How to get Spinner Selected Item in Android

问题:

I am making a currency converter with two spinners. I want to make an "if" function using the values of the spinner's selected item like below.

    @Override
    public void onClick(View v) {
        if (spinner1.getSelectedItem()=="Dollars" && spinner2.getSelectedItem()=="Euros") {
            convertDollarstoEuros();
        }
        if (spinner1.getSelectedItem()=="Euros" && spinner2.getSelectedItem()=="Euros") {
            convertEurostoEuros();
        }
    Toast.makeText(MainActivity.this,
            "OnClickListener : " + 
                    "\nSpinner 1 : "+ String.valueOf(spinner1.getSelectedItem()) + 
                    "\nSpinner 2 : "+ String.valueOf(spinner2.getSelectedItem()),
                Toast.LENGTH_SHORT).show();
        }

The problem is that the toast is showing, but the currencies aren't converting. The toast part is working, but the spinner part isn't. Any help would be greatly appreciated. Here is my LogCat:

回答1:

Try this :

if (spinner1.getSelectedItem().toString().equals("Dollars") && spinner2.getSelectedItem().toString().equals("Euros")
...

getSelectedItem() returns an Object . info . So you have to get the corresponding string first. Then java compares strings using equals().

回答2:

if (spinner1.getSelectedItem()=="Dollars" && spinner2.getSelectedItem()=="Euros") {

You can't compare Strings like that. You have to use the equals() method to compare them. Use this:

if (spinner1.getSelectedItem().toString().equals("Dollars") && spinner2.getSelectedItem().toString().equals("Euros")) {}

回答3:

Check whether you called the id correctly or not? When I was working when improper id was called this exception used to arise. For eg In TextView, findViewById(R.id.textView1) but in xml file we may have set it to textView2.