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Android

chelseahansell
chelseahansell
1,795 Points
Posted by chelseahansell
chelseahansell
1,795 Points

Android development: unexpected token, unknown class, identifier expected, cannot resolve symbol, etc.

I have 23 errors as I'm trying to add an array to my java in the Introduction to Arrays lesson. I can't see what changed and I tried erasing the changes I made. I also tried cleaning the project and re-building. Nothing has worked.

Help please!

The issues appear to start in the if else statement section, but it also says "cannot resolve listener."

if(randomNumber==0) { fact = "Ants stretch when they wake up in the morning."; }

        else if(randomNumber==1)

        {
            fact = "Ostriches can run faster than horses.";
        }

        else if(randomNumber==2)

        {
            fact = "Olympic gold medals are actually made mostly of silver.";
        }

        else

        {
            fact = "Sorry, there was an error!";
        }


        //Update the label with our dynamic fact
        factLabel.setText(fact);

    }
    };
    showFactButton.setOnClickListener(listener);
}
Daniel Hartin
Daniel Hartin
18,106 Points
Daniel Hartin
Daniel Hartin
18,106 Points

Hi chelsea,

Can't see anything wrong with the code you have posted. Can you post the entire code please. I suspect something went wrong when you set you listener variable to a new onClickListener, but I can't tell without seeing the entire code

Thanks Daniel

miguelcastro2
miguelcastro2
Courses Plus Student 6,573 Points

From what I see thus far you have not defined the event listener. Have you defined it elsewhere?

You can define an anonymous listener like this:

showFactButton.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
        // Your code goes here.
    }
});

4 Answers

Daniel Hartin
Daniel Hartin
18,106 Points
Daniel Hartin
Daniel Hartin
18,106 Points

Hi Chelsea

I've spotted a couple of things although not sure if it causing all the errors so you will have to make the changes below and comment back if you are still having problems.

  • You are missing the ) at the end of you onCllick() method.
  • The entire if statement is not necessary as you should now be getting facts from your facts array.

-The closure of your onClick() methos is above the String fact = "" line when it should encapsulate all you code apart from the last line showFactButton.setOnClickListener(listener);

I have posted the corrected code below

public class FunFactsActivity extends Activity {

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

    //Declare View variables and assign them the Views from the layout file
    final TextView factLabel = (TextView) findViewById(R.id.factTextView);
    Button showFactButton = (Button) findViewById(R.id.showFactButton);
    View.OnClickListener listener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String[] facts = {
                    "Ants stretch when they wake up in the morning.",
                    "Ostriches can run faster than horses.",
                    "Olympic gold medals are actually made mostly of silver.",
                    "You are born with 300 bones; by the time you are an adult you will have 206.",
                    "It takes about 8 minutes for light from the Sun to reach Earth.",
                    "Some bamboo plants can grow almost a meter in just one day.",
                    "The state of Florida is bigger than England.",
                    "Some penguins can leap 2-3 meters out of the water.",
                    "On average, it takes 66 days to form a new habit.",
                    "Mammoths still walked the earth when the Great Pyramid was being built."};



        //The button was clicked, so update the fact label with a new fact
        String fact;
        //Randomly select a fact
        Random randomGenerator = new Random();  //Construct a new random variable generator
        int randomNumber = randomGenerator.nextInt(10);

        fact = facts[randomNumber];


        //Update the label with our dynamic fact
        factLabel.setText(fact);


    });
    showFactButton.setOnClickListener(listener);
}

Hope this helps

Daniel

chelseahansell
chelseahansell
1,795 Points
chelseahansell
chelseahansell
1,795 Points

Here is the entire code. I followed the videos carefully and everything worked until I started adding array data. I'm guessing I either deleted something that broke the rest of the code or forgot a symbol, but I'm too inexperienced to see where it went wrong. Thank you everyone!

public class FunFactsActivity extends Activity {

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

    //Declare View variables and assign them the Views from the layout file
    final TextView factLabel = (TextView) findViewById(R.id.factTextView);
    Button showFactButton = (Button) findViewById(R.id.showFactButton);
    View.OnClickListener listener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String[] facts = {
                    "Ants stretch when they wake up in the morning.",
                    "Ostriches can run faster than horses.",
                    "Olympic gold medals are actually made mostly of silver.",
                    "You are born with 300 bones; by the time you are an adult you will have 206.",
                    "It takes about 8 minutes for light from the Sun to reach Earth.",
                    "Some bamboo plants can grow almost a meter in just one day.",
                    "The state of Florida is bigger than England.",
                    "Some penguins can leap 2-3 meters out of the water.",
                    "On average, it takes 66 days to form a new habit.",
                    "Mammoths still walked the earth when the Great Pyramid was being built."};

        }

        //The button was clicked, so update the fact label with a new fact
        String fact = "";
        //Randomly select a fact
        Random randomGenerator = new Random();  //Construct a new random variable generator
        int randomNumber = randomGenerator.nextInt(10);

        if(randomNumber==0)

        {
            fact = "Ants stretch when they wake up in the morning.";
        }

        else if(randomNumber==1)

        {
            fact = "Ostriches can run faster than horses.";
        }

        else if(randomNumber==2)

        {
            fact = "Olympic gold medals are actually made mostly of silver.";
        }

        else

        {
            fact = "Sorry, there was an error!";
        }


        //Update the label with our dynamic fact
        factLabel.setText(fact);


    };
    showFactButton.setOnClickListener(listener);
}
Steven Byrne
Steven Byrne
4,120 Points
Steven Byrne
Steven Byrne
4,120 Points

Your indentation makes me think that your "if" code is not in the onClick method. The variable decls are not causing errors because they are member variables in the anon inner class. Perhaps you want to move the closing brace here

  "Mammoths still walked the earth when the Great Pyramid was being built."};

        }  <--------------------
// line numbers in the example would help -- don't know if that's an option

down to below your executable code.

chelseahansell
chelseahansell
1,795 Points
chelseahansell
chelseahansell
1,795 Points

It turned out to be a } in the wrong place. I'm still not sure how it got out of place, but I moved it all over with no luck. Then I went back and examined the code from the video line by line. It's in the right place now.

Thanks guys!