在Android开发中使用Spinner

Question

I'm new to android development, I have some experiences on C# windows programming, but also very little. I'm working on an android application which uses spinners. So far, I found a tutorial which make spinner items, and displays spinner text in text view, as you select spinner item. The code lookes like this:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    spinner =(Spinner)findViewById(R.id.sp);
    text=(TextView)findViewById(R.id.tv);
    ArrayAdapter<CharSequence> adapter =ArrayAdapter.createFromResource(this, R.array.spinnerarray, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  spinner.setAdapter(adapter);
  spinner.setOnItemSelectedListener(new function());
}


public class function implements OnItemSelectedListener {

    @Override
    public void onItemSelected(AdapterView<?> parent, View arg1, int pos,
            long id) {
        // TODO Auto-generated method stub
        String str=parent.getItemAtPosition(pos).toString();
        text.setText(str);

    }

I want to make an application, which will calculate some points, with the grade user would choose. Example: spinner will contain grades, such as Negative(1), Positive(2),Good(3), Very Good(4), Excellent(5). I want to achieve, that when an user chooses one grade, lets say very good, that the application will use the grade for very good which is 4, and it would transform it to some points, determined by me ( 1=20, 2=40,3=60,4=80,5=100). The points will be later used in calculation, but I have no idea how to assign points to certain grade. I hope you understand my question and thank you for your help.

I had the same app for windows, there I just used something like: if(veryGood.IsSelected==true){points = 20}, and i want to achieve same effect here.

Answer 1

You need a simple modifications on your function class:

public class function implements OnItemSelectedListener {

   private final static int[] grades = new int[]{20,40,60,80,100}; //change in whatever you want. The length of the array must be the same of the adapter, or an ArrayIndexOutOfBoundException may be throwed.

   @Override
   public void onItemSelected(AdapterView<?> parent, View arg1, int pos, long id) {
       text.setText(grades[pos] + " points!");
   }
}

PS: in Java is a good practice to use upper case initial on class names eg Function instead of function.