Android Studio：三位数的数字不加到++

Question

For practice purposes I'am building a braintrainer app. It looks like this:

You can click on the number that you think is the correct one. Foreach click on a number the top right counter will increase with one. If you clicked the correct number the counter next to it will also increase with one.

My problem is this:

If the correct answer is made out of 2 digits. Both counters will increase. However, if the correct answer is made out of 3 digits. Only the top right counter will increase. Tracking some values give me these logs:

Here is the code that checks if the correct answer is pressed:

public void guessFunction(View view){
    TextView guessView = (TextView) view;
    String buttonText = guessView.getText().toString();
    Log.i("correctAnswer: ", String.valueOf(correctAnswer));
    Log.i("buttonText: ", buttonText);

    if (buttonText == String.valueOf(correctAnswer)){
        correctCount++;
        TextView correctText = (TextView) findViewById(R.id.correctText);
        correctText.setText(String.valueOf(correctCount));
    }
    Log.i("count: ", String.valueOf(correctCount));


    shuffleFunction();
}

Please let me know if more codesamples are needed.

Answer 1

if (buttonText.equals(String.valueOf(correctAnswer)){ ... }

By putting object == otherObject you ask about the identity of two objects, whether or not they are one and the same instance (referenced by two variables). By putting object.equals(otherObject) you ask about the equality of two distinct objects, that is whether two objects are equal in a certain respect (implemented in an equals() method) or not.

In Java, you will almost always want to compare String s with the equals() method of the String class. In your case it is obvious that you are comparing two separate objects (you just created the second String with the static valueOf method of the String class); therefore you need to use equals() .

Answer 2

This is wrong.

if (buttonText == String.valueOf(correctAnswer))

Do not use == to compare strings in Java. Use equals instead.