如果您在从数据库游标填充项时遇到此问题，

我在这个SO答案中找到的最简单的解决方案:

在游标适配器查询中使用UNION，并将id= -1的附加项添加到查询结果中，而不真正将其添加到DB中:

喜欢的东西:

db.rawQuery("SELECT iWorkerId as _id, nvLastName as name  FROM  Worker
w  UNION  SELECT -1 as _id , '' as name",null);

如果选择的项目是-1，那么它是默认值。否则 这是桌子上的记录。

我认为最简单的方法是在索引0上创建一个虚拟的项目，输入“select one”，然后在保存时检查是否选择不为0。

对此，我找到了很多好的解决方案。大多数是通过在适配器的末尾添加一个项来工作的，并且不在下拉列表中显示最后一个项。 对我来说最大的问题是旋转器下拉列表将从列表的底部开始。所以用户看到的最后一个项目，而不是第一个项目(在情况下有许多项目显示)，触摸转轮后，第一次。

所以我把提示项放在列表的开头。并在下拉列表中隐藏第一项。

private void loadSpinner(){

    HintArrayAdapter hintAdapter = new HintArrayAdapter<String>(context, 0);

    hintAdapter.add("Hint to be displayed");
    hintAdapter.add("Item 1");
    hintAdapter.add("Item 2");
            .
            .
    hintAdapter.add("Item 30");

    spinner1.setAdapter(hintAdapter);

    //spinner1.setSelection(0); //display hint. Actually you can ignore it, because the default is already 0
    //spinner1.setSelection(0, false); //use this if don't want to onItemClick called for the hint

    spinner1.setOnItemSelectedListener(yourListener);
}

private class HintArrayAdapter<T> extends ArrayAdapter<T> {

    Context mContext;

    public HintArrayAdapter(Context context, int resource) {
        super(context, resource);
        this.mContext = context
    }

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

        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(android.R.layout.simple_spinner_item, parent, false);
        TextView texview = (TextView) view.findViewById(android.R.id.text1);

        if(position == 0) {
            texview.setText("");
            texview.setHint(getItem(position).toString()); //"Hint to be displayed"
        } else {
            texview.setText(getItem(position).toString());
        }

        return view;
    }

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

        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        View view;

        if(position == 0){
            view = inflater.inflate(R.layout.spinner_hint_list_item_layout, parent, false); // Hide first row
        } else {
            view = inflater.inflate(android.R.layout.simple_spinner_dropdown_item, parent, false);
            TextView texview = (TextView) view.findViewById(android.R.id.text1);
            texview.setText(getItem(position).toString());
        } 

        return view;
    }
}

在@Override getDropDownView()中设置下面的布局，当position为0时，隐藏第一个提示行。

R.layout.spinner_hint_list_item_layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

</LinearLayout>

When extending SpinnerAdapter, you override two View-producing methods, getView(int, View, ViewGroup) and getDropDownView(int, View, ViewGroup). The first one supplies the View inserted into the Spinner itself; the second supplies the View in the drop-down list (as the name suggests). You can override the getView(...) so that, until an item has been selected, it displays a TextView containing a prompt; then, when you detect an item has been selected, you change it to display a TextView corresponding to that.

public class PromptingAdapter extends SpinnerAdapter {

    //... various code ...

    private boolean selectionmade = false;

    //call this method from the OnItemSelectedListener for your Spinner
    public setSelectionState(boolean b) {
        selectionmade = b;
    }

    @Override
    public View getView(int position, View recycle, ViewGroup container) {
        if(selectionmade) {
            //your existing code to supply a View for the Spinner
            //you could even put "return getDropDownView(position, recycle, container);"
        }
        else {
            View output;
            if(recycle instanceof TextView) {
                 output = recycle;
            }
            else {
                 output = new TextView();
                 //and layout stuff
            }
            output.setText(R.string.please_select_one);
            //put a string "please_select_one" in res/values/strings.xml
            return output;
        }
    }

//...
}

XML文件:

<Spinner android:id="@+id/locationSpinner"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:prompt="@string/select_location" />

活动:

private Spinner featuresSelection;
private ArrayAdapter<CharSequence> featuresAdapter;
private List<CharSequence> featuresList;

onCreate:

featuresList = new ArrayList<CharSequence>();
featuresAdapter = new ArrayAdapter<CharSequence>(this,
  android.R.layout.simple_spinner_item, featuresList);
featuresAdapter.setDropDownViewResource(
  android.R.layout.simple_spinner_dropdown_item);
featuresSelection = ((Spinner) yourActivity.this
  .findViewById(R.id.locationSpinner));
featuresSelection.setAdapter(featuresAdapter);
featuresSelection.setOnItemSelectedListener(
  new MyOnItemSelectedListener());

某些函数(以编程方式向适配器添加内容)>

featuresAdapter.add("some string");

现在你有一个空的转轮，你可以写代码不打开对话框，如果是空的。或者他们可以反击。但是您也可以在运行时用函数或另一个列表填充它。

我昨天遇到了同样的问题，不想向ArrayAdapter添加隐藏项或使用反射，这工作得很好，但有点脏。

在阅读了许多帖子和尝试之后，我通过扩展ArrayAdapter和覆盖getView方法找到了一个解决方案。

import android.content.Context;
import android.support.annotation.NonNull;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

/**
 * A SpinnerAdapter which does not show the value of the initial selection initially,
 * but an initialText.
 * To use the spinner with initial selection instead call notifyDataSetChanged().
 */
public class SpinnerAdapterWithInitialText<T> extends ArrayAdapter<T> {

    private Context context;
    private int resource;

    private boolean initialTextWasShown = false;
    private String initialText = "Please select";

    /**
     * Constructor
     *
     * @param context The current context.
     * @param resource The resource ID for a layout file containing a TextView to use when
     *                 instantiating views.
     * @param objects The objects to represent in the ListView.
     */
    public SpinnerAdapterWithInitialText(@NonNull Context context, int resource, @NonNull T[] objects) {
        super(context, resource, objects);
        this.context = context;
        this.resource = resource;
    }

    /**
     * Returns whether the user has selected a spinner item, or if still the initial text is shown.
     * @param spinner The spinner the SpinnerAdapterWithInitialText is assigned to.
     * @return true if the user has selected a spinner item, false if not.
     */
    public boolean selectionMade(Spinner spinner) {
        return !((TextView)spinner.getSelectedView()).getText().toString().equals(initialText);
    }

    /**
     * Returns a TextView with the initialText the first time getView is called.
     * So the Spinner has an initialText which does not represent the selected item.
     * To use the spinner with initial selection instead call notifyDataSetChanged(),
     * after assigning the SpinnerAdapterWithInitialText.
     */
    @Override
    public View getView(int position, View recycle, ViewGroup container) {
        if(initialTextWasShown) {
            return super.getView(position, recycle, container);
        } else {
            initialTextWasShown = true;
            LayoutInflater inflater = LayoutInflater.from(context);
            final View view = inflater.inflate(resource, container, false);

            ((TextView) view).setText(initialText);

            return view;
        }
    }
}

Android在初始化Spinner时所做的，是在为T[]对象中的所有项目调用getView之前为所选项目调用getView。 SpinnerAdapterWithInitialText在第一次调用时返回带有initialText的TextView。 其他时间都调用super。getView是ArrayAdapter的getView方法如果你正常使用Spinner，它会被调用。

要找出用户是否选择了一个微调项，或者微调器是否仍然显示initialText，请调用selectionMade并移交适配器分配给的微调器。