInt(10));

    // Reverse animation at the end so the button will fade back in
    animation.setRepeatMode(Animation.REVERSE);

    //Button 1 Flashes
    final Button btn = (Button) findViewById(R.id.button);
    btn.startAnimation(animation);
    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(final View view) {
            view.clearAnimation();
        }
    });
}

I want to display the result of what ever random number has been generated via the randomTextView TextView. This part is critical so that I know that the random function is working as it is supposed to. I have already tried

randomTextView.setText(r.nextInt(10));

However it didn't like it. Any ideas on how to get the random number selected would be greatly appreciated ?

what don't you like about `randomTextView.setText(r.nextInt(10))` ? — TWL, Jan 11 '17 at 18:38
@TWL `setText()` needs a CharSequence or a resource id. Which is obviously not the case. — Phantômaxx, Jan 11 '17 at 19:13

score 1 · Accepted Answer · answered Jan 11 '17 at 18:55

Hope this helps -

private void sequenceFunction() {
    //Change Alpha from Fully Visible to Invisible
    final Animation animation = new AlphaAnimation(1, 0);
    //Duration - A Second
    animation.setDuration(1000);
    //Animation Rate
    animation.setInterpolator(new LinearInterpolator());
    animation.setStartOffset(250);
    //Repeat Animation
    int randomValue = r.nextInt();
    // code to add value to array
    animation.setRepeatCount(randomValue);
    randomTextView.setText(String.valueOf(randomValue));

    // Reverse animation at the end so the button will fade back in
    animation.setRepeatMode(Animation.REVERSE);

    //Button 1 Flashes
    final Button btn = (Button) findViewById(R.id.button);
    btn.startAnimation(animation);
    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(final View view) {
            view.clearAnimation();
        }
    });


}

score 0 · Answer 2 · answered Jan 11 '17 at 18:33

0

If you have look in the documentation of TextView, you can see that setText(int) actually expects a resource id: https://developer.android.com/reference/android/widget/TextView.html#setText(int)

So you have to turn your int to a CharSequence, you could simply do

randomTextView.setText("" + r.nextInt(10));

which converts your integer to a string.

answered Jan 11 '17 at 18:33

SimMac

479
5
16

Hi Thanks for your reply how would I get the number of animation.setRepeatCount(r.nextInt(10)); as when I do the randomTextView.setText(r.nextInt(10)+""); it sees it as a new random number and not the one I am using to generate the animation flashes ? – Leo_D Jan 11 '17 at 18:35
In this case, just store the value in a variable like this: `int randomNumber = r.nextInt(10);` `animation.setRepeatCount(randomNumber);` `...` `randomTextView.setText(Integer.toString(random));` – SimMac Jan 11 '17 at 18:40
save `r.nextint(10)` in some variable then pass it to `animation.setRepeatCount()` and use it anywhere. – jack jay Jan 11 '17 at 18:41
@SimMac Please refer to [this answer](http://stackoverflow.com/a/4105406/2948765) for an explanation why `"" + ...` is bad style. – Tobias Jan 11 '17 at 19:26

Tobias · Answer 3 · 2017-01-11T18:43:53.807

0

TextView.setText can be used with either a resource ID (which is an integer) or with a CharSequence, for example a String.

There are many ways to do this, including

int random = r.nextInt(10);
randomTextView.setText(String.valueOf(random);
randomTextView.setText(Integer.toString(random);
randomTextView.setText(String.format("%d", random);

Do not use "" + r.nextInt(10). I know, it is short, it is handy, but it is simply inefficient and bad style.

edited Jan 11 '17 at 18:43

answered Jan 11 '17 at 18:36

Tobias

7,723
1
27
44

Hi thanks for the recorrection however how would I use this to get the exact random number that is being generated by animation.setRepeatCount(r.nextInt(10)); ? – Leo_D Jan 11 '17 at 18:39
This code displays the generated number in the `TextView`. If you want to use the number multiple times, you will need to cache it in a variable like this: `int number = r.nextInt(10); randomTextView.setText(String.valueOf(number));` and then use the variable `number`. – Tobias Jan 11 '17 at 18:41

How do I display a Random number generated in a TextView?

3 Answers3