about UITextFieldDelegate on ios

Question

We are porting a libgdx game to ios.
I create a UITextField and set delegate, here is the code:

this.textField.setDelegate(new Delegate(textField));

public static class Delegate extends UITextFieldDelegate.Adapter
{
    private UITextField mTextField;

    public Delegate(UITextField textField)
    {
        this.mTextField = textField;
    }

    @Override
    public void didBeginEditing(UITextField textField) {
        // TODO Auto-generated method stub
        Gdx.app.debug(TAG, "didBeginEditing");
    }

    @Override
    public void didEndEditing(UITextField textField) {
        // TODO Auto-generated method stub
        Gdx.app.debug(TAG, "didEndEditing");
    }

    @Override
    public boolean shouldBeginEditing(UITextField textField) {
        // TODO Auto-generated method stub
        Gdx.app.debug(TAG, "shouldBeginEditing");
        return true;
    }

    @Override
    public boolean shouldChangeCharacters(UITextField textField,
            NSRange range, String string) {
        // TODO Auto-generated method stub
        Gdx.app.debug(TAG, "shouldChangeCharacters");
        return true;
    }

    @Override
    public boolean shouldClear(UITextField textField) {
        // TODO Auto-generated method stub
        Gdx.app.debug(TAG, "shouldClear");
        return true;
    }

    @Override
    public boolean shouldEndEditing(UITextField textField) {
        // TODO Auto-generated method stub
        Gdx.app.debug(TAG, "shouldEndEditing");
        return true;
    }

    @Override
    public boolean shouldReturn(UITextField textField) {
        // TODO Auto-generated method stub
        if(this.mTextField == textField)
        {
            textField.resignFirstResponder();
        }
        Gdx.app.debug(TAG, "shouldReturn");
        return true;
    }
}

on ios simulator,when I click the textfield, the app will crash, and there is no error message on the console. how to solve it? Any information will be appreciate! thanks in advance!!

Answer 1

Your Delegate instance has probably been GCed before it is called. Try this:

Delegate delegate = new Delegate(textField);
this.textField.setDelegate(delegate);
this.textField.addStrongRef(delegate);

The addStrongRef(...) call prevents the Delegate Java instance from being GCed until the UITextField Objective-C instance is deallocated. This is required since UITextField does not retain (increase the reference count of) the instance you set as delegate.

In a future version of RoboVM the addStrongRef(...) call will be done automatically for you.