Spinner: getItemAtPosition(position) is returning always null/empty

问题

I wanted to display selected item in the textView when selected from dropdown list of spinner I implemented AdapterView.OnItemSelectedListener but when I'm selecting item its always null/empty here is my code:

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

    spinner = (Spinner) findViewById(R.id.spinner);
    spinner.setAdapter(new CustomAdapter(MainActivity.this, Languages));

    btn.setOnClickListener(this);
    spinner.setOnItemSelectedListener(this);

}

@Override
public void onItemSelected(AdapterView<?> parent, 
                        View view, int position, long id) {

    item = (String)parent.getItemAtPosition(position);

        Toast.makeText(MainActivity.this, item.toString(),
                Toast.LENGTH_SHORT).show();
}

@Override
public void onNothingSelected(AdapterView<?> parent) {
}

回答1:

SO answer source: https://stackoverflow.com/a/49301966/5461982

I know this is an older question now but if anyone else comes across it be sure to check that your custom implementation of the Adapter you're setting for your Spinner overrides the getItem method:

@Override
public Object getItem(int position) {
    return spinnerItems.get(position);
}

By default, you're required to override this method when implementing a custom BaseAdapter but the default return type is null. Be sure to modify the return type to return spinnerItems.get(position).

Hope this helps, I spent around 30 mins trying to work this out originally!

回答2:

Try this,

String selected_item = spinner.getSelectedItem().toString();

回答3:

Just retrieve value from String Array:

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    final String item = Languages[position];
    Toast.makeText(MainActivity.this, item, Toast.LENGTH_SHORT).show();
}

回答4:

try this

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            sSelectedItem = arr_spiner.get(spinner.getSelectedItemPosition())
                    .getName();
            txtSpinnerValue.setText(sSelectedItem);
        }
        @Override
        public void onNothingSelected(AdapterView<?> parent) {
        }
    });

https://stackoverflow.com/questions/45159011/spinner-item-is-not-visible-data-is-coming-from-server-android/45161202#45161202

回答5:

Try This

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

    spinner = (Spinner) findViewById(R.id.spinner);
    spinner.setAdapter(new CustomAdapter(MainActivity.this, Languages));

    btn.setOnClickListener(this);
    spinner.setOnItemSelectedListener(this);

}

@Override
public void onItemSelected(AdapterView<?> parent, 
                        View view, int position, long id) {

    //item = (String)parent.getItemAtPosition(position);
      item = (String) spinner.getSelectedItem().toString(); //Here is the Change

        Toast.makeText(MainActivity.this, item.toString(),
                Toast.LENGTH_SHORT).show();
}

@Override
public void onNothingSelected(AdapterView<?> parent) {
}

The change here is

From

item = (String)parent.getItemAtPosition(position);

item = (String) spinner.getSelectedItem().toString();

来源：https://stackoverflow.com/questions/45188309/spinner-getitematpositionposition-is-returning-always-null-empty

标签

java

android

android-spinner

onitemselectedlistener