How to display validation error for a spinner widg

问题:

How to display validation error for a spinner widget similar to TextView.setError() I don't want to open a new dialog box for every spinner validation error, android.widget.Spinner class doesn’t have setError method

回答1:

If your spinner is set-up with default item views the getSelectedView() method on Spinner class will return a TextView. And on that you can call setError(CharSequence) Here is what I did:

View selectedView = spinner.getSelectedView();
if (selectedView != null && selectedView instanceof TextView) {
    TextView selectedTextView = (TextView) selectedView;
    if (!valid) {
        String errorString = selectedTextView.getResources().getString(mErrorStringResource);
        selectedTextView.setError(errorString);
    }
    else {
        selectedTextView.setError(null);
    }
}

Result looks like this on Android 4.4:

回答2:

A somewhat cleaner way of doing Diederik's code:

static public void setSpinnerError(Spinner spinner, String error){
    View selectedView = spinner.getSelectedView();
    if (selectedView != null && selectedView instanceof TextView) {
        TextView selectedTextView = (TextView) selectedView;
        selectedTextView.setError(error);
    }
}

Just set error to null if you want to dismiss it.

回答3:

So, you can use 'setError' in your getView in the adapter of spinner. Of course, if your item's xml of your spinner has a TextView:

if(requeriedField && item.getValue() == 0){
    img_tittle_spinner.setError(activity.getResources().getString(R.string.FieldRequired));
}