Question

我想使用微调器提示，例如＆＃34;选择城市＆＃34;。我在布局select_city中的字符串布局使用中设置了android:prompt="@string/select_city"的值，但它没有用。也尝试使用sp_city.setPrompt("Select City");也没有用。

我的问题是什么？我该如何解决它并设置提示？

布局：

<Spinner
    android:id="@+id/spinner_poi_city"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:drawable/btn_dropdown"
    android:spinnerMode="dropdown"/>

类别：

public class FirstPOIPreference extends DialogPreference {

    private Spinner sp_city;
    private ArrayAdapter<String> adapter;
    private POI poiDialog = new POI();

    public FirstPOIPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        setPersistent(false);
        setDialogLayoutResource(R.layout.pref_poi_dialog);
        setPositiveButtonText(android.R.string.ok);
        setNegativeButtonText(android.R.string.cancel);
    }

    @Override
    protected void onBindDialogView(View view) {
        super.onBindDialogView(view);
        initViews(view);
    }

    private void initViews(View view) {
        sp_city = (Spinner) view.findViewById(R.id.spinner_poi_city);
        sp_city.setPrompt("City");
        String[] arrayCity = new String[]{"Erie", "Pittsburgh", "Cleveland", "Buffalo", "Niagara Falls", "Jamestown"};
        adapter = new ArrayAdapter <> (this.getContext(), android.R.layout.simple_spinner_dropdown_item, arrayCity);
        sp_city.setAdapter(adapter);

        sp_city.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView <?> parentView, View selectedItemView, int position, long id) {
                poiDialog.setCity(sp_city.getSelectedItem().toString());
            }

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

}

Answer 1

你可以这样做，我已经做了一些棘手的方式。它可以帮助你

private void initViews(View view) {

sp_city = (Spinner) view.findViewById(R.id.spinner_poi_city);

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item) {

                @Override
                public View getView(int position, View convertView, ViewGroup parent) {

                    View v = super.getView(position, convertView, parent);
                    if (position == getCount()) {
                        ((TextView) v.findViewById(android.R.id.text1)).setText("");
                        ((TextView) v.findViewById(android.R.id.text1)).setHint(getItem(getCount())); //"Hint to be displayed"
                    }
                    return v;
                }

                @Override
                public int getCount() {
                    return super.getCount() - 1; // you dont display last item. It is used as hint.
                }
            };
            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            adapter.add("Erie");
            adapter.add("Pittsburgh");
            adapter.add("Cleveland");
            adapter.add("Buffalo");
            adapter.add("Niagara Falls");
            adapter.add("Jamestown");
            adapter.add("Select City"); //This is the text that will be displayed as hint.

            sp_city.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
                    String spinnerValue = String.valueOf(sp_city.getSelectedItem().toString());
                    if (!spinnerValue.equalsIgnoreCase("Select City")) {
                        //do your code
                        Toast.makeText(this, sp_city.getSelectedItem().toString(), Toast.LENGTH_LONG).show();
                    }
                }
                @Override
                public void onNothingSelected(AdapterView<?> parentView) {
                }
            });

            sp_city.setAdapter(adapter);
            sp_city.setSelection(adapter.getCount()); //set the hint the default selection so it appears on launch.
        }

Answer 2

我认为更好的解决方案是使用“选择城市”作为您将添加到微调器的数组的第一项。因此，默认情况下，它将显示选择城市。您可以通过检查微调器选择的位置来检查是否选择了城市。如果位置为0，则显示吐司或“请选择城市”。

Answer 3

您错误地提示默认文字。点击微调器，您将看到＆＃34;选择City＆＃34;作为标题

提示用于在下拉弹出窗口中显示标题，而不是默认文本。

如果要在微调器上选择默认值当您没有从微调器下拉列表中选择任何值时。然后你必须使用

NothingSelectedSpinnerAdapter

How to make an Android Spinner with initial text "Select One"

微调器提示不会显示

3 个答案: