ActionBarSherlock和ActionBar.OnNavigationListener

Question

我有带列表导航的ActionBar。 正如我所看到的，仅为新选择的位置调用ActionBar.OnNavigationListener。 有没有办法让每个选项都有回调，即使我选择了已选择的项目？

Answer 1

我只有一个hacky解决方案，我愿意接受如何改进它的建议。但它的确有效。

诀窍是在实际选择之后有一个不可见的项目被选中。这样，当您重新选择所选项时，会再次调用onNavigationItemSelected。

public class ReselectAdapter extends ArrayAdapter<String> {
    private Context mContext;
    private ArrayList<String> mItems;
    private int mInternalPosition;

    public ReselectAdapter(Context context, ArrayList<String> items) {
        super(context, R.layout.sherlock_spinner_item, items);
        mContext = context;
        mItems = items;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        TextView textView = (TextView) convertView;
        if (textView == null) {
            textView = (TextView) LayoutInflater.from(mContext).inflate(
                    R.layout.sherlock_spinner_item, null);
            textView.setText(mItems.get(mInternalPosition));
        }
        return textView;
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup
            parent) {
        TextView textView = null;
        if (position == mItems.size() - 1) {
            textView = new TextView(mContext);
            textView.setHeight(0);
        } else {
            textView = (TextView) LayoutInflater.from(mContext)
                    .inflate(R.layout.sherlock_spinner_dropdown_item, 
                            parent, false);
            textView.setText(mItems.get(position));
        }
        parent.setVerticalScrollBarEnabled(false);
        return textView;
    }

    public void setInternalPosition(int internalPosition) {
        mInternalPosition = internalPosition;
    }
}

@Override
public void onCreate(Bundle savedInstanceState) {
    // [...]
    ArrayList<String> items = new ArrayList<String>();
    items.add("A");
    items.add("B");
    items.add("C");
    items.add(""); // the last item is the invisible one
    mReselectAdapter = new ReselectAdapter(context, items);
    getSupportActionBar().setListNavigationCallbacks(mReselectAdapter, this);
}

@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId) {
    int navigationItemCount = getSupportActionBar().getNavigationItemCount();
    if (itemPosition == navigationItemCount - 1) {
        return true;
    }
    Log.i("onNavigationItemSelected", mReselectAdapter.getItem(itemPosition));
    mReselectAdapter.setInternalPosition(itemPosition);
    getSupportActionBar().setSelectedNavigationItem(navigationItemCount - 1);
    return true;
}