android - 在 Android 的 Spinner 中未选择位置 0

Question

我创建了一个包含三个项目的微调器

每日

每周

每月

我在我的 java 文件中执行了以下操作:

navSpinner = new ArrayList<SpinnerNavItem>();
        navSpinner.add(new SpinnerNavItem(getResources().getString(R.string.dailyview)));
        navSpinner.add(new SpinnerNavItem(getResources().getString(R.string.weekview)));
        navSpinner.add(new SpinnerNavItem(getResources().getString(R.string.monthview)));

        adapter = new TitleNavigationAdapter(getActivity().getApplicationContext(), navSpinner);
        mSpinner = (Spinner) rootView.findViewById(R.id.spinner);
        mSpinner.setAdapter(adapter);
        mSpinner.setOnItemSelectedListener(this);

OnItemSelected 方法(实现 AdapterView.OnItemSelectedListener)

public void onItemSelected(AdapterView<?> parentView, View v, int position, long id) {

        Log.e("Position", "= " + position);

        if (mNaviFirstHit)
        {
            mNaviFirstHit = false;
        }
        else
        {

            Fragment fragment = null;
            switch (position) {
                case 0:

                    Log.e("Week", "= " + position);
                    break;

                case 1:

                    backspace = 1;

                    Log.e("Week", "= " + position);

                    break;

                case 2:

                    backspace = 1;

                    Log.e("Week", "= " + position);

                    break;

                default:
                    break;
            }
        }
    }

    public void onNothingSelected(AdapterView<?> parentView) {

    }

适配器:

public class TitleNavigationAdapter extends BaseAdapter 
{
    private TextView txtTitle;
    private ArrayList<SpinnerNavItem> spinnerNavItem;
    private Context context;
    private TextView txtHeading;
    private SharedPreferences pref;

    public TitleNavigationAdapter(Context context, ArrayList<SpinnerNavItem> spinnerNavItem) 
    {
        this.spinnerNavItem = spinnerNavItem;
        this.context = context;
    }

    @Override
    public int getCount() 
    {
        return spinnerNavItem.size();
    }

    @Override
    public Object getItem(int index) 
    {
        return spinnerNavItem.get(index);
    }

    @Override
    public long getItemId(int position) 
    {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) 
    { 
        if (convertView == null) 
        {
            LayoutInflater mInflater = (LayoutInflater)
                    context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(R.layout.list_item_title, null);
        }

        txtTitle = (TextView) convertView.findViewById(R.id.txtTitle);
        txtTitle.setText(spinnerNavItem.get(position).getTitle());

        txtTitle.setTextColor(context.getResources().getColor(R.color.orangeText));
        txtTitle.setTextSize(TypedValue.COMPLEX_UNIT_SP, 12);

        pref = context.getSharedPreferences("MyPref", Context.MODE_PRIVATE);
        String text = pref.getString("selectedItem", context.getResources().getString(R.string.transaction_main_gridview));

        if (text.equalsIgnoreCase(convertView.getResources().getString(R.string.transaction_main_gridview)))
        {
            txtTitle.setText(convertView.getResources().getString(R.string.transaction_main_gridview_text));
        }
        else if (text.equalsIgnoreCase(convertView.getResources().getString(R.string.transaction_main_weekview)))
        {
            txtTitle.setText(convertView.getResources().getString(R.string.transaction_main_weekly_text));
        }
        else if (text.equalsIgnoreCase(convertView.getResources().getString(R.string.transaction_main_monthview)))
        {
            txtTitle.setText(convertView.getResources().getString(R.string.transaction_main_monthly_text));
        }

        return convertView;
    }


    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) 
    {
        if (convertView == null) 
        {
            LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(R.layout.list_item_title, null);
        }

        txtTitle = (TextView) convertView.findViewById(R.id.txtTitle);
        txtTitle.setPadding(20, 20, 0, 20);

        txtHeading = (TextView) convertView.findViewById(R.id.txtheading);
        txtHeading.setVisibility(View.GONE);

        txtTitle.setText(spinnerNavItem.get(position).getTitle());
        return convertView;
    }

}

当我选择位置 1 或 2(我正确获取日志)时，上面的代码工作正常，然后如果我选择位置 0，则从位置 1 或 2 根本不打印日志。位置没有被调用。即使只是位置日志也不会打印出来。

这真的很奇怪，我不确定为什么会这样？有人可以帮我吗？

谢谢!

Answer 1

如果你想在Fragment中制作一个Spinner，你必须在Fragment的onCreatedView()中声明它。不在 FragmentActivity 的 onCreate() 中。

OnItemSelectedListener 必须在 FragmentMain 内实现，而不是在 Activity 内实现，如果您想在 Fragment 内的微调器上使用监听器。

对您的代码所做的这些更改已经过测试。

您的上下文返回 null(无论如何在我的测试代码中):

Context mContext = getActivity().getApplicationContext();// returns null !

所以改为:

TitleNavigationAdapter adapter = new TitleNavigationAdapter(this,navSpinner);//添加了这个

您的 Activity 是否实现了 OnItemSelectedListener ？:

        public class InformationList  extends Activity implements OnItemSelectedListener {
    .....

我也会在 TitleNavigationAdapter 中更改它:

    @Override
public SpinnerNavItem getItem(int index) //SpinnerNavItem from Object
    {
        return spinnerNavItem.get(index);
    }

结果:

07-18 19:46:53.468: E/Position(27325): = 0
07-18 19:46:53.468: E/day(27325): = 0
07-18 19:47:04.487: E/Position(27325): = 1
07-18 19:47:04.488: E/Week(27325): = 1
07-18 19:47:06.426: E/Position(27325): = 2
07-18 19:47:06.426: E/month(27325): = 2

正常运行。